Spero Therapeutics, Inc.

Previous wording

Pursuant to our previously announced restructuring, we suspended development of our SPR720 oral program and have shifted our focus and resources to advancing the clinical development of our tebipenem HBr program, as well as other corporate activities. We have also discontinued development of SPR206. Consequently, our business and prospects are substantially dependent on our tebipenem program and our collaboration with GSK. If we fail to execute successfully on this re-prioritized strategic focus, our business and prospects may be materially adversely affected.

Current wording

As of November 2025, we have ceased development of our SPR720 oral program and have shifted our focus and resources to advancing the clinical development of our tebipenem HBr program, as well as other corporate activities. Consequently, our business and prospects are substantially dependent on our tebipenem program and our collaboration with GSK. If we fail to execute successfully on this re-prioritized strategic focus, or our collaboration with GSK fails to advance the clinical development of the tebipenem HBr program, our business and prospects may be materially adversely affected.

Previous wording

On October 29, 2024, we announced that we suspended development activities for our SPR720 oral program based on an interim analysis of the Phase 2a proof-of-concept study of SPR720 for the treatment of NTM-PD not meeting its primary endpoint. While the data showed antimicrobial activity associated with SPR720, the interim analysis did not show sufficient separation from placebo and highlighted potential dose limiting safety issues in subjects dosed at 1,000 mg orally once daily, including three cases of reversible grade 3 hepatotoxicity. In evaluating the totality of both the efficacy and safety data, we elected to suspend our development program for SPR720 and continue to determine next steps. As a result, we have restructured our operations to focus on supporting the development of tebipenem HBr and other corporate activities while we continue to seek a pathway forward for SPR720. Further, in March 2025, we announced that we discontinued development of SPR206. We believe this re-prioritized strategic focus is the best way to optimize our financial and other resources to advance our goal of developing and commercializing product candidates to address the unmet need for solutions to antibiotic resistant pathogens. However, there is no assurance that we will successfully execute this strategy. As described below, there are risks inherent in the clinical development process, especially for earlier-stage programs, and the regulatory path for SPR720 remains uncertain at this time. If we are unable to execute successfully on this re-prioritized strategic focus, our business and prospects may be materially adversely affected.

Current wording

As of November 2025, we have ceased development of our SPR720 oral program and have shifted our focus and resources to advancing the clinical development of our tebipenem HBr program, as well as other corporate activities. Additionally, in March 2025, we announced that we ceased development of SPR206. We believe this re-prioritized strategic focus is the best way to optimize our financial and other resources to advance our goal of identifying and developing novel treatments for rare diseases and diseases caused by MDR bacterial infections with high unmet need. However, there is no assurance that we will successfully execute this strategy. As described below, there are risks inherent in the clinical development process, especially for earlier-stage programs. If we are unable to execute successfully on this re-prioritized strategic focus, our business and prospects may be materially adversely affected.

Previous wording

If our clinical trials fail to produce favorable results, we may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of such product candidates.

Current wording

If our clinical trials fail to produce favorable results, we may incur additional costs or experience delays in completing, or ultimately be unable to complete, the development and commercialization of any of our product candidates.

Previous wording

The timely completion of clinical trials in accordance with their protocols depends, among other things, on our ability to enroll a sufficient number of patients who remain in the study until its conclusion. We may not be able to initiate, continue or complete clinical trials of our product candidates if we are unable to locate and enroll a sufficient number of eligible patients to participate in clinical trials as required by the FDA or comparable foreign regulatory authorities, such as the EMA. Patient enrollment is a significant factor in the timing of clinical trials, and is affected by many factors, including:

Current wording

The timely completion of clinical trials in accordance with their protocols depends, among other things, on our ability to enroll a sufficient number of patients who remain in the study until its conclusion. The initiation, continuation and completion of our clinical trials relies on our ability to locate and enroll a sufficient number of eligible patients to participate in clinical trials as required by the FDA or comparable foreign regulatory authorities, such as the EMA. Patient enrollment is a significant factor in the timing of clinical trials, and is affected by many factors, including:

Previous wording

Our inability to enroll a sufficient number of patients for our clinical trials would result in significant delays or might require us to abandon one or more clinical trials altogether. Enrollment delays in our clinical trials may result in increased development costs for our product candidates, slow down or halt our product candidate development and approval process and jeopardize our ability to seek and obtain the marketing approval required to commence product sales and generate revenue, which would cause the value of our company to decline and limit our ability to obtain additional financing if needed.

Current wording

Our inability to enroll a sufficient number of patients for our clinical trials would result in significant delays or might require us to abandon one or more clinical trials altogether. Enrollment delays in our clinical trials may result in increased development costs for any of our product candidates, slow down or halt our product candidate development and approval process and jeopardize our ability to seek and obtain the marketing approval required to commence product sales and generate revenue, which would cause the value of our company to decline and limit our ability to obtain additional financing if needed.

Previous wording

In June 2024, as mandated by the FDCA, the FDA issued draft guidance outlining the general requirements for DAPs. Unlike most guidance documents issued by the FDA, the DAP guidance when finalized will have the force of law because FDORA specifically dictates that the form and manner for submission of DAPs are specified in FDA guidance. On January 27, 2025, in response to an executive order issued by President Trump on January 21, 2025 on Diversity, Equity and Inclusion programs, the FDA removed the draft DAP guidance from its website. That action, along with similar actions by the Trump Administration to remove many other healthcare webpages, is currently the subject of ongoing litigation. On July 3, 2025, the U.S. District Court for the District of Columbia ruled that the administration’s actions to remove these webpages, including the draft DAP guidance, is unlawful under the Administrative Procedure Act. The court ordered the restoration of many of these webpages. In late July 2025, the FDA restored the draft DAP guidance to its website with a statement that “information on this page may be modified and/or removed in the future subject to the terms of the court’s order and implemented consistent with applicable law.” Accordingly, in light of these ongoing actions, there is considerable uncertainty surrounding the draft DAP guidance and how the FDA will consider DAPs in connection with its review of marketing applications.

Current wording

In June 2024, as mandated by the FDCA, the FDA issued draft guidance outlining the general requirements for DAPs. Unlike most guidance documents issued by the FDA, the DAP guidance when finalized will have the force of law because Food and Drug Omnibus Reform Act of 2022 (“FDORA”) specifically dictates that the form and manner for submission of DAPs are specified in FDA guidance. On January 27, 2025, in response to an executive order issued by President Trump on January 21, 2025 on Diversity, Equity and Inclusion programs, the FDA removed the draft DAP guidance from its website. That action, along with similar actions by the Trump Administration to remove many other healthcare webpages, is currently the subject of ongoing litigation. On July 3, 2025, the U.S. District Court for the District of Columbia ruled that the administration’s actions to remove these webpages, including the draft DAP guidance, is unlawful under the Administrative Procedure Act. The court ordered the restoration of many of these webpages. In late July 2025, the FDA restored the draft DAP guidance to its website with a statement that “information on this page may be modified and/or removed in the future subject to the terms of the court’s order and implemented consistent with applicable law.” Accordingly, in light of these ongoing actions, there is considerable uncertainty surrounding the draft DAP guidance and how the FDA will consider DAPs in connection with its review of marketing applications.

Previous wording

In some instances, there can be significant variability in safety and efficacy results between different clinical trials of the same product candidate due to numerous factors, including changes in trial protocols, differences in size and type of the patient populations, differences in and adherence to the dosing regimen and other trial protocols and the rate of dropout among clinical trial participants.

Current wording

In some instances, there can be significant variability in safety and efficacy results between different clinical trials of the same product candidate due to numerous factors, including changes in trial protocols, differences in size and type of the patient populations, differences in and adherence to the dosing regimen and other trial protocols and the rate of dropout among clinical trial participants. We therefore do not know whether any clinical trials we may conduct will demonstrate consistent or adequate efficacy and safety sufficient to obtain marketing approval to market our product candidates.

Previous wording

Because we have limited financial and managerial resources, we intend to focus on developing product candidates for specific indications that we identify as most likely to succeed, in terms of both their potential for marketing approval and commercialization. As a result, we may forego or delay pursuit of opportunities with other product candidates or for other indications that may prove to have greater commercial potential. For example, on October 29, 2024, we announced that we suspended development activities for our SPR720 oral program based on an interim analysis of the Phase 2a proof-of-concept study of SPR720 for the treatment of NTM-PD not meeting its primary endpoint. While the data showed antimicrobial activity associated with SPR720, the interim analysis did not show sufficient separation from placebo and highlighted potential dose limiting safety issues in subjects dosed at 1,000 mg orally once daily, including three cases of reversible grade 3 hepatotoxicity. In evaluating the totality of both the efficacy and safety data, we elected to suspend our development program for SPR720 and continue to determine next steps. As a result, we have restructured our operations to focus on supporting the development of tebipenem HBr and other corporate activities while we continue to seek a pathway forward for SPR720. Further, in March 2025, we announced that we have discontinued development of SPR206.

Current wording

Because we have limited financial and managerial resources, we intend to focus on developing product candidates for specific indications that we identify as most likely to succeed, in terms of both their potential for marketing approval and commercialization. As a result, we may forego or delay pursuit of opportunities with other product candidates or for other indications that may prove to have greater commercial potential. For example, as of November 2025, we have ceased development of our SPR720 oral program and have shifted our focus and resources to advancing the clinical development of our tebipenem HBr program, as well as other corporate activities. Additionally, in March 2025, we announced that we have ceased development of SPR206.

Previous wording

We intend to use collaborators to assist with the commercialization of any of our product candidates, including the GSK License Agreement for the development and commercialization of tebipenem HBr. As a result of entering into arrangements with third parties to perform sales, marketing and distribution services, our product revenues or the profitability of these product revenues to us would likely be lower than if we were to directly market and sell products in those markets. Furthermore, we may be unsuccessful in entering into the necessary arrangements with third parties or may be unable to do so on terms that are favorable to us. In addition, we likely would have little control over such third parties, and any of them might fail to devote the necessary resources and attention to sell and market our products effectively.

Current wording

We intend to use collaborators to assist with the commercialization of any of our current and future product candidates, including the GSK License Agreement for the development and commercialization of tebipenem HBr. As a result of entering into arrangements with third parties to perform sales, marketing and distribution services, our product revenues or the profitability of these product revenues to us would likely be lower than if we were to directly market and sell products in those markets. Furthermore, we may be unsuccessful in entering into the necessary arrangements with third parties or may be unable to do so on terms that are favorable to us. In addition, we likely would have little control over such third parties, and any of them might fail to devote the necessary resources and attention to sell and market our products effectively.

Previous wording

There are several IV-administered products marketed for the treatment of infections resistant to first-line therapy for Gram-negative infections, including Avycaz (ceftazidime-avibactam) from Allergan plc and Pfizer, Zerbaxa (ceftolozane-tazobactam) from Merck & Co., imipenem/cilastatin and Recarbrio (relebactam) from Merck & Co., Zemdri (plazomicin) from Cipla Therapeutics, Inc., Fetroja (cefiderocol) from Shionogi & Co. Ltd., Xerava (eravacycline) from Innoviva, Inc. and Vabomere (meropenem-vaborbactam) from Melinta Therapeutics, Inc., and Exblifep (cefepime/enmetazobactam) from Allecra Therapeutics.

Current wording

There are several IV-administered products marketed for the treatment of infections resistant to first-line therapy for Gram-negative infections, including Avycaz (ceftazidime-avibactam) from Allergan plc and Pfizer, Zerbaxa (ceftolozane-tazobactam) from Merck & Co., imipenem/cilastatin and Recarbrio (relebactam) from Merck & Co., Zemdri (plazomicin) from Cipla Therapeutics, Inc., Fetroja (cefiderocol) from Shionogi & Co. Ltd., and Vabomere (meropenem-vaborbactam) from CorMedix Inc., and Exblifep (cefepime/enmetazobactam) from Allecra Therapeutics.

Previous wording

Although a substantial amount of our efforts will focus on our ongoing and planned clinical trials and potential approval of our product candidate, tebipenem HBr, as well as determining next steps for SPR720, a key element of our strategy is to develop and commercialize a portfolio of therapeutics to treat drug resistant bacterial infections. We are exploring, and intend to explore in the future, strategic partnerships for the development of new product candidates.

Current wording

Although a substantial amount of our efforts are currently focused on our potential approval of our product candidate, tebipenem HBr, a key element of our strategy is to develop and commercialize a portfolio of therapeutics to treat drug resistant bacterial infections. We are exploring, and intend to explore in the future, strategic partnerships for the development of new product candidates.

Previous wording

We have not generated any revenue from the sale of our products and have incurred losses in most years since our inception in 2013. Our net loss was $1.7 million and $15.6 million during the three and six months ended June 30, 2025, respectively. All of our product candidates are in development, none have been approved for sale and we may never have a product candidate approved for commercialization.

Current wording

We have not generated any revenue from the sale of our products and have incurred losses in most years since our inception in 2013. Our net loss was $7.4 million and $22.9 million during the three and nine months ended September 30, 2025, respectively. We have yet to have a product candidate approved for sale and we may never have a product candidate approved for commercialization.

Previous wording

In accordance with ASU 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205- 40), we have evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date that these consolidated financial statements are issued. Based on our cash and cash equivalents as of June 30, 2025, together with earned and non-contingent development milestone payments from GSK, including the final payment under the GSK License Agreement of $23.8 million received in the third quarter of 2025, and the decrease in clinical expense as a result of the PIVOT-PO Phase 3 trial for tebipenem HBr stopping early for efficacy following positive interim analysis results, we believe that our cash runway will be sufficient to fund our operating expenses and required capital expenditures into 2028. During this period, we plan to prioritize finalizing the Phase 3 clinical trial activities for tebipenem HBr under our GSK License Agreement. Beyond this point, or in the event we change our current operating plan, we will need additional funding, which we expect will primarily consist of raising additional capital through some combination of equity or debt financings, potential new collaborations or additional grant funding. If we are not able to secure adequate additional funding, we plan to make further reductions in spending. In that event, we may have to delay, scale back, or eliminate some or all of our planned development activities. The actions necessary to reduce spending under this plan at a level that mitigates the factors described above is not considered probable, as defined in the accounting standards and therefore, the full extent to which management may extend our funds through these actions may not be considered in management’s assessment of our ability to continue as a going concern.

Current wording

In accordance with ASU 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40), we have evaluated whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern within one year after the date that these consolidated financial statements are issued. Based on our cash and cash equivalents as of September 30, 2025 and the decrease in clinical expense as a result of the completion of the PIVOT-PO Phase 3 trial for tebipenem HBr and the decision to cease development of SPR720, we believe that our cash runway will be sufficient to fund our operating expenses and required capital expenditures into 2028. During this period, we plan to prioritize finalizing the Phase 3 clinical trial activities for tebipenem HBr under our GSK License Agreement. Beyond this point, or in the event we change our current operating plan, we will need additional funding, which we expect will primarily consist of raising additional capital through some combination of equity or debt financings, potential new collaborations or additional grant funding. If we are not able to secure adequate additional funding, we plan to make further reductions in spending. In that event, we may have to delay, scale back, or eliminate some or all of our planned development activities. The actions necessary to reduce spending under this plan at a level that mitigates the factors described above is not considered probable, as defined in the accounting standards and therefore, the full extent to which management may extend our funds through these actions may not be considered in management’s assessment of our ability to continue as a going concern.

Previous wording

We currently have no products approved for sale and have historically invested a significant portion of our efforts and financial resources in the development of our product candidates, including tebipenem HBr, SPR206, and SPR720. Although we decided to discontinue further development of SPR206 and are exploring strategic options, including potential out-licensing, to maximize the value for the program and allow us to leverage the expertise of strategic partners and although we have suspended our development efforts with respect to the SPR720 oral program and are continuing to determine next steps, our business remains heavily dependent on the successful development, regulatory approval, and, if approved, commercialization of tebipenem HBr and other future product candidates. We cannot be certain that any product candidate will receive regulatory approval or will be successfully commercialized even if it receives regulatory approval.

Current wording

We currently have no products approved for sale and have historically invested a significant portion of our efforts and financial resources in the development of our product candidates, including tebipenem HBr, SPR206, and SPR720. Although we decided to cease further development of SPR206 and SPR720, our business remains heavily dependent on the successful development, regulatory approval, and, if approved, commercialization of tebipenem HBr and any future product candidates. We cannot be certain that any product candidate will receive regulatory approval or will be successfully commercialized even if it receives regulatory approval.

Previous wording

We expect that we will need substantial additional funding. If we are unable to raise capital when needed, or do not receive payments under our government awards or from our commercial partnership agreements, we could be forced to delay, reduce or eliminate our product development programs.

Current wording

If we are unable to raise capital when needed, or do not receive payments under our government awards or from our commercial partnership agreements, it could limit our ability to support our operations and explore our growth strategy.

Previous wording

Developing pharmaceutical products, including conducting preclinical studies and clinical trials, is a time-consuming, expensive and uncertain process that takes years to complete. Our expenses are likely to increase as we commence and advance our ongoing and planned clinical trials and other studies for our current and future product candidates, as well as determining next steps for SPR720. If we obtain marketing approval for any product candidate, we expect to incur significant expenses related to development, product sales, marketing, distribution and manufacturing. Some of these expenses may be incurred in advance of marketing approval and could be substantial. Accordingly, we will be required to obtain further funding through public or private equity offerings, debt financings, collaborations, licensing arrangements, government funding or other sources. Adequate additional financing may not be available to us on acceptable terms, or at all. Our failure to raise capital as and when needed would have a negative effect on our financial condition and our ability to pursue our business strategy.

Current wording

Developing pharmaceutical products, including conducting preclinical studies and clinical trials, is a time-consuming, expensive and uncertain process that takes years to complete. Our expenses are likely to increase if we commence and advance additional studies for any future product candidates. If we obtain marketing approval for any product candidate, we expect to incur significant expenses related to development, product sales, marketing, distribution and manufacturing. Some of these expenses may be incurred in advance of marketing approval and could be substantial. Accordingly, we will be required to obtain further funding through public or private equity offerings, debt financings, collaborations, licensing arrangements, government funding or other sources. Adequate additional financing may not be available to us on acceptable terms, or at all. Our failure to raise capital as and when needed would have a negative effect on our financial condition and our ability to pursue our business strategy.

Previous wording

Based on our cash and cash equivalents as of June 30, 2025, together with earned and non-contingent development milestone payments from GSK, and the decrease in clinical expense as a result of the PIVOT-PO Phase 3 trial for tebipenem HBr stopping early for efficacy following positive interim analysis results, we believe that our cash runway will be sufficient to fund our operating expenses and capital expenditures into 2028. During this period, we plan to prioritize finalizing the Phase 3 clinical trial activities for tebipenem HBr under our GSK License Agreement. Beyond this point, or in the event we change our current operating plan, we will need substantial additional funding to support our continuing operations and pursue our growth strategy. Until such time as we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of equity offerings, debt financings, government funding arrangements, collaborations, strategic alliances and marketing, distribution or licensing arrangements. If we are not able to secure adequate additional funding, we plan to make further reductions in spending. In that event, we may have to delay, scale back, or eliminate some or all of our planned development activities, including:

Current wording

Based on our cash and cash equivalents as of September 30, 2025, and the decrease in clinical expense as a result of the completion of the PIVOT-PO Phase 3 trial for tebipenem HBr and the decision to cease development of SPR720, we believe that our cash runway will be sufficient to fund our operating expenses and capital expenditures into 2028. During this period, we plan to prioritize finalizing the Phase 3 clinical trial activities for tebipenem HBr under our GSK License Agreement. Beyond this point, or in the event we change our current operating plan, we will need additional funding to support our continuing operations and explore our growth strategy. Until such time as we can generate significant revenue from product sales, if ever, we expect to finance our operations through a combination of equity offerings, debt financings, government funding arrangements, collaborations, strategic alliances and marketing, distribution or licensing arrangements. If we are not able to secure adequate additional funding, we plan to make further reductions in spending. In that event, we may have to delay, scale back, or eliminate some or all of our planned development activities, including:

Previous wording

Our operations to date have been limited to financing and staffing our company, and performing research and development activities to advance our product candidates. Each of our product candidates is either in clinical or preclinical development. We have not yet demonstrated an ability to successfully obtain marketing approval, manufacture a commercial scale product, or arrange for a third party to do so on our behalf, or conduct sales and marketing activities necessary for successful product commercialization. Consequently, predictions about our future success or viability may not be as accurate as they could be if we had a longer operating history or a history of successfully developing and commercializing pharmaceutical products.

Current wording

Our operations to date have been limited to financing and staffing our company, and performing research and development activities to advance our product candidates. We have not yet demonstrated an ability to successfully obtain marketing approval, manufacture a commercial scale product, or arrange for a third party to do so on our behalf, or conduct sales and marketing activities necessary for successful product commercialization. Consequently, predictions about our future success or viability may not be as accurate as they could be if we had a longer operating history or a history of successfully developing and commercializing pharmaceutical products.

Previous wording

We may not achieve the milestones triggering payments to us in our license and collaboration agreements with third parties.

Current wording

We may not achieve the milestones triggering payments to us in our existing, or any future, license and collaboration agreements with third parties.

Previous wording

We contract with third parties for the manufacture of preclinical and clinical supplies of our product candidates and expect to continue to do so in connection with any future commercialization and for any future clinical trials and commercialization of our other product candidates and potential product candidates. This reliance on third parties increases the risk that we will not have sufficient quantities of our product candidates or such quantities at an acceptable cost, which could delay, prevent or impair our development or commercialization efforts.

Current wording

We contract with third parties for the manufacture of clinical supplies of tebipenem HBr and expect to continue to do so in connection with any future commercialization and for any future clinical trials and commercialization of any potential product candidates. This reliance on third parties increases the risk that we will not have sufficient quantities of our product candidates or such quantities at an acceptable cost, which could delay, prevent or impair our development or commercialization efforts.

Previous wording

If we fail to comply with our obligations in the agreements under which we in-license or out-license or acquire development or commercialization rights to products, technology or data from or to third parties, we could lose rights that are important to our business.

Current wording

If we fail to comply with our obligations in the agreements under which we in-license or acquire development or commercialization rights to products, technology or data from or to third parties, we could lose rights that are important to our business.

Previous wording

We are a party to agreements with Meiji and GSK for tebipenem HBr, Vertex Pharmaceuticals for SPR720 and Pfizer, Everest and PBB Distributions Limited for SPR206, and we may enter into additional agreements, including license agreements, with other parties in the future that impose diligence, development and commercialization timelines, milestone payments, royalties, insurance and other obligations on us.

Current wording

We are a party to agreements with Meiji and GSK for tebipenem HBr, and have legacy agreements with Vertex Pharmaceuticals for SPR720 and Pfizer, Everest and PBB Distributions Limited for SPR206, and we may enter into additional agreements, including license agreements, with other parties in the future that impose diligence, development and commercialization timelines, milestone payments, royalties, insurance and other obligations on us.

Previous wording

In addition, pursuant to our GSK License Agreement, we granted GSK an exclusive royalty-bearing license, with the right to grant sublicenses, under our intellectual property and regulatory documents and a sublicense under certain intellectual property of Meiji and Meiji’s regulatory documents to develop, manufacture and commercialize the GSK Licensed Products in the GSK Territory. Under the terms of the GSK License Agreement, we received an upfront payment of $66.0 million for GSK to secure rights to tebipenem pivoxil and tebipenem HBr, a $30.0 million milestone payment upon achievement of a development milestone in the third quarter of 2023, and are entitled to receive a $95.0 million development milestone payment that is payable in four equal semi-annual installments, of which we received $23.8 million in the first quarter of 2024, the third quarter of 2024, the first quarter of 2025 and the third quarter of 2025. Remaining potential payments under the GSK License Agreement are milestone based and are (i) $25.0 million for GSK’s submission of a NDA with the FDA for tebipenem HBr, (ii) up to $101.0 million in commercial milestone payments, and (iii) up to $225.0 million in sales milestone payments. In addition to the milestones described above, GSK is obligated to pay royalties to us on annual net sales of GSK Licensed Products in the GSK Territory. Such royalties are 1% for annual sales up to $750.0 million each year and range from high single-digit percentages on annual net sales above $750.0 million each year to low double-digit percentages on annual net sales above $1,000 million each year.

Current wording

In addition, pursuant to our GSK License Agreement, we granted GSK an exclusive royalty-bearing license, with the right to grant sublicenses, under our intellectual property and regulatory documents and a sublicense under certain intellectual property of Meiji and Meiji’s regulatory documents to develop, manufacture and commercialize the GSK Licensed Products in the GSK Territory. Under the terms of the GSK License Agreement, we received an upfront payment of $66.0 million for GSK to secure rights to tebipenem pivoxil and tebipenem HBr, a $30.0 million milestone payment upon achievement of a development milestone in the third quarter of 2023, and are entitled to receive a $95.0 million development milestone payment that is payable in four equal semi-annual installments, of which we received $23.8 million in the first quarter of 2024, the third quarter of 2024, the first quarter of 2025 and the third quarter of 2025. Remaining potential payments under the GSK License Agreement are milestone based and are (i) $25.0 million for GSK’s submission of a NDA with the FDA for tebipenem HBr, (ii) up to $101.0 million in commercial milestone payments, and (iii) up to $225.0 million in sales milestone payments. In addition to the milestones described above, GSK is obligated to pay royalties to us on annual net sales of GSK Licensed Products in the GSK Territory. Such royalties are 1% for annual sales up to $750.0 million each year and range from high single-digit percentages on annual net sales above $750.0 million each year to low double-digit percentages on annual net sales above $1,000.0 million each year.

Previous wording

While we have negotiated a SPA agreement with the FDA relating to our pivotal Phase 3 clinical trial of tebipenem HBr in patients with cUTI, including acute pyelonephritis, this agreement does not guarantee approval of tebipenem HBr or any other particular outcome from regulatory review of the clinical trial or the product candidate.

Current wording

While we have negotiated an SPA agreement with the FDA relating to our pivotal Phase 3 clinical trial of tebipenem HBr in patients with cUTI, including acute pyelonephritis, this agreement does not guarantee approval of tebipenem HBr or any other particular outcome from regulatory review of the clinical trial or the product candidate.

Previous wording

On July 31, 2023, the Company announced that it received written agreement from the FDA, under a special protocol assessment (“SPA”), on the design and size of PIVOT-PO, a pivotal Phase 3 clinical trial of tebipenem HBr in patients with cUTI, including acute pyelonephritis. The FDA’s SPA process is designed to allow the FDA to evaluate the proposed design and size of clinical trials that are intended to form the primary basis for determining a drug product’s efficacy, among other eligible protocols. Upon specific written request by a clinical trial sponsor, the FDA will evaluate the planned protocol and respond to a sponsor’s questions regarding, among other things, primary efficacy endpoints, trial conduct and data analysis. The FDA ultimately assesses whether the protocol design and planned analysis of the trial adequately address scientific and regulatory requirements for the particular purposes identified by the sponsor, which in this case was that the PIVOT-PO protocol can be considered an adequate and well-controlled study in support of our future resubmission of the tebipenem HBr marketing application. All agreements between the FDA and the sponsor regarding an SPA must be clearly documented in writing, either in the form of an SPA letter or minutes of a meeting between the sponsor and the FDA at which the SPA agreement was reached.

Current wording

On July 31, 2023, the Company announced that it received written agreement from the FDA, under an SPA, on the design and size of PIVOT-PO, a pivotal Phase 3 clinical trial of tebipenem HBr in patients with cUTI, including acute pyelonephritis. The FDA’s SPA process is designed to allow the FDA to evaluate the proposed design and size of clinical trials that are intended to form the primary basis for determining a drug product’s efficacy, among other eligible protocols. Upon specific written request by a clinical trial sponsor, the FDA will evaluate the planned protocol and respond to a sponsor’s questions regarding, among other things, primary efficacy endpoints, trial conduct and data analysis. The FDA ultimately assesses whether the protocol design and planned analysis of the trial adequately address scientific and regulatory requirements for the particular purposes identified by the sponsor, which in this case was that the PIVOT-PO protocol can be considered an adequate and well-controlled study in support of our future resubmission of the tebipenem HBr marketing application. All agreements between the FDA and the sponsor regarding an SPA must be clearly documented in writing, either in the form of an SPA letter or minutes of a meeting between the sponsor and the FDA at which the SPA agreement was reached.

Previous wording

In March 2020, the FDA granted orphan drug designation for SPR720. We may seek orphan drug designation for certain of our other product candidates. We may not be able to obtain or maintain orphan drug designations for any of our other product candidates, and we may be unable to take advantage of the benefits associated with orphan drug designation, including the potential for market exclusivity.

Current wording

We may seek orphan drug designation for one or more of our product candidates. We may not be able to obtain or maintain orphan drug designations for any of our product candidates, and we may be unable to take advantage of the benefits associated with orphan drug designation, including the potential for market exclusivity.

Previous wording

Even though we have obtained orphan drug designation for SPR720 and may seek orphan drug designation for other product candidates in the future, there is no assurance that we or any third party partner we may have in the future will be the first to obtain marketing approval for NTM infection or for any particular rare indication. Further, even though we have obtained orphan drug designation for SPR720, or even if we obtain orphan drug designation for other product candidates, such designation may not effectively protect us from competition because different drugs can be approved for the same condition and the same drug can be approved for different conditions and potentially used off-label in the orphan indication. Even after an orphan drug is approved, the FDA can subsequently approve a competing drug for the same condition for several reasons, including, if the FDA concludes that the later drug is safer or more effective or makes a major contribution to patient care. Orphan drug designation neither shortens the development time or regulatory review time of a drug, nor gives the drug any advantage in the regulatory review or approval process.

Current wording

In March 2020, the FDA granted orphan drug designation for SPR720. However, in November 2025, we announced that we were ceasing development of SPR720. Even though we may seek orphan drug designation for other product candidates in the future, there is no assurance that we or any third party partner we may have in the future will obtain orphan drug designation and/or be the first to obtain marketing approval for any particular rare indication. Further, even if we obtain orphan drug designation for other product candidates, such designation may not effectively protect us from competition because different drugs can be approved for the same condition and the same drug can be approved for different conditions and potentially used off-label in the orphan indication. Even after an orphan drug is approved, the FDA can subsequently approve a competing drug for the same condition for several reasons, including, if the FDA concludes that the later drug is safer or more effective or makes a major contribution to patient care. Orphan drug designation neither shortens the development time or regulatory review time of a drug, nor gives the drug any advantage in the regulatory review or approval process.

Previous wording

While the FDA’s review of marketing applications and other activities for new drugs and biologics is largely funded through the user fee program established under the Prescription Drug User Fee Act (“PDUFA”), it remains unclear how the administration’s RIF and budget cuts will impact this program and the ability of the FDA to provide guidance and review our product candidates in a timely manner. For example, while the FDA RIF did not reportedly specifically target FDA reviewers, many operations, administrative and policy staff that help support such reviews were affected and those losses could lead to delays in PDUFA reviews and related activities. As of July 15, 2025, there has been at least one report in which the FDA failed to meet a PDUFA goal date for approval of an NDA due to heavy workload and limited resources. In addition, while currently unclear, there is a risk that the RIF and budget cutbacks could threaten the integrity of the PDUFA program itself. That is because, for the FDA to obligate user fees collected under PDUFA in the first place, a certain amount of non-user fee appropriations must be spent on the process for the review of applications plus certain other costs during the same fiscal year.

Current wording

While the FDA’s review of marketing applications and other activities for new drugs and biologics is largely funded through the user fee program established under the Prescription Drug User Fee Act (“PDUFA”), it remains unclear how the administration’s RIF and budget cuts will impact this program and the ability of the FDA to provide guidance and review our product candidates in a timely manner. For example, while the FDA RIF did not reportedly specifically target FDA reviewers, many operations, administrative and policy staff that help support such reviews were affected and those losses could lead to delays in PDUFA reviews and related activities. There has been at least one report in which the FDA failed to meet a PDUFA goal date for approval of an NDA due to heavy workload and limited resources. In addition, while currently unclear, there is a risk that the RIF and budget cutbacks could threaten the integrity of the PDUFA program itself. That is because, for the FDA to obligate user fees collected under PDUFA in the first place, a certain amount of non-user fee appropriations must be spent on the process for the review of applications plus certain other costs during the same fiscal year.

Previous wording

There is also substantial uncertainty as to how regulatory reform measures being implemented by the Trump Administration across the government will impact the FDA and other federal agencies with jurisdiction over our activities. For example, since taking office, the President has issued a number of executive orders that could have a significant impact on the manner in which the FDA conducts its operations and engages in regulatory and oversight activities. These include Executive Order 14192, “Unleashing Prosperity Through Deregulation,” January 31, 2025; Executive Order 14212, “Establishing the President’s Make America Healthy

Current wording

There is also substantial uncertainty as to how regulatory reform measures being implemented by the Trump Administration across the government will impact the FDA and other federal agencies with jurisdiction over our activities. For example, since taking office, the President has issued a number of executive orders that could have a significant impact on the manner in which the FDA conducts its operations and engages in regulatory and oversight activities. These include Executive Order 14192, “Unleashing Prosperity Through Deregulation,” January 31, 2025; Executive Order 14212, “Establishing the President’s Make America Healthy Again Commission,” February 13, 2025; and Executive Order 14219, “Ensuring Lawful Governance and Implementing the President’s ‘Department of Government Efficiency’ Deregulatory Initiative,” February 21, 2025. If these or other orders or executive actions impose constraints on the FDA’s ability to engage in oversight and implementation activities in the normal course, our business may be negatively impacted.

Previous wording

This past spring, the U.S. government initiated a series of tariff-related actions against U.S. trading partners. On April 2, 2025, President Trump issued an executive order announcing a “baseline” reciprocal tariff of 10% on all U.S. trading partners effective April 5, 2025, and higher individualized reciprocal tariffs on 57 countries (with certain product exemptions for pharmaceutical-related products, among others). Previously, the Trump administration had imposed a 25% tariff on Canada and Mexico for goods not covered by the United States-Mexico-Canada Agreement (“USMCA”) and tariffs equaling 20% on China. In response, several countries threatened retaliatory measures, including Canada and China, which then imposed retaliatory tariffs. Prior to when the country-specific reciprocal tariffs were scheduled to take effect, the Trump administration delayed the effective date of such tariffs for all countries except China to August 1, 2025. Later, the United States and China reached a framework agreement that resulted in the suspension of the higher reciprocal tariffs on China until August 12, 2025. Several countries including, among others, the European Union, Japan, and the United Kingdom, have reached deals with the U.S. that include reduced tariff rates to varying levels and other measures. The Trump administration has not definitively indicated the effective date for these deals. As of July 31, 2025, the 10% baseline reciprocal tariff announced in April on all countries remains in effect, in addition to the other tariffs on China (which were a minimum of an additional 20% as of July 15, 2025) and on Canada and Mexico (which were 25% as of July 15, 2025 for goods that are not covered by the USMCA). Sustained uncertainty about, or the further escalation of, trade and political tensions between the United States and China could result in a disadvantageous research and manufacturing environment in China, particularly for U.S. based companies, including retaliatory restrictions that hinder or potentially inhibit our ability to rely on CMOs and other service providers that operate in China.

Current wording

This past spring, the U.S. government initiated a series of tariff-related actions against U.S. trading partners. On April 2, 2025, President Trump issued an executive order announcing a “baseline” reciprocal tariff of 10% on all U.S. trading partners effective April 5, 2025, and higher individualized reciprocal tariffs on 57 countries (with certain product exemptions for pharmaceutical-related products, among others). Previously, the Trump administration had imposed a 25% tariff on Canada and Mexico for goods not covered by the United States-Mexico-Canada Agreement (“USMCA”) and tariffs equaling 20% on China. In response, several countries threatened retaliatory measures, including Canada and China, which then imposed retaliatory tariffs. Prior to when the country-specific reciprocal tariffs were scheduled to take effect, the Trump administration delayed the effective date of such tariffs for all countries except China to August 1, 2025. Later, the United States and China reached a framework agreement that ultimately resulted in the suspension of the higher reciprocal tariffs on China until November 11, 2025. Since the April announcement, several countries including the European Union, Japan, South Korea and the United Kingdom, among others, have reached deals with the U.S. that include reduced tariff rates to varying levels and other measures. On July 31, 2025, President Trump issued an Executive Order detailing new reciprocal tariff rates for individual countries that took effect on August 7, 2025. The new reciprocal rates, which are consistent with the rates reflected in the trade deals already announced, range from 10% to 41%. The new rates do not apply to Canada, China, Mexico and a few other countries. For China, the 10% baseline reciprocal tariff announced in April remains in effect, in addition to a minimum of an additional 20%. Regarding Canada and Mexico, the rate remains 25% for goods that are not covered by the USMCA for Mexico and, effective August 1, 2025, was increased to 35% on imports from Canada that are not covered by the USMCA. Sustained uncertainty about, or the further escalation of, trade and political tensions between the United States and China could result in a disadvantageous research and manufacturing environment in China, particularly for U.S. based companies, including retaliatory restrictions that hinder or potentially inhibit our ability to rely on CMOs and other service providers that operate in China. Certain countries have reached agreements with the U.S. that cap pharmaceutical tariffs at 15%. These include the European Union, Japan, South Korea and the United Kingdom.

Previous wording

On October 29, 2024, we implemented a restructuring plan that reduced our workforce by approximately 39%. While we have confidence in our remaining employees, and our leadership team, including our current President, Chief Executive Officer and Chief Financial Officer, Ms. Rajavelu, who was appointed President and Chief Executive Officer effective as of May 2, 2025 following our separation with Mr. Shukla, the inherent uncertainty following this restructuring may cause concerns from third parties with whom we do business, and may increase the likelihood of turnover of other key officers and employees. Continued disruption caused by the transition or by the loss of ongoing services of any qualified scientific and management personnel could delay or prevent the successful development of our product candidates.

Current wording

In October 2024, we implemented a restructuring plan that reduced our workforce by approximately 39%. While we have confidence in our remaining employees, and our leadership team, including our current President, Chief Executive Officer and Chief Financial Officer, Ms. Rajavelu, who was appointed President and Chief Executive Officer effective as of May 2, 2025 following our separation with Mr. Shukla, the inherent uncertainty following this restructuring may cause concerns from third parties with whom we do business, and may increase the likelihood of turnover of other key officers and employees. Continued disruption caused by the transition or by the loss of ongoing services of any qualified scientific and management personnel could delay or prevent the successful development of our product candidates.

Previous wording

On October 29, 2024, we announced a restructuring plan and implemented a workforce reduction. There can be no assurance that our restructuring will achieve the cost savings, operating efficiencies or other benefits that we may initially expect. Restructuring activities may also result in a loss of continuity, accumulated knowledge and inefficiency during transitional periods and thereafter. Further, internal restructurings can require a significant amount of time and focus from management and other employees, which may divert attention from operations.

Current wording

In October 2024, we announced a restructuring plan and implemented a workforce reduction. There can be no assurance that our restructuring will achieve the cost savings, operating efficiencies or other benefits that we may initially expect. Restructuring activities may also result in a loss of continuity, accumulated knowledge and inefficiency during transitional periods and thereafter. Further, internal restructurings can require a significant amount of time and focus from management and other employees, which may divert attention from operations.

Previous wording

In addition, the stock market has experienced significant volatility, particularly with respect to pharmaceutical, biotechnology and other life sciences company stocks. The volatility of pharmaceutical, biotechnology and other life sciences company stocks often does not relate to the operating performance of the companies represented by the stock. In the past, securities class action litigation has often been initiated against companies following periods of volatility in their stock price, such as the two putative class action lawsuits filed against us and certain of our current and former officers in 2022 and the stockholder derivative action filed against us and certain of our current and former officers in 2023 and 2024. This type of litigation could result, and has in the past resulted, in substantial costs and divert our management’s attention and resources, and could also require us to make substantial payments to satisfy judgments or to settle litigation.

Current wording

In addition, the stock market has experienced significant volatility, particularly with respect to pharmaceutical, biotechnology and other life sciences company stocks. The volatility of pharmaceutical, biotechnology and other life sciences company stocks often does not relate to the operating performance of the companies represented by the stock. In the past, securities class action litigation has often been initiated against companies following periods of volatility in their stock price, such as the two putative class action lawsuits filed in 2022 against us and certain of our former officers and the stockholder derivative actions filed in 2023 and 2024 against us and certain of our former officers. This type of litigation could result, and has in the past resulted, in substantial costs and divert our management’s attention and resources, and could also require us to make substantial payments to satisfy judgments or to settle litigation.

Previous wording

In the past, we have failed to maintain certain continued listing requirements of the Nasdaq GS and could fail to maintain those requirements again in the future, which could negatively affect the market price of our common stock, our liquidity and our ability to raise capital. Our potential failure to meet the continued listing requirements of Nasdaq GS in the future could result in a delisting of our common stock.

Current wording

In the past, we have failed to maintain certain continued listing requirements of the Nasdaq GS and could fail to maintain those requirements again in the future, which could negatively affect the market price of our common stock, our liquidity and our ability to raise capital. Our potential failure to meet the continued listing requirements of Nasdaq GS in the future could result in the delisting of our common stock.

Previous wording

price of our common stock. Our outstanding shares of common stock may be freely sold in the public market at any time to the extent permitted by Rules 144 and 701 under the Securities Act, or to the extent that such shares have already been registered under the Securities Act and are held by non-affiliates of ours. Moreover, holders of a substantial number of shares of our common stock have rights, subject to conditions, to require us to file registration statements covering their shares or to include their shares in registration statements that we may file for ourselves or other stockholders. We also have registered all shares of common stock that we may issue under our equity compensation plans or that are issuable upon exercise of outstanding options. These shares can be freely sold in the public market upon issuance and once vested, subject to volume limitations applicable to affiliates. If any of these additional shares are sold, or if it is perceived that they will be sold, in the public market, the market price of our common stock could decline.

Current wording

Sales of a substantial number of shares of our common stock in the public market could occur at any time. These sales, or the perception in the market that the holders of a large number of shares of common stock intend to sell shares, could reduce the market price of our common stock. Our outstanding shares of common stock may be freely sold in the public market at any time to the extent permitted by Rules 144 and 701 under the Securities Act, or to the extent that such shares have already been registered under the Securities Act and are held by non-affiliates of ours. Moreover, holders of a substantial number of shares of our common stock have rights, subject to conditions, to require us to file registration statements covering their shares or to include their shares in registration statements that we may file for ourselves or other stockholders. We also have registered all shares of common stock that we may issue under our equity compensation plans or that are issuable upon exercise of outstanding options. These shares can be freely sold in the public market upon issuance and once vested, subject to volume limitations applicable to affiliates. If any of these additional shares are sold, or if it is perceived that they will be sold, in the public market, the market price of our common stock could decline.

Previous wording

Securities litigation often follows certain significant business activities, such as the announcement of a strategic restructuring, or the announcement of negative events, such as negative results from clinical trials. We may be exposed to such litigation even if no wrongdoing occurred. We have in the past, and may in the future, become subject to securities litigation. For example, two putative class action lawsuits were filed against us and certain of our current and former officers in 2022 and a stockholder derivative action was filed against us and certain of our current and former officers in 2023 and 2024. Litigation is usually expensive and diverts management’s attention and resources, which could adversely affect our business and cash resources and our ability to execute on our partnership with GSK to eventually commercialize tebipenem HBr, or the ultimate value our stockholders receive in such partnership or other opportunity.

Current wording

Securities litigation often follows certain significant business activities, such as the announcement of a strategic restructuring, or the announcement of negative events, such as negative results from clinical trials. We may be exposed to such litigation even if no wrongdoing occurred. We have in the past, and may in the future, become subject to securities litigation. For example, two putative class action lawsuits were filed in 2022 against us and certain of our former officers and stockholder derivative actions were filed in 2023 and 2024 against us and certain of our former officers. Litigation is usually expensive and diverts management’s attention and resources, which could adversely affect our business and cash resources and our ability to execute on our partnership with GSK to eventually commercialize tebipenem HBr, or the ultimate value our stockholders receive in such partnership or other opportunity.