Spero Therapeutics, Inc.
For the period ended Sep 30, 2025. Filed Nov 13, 2025.
View on SEC.govAbout this filing
A company's report for each of its first three quarters. The financial statements are not audited. It shows how the business has moved since the last annual report, and what management says changed.
Sep 30, 2025 · Filed Nov 13, 2025
SPRO$1.03+1.0%Stored close · as of Nov 6, 2026
What changed in Management’s Discussion and Analysis?
Read the current filingPrevious report: 10-Q
Period ended 2025-06-30; filed 2025-08-12.
0000950170-25-107388
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of OperationsCurrent report: 10-Q
Period ended 2025-09-30; filed 2025-11-13.
0001193125-25-280174
Item 2. Management’s Discussion and Analysis of Financial Condition and Results of OperationsThe baseline is this issuer’s latest earlier reporting period of the same form that was filed before the current report. A previous 10-Q is a different quarter, not a year-over-year comparison. Amendments are excluded.
Compared 129 previous paragraphs and 125 current paragraphs.
77 unchanged; 37 reworded; 10 added; 15 removed; 0 previous and 1 current paragraphs rearranged.
Tables are not compared: 12 previous and 12 current tables excluded. Dates, whitespace, punctuation and numbering changes are ignored; changes to financial figures remain significant.
A changed paragraph is not evidence that risk increased or decreased. An unchanged paragraph does not establish that risk stayed the same.
Added paragraphs (10)
Current report
In March 2025, following a reprioritization of our programs, we announced that we were no longer pursuing a Phase 2 clinical trial for SPR206 and we have now ceased further development of the program. Additionally, in November 2025, we announced that we ceased development of SPR720, a product candidate for first-line treatment of NTM-PD. Following the termination of our earlier stage programs, we remain focused on completing our obligations under the GSK License Agreement and other corporate activities.
Current report
SPR720
Current report
In November 2025, we announced that we have ceased development of SPR720.
Current report
During the third quarter of 2025, we evaluated our real estate lease in light of our new sublease agreements. As a result of the evaluation, we recorded an impairment charge of $0.6 million associated with the right-of-use asset in the third quarter of 2025.
Current report
In October 2024, we implemented a strategic restructuring initiative and corresponding reduction in workforce. We restructured our operations to reduce costs and reallocate resources in support of the development of tebipenem HBr and other corporate activities. As of September 30, 2025, we had recognized $1.1 million in expense related to the October 2024 restructuring and do not expect to incur any further charges related to this restructuring.
Current report
The decrease in personnel-related costs of $0.9 million was primarily a result of reduced headcount costs as a result of the restructuring in the fourth quarter of 2024. Personnel-related costs for the three months ended September 30, 2025 and 2024 included stock-based compensation expense of $0.7 million and $1.5 million, respectively.
Current report
Impairment charges related to our right of use asset were $0.6 million for the three months ended September 30, 2025, compared to no charges for the three months ended September 30, 2024.
Current report
Comparison of the Nine Months Ended September 30, 2025 and 2024
Current report
The decrease in personnel-related costs of $2.6 million was primarily a result of reduced headcount costs as a result of the restructuring in the fourth quarter of 2024. Personnel-related costs for the nine months ended September 30, 2025 and 2024 included stock-based compensation expense of $1.3 million and $2.1 million, respectively.
Current report
Impairment charges related to our right of use asset were $0.6 million for the nine months ended September 30, 2025, compared to no charges for the nine months ended September 30, 2024.
Removed paragraphs (15)
Previous report
Nasdaq Deficiency Letter and Regained Compliance
Previous report
On February 25, 2025, we received a deficiency letter from the Listing Qualifications Department of the Nasdaq Stock Market LLC informing us that we were not in compliance with the continued listing requirements of the Nasdaq GS because the bid price for our common stock had closed below $1.00 per share for 30 consecutive business days. On June 12, 2025, we received a letter from the Listing Qualifications Department informing us that we had regained compliance with the bid price requirement and the matter is now closed.
Previous report
Management Transitions and Board Composition
Previous report
In January 2025, the independent directors of our Board of Directors approved the following actions as a matter of corporate governance best practices and to enable us to maintain focus on pursuing our business objectives pending resolution of a “Wells Notice” received from the Staff of the SEC, as further described in Part II, Item 1 “Legal Proceedings” of this Quarterly Report on Form 10-Q.
Previous report
The Board of Directors appointed director Frank Thomas to serve as the Chairman of the Board of Directors, stepping in for Ankit Mahadevia, M.D.
Previous report
Mr. Shukla agreed to a paid administrative leave from his role as President and Chief Executive Officer. During such leave, Mr. Shukla remained an employee and continued to serve as a member of the Board of Directors.
Previous report
The Board of Directors appointed Esther Rajavelu, our then-current Chief Financial Officer, Chief Business Officer and Treasurer, to serve as Interim President and Chief Executive Officer during the term of Mr. Shukla’s administrative leave.
Previous report
The terms of Ms. Rajavelu’s existing employment arrangement with the Company were amended to provide that she would receive additional cash compensation of $20,000 per month while she served as the Interim President and Chief Executive Officer, in addition to her role as Chief Financial Officer and Chief Business Officer.
Previous report
Effective May 2, 2025, Ms. Rajavelu was appointed as our President and Chief Executive Officer. She continues to serve as our Chief Financial Officer and Treasurer. In connection with the foregoing, Ms. Rajavelu was nominated for election to serve as a member of our Board of Directors at our 2025 annual meeting of stockholders and was elected to the Board of Directors in June 2025. In connection with the foregoing, we and Ms. Rajavelu entered into an Amended and Restated Employment Agreement, dated April 28, 2025.
Previous report
We and Mr. Shukla mutually decided to separate, effective May 2, 2025. In connection with the foregoing, we and Mr. Shukla entered into a Separation Agreement, dated April 28, 2025. In addition, Mr. Shukla stepped down from the Board of Directors, effective May 2, 2025.
Previous report
For more information about the foregoing, please see our Current Report on Form 8-K filed with the SEC on April 28, 2025.
Previous report
In light of our decision to suspend planned development activities for our oral SPR720 program and the strategic restructuring implemented in October 2024, we expect that our future expenses relating to development activities with respect to SPR720 will be substantially reduced as we determine next steps for SPR720. In connection with our restructuring, we estimated that we would incur approximately $1.1 million of costs in connection with the reduction in workforce related to severance pay and other related termination benefits of which we incurred $0.9 million during the year ended December 31, 2024, $0.2 million during the quarter ended March 31, 2025, and less than $0.1 million during the quarter ended June 30, 2025. We have incurred all of the costs associated with our workforce reduction as of June 30, 2025.
Previous report
The increase in personnel-related costs of $0.2 million was primarily a result of retention program costs in our general and administrative functions during the period, offsetting reduced headcount costs as a result of the previously announced restructuring in the fourth quarter of 2024. Personnel-related costs for the three months ended June 30, 2025 and 2024 included stock-based compensation expense of $0.3 million and $1.4 million, respectively.
Previous report
Comparison of the Six Months Ended June 30, 2025 and 2024
Previous report
The decrease in personnel-related costs of $1.0 million was primarily a result of increased retention program costs in our research and development functions offset by reduced headcount costs as a result of the previously announced restructuring in the fourth quarter of 2024. Personnel-related costs for the six months ended June 30, 2025 and 2024 included stock-based compensation expense of $0.9 million and $1.4 million, respectively.
Reworded paragraphs (37)
Previous wording
Our most advanced clinical-stage product candidate, tebipenem HBr, is in Phase 3 development, with the potential to be the first broad-spectrum oral carbapenem to treat adult patients with cUTIs, including pyelonephritis, caused by certain microorganisms. In May 2025, we and GSK announced that the pivotal Phase 3 PIVOT-PO trial evaluating tebipenem HBr met its primary endpoint and had stopped early for efficacy. The other program in our pipeline is SPR720, a product candidate for first-line treatment of nontuberculous mycobacterial (“NTM”) pulmonary disease (“NTM-PD”). In October 2024, we announced that results from a planned interim analysis of our Phase 2a clinical trial for SPR720 demonstrated the oral agent did not meet its primary endpoint and we elected to suspend development of SPR720 in its oral formulation. We are currently determining next steps for SPR720. Additionally, in March 2025, following a reprioritization of our programs, we announced that we are no longer pursuing a Phase 2 clinical trial for SPR206, which was previously included in our pipeline.
Current wording
Our clinical-stage product candidate, tebipenem HBr, has completed a Phase 3 trial with the potential to be the first broad-spectrum oral carbapenem to treat adult patients with cUTIs, including pyelonephritis, caused by certain microorganisms. In May 2025, we and GSK announced that the pivotal Phase 3 PIVOT-PO trial evaluating tebipenem HBr met its primary endpoint and was stopped early for efficacy. Results from the Phase 3 PIVOT-PO trial were featured in a late breaking oral presentation on October 20, 2025, at IDWeek in Atlanta, GA. GSK plans to submit the data from the trial as part of an FDA filing during the fourth quarter of 2025.
Previous wording
We have experienced mostly net losses and significant cash outflows from cash used in operating activities since our inception. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of one or more of our product candidates. As of June 30, 2025, we had an accumulated deficit of $475.2 million, and cash and cash equivalents of $31.2 million. We expect to continue to incur significant expenses and operating losses for at least the next year. 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 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. 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
We have experienced mostly net losses and significant cash outflows from cash used in operating activities since our inception. Our ability to generate product revenue sufficient to achieve profitability will depend heavily on the successful development and eventual commercialization of tebipenem HBr, or any product candidate we may develop in the future. As of September 30, 2025, we had an accumulated deficit of $482.6 million, and cash and cash equivalents of $48.6 million. We expect to continue to incur significant expenses and operating losses for at least the next year. 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 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 will have 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 are 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 will not generate revenue from product sales unless and until we successfully complete clinical development and obtain regulatory approval for our product candidates. If we obtain regulatory approval for any of our product candidates and do not enter into a commercialization partnership, we expect to incur significant expenses related to developing our internal commercialization capability to support product sales, marketing and distribution. Further, we expect to incur additional costs associated with our continued operation as a public company.
Current wording
We will not generate revenue from product sales unless and until we successfully complete clinical development and obtain regulatory approval for our product candidates. If we obtain regulatory approval for any of our future product candidates and do not enter into a commercialization partnership, we expect to incur significant expenses related to developing our internal commercialization capability to support product sales, marketing and distribution. Further, we expect to incur additional costs associated with our continued operation as a public company.
Previous wording
The trial met the primary endpoint of non-inferiority of tebipenem HBr compared to intravenous imipenem-cilastatin in hospitalized adult patients with cUTI, including pyelonephritis, on overall response (composite of clinical cure plus microbiological eradication) at the test-of-cure visit. The IDMC review did not identify any new safety concerns beyond what has been reported in other studies with tebipenem, with diarrhea and headache as the two most reported adverse events. GSK plans to work with U.S. regulatory authorities to include the data as part of a filing in the second half of 2025. Full results will be submitted for presentation at an upcoming scientific meeting and for publication in a peer-reviewed journal.
Current wording
The trial met the primary endpoint of non-inferiority of tebipenem HBr compared to intravenous imipenem-cilastatin in hospitalized adult patients with cUTI, including pyelonephritis, on overall response (composite of clinical cure plus microbiological eradication) at the test-of-cure visit. The IDMC review did not identify any new safety concerns beyond what has been reported in other studies with tebipenem, with diarrhea and headache as the two most reported adverse events. Results from the Phase 3 PIVOT-PO trial were featured in a late breaking oral presentation on October 20, 2025, at IDWeek in Atlanta, GA. GSK plans to submit the data from the trial as part of an FDA filing during the fourth quarter of 2025.
Previous wording
*Under the terms of the GSK License Agreement, the maximum potential milestone amount was revised from $150.0 million after PIVOT-PO was stopped early for efficacy following completion of a pre-specified interim analysis of data from 1,690 patients enrolled in the trial, thereby reducing the overall cost of the trial to the Company; the maximum potential milestone payment of $150.0 million was contingent upon the trial continuing to full enrollment, with 2,637 patients enrolled in the trial.
Current wording
*Under the terms of the GSK License Agreement, the maximum potential milestone amount was revised from $150.0 million after PIVOT-PO was stopped early for efficacy following completion of a pre-specified interim analysis of data from 1,690 patients enrolled in the trial, thereby reducing the overall cost of the trial to us; the maximum potential milestone payment of $150.0 million was contingent upon the trial continuing to full enrollment, with 2,637 patients enrolled in the trial.
Previous wording
In addition to the milestones described above, GSK is obligated to pay royalties to the Company 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 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
In March 2025, following a reprioritization of its programs, we announced that we are no longer pursuing a Phase 2 clinical trial for SPR206. On April 4, 2025, NIAID informed us that it was canceling the five-year contract, awarded in May 2021, under the Agency’s Omnibus Broad Agency Announcement No. HHS-NIH-NIAID-BAA2020-1 award mechanism to support further development of SPR206, effective immediately, for its convenience.
Current wording
In March 2025, following a reprioritization of our programs, we announced that we were no longer pursuing a Phase 2 clinical trial for SPR206 and had ceased further development of the program. On April 4, 2025, the National Institute of Allergy and Infectious Diseases (“NIAID”) informed us that it was canceling the five-year contract, awarded in May 2021, under the Agency’s Omnibus Broad Agency Announcement No. HHS-NIH-NIAID-BAA2020-1 award mechanism to support further development of SPR206, effective immediately, for its convenience.
Previous wording
To date, we have not generated any revenue from product sales. If our development efforts for our product candidates are successful and result in regulatory approval, we may generate revenue in the future from product sales. We cannot predict if, when, or to what extent we will generate revenue from the commercialization and sale of our product candidates. We may never succeed in obtaining regulatory approval for any of our product candidates.
Current wording
To date, we have not generated any revenue from product sales. If our development efforts for our current and future product candidates are successful and result in regulatory approval, we may generate revenue in the future from product sales. We cannot predict if, when, or to what extent we will generate revenue from the commercialization and sale of our product candidates. We may never succeed in obtaining regulatory approval for any of our product candidates.
Previous wording
Interest income (expense) during the three and six months ended June 30, 2025 and 2024 consists of interest income related to the significant financing component related to the GSK License Agreement and interest earned on our cash equivalents, which are primarily invested in money market accounts, as well as interest earned on our investments in marketable securities.
Current wording
Interest income (expense) during the three and nine months ended September 30, 2025 and 2024 consists of interest income related to the significant financing component related to the GSK License Agreement and interest earned on our cash equivalents, which are primarily invested in money market accounts, as well as interest earned on our investments in marketable securities.
Previous wording
The following table summarizes our results of operations for the three months ended June 30, 2025 and 2024 (in thousands):
Current wording
The following tables summarize our results of operations for the three months ended September 30, 2025 and 2024 (in thousands):
Previous wording
Grant revenue recognized during the three months ended June 30, 2025 and 2024 consisted of the reimbursement of qualifying expenses incurred in connection with our various government awards. The decrease in grant revenue during the three months ended June 30, 2025 was primarily due to a decrease of $1.7 million under our BARDA contract for tebipenem HBr, and a decrease of $0.1 million under our NIAID agreement relating to SPR206.
Current wording
Grant revenue recognized during the three months ended September 30, 2025 and 2024 consisted of the reimbursement of qualifying expenses incurred in connection with our various government awards. The decrease in grant revenue during the three months ended September 30, 2025 was primarily due to a decrease of $3.2 million under our BARDA contract for tebipenem HBr, and a decrease of $0.1 million under our NIAID agreement relating to SPR206.
Previous wording
During the three months ended June 30, 2025, we recognized $11.8 million in collaboration revenue related to our agreement with GSK and no revenue related to our agreement with Pfizer. During the three months ended June 30, 2024, we recognized $5.9 million in collaboration revenue related to our agreement with GSK and $0.1 million in collaboration revenue related to our agreement with Pfizer. The increase in revenue under the GSK License Agreement was directly related to the adjusted service period due to the pivotal Phase 3 PIVOT-PO trial stopping early for efficacy in the first half of 2025 following the pre-specified interim analysis.
Current wording
During the three months ended September 30, 2025, we recognized $3.0 million in collaboration revenue related to our agreement with GSK and no revenue related to our agreement with Pfizer. During the three months ended September 30, 2024, we recognized $7.8 million in collaboration revenue related to our agreement with GSK and $0.1 million in collaboration revenue related to our agreement with Pfizer. The decrease in revenue under the GSK License Agreement was directly related to the adjusted service period due to the pivotal Phase 3 PIVOT-PO trial stopping early for efficacy in the first half of 2025 following the pre-specified interim analysis.
Previous wording
Direct costs related to our tebipenem HBr program decreased by $7.6 million during the three months ended June 30, 2025, compared to the three months ended June 30, 2024, due to a decrease in clinical activities related to our pivotal Phase 3 PIVOT-PO trial, which met its primary endpoint and was stopped early for efficacy during the first half of 2025.
Current wording
Direct costs related to our tebipenem HBr program decreased by $13.1 million during the three months ended September 30, 2025, compared to the three months ended September 30, 2024, due to a decrease in clinical activities related to our pivotal Phase 3 PIVOT-PO trial, which met its primary endpoint and was stopped early for efficacy during the first half of 2025.
Previous wording
Direct costs related to our SPR720 program decreased by $4.5 million during the three months ended June 30, 2025, as compared to the three months ended June 30, 2024, due to decreased clinical activity during the period related to our Phase 2a clinical trial of SPR720, which completed enrollment in the second quarter of 2024. Subsequently, in October 2024, we announced that we would suspend current development activities for SPR720 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.
Current wording
Direct costs related to our SPR720 program decreased by $3.7 million during the three months ended September 30, 2025, as compared to the three months ended September 30, 2024, due to decreased clinical activity during the period related to our Phase 2a clinical trial of SPR720. Subsequently, in November 2025, we announced that we ceased development of SPR720.
Previous wording
Direct costs related to our SPR206 program decreased by $0.1 million during the three months ended June 30, 2025, primarily due to decreased preclinical activity. In March 2025, following a reprioritization of our programs, we announced that we are no longer pursuing a planned Phase 2 clinical trial for SPR206.
Current wording
Direct costs related to our SPR206 program decreased by $0.2 million during the three months ended September 30, 2025, primarily due to decreased preclinical activity. In March 2025, following a reprioritization of our programs, we announced that we ceased development of SPR206.
Previous wording
The decrease in personnel-related costs of $0.8 million was primarily a result of increased retention program costs in our research and development functions offset by reduced headcount costs as a result of the previously announced restructuring in the fourth quarter of 2024. Personnel-related costs for the three months ended June 30, 2025 and 2024 included stock-based compensation expense of $0.4 million and $0.7 million, respectively.
Current wording
The decrease in personnel-related costs of $1.6 million was primarily a result of reduced headcount costs as a result of the restructuring in the fourth quarter of 2024. Personnel-related costs for the three months ended September 30, 2025 and 2024 included stock-based compensation expense of $0.4 million and $0.7 million, respectively.
Previous wording
The increase in professional and consultant fees of $0.4 million was primarily due to an increase in legal and consulting expenses incurred in the six months ended June 30, 2025.
Current wording
The decrease in professional and consultant fees of $0.2 million was primarily due to a decrease in legal and consulting expenses incurred in the three months ended September 30, 2025.
Previous wording
Other income (expense), net was $0.7 million for the three months ended June 30, 2025, compared to $1.2 million for the three months ended June 30, 2024. Total other income for the three months ended June 30, 2025, included $0.7 million of interest income, of which $0.4 million related to the significant financing component recognized under the GSK License Agreement, offset by immaterial fluctuations in unrealized foreign currency. Total other income for the three months ended June 30, 2024, included $1.2 million of interest income, of which $0.4 million related to the significant financing component recognized under the GSK License Agreement, offset by immaterial fluctuations in unrealized foreign currency.
Current wording
Other income (expense), net was $0.5 million for the three months ended September 30, 2025, compared to $1.2 million for the three months ended September 30, 2024. Total other income for the three months ended September 30, 2025, included $0.5 million of interest income, of which $0.2 million related to the significant financing component recognized under the GSK License Agreement, offset by immaterial fluctuations in unrealized foreign currency. Total other income for the three months ended September 30, 2024, included $1.2 million of interest income, of which $0.4 million related to the significant financing component recognized under the GSK License Agreement, offset by immaterial fluctuations in unrealized foreign currency.
Previous wording
The following table summarizes our results of operations for the six months ended June 30, 2025 and 2024 (in thousands):
Current wording
The following tables summarize our results of operations for the nine months ended September 30, 2025 and 2024 (in thousands):
Previous wording
Grant revenue recognized during the six months ended June 30, 2025 and 2024 consisted of the reimbursement of qualifying expenses incurred in connection with our various government awards. The decrease in grant revenue during the six months ended June 30, 2025 was primarily due to a decrease of $5.9 million under our BARDA contract for tebipenem HBr, and a decrease of $0.2 million under our NIAID agreement relating to SPR206.
Current wording
Grant revenue recognized during the nine months ended September 30, 2025 and 2024 consisted of the reimbursement of qualifying expenses incurred in connection with our various government awards. The decrease in grant revenue during the nine months ended September 30, 2025 was primarily due to a decrease of $9.1 million under our BARDA contract for tebipenem HBr, and a decrease of $0.3 million under our NIAID agreement relating to SPR206.
Previous wording
During the six months ended June 30, 2025, we recognized $16.9 million in collaboration revenue related to our agreement with GSK and under $0.1 million in collaboration revenue related to our agreement with Pfizer. During the six months ended June 30, 2024, we recognized $10.0 million in collaboration revenue related to our agreement with GSK and $0.3 million in collaboration revenue related to our agreement with Pfizer. The increase in revenue under the GSK License Agreement was directly related to the adjusted service period due to the pivotal Phase 3 PIVOT-PO trial stopping early for efficacy in the first half of 2025 following the pre-specified interim analysis.
Current wording
During the nine months ended September 30, 2025, we recognized $19.9 million in collaboration revenue related to our agreement with GSK and less than $0.1 million in collaboration revenue related to our agreement with Pfizer. During the nine months ended September 30, 2024, we recognized $17.7 million in collaboration revenue related to our agreement with GSK and $0.3 million in collaboration revenue related to our agreement with Pfizer. The increase in revenue under the GSK License Agreement was directly related to the adjusted service period due to the pivotal Phase 3 PIVOT-PO trial stopping early for efficacy in the first half of 2025 following the pre-specified interim analysis.
Previous wording
Direct costs related to our tebipenem HBr program decreased by $6.7 million during the six months ended June 30, 2025, compared to the six months ended June 30, 2024, due to a decrease in clinical activities related to our pivotal Phase 3 PIVOT-PO trial which met its primary endpoint and was stopped early for efficacy during the first half of 2025.
Current wording
Direct costs related to our tebipenem HBr program decreased by $19.6 million during the nine months ended September 30, 2025, compared to the nine months ended September 30, 2024, due to a decrease in clinical activities related to our pivotal Phase 3 PIVOT-PO trial which met its primary endpoint and was stopped early for efficacy during the first half of 2025.
Previous wording
Direct costs related to our SPR720 program decreased by $8.4 million during the six months ended June 30, 2025, as compared to the six months ended June 30, 2024, due to decreased clinical activity during the period related to our Phase 2a clinical trial of SPR720, which completed enrollment in the second quarter of 2024. Subsequently, in October 2024, we announced that we would suspend current development activities for SPR720 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.
Current wording
Direct costs related to our SPR720 program decreased by $12.1 million during the nine months ended September 30, 2025, as compared to the nine months ended September 30, 2024, due to decreased clinical activity during the period related to our Phase 2a clinical trial of SPR720. Subsequently, in November 2025, we announced that we ceased development of SPR720.
Previous wording
Direct costs related to our SPR206 program decreased by $0.3 million during the six months ended June 30, 2025, primarily due to decreased preclinical activity. In March 2025, following a reprioritization of our programs, we announced that we are no longer pursuing a planned Phase 2 clinical trial for SPR206.
Current wording
Direct costs related to our SPR206 program decreased by $0.5 million during the nine months ended September 30, 2025, primarily due to decreased preclinical activity. In March 2025, following a reprioritization of our programs, we announced that we ceased development of SPR206.
Previous wording
The increase in personnel-related costs of $1.0 million was primarily a result of retention bonus and executive severance expense in our general and administrative functions during the period offsetting reduced headcount costs as a result of the previously announced restructuring in the fourth quarter of 2024. Personnel-related costs for the six months ended June 30, 2025 and 2024 included stock-based compensation expense of $1.3 million and $2.7 million, respectively.
Current wording
The increase in personnel-related costs of $0.1 million was primarily a result of retention bonus and executive severance expense in our general and administrative functions during the period offsetting reduced headcount costs as a result of the restructuring in the fourth quarter of 2024. Personnel-related costs for the nine months ended September 30, 2025 and 2024 included stock-based compensation expense of $2.0 million and $4.2 million, respectively.
Previous wording
The increase in professional and consultant fees of $0.2 million was primarily due to an increase in legal and consulting expenses incurred in the three months ended June 30, 2025.
Current wording
The increase in professional and consultant fees of $0.3 million was primarily due to an increase in legal and consulting expenses incurred in the nine months ended September 30, 2025.
Previous wording
Total other income (expense), net was $1.6 million for the six months ended June 30, 2025, compared to $2.5 million for the six months ended June 30, 2024. Total other income for the six months ended June 30, 2025, included $1.6 million of interest income, of which $0.7 million related to the significant financing component recognized under the GSK License Agreement, offset by immaterial fluctuations in unrealized foreign currency. Total other income for the six months ended June 30, 2024, included $1.7 million of interest income, of which $0.8 million related to the significant financing component recognized under the GSK License Agreement, offset by immaterial fluctuations in unrealized foreign currency.
Current wording
Total other income (expense), net was $2.1 million for the nine months ended September 30, 2025, compared to $3.7 million for the nine months ended September 30, 2024. Total other income for the nine months ended September 30, 2025, included $2.1 million of interest income, of which $0.9 million related to the significant financing component recognized under the GSK License Agreement, offset by immaterial fluctuations in unrealized foreign currency. Total other income for the nine months ended September 30, 2024, included $3.7 million of interest income, of which $1.2 million related to the significant financing component recognized under the GSK License Agreement, offset by immaterial fluctuations in unrealized foreign currency.
Previous wording
Since our inception, we have incurred significant operating losses. We have recognized revenue to date from funding arrangements with the U.S. Department of Defense, NIAID, CARB-X and BARDA, the GSK License Agreement and our license agreements with Everest and Pfizer. We have not yet commercialized any of our product candidates and we may not generate revenue from sales of any product candidates. To date, we have funded our operations with payments received under license and collaboration agreements and funding from government contracts, and from the proceeds of multiple common stock offerings. As of June 30, 2025, we had cash and cash equivalents of $31.2 million. In the third quarter of 2025, we received the final payment under the GSK License Agreement of $23.8 million.
Current wording
Since our inception, we have incurred significant operating losses. We have recognized revenue to date from funding arrangements with the U.S. Department of Defense, NIAID, CARB-X and BARDA, the GSK License Agreement and our license agreements with Everest and Pfizer. We have not yet commercialized any product candidates and we may not generate revenue from sales of any product candidate. To date, we have funded our operations with payments received under license and collaboration agreements and funding from government contracts, and from the proceeds of multiple common stock offerings. As of September 30, 2025, we had cash and cash equivalents of $48.6 million.
Previous wording
During the three and six months ended June 30, 2025, we did not sell any shares of our common stock under the Sales Agreement.
Current wording
During the three and nine months ended September 30, 2025, we did not sell any shares of our common stock under the Sales Agreement.
Previous wording
The following table summarizes our sources and uses of cash for the six months ended June 30, 2025 and 2024 (in thousands):
Current wording
The following table summarizes our sources and uses of cash for the nine months ended September 30, 2025 and 2024 (in thousands):
Previous wording
Net cash used in operating activities for the six months ended June 30, 2025, was $21.7 million, primarily resulting from our net loss of $15.6 million, adjusted for an increase to non-cash items of $2.8 million (primarily stock-based compensation). Net cash used by changes in our operating assets and liabilities was $9.0 million and consisted primarily of a $24.9 million decrease in the collaboration receivable-related party, due to the receipt of the third installment payment from GSK (see Note 10), a $16.9 million decrease in deferred revenue, a $11.0 million decrease in accrued expenses, a $6.5 million decrease in accounts payable, a $0.6 million increase in prepaid expenses, a $0.6 million net increase in other receivables, and a $0.7 million decrease in operating lease liability.
Current wording
Net cash used in operating activities for the nine months ended September 30, 2025, was $4.3 million, primarily resulting from our net loss of $22.9 million, adjusted for an increase to non-cash items of $4.7 million (primarily stock-based compensation). Net cash provided by changes in our operating assets and liabilities was $13.9 million and consisted primarily of a $48.5 million decrease in the collaboration receivable-related party, due to the receipt of the third and fourth installment payments from GSK (see Note 11), a $20.0 million decrease in deferred revenue, a $9.9 million decrease in accrued expenses, a $5.9 million decrease in accounts payable, a $0.7 million increase in prepaid expenses and other assets, a $1.5 million net increase in other receivables, and a $0.9 million decrease in operating lease liability and other liabilities.
Previous wording
Net cash used in operating activities for the six months ended June 30, 2024, was $12.8 million, primarily resulting from our net loss of $30.5 million, adjusted for an increase to non-cash items of $4.7 million (primarily stock-based compensation). Net cash provided by changes in our operating assets and liabilities was $13.1 million and consisted primarily of a $21.4 million decrease in our related party collaboration receivable, due to the receipt of the first installment payment from GSK (see Note 10), a $10.2 million decrease in deferred revenue, a $3.2 million net decrease in receivables, a $1.3 million increase in accounts payable, an increase of $3.5 million in accrued expenses, and a $0.6 million decrease in operating lease liability.
Current wording
$45.2 million decrease in our related party collaboration receivable, due to the receipt of the first and second installment payments from GSK (see Note 11), a $18.0 million decrease in deferred revenue, a $1.2 million net increase in receivables, a $4.7 million increase in accounts payable, a $2.4 million increase in prepaid expenses and other assets, an increase of $8.8 million in accrued expenses, and a $1.3 million decrease in operating lease liability and other liabilities.
Previous wording
We did not undertake any investing activities during the six months ended June 30, 2025 or 2024.
Current wording
We did not undertake any investing activities during the nine months ended September 30, 2025 or 2024.
Previous wording
We did not undertake any financing activities during the six months ended June 30, 2025 or 2024.
Current wording
We did not undertake any financing activities during the nine months ended September 30, 2025 or 2024.
Previous wording
the timing and costs of our ongoing and planned clinical trials;
Current wording
the timing and costs of any ongoing and planned clinical trials;
Previous wording
As of June 30, 2025, we had cash and cash equivalents of $31.2 million. In accordance with ASU 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40), we are required to evaluate whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern from the issuance date of our financial statements. Based on such 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 enable us to fund our operating expenses and capital expenditure requirements for at least 12 months from the issuance of the financial statements included in this report and into 2028.
Current wording
As of September 30, 2025, we had cash and cash equivalents of $48.6 million. In accordance with ASU 2014-15, Disclosure of Uncertainties about an Entity’s Ability to Continue as a Going Concern (Subtopic 205-40), we are required to evaluate whether there are conditions and events, considered in the aggregate, that raise substantial doubt about our ability to continue as a going concern from the issuance date of our financial statements. Based on such 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 enable us to fund our operating expenses and required capital expenditure requirements for at least 12 months from the issuance of the financial statements included in this report and into 2028.
Previous wording
During the three and six months ended June 30, 2025, there have been no material changes to our contractual obligations and commitments from those described under the heading “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Contractual Obligations and Commitments” in our Annual Report on Form 10-K for the year ended December 31, 2024.
Current wording
During the three and nine months ended September 30, 2025, there have been no material changes to our contractual obligations and commitments from those described under the heading “Management’s Discussion and Analysis of Financial Condition and Results of Operations—Contractual Obligations and Commitments” in our Annual Report on Form 10-K for the year ended December 31, 2024.
Rearranged current paragraphs (1)
Current report — wording carried from elsewhere
Net cash used in operating activities for the nine months ended September 30, 2024, was less than $0.1 million, primarily resulting from our net loss of $47.7 million, adjusted for an increase to non-cash items of $7.1 million (primarily stock-based compensation). Net cash provided by changes in our operating assets and liabilities was $40.6 million and consisted primarily of a