Tectonic Therapeutic, Inc.

Previous wording

Our lead asset, TX45, is an Fc-relaxin fusion molecule that activates the RXFP1 receptor, the GPCR target of the hormone, relaxin. In September 2024, we announced favorable results from a Phase 1a trial evaluating safety, tolerability and pharmacokinetic (“PK”) and pharmacodynamic (“PD”) properties for TX45. In this trial, TX45 was well-tolerated with no drug-related severe adverse events, no observed immunogenicity and demonstrated a favorable PK/PD relationship. Renal plasma flow was measured in each patient at several time points as a pharmacodynamic marker. This data was used to develop an exposure-response model which enabled the selection of doses for the APEX Phase 2 trial.

Current wording

In September 2024, we announced favorable results from a Phase 1a clinical trial evaluating safety, tolerability and pharmacokinetic (“PK”) and pharmacodynamic (“PD”) properties for TX45. In this clinical trial, TX45 was well-tolerated with no drug-related severe adverse events, no observed immunogenicity and demonstrated a favorable PK/PD relationship. Renal plasma flow was measured in each patient at several time points as a PD marker. This data was used to develop an exposure-response model which enabled the selection of doses for the APEX Phase 2 clinical trial.

Previous wording

We are currently evaluating TX45 in a Phase 1b hemodynamic clinical trial and in a Phase 2 clinical trial. Part A of the TX45 Phase 1b hemodynamic clinical trial is a single dose IV, open-label clinical trial evaluating the safety, tolerability and acute hemodynamic effects of TX45 in patients with Group 2 PH in Heart Failure with Preserved Ejection Fraction (“PH-HFpEF”). We have completed dosing of all 19 patients in the Part A of the Phase 1b trial. A preliminary analysis of hemodynamic data from 16 out of 19 patients demonstrated improvements which met and or exceeded our prespecified goals and demonstrated that TX45 both improved left heart function and pulmonary hemodynamics over the 8 hour period post dosing which was evaluated. Part B of the Phase 1b trial which is assessing acute hemodynamics effects of TX45 in patients with Group 2 PH-HFrEF is expected to enroll the first patient in the first half of 2025 with data expected to be announced in the second half of 2025. We dosed our first subject in the APEX Phase 2 clinical trial in October 2024. The APEX Phase 2 clinical trial is a global, 24-week, placebo-controlled trial designed to evaluate the safety and efficacy TX45 administered subcutaneously (“SC”) in subjects with PH-HFpEF. Subjects will be randomized to 300 mg SC (2ml injection) once monthly of TX45, 300 mg SC once every other week of TX45, or placebo. We expect topline trial results from the APEX trial in 2026.

Current wording

The ongoing APEX Phase 2 clinical trial is a global, 24-week, placebo-controlled trial designed to evaluate the safety and efficacy of TX45 administered subcutaneously (“SC”) in subjects with PH-HFpEF, enriched for CpcPH. We dosed our first subject in the APEX Phase 2 clinical trial in October 2024. Subjects are being randomized to 300 mg SC (2 ml injection) once monthly of TX45, 300 mg SC once every other week of TX45, or placebo. We expect topline results from the APEX clinical trial in 2026.

Previous wording

We are also evaluating TX002100 (“TX2100”) as our second development candidate for the treatment of Hereditary Hemorrhagic Telangiectasia (“HHT”), the second most common genetic bleeding disorder with no approved therapy. TX2100 is a VHH-Fc fusion antagonist antibody that binds to an undisclosed GPCR target (“GPCR3”) which plays a key role in pathogenic angiogenesis. A rodent surrogate of TX2100 demonstrated reduced arteriovenous malformation development and bleeding in an animal model of HHT. A 4-week non-human primate dose-range study with a functionally equivalent precursor to TX2100 showed no treatment-related toxicity observed at doses up to 100 mg/kg. A formulation supporting TX2100 SC dosing has been identified. Both IND enabling NHP GLP toxicology studies and technical development activities to generate GMP drug supply and drug product for TX2100 started in the second quarter of 2025. We expect to initiate a Phase 1 clinical trial for TX2100 in the fourth quarter of 2025 or the first quarter of 2026, subject to the results of IND enabling studies.

Current wording

We are also evaluating TX002100 (“TX2100”) as our second development candidate for the treatment of Hereditary Hemorrhagic Telangiectasia (“HHT”), the second most common genetic bleeding disorder with no approved therapy. TX2100 is a VHH-Fc fusion antagonist antibody that binds to an undisclosed GPCR target (“GPCR3”) which plays a key role in pathogenic angiogenesis. A rodent surrogate of TX2100 demonstrated reduced arteriovenous malformation development and bleeding in an animal model of HHT. A 4-week non-human primate dose-range study with a functionally equivalent precursor to TX2100 showed no treatment-related toxicity observed at doses up to 100 mg/kg. A formulation supporting TX2100 SC dosing has been identified. Both IND-enabling NHP GLP toxicology studies and technical development activities to generate GMP drug supply and drug product for TX2100 started in the second quarter of 2025. We expect to initiate a Phase 1 clinical trial in healthy volunteers for TX2100 in the first quarter of 2026 subject to the conclusion of IND-enabling studies. In addition, subject to positive Phase 1 data, we plan to initiate a Phase 2 clinical trial for TX2100 in early 2027.

Previous wording

In February 2025, we entered into a securities purchase agreement (the “Private Placement”) pursuant to which we issued an aggregate of 3,689,465 shares of common stock, at a price of $50.00 per share to institutional accredited investors and $54.14 per share to accredited individual investors that are either an officer or director of our Company, in exchange for aggregate consideration of approximately $185.0 million.

Current wording

In February 2025, we entered into a securities purchase agreement (the “Private Placement”) pursuant to which we issued an aggregate of 3,689,465 shares of common stock, at a price of $50.00 per share to institutional accredited investors and $54.14 per share to accredited individual investors that are either an officer or director of our Company. The net proceeds from the Private Placement were approximately $173.1 million.

Previous wording

Costs that are deployed across multiple internal programs, including programs aimed at the discovery and development of potential therapies for fibrotic disease, and our platform technology and are not directly attributable to any single program are not allocated to any single program and, as such, are not separately classified. These costs include multi-program employee-related costs, cross-program payments made under third-party licensing agreements, costs of laboratory supplies and facilities expenses, including rent, depreciation and other indirect costs, the costs of our discovery efforts and projects, and other expenses.

Current wording

Costs that are deployed across multiple internal programs, including programs aimed at the discovery and development of potential therapies for fibrotic and other diseases, and our platform technology and are not directly attributable to any single program are not allocated to any single program and, as such, are not separately classified. These costs include multi-program employee-related costs, cross-program payments made under third-party licensing agreements, costs of laboratory supplies and facilities expenses, including rent, depreciation and other indirect costs, the costs of our discovery efforts and projects, and other expenses.

Previous wording

General and administrative expenses consist primarily of employee-related costs, including salaries and bonuses, related benefits and stock-based compensation expense, for our personnel in executive, legal, accounting, human resources and other administrative functions. General and administrative expenses also include legal fees relating to patents and corporate matters, professional fees paid for accounting, auditing, consulting and tax services, insurance, travel expenses, office and information technology costs and facilities and utilities, depreciation and other expenses related to general and administrative activities.

Current wording

General and administrative expenses consist primarily of employee-related costs, including salaries and bonuses, related benefits and stock-based compensation expense, for our personnel in executive, legal, accounting, human resources, information technology, and other administrative functions. General and administrative expenses also include legal fees relating to patents and corporate matters, professional fees paid for accounting, auditing, consulting and tax services, insurance, travel expenses, office and information technology costs, and facilities and utilities comprised of depreciation and other expenses.

Previous wording

We anticipate that our general and administrative expenses will increase in the future as we expect to incur increased accounting, audit, legal, regulatory, compliance, director and officer insurance, and investor and public relations expenses associated with operating as a public company. We also expect to incur additional intellectual property-related expenses as we file patent applications to protect innovations arising from our research and development activities.

Current wording

We anticipate that our general and administrative expenses will increase in the future as we expect to incur increased accounting, audit, information technology, legal, regulatory, compliance, director and officer insurance, and investor and public relations expenses associated with operating as a public company. We also expect to incur additional intellectual property-related expenses as we file patent applications to protect innovations arising from our research and development activities.

Previous wording

Total research and development expenses increased $2.2 million for the three months ended March 31, 2025, compared to the three months ended March 31, 2024. The increase in research and development expense was primarily the result of increased CRO and CDMO costs related to the discovery and development of TX2100.

Current wording

Total research and development expenses increased $10.1 million for the three months ended June 30, 2025, compared to the three months ended June 30, 2024. The increase in research and development expense was primarily the result of increased

Previous wording

Interest income increased by $2.2 million for the three months ended March 31, 2025 compared to the three months ended March 31, 2024 primarily due to an increase in cash and cash equivalents as a result of the Merger and Private Placement.

Current wording

Interest income increased $3.1 million for the three months ended June 30, 2025 compared to the three months ended June 30, 2024 primarily due to an increase in cash and cash equivalents as a result of the Merger and Private Placement.

Previous wording

General and administrative expenses increased $3.1 million for the three months ended March 31, 2025 compared to the three months ended March 31, 2024. Personnel-related expenses increased $1.3 million during the three months ended March 31, 2025 compared to the three months ended March 31, 2024. The increase in personnel-related expenses was primarily due to an increase in stock-based compensation for newly granted stock-based awards. Professional and consulting fees increased $1.5 million during the three months ended March 31, 2025 compared to the three months ended March 31, 2024 due to an increase in audit, legal and administrative services to support our operations as a public company.

Current wording

General and administrative expenses increased $3.9 million for the six months ended June 30, 2025 compared to the six months ended June 30, 2024. Employee-related expenses increased $2.7 million during the six months ended June 30, 2025 compared to the six months ended June 30, 2024. The increase in employee-related expenses was primarily due to an increase in stock-based compensation for newly granted stock-based awards. Professional and consulting fees increased $1.4 million during the six months ended June 30, 2025 compared to the six months ended June 30, 2024 due to an increase in audit, legal and administrative services to support our operations as a public company.

Previous wording

We do not currently have any approved products and have never generated any revenue from product sales. We have funded our operations with proceeds from the sale of convertible preferred stock, the issuance of convertible promissory notes, the Merger, and sale of common stock. In February 2025, we sold shares of our common stock under a securities purchase agreement in exchange for gross proceeds of approximately $185.0 million. As of March 31, 2025, we had $306.2 million in cash and cash equivalents and an accumulated deficit of $164.5 million. Based on our current business plans, management believes that our cash, cash equivalents and marketable securities on hand at December 31, 2024 are sufficient to meet our operating requirements for at least the next 12 months from the issuance of the consolidated financial statements included in this Quarterly Report. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our capital resources sooner than we expect.

Current wording

We do not currently have any approved products and have never generated any revenue from product sales. We have funded our operations with proceeds from the sale of convertible preferred stock, the issuance of convertible promissory notes, the Merger, and sale of common stock. In February 2025, we sold shares of our common stock in the Private Placement. The net proceeds from the Private Placement were approximately $173.1 million. As of June 30, 2025, we had $287.4 million in cash and cash equivalents and an accumulated deficit of $184.5 million. Based on our current business plans, management believes that our cash and cash equivalents on hand at June 30, 2025 are sufficient to meet our operating requirements for at least the next 12 months from the issuance of the consolidated financial statements included in this Quarterly Report. We have based this estimate on assumptions that may prove to be wrong, and we could exhaust our capital resources sooner than we expect.

Previous wording

The following table shows a summary of our cash flows for the three months ended March 31, 2025 and 2024:

Current wording

The following table shows a summary of our cash flows for the six months ended June 30, 2025 and 2024:

Previous wording

During the three months ended March 31, 2025, cash used in operating activities was $13.1 million. Cash used in operating activities was primarily used to fund our operations to develop our product candidates resulting in a net loss of $15.9 million partially offset by non-cash charges of $3.0 million related to stock-based compensation expense, depreciation and amortization expense and lease expense.

Current wording

During the six months ended June 30, 2025, cash used in operating activities was $27.8 million. Cash used in operating activities was primarily used to fund our operations to develop our product candidates resulting in a net loss of $35.9 million partially offset by non-cash charges of $6.5 million and $1.6 million of changes in operating assets and liabilities related to the timing of the vendor payments.

Previous wording

During the three months ended March 31, 2024, cash used in operating activities was $9.3 million. Cash used in operating activities was primarily due to the use of funds in our operations to develop our product candidates resulting in a net loss of $15.2 million, and changes in our operating assets and liabilities of $2.9 million, partially offset by non-cash charges of $3.1 million related to the change in the fair value of the SAFE liabilities, depreciation and amortization expense, stock-based compensation expense, and lease expense. The increase in operating assets and liabilities relates to accrued expenses, timing of vendor payments, and timing of lease repayments.

Current wording

During the six months ended June 30, 2024, cash used in operating activities was $22.7 million. Cash used in operating activities was primarily used to fund our operations to develop our product candidates resulting in a net loss of $27.9 million, and changes in our operating assets and liabilities of $0.4 million, partially offset by non-cash charges of $5.6 million related to the change in the fair value of the SAFE liabilities, depreciation and amortization expense, stock-based compensation expense, and lease expense. The increase in operating assets and liabilities relates to accrued expenses, timing of vendor payments, and timing of lease repayments.

Previous wording

During the three months ended March 31, 2025 and 2024, net cash used in investing activities was nominal and related to purchases of property and equipment.

Current wording

During the six months ended June 30, 2025 and 2024, net cash provided by investing activities was nominal and related to the purchase and sale of property and equipment.

Previous wording

During the three months ended March 31, 2025, net cash provided by financing activities was $178.1 million, primarily due to net proceeds of $177.3 million from the sale of shares pursuant to the Private Placement and $1.0 million in proceeds from the exercise of stock options. Net cash used in financing activities during the three months ended March 31, 2024 was primarily due to the payment of $0.6 million of deferred offering costs related to the Merger.

Current wording

Net cash provided by financing activities during the six months ended June 30, 2024 was $179.1 million, primarily due to net proceeds of $94.6 million from the sale of shares pursuant to the Subscription Agreement, $84.1 million of cash acquired in connection with the Merger, net of transaction costs, and $0.6 million in proceeds from the exercise of stock options.

Previous wording

We expect our expenses to increase in connection with our ongoing activities, particularly as we continue the research and development of, continue or initiate clinical trials of, and seek marketing approval for, our product candidates including our lead product candidate TX45 and TX2100. In addition, if we obtain marketing approval for TX45, TX2100 or any of our other product candidates, we expect to incur significant commercialization expenses related to program sales, marketing, manufacturing and distribution to the extent that such sales, marketing and distribution are not the responsibility of potential collaborators. Furthermore, we expect to incur additional costs associated with operating as a public company. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs or future commercialization efforts.

Current wording

We expect our expenses to increase in connection with our ongoing activities, particularly as we continue the research and development of, continue or initiate clinical trials of, and seek marketing approval for, our product candidates including our lead product candidates TX45 and TX2100. In addition, if we obtain marketing approval for TX45, TX2100 or any of our other product candidates, we expect to incur significant commercialization expenses related to program sales, marketing, manufacturing and distribution to the extent that such sales, marketing and distribution are not the responsibility of potential collaborators. Furthermore, we expect to incur additional costs associated with operating as a public company. Accordingly, we will need to obtain substantial additional funding in connection with our continuing operations. If we are unable to raise capital when needed or on attractive terms, we would be forced to delay, reduce or eliminate our research and development programs or future commercialization efforts.

Previous wording

We have lease obligations including amounts due on leases of certain laboratory equipment and office and laboratory space under the terms of non-cancelable operating and finance leases. The leases expire at various times through 2027. Minimum lease payments as of March 31, 2025 are $2.2 million in 2025, $0.5 million in 2026, and $0.1 million in 2027. The commitment amounts are associated with contracts that are enforceable and legally binding and that specify all significant terms, including fixed or minimum services to be used, fixed, minimum or variable price provisions, and the approximate timing of the actions under the contracts. Such amounts do not include obligations under agreements that we can cancel without a significant penalty.

Current wording

We have lease obligations including amounts due on leases of certain laboratory equipment and office and laboratory space under the terms of non-cancelable operating and finance leases. The leases expire at various times through 2027. Minimum lease payments as of June 30, 2025 are $1.5 million in 2025, $0.5 million in 2026, and $0.1 million in 2027. The commitment amounts are associated with contracts that are enforceable and legally binding and that specify all significant terms, including fixed or minimum services to be used, fixed, minimum or variable price provisions, and the approximate timing of the actions under the contracts. Such amounts do not include obligations under agreements that we can cancel without a significant penalty.