Tectonic Therapeutic (TECX) finishes TX45 Phase 2 APEX enrollment, sets early Q1 2027 data

Rhea-AI Filing Summary

Tectonic Therapeutic, Inc. reported results from its 2026 Annual Meeting and a key clinical milestone. Stockholders elected Timothy A. Springer and Stefan Vitorovic as Class II directors, with up to 13.9 million votes for each candidate, and ratified Deloitte & Touche LLP as independent auditor with 17,225,948 votes for and minimal opposition. Stockholders also approved, on an advisory basis, executive compensation with 14,292,497 votes in favor.

The company announced completion of enrollment in APEX, its 24‑week, global Phase 2 trial of TX45 in pulmonary hypertension associated with heart failure with preserved ejection fraction (PH‑HFpEF). APEX enrolled 191 patients across 14 countries, including 137 with the more severe combined pre‑ and post‑capillary pulmonary hypertension (CpcPH) and pulmonary vascular resistance above 3 Wood Units. Tectonic plans to report topline APEX results in early Q1 2027.

Insights

Biotech clinical development analyst

Governance items passed and TX45 Phase 2 enrollment completed, with data expected in early Q1 2027.

Tectonic Therapeutic confirmed routine annual-meeting outcomes: both Class II director nominees were elected, the auditor ratification passed with over 99% support, and executive compensation received strong advisory approval. These decisions help preserve continuity in board oversight and financial reporting.

Clinically, the company completed enrollment of 191 patients in the APEX Phase 2 trial of TX45 for PH‑HFpEF, enriching for 137 CpcPH patients with pulmonary vascular resistance above 3 Wood Units. Mean baseline PVR was 4.2 WU overall and 5.2 WU in the CpcPH subset, framing disease severity for interpreting results.

APEX uses a randomized, double‑blind, placebo‑controlled design testing two subcutaneous 300 mg dosing regimens over 24 weeks, with change in PVR in the PVR>3 WU population as the primary endpoint. Topline data are expected in early Q1 2027, which will be an important inflection point for assessing TX45’s proof‑of‑concept in this high‑need indication.

8-K Event Classification

3 items: 5.07, 8.01, 9.01

3 items

Item 5.07 Submission of Matters to a Vote of Security Holders Governance

Results of a shareholder vote on proposals at an annual or special meeting.

Item 8.01 Other Events Other

Voluntary disclosure of events the company deems important to shareholders but not covered by other items.

Item 9.01 Financial Statements and Exhibits Exhibits

Financial statements, pro forma financial information, and exhibit attachments filed with this report.

Key Figures

Shares entitled to vote: 18,848,500 shares Votes for Springer: 11,461,485 votes Votes for Vitorovic: 13,937,996 votes +5 more

8 metrics

Shares entitled to vote 18,848,500 shares Common stock outstanding as of April 13, 2026 record date

Votes for Springer 11,461,485 votes Election of director Timothy A. Springer

Votes for Vitorovic 13,937,996 votes Election of director Stefan Vitorovic

Auditor ratification support 17,225,948 votes for Ratification of Deloitte & Touche LLP for fiscal year ending December 31, 2026

Say-on-pay support 14,292,497 votes for Advisory approval of executive compensation

APEX total enrollment 191 patients TX45 Phase 2 trial in PH-HFpEF

CpcPH enrollment 137 patients CpcPH with PVR >3 Wood Units at baseline in APEX

Baseline PVR overall/CpcPH 4.2 WU / 5.2 WU Mean baseline pulmonary vascular resistance in APEX populations

Key Terms

PH-HFpEF, CpcPH, pulmonary vascular resistance, randomized, double-blind, placebo-controlled, +2 more

6 terms

PH-HFpEF medical

"Phase 2 clinical trial evaluating the safety and efficacy of TX45 in patients with pulmonary hypertension associated with heart failure with preserved ejection fraction"

Pulmonary hypertension associated with heart failure with preserved ejection fraction (PH‑HFpEF) is a condition where high blood pressure builds up in the lungs because the heart’s left side is stiff and doesn’t fill properly, even though its pumping strength looks normal. For investors, it matters because it defines a specific patient group and treatment need that shapes clinical trial design, drug approval chances, market size, and potential revenue for companies developing therapies; think of it as a distinct customer segment with a clear unmet need.

CpcPH medical

"a more severe disease subtype of combined pre- and post-capillary pulmonary hypertension (“CpcPH”) patients"

pulmonary vascular resistance medical

"patients with CpcPH and PVR>3 WU at baseline, consistent with the goal"

Pulmonary vascular resistance is the opposition blood faces as it flows through the small arteries and vessels in the lungs — think of it like the narrowness or roughness inside a garden hose that makes water harder to push through. Investors care because higher resistance indicates strain on the heart and worse outcomes for patients, so drugs, devices or tests that reliably lower it can drive clinical approvals, reduce hospital stays and create meaningful commercial value.

randomized, double-blind, placebo-controlled medical

"a global, randomized, double-blind, placebo-controlled, proof-of-concept trial designed to evaluate the safety and efficacy"

A "randomized, double-blind, placebo-controlled" process is a method used to test the effectiveness of a new treatment or intervention. Participants are randomly assigned to different groups, with one receiving the real treatment and the other a fake version, called a placebo. Neither the participants nor the researchers know who is receiving which, which helps ensure unbiased results. For investors, this rigorous approach increases confidence that the findings are accurate and not influenced by guesswork or bias.

G-protein coupled receptors medical

"therapeutic proteins and antibodies that modulate the activity of G-protein coupled receptors (“GPCRs”)"

Cell-surface proteins that detect outside signals — such as hormones, neurotransmitters or sensory cues — and translate them into internal actions that change how a cell behaves, like a doorbell that triggers different responses inside a house. They are prime drug targets because tweaking these receptors can alter important biological processes; successful drugs that activate or block them often drive clinical advances, approvals and significant revenue for pharmaceutical portfolios, so their status matters to investors.

forward-looking statements regulatory

"This press release contains “forward-looking statements” within the meaning of the “safe harbor” provisions"

Forward-looking statements are predictions or plans that companies share about what they expect to happen in the future, like estimating sales or profits. They matter because they help investors understand a company's outlook, but since they are based on guesses and assumptions, they can sometimes be wrong.

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Understanding 8-K Material Events →

false 0001681087 0001681087 2026-06-08 2026-06-08

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): June 8, 2026

Tectonic Therapeutic, Inc.

(Exact name of registrant as specified in its charter)

Delaware		001-38537		81-0710585
(State or other jurisdiction of incorporation)		(Commission File Number)		(IRS Employer Identification No.)

490 Arsenal Way, Suite 200 Watertown, Massachusetts		02472
(Address of principal executive offices)		(Zip Code)

(Registrant’s telephone number, including area code): (339) 666-3320

Not Applicable

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

Securities registered pursuant to Section 12(b) of the Act:

Title of Each Class		Trading Symbol		On Which Registered
Common Stock, $0.0001 par value per share		TECX		The Nasdaq Stock Market LLC

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

Emerging growth company ☐

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Item 5.07 Submission of Matters to a Vote of Security Holders.

On June 8, 2026, Tectonic Therapeutic, Inc. (the “Company”) held its 2026 Annual Meeting of Stockholders (the “Annual Meeting”). As of the close of business on April 13, 2026, the record date for the Annual Meeting, 18,848,500 shares of common stock were outstanding and entitled to vote at the Annual Meeting. A summary of the matters voted upon by stockholders at the Annual Meeting is set forth below.

Proposal 1: Election of Directors

Timothy A. Springer and Stefan Vitorovic were elected as Class II directors, to hold office until the 2029 Annual Meeting of Stockholders and their successors are duly elected and qualified, or until their earlier death, resignation or removal. The final voting results are as follows:

Name of Director Elected		Votes For				Votes Withheld				Broker Non-Votes
Timothy A. Springer			11,461,485				2,963,750				2,806,066
Stefan Vitorovic			13,937,996				487,239				2,806,066

Proposal 2: Ratification of Appointment of the Company’s Independent Registered Public Accounting Firm

The Company’s stockholders ratified the appointment by the Audit Committee of the Company’s Board of Directors of Deloitte & Touche LLP as the Company’s independent registered public accounting firm for the fiscal year ending December 31, 2026. The final voting results are as follows:

Votes For		Votes Against		Abstentions		Broker Non-Votes
17,225,948		3,831		1,522		0

Proposal 3: Advisory Approval on Executive Compensation

The stockholders approved, on an advisory (non-binding) basis, the compensation of the Company’s Named Executive Officers, as disclosed in the Company’s proxy statement for the 2026 Annual Meeting. The final voting results are as follows:

Votes For		Votes Against		Abstentions		Broker Non-Votes
14,292,497		118,271		14,467		2,806,066

Item 8.01 Other Events.

On June 10, 2026, the Company issued a press release titled “Tectonic Therapeutic Completes Enrollment in TX45 APEX Phase 2 Clinical Trial in PH-HFpEF Patients.” A copy of the press release is attached as Exhibit 99.1 to this Current Report on Form 8-K and, other than the quotes contained therein, is incorporated herein by reference.

Item 9.01 Financial Statements and Exhibits.

(d) Exhibits

Exhibit No.		Description
99.1		Press Release dated June 10, 2026.
104		Cover Page Interactive Data File (the cover page XBRL tags are embedded within the Inline XBRL document).

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

				Tectonic Therapeutic, Inc.
Date: June 10, 2026				By:		/s/ Daniel Lochner
						Daniel Lochner
						Chief Financial Officer

Exhibit 99.1

Tectonic Therapeutic Completes Enrollment in TX45 APEX Phase 2 Clinical Trial in PH-HFpEF Patients

• APEX 24-week Phase 2 trial is evaluating the safety and efficacy of TX45 in patients with pulmonary hypertension associated with heart failure with preserved ejection fraction (PH-HFpEF)

• APEX Phase 2 trial enrolled 191 patients across 14 countries, with approximately 72% of patients in the enriched population of CpcPH with a pulmonary vascular resistance (PVR) >3 WU at baseline

• TX45 APEX Phase 2 topline results expected in early Q1 2027

WATERTOWN, Mass., June 10, 2026 (GLOBE NEWSWIRE) – Tectonic Therapeutic, Inc. (NASDAQ: TECX) (“Tectonic” or the “Company”), a clinical stage biotechnology company focused on the discovery and development of therapeutic proteins and antibodies that modulate the activity of G-protein coupled receptors (“GPCRs”), today announced the completion of enrollment for the APEX trial, a 24-week Phase 2 clinical trial evaluating the safety and efficacy of TX45 in patients with pulmonary hypertension associated with heart failure with preserved ejection fraction (“PH-HFpEF”). The trial was designed to include an enriched population of a more severe disease subtype of combined pre- and post-capillary pulmonary hypertension (“CpcPH”) patients with a pulmonary vascular resistance (“PVR”)>3 Wood Units (“WU”) at baseline.

“Reaching full enrollment in our APEX Phase 2 clinical trial represents a critical milestone for our TX45 clinical development program and brings us one step closer to potentially delivering a much-needed therapeutic option to patients suffering from PH-HFpEF,” said Alise Reicin, M.D., President and Chief Executive Officer of Tectonic. “We are deeply grateful to the clinical investigators, study coordinators, and, most importantly, the patients and their families whose participation makes this vital research possible. The strong momentum we experienced during enrollment underscores the significant unmet medical need in PH-HFpEF, especially in patients with CpcPH. With the trial now fully enrolled, we look forward to the upcoming topline results for APEX, expected in early Q1 2027, which will help further characterize the therapeutic profile of our candidate and guide our strategy moving forward.”

The APEX Phase 2 clinical trial enrolled a total of 191 patients across 14 countries of which 137 patients were enrolled with CpcPH and PVR>3 WU at baseline, consistent with the goal for this patient population to represent approximately 70% of the overall patients enrolled in APEX. In the APEX clinical trial, the mean baseline PVR in the overall patient population and the subset of patients with CpcPH and PVR>3 WU was 4.2 WU¹ and 5.2 WU¹, respectively. Tectonic expects topline results from the APEX clinical trial in early Q1 2027.

The APEX Phase 2 clinical trial is a global, randomized, double-blind, placebo-controlled, proof-of-concept trial designed to evaluate the safety and efficacy of two dose regimens of TX45 administered subcutaneously (“SC”) in patients with PH-HFpEF, enriched for patients with CpcPH. Patients were randomized to receive 300 mg SC (2 ml injection) once monthly of TX45, 300 mg SC every other week of TX45, or a placebo. Change from baseline in PVR in the PVR>3 WU population is the primary endpoint of the trial.

¹ Baseline characteristics are preliminary and subjective to change.

About Group 2 Pulmonary Hypertension in HFpEF

The World Health Organization has defined 5 groups of pulmonary hypertension (“PH”). Tectonic is focused on the Group 2 subtype, a condition that develops due to left-sided heart disease, specifically PH-HFpEF. In patients with PH-HFpEF, chronic heart failure leads to increased blood pressure in the pulmonary arteries, exerting severe strain on the right side of the heart, which adapts poorly to the increased pressure. This increased pulmonary pressure gradually causes worsening exercise capacity, shortness of breath and right-sided heart failure, which can lead to death. PH-HFpEF is further segmented based on pulmonary hemodynamics into Isolated, post-capillary PH (“IpcPH”) and CpcPH. CpcPH is more severe, accounts for about one third to one half of the 1.4 million PH-HFpEF patients in the U.S. and is characterized by additional, abnormal changes to the pulmonary vasculature, leading to an increase in PVR. Although several Group 1 PH (Pulmonary Arterial Hypertension, “PAH”) medications have been explored in Group 2 PH, to date, no medications have been approved for its treatment.

About TX45, a long-acting Fc-relaxin fusion protein

TX45 is an Fc-relaxin fusion protein with optimized pharmacokinetics and biophysical properties that activates the RXFP1 receptor, the G-protein coupled receptor target of the hormone relaxin. Relaxin is an endogenous protein, expressed at low levels in both men and women that is a pulmonary and systemic vasodilator with lusitropic, anti-fibrotic and anti-inflammatory activity. In normal human physiology, relaxin is upregulated during pregnancy where it exerts vasodilative effects, reduces systemic and pulmonary vascular resistance and increases cardiac output to accommodate the increased demand for oxygen and nutrients from the developing fetus. Relaxin also exerts anti-fibrotic effects on pelvic ligaments to facilitate delivery of the baby.

About Tectonic

Tectonic Therapeutic is a clinical-stage biotechnology company focused on the discovery and development of therapeutic proteins and antibodies that modulate the activity of GPCRs. Leveraging its proprietary technology platform called GEODe^™ (GPCRs Engineered for Optimal Discovery), Tectonic is focused on developing biologic medicines that overcome the existing challenges of GPCR-targeted drug discovery and harness the human body to modify the course of disease. Tectonic focuses on areas of significant unmet medical need, often where therapeutic options are poor or nonexistent, as these are areas where new medicines have the potential to improve patient quality of life. Tectonic is headquartered in Watertown, Massachusetts. For more information, please visit https://tectonictx.com/ and follow us on LinkedIn.

Forward-Looking Statements

This press release contains “forward-looking statements” within the meaning of the “safe harbor” provisions of the Private Securities Litigation Reform Act of 1995. All statements in this press release other than statements of historical facts are “forward-looking statements.” These statements may be identified by words such as “aims,” “anticipates,” “believes,” “could,” “estimates,” “expects,” “forecasts,” “goal,” “intends,” “may,” “plans,” “possible,” “potential,” “seeks,” “will” and variations of these words or similar expressions that are intended to identify forward-looking statements, although not all forward-looking statements contain these words. Forward-looking statements in this press release include, but are not limited to, statements regarding: the design, objectives, initiation, timing, progress and expected results of current clinical trials of Tectonic’s product candidates, including the ongoing APEX Phase 2 clinical trials for its lead

product candidate, TX45, in patients with PH-HFpEF. These forward-looking statements are based on Tectonic’s expectations and assumptions as of the date of this press release. Each of these forward-looking statements involves risks and uncertainties that could cause Tectonic’s clinical development programs, future results or performance to differ materially from those expressed or implied by the forward-looking statements. Many factors may cause differences between current expectations and actual results, including: the potential that success in preclinical testing and earlier clinical trials does not ensure that later clinical trials will generate the same results or otherwise provide adequate data to demonstrate the efficacy and safety of a product candidate; the impacts of macroeconomic conditions, including the conflict in Ukraine and the conflict in the Middle East, heightened inflation and uncertain credit and financial markets, on Tectonic’s business, clinical trials and financial position; unexpected safety or efficacy data observed during preclinical studies or clinical trials; clinical trial site activation or enrollment rates that are lower than expected; Tectonic’s ability to realize the benefits of its collaborations and license agreements; changes in expected or existing competition; changes in the regulatory environment; the uncertainties and timing of the regulatory approval process; and unexpected litigation or other disputes. Other factors that may cause Tectonic’s actual results to differ from those expressed or implied in the forward-looking statements in this press release are identified under the heading “Risk Factors” in Tectonic’s quarterly report on Form 10-Q filed for the quarter ended March 31, 2026 and in other filings that Tectonic makes and will make with the SEC in the future. Tectonic expressly disclaims any obligation to update any forward-looking statements contained herein, whether as a result of any new information, future events, changed circumstances or otherwise, except as otherwise required by law.

Contacts:

Investors:

Dan Ferry

LifeSci Advisors

daniel@lifesciadvisors.com

(617) 430-7576

Media:

Kathryn Morris

The Yates Network

kathryn@theyatesnetwork.com

(914) 204-6412

FAQ

What governance decisions did Tectonic Therapeutic (TECX) stockholders make at the 2026 annual meeting?

Stockholders elected Timothy A. Springer and Stefan Vitorovic as Class II directors, ratified Deloitte & Touche LLP as independent auditor, and approved executive compensation on an advisory basis. These outcomes maintain current leadership, auditing arrangements, and compensation structure at Tectonic Therapeutic.

How many Tectonic Therapeutic (TECX) shares were entitled to vote at the 2026 annual meeting?

As of the April 13, 2026 record date, 18,848,500 shares of common stock were outstanding and entitled to vote. This figure defines the potential voting base for director elections, auditor ratification, and advisory say‑on‑pay at the annual meeting.

What is the status of Tectonic Therapeutic’s TX45 APEX Phase 2 trial in PH-HFpEF?

Tectonic completed enrollment in the APEX Phase 2 trial of TX45 in PH‑HFpEF. The 24‑week, randomized, double‑blind, placebo‑controlled study includes 191 patients across 14 countries, with topline results planned for early Q1 2027 to evaluate safety and efficacy.

How is the APEX trial for TX45 in PH-HFpEF designed and what is the primary endpoint?

APEX is a global, randomized, double‑blind, placebo‑controlled Phase 2 trial testing two 300 mg subcutaneous TX45 regimens versus placebo over 24 weeks. Its primary endpoint is change from baseline in pulmonary vascular resistance in patients with PVR greater than 3 Wood Units.

How many CpcPH patients are enrolled in Tectonic Therapeutic’s APEX Phase 2 trial?

The APEX trial enrolled 191 patients overall, including 137 with combined pre‑ and post‑capillary pulmonary hypertension (CpcPH) and pulmonary vascular resistance above 3 Wood Units. This CpcPH group represents about 70% of enrolled patients, aligning with the trial’s enrichment strategy.

What baseline pulmonary vascular resistance values were observed in the APEX TX45 trial?

In APEX, mean baseline pulmonary vascular resistance was 4.2 Wood Units in the overall population and 5.2 Wood Units in the subset with CpcPH and PVR above 3 Wood Units. These values highlight the hemodynamic burden in enrolled PH‑HFpEF patients.

Filing Exhibits & Attachments

4 documents

Press Releases

• EX-99.1 EX-99.1 15.9 KB

Other Documents

• EX-101 XBRL TAXONOMY EXTENSION SCHEMA 3.1 KB
• EX-101 XBRL TAXONOMY EXTENSION LABEL LINKBASE 17.6 KB
• EX-101 XBRL TAXONOMY EXTENSION PRESENTATION LINKBASE 11.0 KB