# EDGAR Filing Document

**Accession Number:** 0001681087
**File Stem:** 0001193125-25-139142
**Filing Date:** 2025-6
**Character Count:** 9872
**Document Hash:** 6c6e796d2c3064bf5c2afaf3126c753d
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001193125-25-139142.hdr.sgml**: 20250611

**ACCESSION NUMBER**: 0001193125-25-139142

**CONFORMED SUBMISSION TYPE**: 424B5

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20250611

**DATE AS OF CHANGE**: 20250611

**FILER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Tectonic Therapeutic, Inc.
- **CENTRAL INDEX KEY:** 0001681087
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 810710585
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 424B5
- **SEC ACT:** 1933 Act
- **SEC FILE NUMBER:** 333-280909
- **FILM NUMBER:** 251039996

**BUSINESS ADDRESS:**
- **STREET 1:** 490 ARSENAL WAY
- **STREET 2:** SUITE 210
- **CITY:** WATERTOWN
- **STATE:** MA
- **ZIP:** 02472
- **BUSINESS PHONE:** (339) 666-3320

**MAIL ADDRESS:**
- **STREET 1:** 490 ARSENAL WAY
- **STREET 2:** SUITE 210
- **CITY:** WATERTOWN
- **STATE:** MA
- **ZIP:** 02472

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** AVROBIO, Inc.
- **DATE OF NAME CHANGE:** 20180131

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** AvroBio, Inc.
- **DATE OF NAME CHANGE:** 20160729

**Filed Pursuant to Rule 424(b)(5) <br> Registration No. 333-280909** 

**PROSPECTUS SUPPLEMENT** 

**(To Prospectus dated April 3, 2025)**![LOGO](g48536g0611224531469.jpg)

## Tectonic Therapeutic, Inc.
**Up to 2,969,583 Shares of Common Stock** 

This prospectus supplement supplements the prospectus dated April 3, 2025 (the "Prospectus"), which forms a part of our registration statement on Form S-1 (No. 333-280909), as amended. This prospectus supplement is being filed to update and supplement the information in the Prospectus with certain information contained in our Quarterly Report on Form 8-K, filed with the Securities and Exchange Commission on June 6, 2025 (the "Current Report"). Accordingly, we have attached the Current Report in relevant part to this prospectus supplement.

The Prospectus and this prospectus supplement relate to the proposed offer and resale or other disposition from time to time by the selling stockholders identified in this prospectus of up to an aggregate of 2,969,583 shares of common stock, par value $0.0001 per share (the "Common Stock"), of Tectonic Therapeutic, Inc.

Our Common Stock is listed on the Nasdaq Global Market under the ticker symbol "TECX." On June 10, 2025, the last reported sales price of our Common Stock was $25.16 per share.

This prospectus supplement should be read in conjunction with the Prospectus, including any amendments or supplements thereto, which is to be delivered with this prospectus supplement. This prospectus supplement is qualified by reference to the Prospectus, including any amendments or supplements thereto, except to the extent that the information in this prospectus supplement updates and supersedes the information contained therein.

This prospectus supplement is not complete without, and may not be delivered or utilized except in connection with, the Prospectus, including any amendments or supplements thereto.

**Investing in our securities involves a high degree of risk. You should review carefully the risks and uncertainties described in the section titled "Risk Factors" beginning on page 9 of the Prospectus, and under similar headings in any amendments or supplements to the Prospectus.** 

**Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities, or passed upon the accuracy or adequacy of this prospectus supplement or the Prospectus. Any representation to the contrary is a criminal offense.** 

**The date of this prospectus supplement is June 11, 2025** 

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**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 6, 2025** 

**(Exact name of registrant as specified in its charter)** 

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| | | |
|:---|:---|:---|
| **Delaware** | **001-38537** | **81-0710585** |
| **(State or other jurisdiction**<br> **of incorporation)** | **(Commission**<br> **File Number)** | **(IRS Employer**<br> **Identification No.)** |
| **490 Arsenal Way, Suite 210**<br> **Watertown, Massachusetts** | **490 Arsenal Way, Suite 210**<br> **Watertown, Massachusetts** | **02472** |
| **(Address of principal executive offices)** | **(Address of principal executive offices)** | **(Zip Code)** |

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**(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:** 

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| | | |
|:---|:---|:---|
| **Title of Each Class** | **Trading**<br> **Symbol** | **On Which Registered** |
| Common Stock, $0.0001 par value per share | TECX | The Nasdaq Stock Market LLC |

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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. ☐

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| | |
|:---|:---|
| **Item 5.07** | **Submission of Matters to a Vote of Security Holders.**  |

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On June 6, 2025, Tectonic Therapeutic, Inc. (the "Company") held its 2025 Annual General Meeting of Stockholders (the "Annual General Meeting"). As of April 14, 2025, the record date for the Annual General Meeting, 18,671,229 shares of common stock were outstanding and entitled to vote at the Annual General Meeting. A summary of the matters voted upon by stockholders at the Annual General Meeting is set forth below.

*Proposal 1: Election of Directors* 

Alise Reicin, M.D. and Praveen Tipirneni, M.D. were elected as a Class I directors, to hold office until the 2028 Annual General 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:

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| | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|
| **Name of Director Elected** | **Votes For** | **Votes For** | **Votes Withheld** | **Votes Withheld** | **Broker Non-Votes** | **Broker Non-Votes** |
|  Alise Reicin, M.D. |  | 14469766 |  | 432093 |  | 1351739 |
|  Praveen Tipirneni, M.D. |  | 14452647 |  | 449212 |  | 1351739 |

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*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, 2025. The final voting results are as follows:

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| | | | |
|:---|:---|:---|:---|
| **Votes For** | **Votes Against** | **Abstentions** | **Broker Non-Votes** |
| 16249011 | 3867 | 720 | 0 |

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*Proposal 3: Advisory Approval on the Compensation of the Company's Named Executive Officers* 

On an advisory basis, the stockholders approved the compensation of the Company's named executive officers, as disclosed in the Company's proxy statement for the Annual General Meeting. The voting results are as follows:

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| | | | |
|:---|:---|:---|:---|
| **Votes For** | **Votes Against** | **Abstentions** | **Broker Non-Votes** |
| 14819757 | 66777 | 15325 | 1351739 |

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*Proposal 4: Advisory Vote on the Frequency of Stockholder Advisory Votes on Executive Compensation* 

The stockholders indicated, on an advisory basis, that the preferred frequency of the advisory vote on the compensation of the Company's named executive officers ("Say on Frequency") occur every year. The voting results were as follows:

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| | | | | |
|:---|:---|:---|:---|:---|
| **1 Year** | **2 Years** | **3 Years** | **Abstentions** | **Broker Non-Votes** |
| 14878746 | 2679 | 19029 | 1405 | 1351739 |

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Consistent with the recommendation of the Company's Board of Directors, as set forth in the Company's proxy statement for the Annual General Meeting, and based on the results of this non-binding advisory vote, it is the Company's intent that future advisory stockholder votes on the compensation of the Company's named executive officers will be held annually and included in the Company's proxy materials for each annual meeting until the next required vote on Say on Frequency.

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**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.

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| | | |
|:---|:---|:---|
|  | **Tectonic Therapeutic, Inc.** | **Tectonic Therapeutic, Inc.** |
| Date: June 6, 2025 | By: | /s/ Daniel Lochner |
|  |  | Daniel Lochner |
|  |  | Chief Financial Officer |

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