# EDGAR Filing Document

**Accession Number:** 0001797409
**File Stem:** 0000897069-25-001795
**Filing Date:** 2025-12
**Character Count:** 8377
**Document Hash:** 32ac9a49b1501c0c37a09ef777a0d945
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000897069-25-001795.hdr.sgml**: 20251210

**ACCESSION NUMBER**: 0000897069-25-001795

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20251209

**FILED AS OF DATE**: 20251210

**DATE AS OF CHANGE**: 20251210

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Cambrian BioPharma Inc
- **CENTRAL INDEX KEY:** 0001797409

**ORGANIZATION NAME:**
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-39980
- **FILM NUMBER:** 251562574

**BUSINESS ADDRESS:**
- **STREET 1:** 228 PARK AVENUE S.
- **STREET 2:** #66643
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10003
- **BUSINESS PHONE:** (516) 962-3186

**MAIL ADDRESS:**
- **STREET 1:** 228 PARK AVENUE S.
- **STREET 2:** #66643
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10003

**FORMER NAME:**
- **FORMER CONFORMED NAME:** Cambrian BioPharma Inc.
- **DATE OF NAME CHANGE:** 20191219
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Sensei Biotherapeutics, Inc.
- **CENTRAL INDEX KEY:** 0001829802
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 1405 RESEARCH BLVD, SUITE 125
- **CITY:** ROCKVILLE
- **STATE:** MD
- **ZIP:** 20850
- **BUSINESS PHONE:** (240) 243-8000

**MAIL ADDRESS:**
- **STREET 1:** 1405 RESEARCH BLVD, SUITE 125
- **CITY:** ROCKVILLE
- **STATE:** MD
- **ZIP:** 20850

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## FORM 4

### STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

[ ] Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

[ ] Check this box to indicate that a transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c). See Instruction 10.

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>Cambrian BioPharma Inc<br><sub>(Last) (First) (Middle)</sub><br>228 PARK AVENUE S.

#66643<br><sub>(Street)</sub><br>NEW YORK, NY 10003<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2025-12-09 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [X] 10% Owner<br>[ ] Officer (give title below) [ ] Other (specify below)<br>_ _ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>Sensei Biotherapeutics, Inc. [ SNSE ] | **4. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  | **6. Individual or Joint/Group Filing (Check Applicable Line)**<br>[X] Form filed by One Reporting Person<br>[ ] Form filed by More than One Reporting Person |

---

## Table I - Non-Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | 3. Transaction Code (V) | 3. Transaction Code (V) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 4. Securities Acquired (A) or Disposed of (D) | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| 1. Title of Security | 2. Transaction Date | 2A. Deemed Execution Date | Code | V | Amount | (A) or (D) | Price | 5. Amount of Securities Beneficially Owned | 6. Ownership Form | 7. Nature of Indirect Beneficial Ownership |
| Common Stock | 2025-12-09 |  | S |  | 3105 | D | 8.59<sup>(1)</sup> | 158254 | D<sup>(2)</sup> |  |
| Common Stock | 2025-12-09 |  | S |  | 2666 | D | 7.95<sup>(3)</sup> | 155588 | D<sup>(2)</sup> |  |
| Common Stock | 2025-12-09 |  | M |  | 395 | A | $6.4 | 155983 | D<sup>(2)</sup> |  |
| Common Stock | 2025-12-09 |  | S |  | 395 | D | $8.04 | 155588 | D<sup>(2)</sup> |  |
| Common Stock | 2025-12-09 |  | S |  | 446 | D | 7.92<sup>(4)</sup> | 155142 | D<sup>(2)</sup> |  |

---

## Table II - Derivative Securities

---

|  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | 4. Transaction Code (V) | 4. Transaction Code (V) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 5. Number of Derivative Securities Acquired (A) or Disposed of (D) | 6. Date Exercisable and Expiration Date | 6. Date Exercisable and Expiration Date | 7. Title and Amount of Underlying Securities | 7. Title and Amount of Underlying Securities | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | 2. Conversion or Exercise Price | 3. Transaction Date | 3A. Deemed Execution Date | Code | V | (A) | (D) | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 8. Price of Derivative Security | 9. Number of Derivative Securities Beneficially Owned | 10. Ownership Form | 11. Nature of Indirect Beneficial Ownership |
| Stock Option (Right to Buy) | $6.4 | 2025-12-09 |  | M |  |  | 395<sup>(5)</sup> | <sup>(6)</sup> | 2035-05-20 | Common Stock | 395 | $0 | 0 | D |  |

---

### Footnotes:

(1) The price reported in Column 4 is a weighted average price. The prices sold ranged from $8.50 to $9.00. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range.

(2) These shares are held by Cambrian Biopharma, Inc., a Delaware corporation ("Cambrian"). The Chief Executive Officer of Cambrian, James Peyer, may direct the voting and disposition of the shares held by Cambrian, subject in certain instances to the approval of Cambrian's Board of Directors. Mr. Peyer disclaims beneficial ownership of such shares.

(3) The price reported in Column 4 is a weighted average price. The prices sold ranged from $7.80 to $8.33. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate price within the range.

(4) The price reported in Column 4 is a weighted average price. The prices sold ranged from $7.91 to $7.95. The reporting person will provide the issuer, any security holder of the issuer, or the SEC staff, upon request, full information regarding the number of shares sold at each separate pricewithin the range.

(5) The amount shown reflects the number of shares held following the reported transaction, as adjusted for a 1-for-20 stock split effectuated by the issuer.

(6) The shares subject to the option vest and become exercisable in 12 equal monthly installments over a one year period such that the option is fully vested on the first anniversary of the date of grant, or May 21, 2026, subject to the Reporting Person's continuous service with the Issuer as of each such vesting date; provided that the option will in any case be fully vested on the date of the Company's next annual stockholder meeting, subject to the Reporting Person's continuous service with the Issuer through such vesting date.

**Signature:** Cambrian BioPharma Inc, by: /s/ James Peyer  
**Date:** 2025-12-10

### Remarks:

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.

**Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.**