# EDGAR Filing Document

**Accession Number:** 0001882782
**File Stem:** 0002044377-26-000002
**Filing Date:** 2026-5
**Character Count:** 14216
**Document Hash:** cc4254859f9d995a5d139e3a79d11faa
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0002044377-26-000002.hdr.sgml**: 20260518

**ACCESSION NUMBER**: 0002044377-26-000002

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13G

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20260518

**DATE AS OF CHANGE**: 20260518

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Odyssey Therapeutics, Inc.
- **CENTRAL INDEX KEY:** 0001882782
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 863384382
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-95704
- **FILM NUMBER:** 26995603

**BUSINESS ADDRESS:**
- **STREET 1:** 51 SLEEPER STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02210
- **BUSINESS PHONE:** (212) 841-1000

**MAIL ADDRESS:**
- **STREET 1:** 51 SLEEPER STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02210
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Lightspeed Venture Partners XV-B (Ignite), L.P.
- **CENTRAL INDEX KEY:** 0002044377

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G

**BUSINESS ADDRESS:**
- **STREET 1:** 2200 SAND HILL ROAD
- **CITY:** MENLO PARK
- **STATE:** CA
- **ZIP:** 94025
- **BUSINESS PHONE:** 650-234-8300

**MAIL ADDRESS:**
- **STREET 1:** 2200 SAND HILL ROAD
- **CITY:** MENLO PARK
- **STATE:** CA
- **ZIP:** 94025

## Exhibit 99.1

EXHIBIT 99.1

JOINT FILING AGREEMENT

We, the undersigned, hereby express our agreement that the attached Schedule 13G (or any amendments thereto) relating to the common stock of Odyssey Therapeutics, Inc. on behalf of each of us.

Dated: May 18, 2026

**Lightspeed Venture Partners XV-B (Ignite), L.P.**

By:

Lightspeed General Partner XV-B (Ignite), L.P.

Its

General Partner

By:

Lightspeed Ultimate General Partner XV-B (Ignite), L.L.C.

Its

General Partner

By:

<u>/s/ Ravi Mhatre</u>

Name: Ravi Mhatre

Title: Managing Member

**Lightspeed General Partner XV-B (Ignite), L.P.**

By:

Lightspeed Ultimate General Partner XV-B (Ignite), L.L.C.

its

General Partner

By:

<u>/s/ Ravi Mhatre</u>

Name: Ravi Mhatre

Title: Managing Member

**Lightspeed Ultimate General Partner XV-B (Ignite), L.L.C.**

By:

<u>/s/ Ravi Mhatre</u>

Name: Ravi Mhatre

Title: Managing Member

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

## SCHEDULE 13G

### Under the Securities Exchange Act of 1934

**Issuer:** Odyssey Therapeutics, Inc.

**Title of Class of Securities:** Common Stock, $0.0001 par value per share

**CUSIP Number:** —

**Date of Event Which Requires Filing of this Statement:** 05/11/2026

**Check the appropriate box to designate the rule pursuant to which this Schedule is filed:**

- [ ] Rule 13d-1(b)

- [x] Rule 13d-1(c)

- [ ] Rule 13d-1(d)

---

| 1. | Names of Reporting Persons<br>Lightspeed Venture Partners XV-B (Ignite), L.P. | Names of Reporting Persons<br>Lightspeed Venture Partners XV-B (Ignite), L.P. |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>DE | Citizenship or Place of Organization<br>DE |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>3608443.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>3608443.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>3608443.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>3608443.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>7.6% | Percent of Class Represented by Amount in Row (9)<br>7.6% |
| 12. | Type of Reporting Person (See Instructions)<br>PN | Type of Reporting Person (See Instructions)<br>PN |

---

| 1. | Names of Reporting Persons<br>Lightspeed General Partner XV-B (Ignite), L.P. | Names of Reporting Persons<br>Lightspeed General Partner XV-B (Ignite), L.P. |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>DE | Citizenship or Place of Organization<br>DE |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>3608443.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>3608443.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>3608443.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>3608443.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>7.6% | Percent of Class Represented by Amount in Row (9)<br>7.6% |
| 12. | Type of Reporting Person (See Instructions)<br>PN | Type of Reporting Person (See Instructions)<br>PN |

---

| 1. | Names of Reporting Persons<br>Lightspeed Ultimate General Partner XV-B (Ignite), L.L.C. | Names of Reporting Persons<br>Lightspeed Ultimate General Partner XV-B (Ignite), L.L.C. |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [x] |
| 3. | SEC Use Only | SEC Use Only |
| 4. | Citizenship or Place of Organization<br>DE | Citizenship or Place of Organization<br>DE |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 5. | Sole Voting Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>3608443.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>0.00 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>3608443.00 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>3608443.00 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>3608443.00 |
| 10. | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] | Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) [ ] |
| 11. | Percent of Class Represented by Amount in Row (9)<br>7.6% | Percent of Class Represented by Amount in Row (9)<br>7.6% |
| 12. | Type of Reporting Person (See Instructions)<br>OO | Type of Reporting Person (See Instructions)<br>OO |

---

**Item 1(a). Name of Issuer:**
Odyssey Therapeutics, Inc.

**Item 1(b). Address of Issuer's Principal Executive Offices:**
51 Sleeper Street, Suite 800, Boston, MA, 02210 .

**Item 2(a). Name of Person Filing:**
The names of the persons filing this report (collectively, the "Reporting Persons") are:

Lightspeed Venture Partners XV-B (Ignite), L.P. ("Lightspeed XV-B")
Lightspeed General Partner XV-B (Ignite), L.P. ("LGP XV-B")
Lightspeed Ultimate General Partner XV-B (Ignite), L.L.C. ("LUGP XV-B")

The Reporting Persons expressly disclaim status as a "group" for purposes of this Schedule 13G.

**Item 2(b). Address of Principal Business Office:**
c/o Lightspeed Venture Partners
2200 Sand Hill Road
Menlo Park, CA 94025

**Item 2(c). Citizenship:**
Lightspeed XV-B	Delaware
LGP XV-B		Delaware
LUGP XV-B		Delaware

**Item 2(d). Title of Class of Securities:**
Common Stock, $0.0001 par value per share

**Item 2(e). CUSIP Number:**
—

**Item 3. If this statement is filed pursuant to §§ 240.13d-1(b) or 240.13d-2(b) or (c), check whether the person filing is a:**

(a) [ ] Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o).

(b) [ ] Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c).

(c) [ ] Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c).

(d) [ ] Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8).

(e) [ ] An investment adviser in accordance with § 240.13d-1(b)(1)(ii)(E);

(f) [ ] An employee benefit plan or endowment fund in accordance with § 240.13d-1(b)(1)(ii)(F);

(g) [ ] A parent holding company or control person in accordance with § 240.13d-1(b)(1)(ii)(G);

(h) [ ] A savings associations as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813);

(i) [ ] A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3);

(j) [ ] A non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), if filing as a non-U.S. institution in accordance with § 240.13d-1(b)(1)(ii)(J), please specify the type of institution:

(k) [ ] Group, in accordance with Rule 240.13d-1(b)(1)(ii)(K).

**Item 4. Ownership:**

**(a) Amount beneficially owned:**

Row 9 of each Reporting Person's cover page to this Schedule 13G sets forth the aggregate number of shares of common stock of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.
The Reporting Persons' ownership of the Issuer's securities consists of 3,608,443 shares of common stock directly held by Lightspeed XV-B.
LUGP XV-B serves as the sole general partner of LGP XV-B, which serves as the sole general partner of Lightspeed XV-B.

**(b) Percent of class:**

Row 11 of each Reporting Person's cover page to this Schedule 13G sets forth the percentages of the shares of common stock of the Issuer beneficially owned by such Reporting Person and is incorporated by reference. The percentage set forth in each row 11 is based upon 47,174,156 shares of common stock outstanding as of May 11, 2026, as reported in the Issuer's prospectus dated May 7, 2026 filed with the Securities and Exchange Commission (the "SEC") on May 8, 2026.

**(c) Number of shares as to which the person has:**

**(i) Sole power to vote or to direct the vote:**

Row 5 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.

**(ii) Shared power to vote or to direct the vote:**

Row 6 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to vote or to direct the vote of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.

**(iii) Sole power to dispose or to direct the disposition of:**

Row 7 of each Reporting Person's cover page to this Schedule 13G sets forth the sole power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.

**(iv) Shared power to dispose or to direct the disposition of:**

Row 8 of each Reporting Person's cover page to this Schedule 13G sets forth the shared power to dispose or to direct the disposition of securities of the Issuer beneficially owned by such Reporting Person and is incorporated by reference.

**Item 5. Ownership of Five Percent or Less of a Class.**

[x] If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following.

**Item 6. Ownership of More than 5 Percent on Behalf of Another Person.**

Not Applicable

**Item 7. Identification and Classification of the Subsidiary**

Not Applicable

**Item 8. Identification and Classification of Members of the Group**

Not Applicable

**Item 9. Notice of Dissolution of Group**

Not Applicable

**Item 10. Certification:**

By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect, other than activities solely in connection with a nomination under § 240.14a-11.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Lightspeed Venture Partners XV-B (Ignite), L.P.**

**Date:** 05/18/2026

**By:** /s/ Ravi Mhatre

**Name & Title:** See Note 1

**Lightspeed General Partner XV-B (Ignite), L.P.**

**Date:** 05/18/2026

**By:** /s/ Ravi Mhatre

**Name & Title:** By Lightspeed Ultimate General Partner XV-B (Ignite), L.L.C., its General Partner, By Ravi Mhatre, Managing Member

**Lightspeed Ultimate General Partner XV-B (Ignite), L.L.C.**

**Date:** 05/18/2026

**By:** /s/ Ravi Mhatre

**Name & Title:** By Ravi Mhatre, Managing Member