# EDGAR Filing Document

**Accession Number:** 0001828522
**File Stem:** 0001104659-23-029659
**Filing Date:** 2023-3
**Character Count:** 31952
**Document Hash:** 7392c5e07c47af211cb1e25964cc81ab
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-23-029659.hdr.sgml**: 20230307

**ACCESSION NUMBER**: 0001104659-23-029659

**CONFORMED SUBMISSION TYPE**: SC 13G

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20230307

**DATE AS OF CHANGE**: 20230307

**GROUP MEMBERS**: ALTITUDE LIFE SCIENCE VENTURES II, LLC

**GROUP MEMBERS**: ALTITUDE LIFE SCIENCE VENTURES SIDE FUND II, L.P.

**GROUP MEMBERS**: DAVID MAKI

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** eFFECTOR Therapeutics, Inc.
- **CENTRAL INDEX KEY:** 0001828522
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **IRS NUMBER:** 853306396
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SC 13G
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-91982
- **FILM NUMBER:** 23713907

**BUSINESS ADDRESS:**
- **STREET 1:** 142 NORTH CEDROS AVENUE, SUITE B
- **CITY:** SOLANA BEACH
- **STATE:** CA
- **ZIP:** 92075
- **BUSINESS PHONE:** (858) 925-8215

**MAIL ADDRESS:**
- **STREET 1:** 142 NORTH CEDROS AVENUE, SUITE B
- **CITY:** SOLANA BEACH
- **STATE:** CA
- **ZIP:** 92075

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Locust Walk Acquisition Corp.
- **DATE OF NAME CHANGE:** 20201015
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Altitude Life Science Ventures Fund II, L.P.
- **CENTRAL INDEX KEY:** 0001638820
- **IRS NUMBER:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

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

**BUSINESS ADDRESS:**
- **STREET 1:** 701 FIFTH AVENUE, SUITE 5400
- **CITY:** SEATTLE
- **STATE:** WA
- **ZIP:** 98074
- **BUSINESS PHONE:** 650-843-5294

**MAIL ADDRESS:**
- **STREET 1:** 701 FIFTH AVENUE, SUITE 5400
- **CITY:** SEATTLE
- **STATE:** WA
- **ZIP:** 98074

**UNITED STATES**

**SECURITIES AND EXCHANGE COMMISSION**

**Washington, D.C. 20549**

**SCHEDULE 13G**

**Under the Securities Exchange Act of 1934**

**(Amendment No.)\***

**eFFECTOR Therapeutics, Inc.**

(Name of Issuer)

**Common stock, $0.0001 par value per share**

(Title of Class of Securities)

**28202V108**

(CUSIP Number)

**August 25, 2021**

(Date of Event Which Requires Filing of this Statement)

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

---

| | |
|:---|:---|
| ◻ | Rule 13d-1(b) |
| ⌧ | Rule 13d-1(c) |
| ◻ | Rule 13d-1(d) |

---

\*The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page.

The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

---

| | | | | |
|:---|:---|:---|:---|:---|
| &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 |
| &nbsp;&nbsp;&nbsp;&nbsp;1. | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures Fund II, L.P. | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures Fund II, L.P. | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures Fund II, L.P. | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures Fund II, L.P. |
| &nbsp;&nbsp;&nbsp;&nbsp;2. | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) |
|  | &nbsp;&nbsp;(a)<br> (b) | &nbsp;&nbsp;◻ ⌧ (1) | &nbsp;&nbsp;◻ ⌧ (1) | &nbsp;&nbsp;◻ ⌧ (1) |
| &nbsp;&nbsp;&nbsp;&nbsp;3. | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only |
| &nbsp;&nbsp;&nbsp;&nbsp;4. | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 5. | &nbsp;&nbsp;Sole Voting Power<br> 0 |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 6. | &nbsp;&nbsp;Shared Voting Power<br> 1,413,175 shares (2) |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 7. | &nbsp;&nbsp;Sole Dispositive Power<br> 0 |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 8. | &nbsp;&nbsp;Shared Dispositive Power<br> 1,413,175 shares (2) |
| &nbsp;&nbsp;&nbsp;&nbsp;9. | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 1,413,175 shares (2) | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 1,413,175 shares (2) | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 1,413,175 shares (2) | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 1,413,175 shares (2) |
| &nbsp;&nbsp;&nbsp;&nbsp;10. | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ |
| &nbsp;&nbsp;&nbsp;&nbsp;11. | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 3.4% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 3.4% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 3.4% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 3.4% (3) |
| &nbsp;&nbsp;&nbsp;&nbsp;12. | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> PN | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> PN | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> PN | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> PN |

---

(1) This Schedule 13G is filed by Altitude Life
 Science Ventures Fund II, L.P. ("Altitude II"), Altitude Life Science Ventures
 Side Fund II, L.P. ("Altitude II SF"), Altitude Life Science Ventures II, LLC
 ("Altitude GP") and David Maki ("Maki" and, with Altitude II, Altitude
 II SF and Altitude GP, collectively, the "Reporting Persons"). The Reporting
 Persons expressly disclaim status as a "group" for purposes of this Schedule
 13G.

(2) The shares are directly held by Altitude
 II. Altitude II GP serves as sole general partner of Altitude II and Maki is the managing
 member of Altitude II GP. Each of Altitude II GP and Maki shares voting and dispositive power
 over the shares held by Altitude II. The foregoing amount does not include 178,703 shares
 of Common Stock potentially issuable to Altitude II upon the satisfaction of certain earn-out
 conditions.

(3) This percentage is calculated based upon
 41,893,140 shares of Common Stock outstanding as of October 31, 2022, as reported in
 the Issuer's Quarterly Report on Form 10-Q filed with the Securities and Exchange
 Commission (the "SEC") on November 7, 2022.

---

| | | | | |
|:---|:---|:---|:---|:---|
| &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 |
| &nbsp;&nbsp;&nbsp;&nbsp;1. | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures Side Fund II, L.P. | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures Side Fund II, L.P. | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures Side Fund II, L.P. | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures Side Fund II, L.P. |
| &nbsp;&nbsp;&nbsp;&nbsp;2. | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) |
|  | &nbsp;&nbsp;(a)<br> (b) | &nbsp;&nbsp;◻ ⌧ (1) | &nbsp;&nbsp;◻ ⌧ (1) | &nbsp;&nbsp;◻ ⌧ (1) |
| &nbsp;&nbsp;&nbsp;&nbsp;3. | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only |
| &nbsp;&nbsp;&nbsp;&nbsp;4. | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 5. | &nbsp;&nbsp;Sole Voting Power<br> 0 |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 6. | &nbsp;&nbsp;Shared Voting Power<br> 1,413,175 shares (2) |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 7. | &nbsp;&nbsp;Sole Dispositive Power<br> 0 |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 8. | &nbsp;&nbsp;Shared Dispositive Power<br> 1,413,175 shares (2) |
| &nbsp;&nbsp;&nbsp;&nbsp;9. | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 1,413,175 shares (2) | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 1,413,175 shares (2) | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 1,413,175 shares (2) | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 1,413,175 shares (2) |
| &nbsp;&nbsp;&nbsp;&nbsp;10. | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ |
| &nbsp;&nbsp;&nbsp;&nbsp;11. | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 3.4% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 3.4% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 3.4% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 3.4% (3) |
| &nbsp;&nbsp;&nbsp;&nbsp;12. | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> PN | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> PN | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> PN | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> PN |

---

(1) This Schedule 13G is filed by the Reporting
 Persons. The Reporting Persons expressly disclaim status as a "group" for purposes
 of this Schedule 13G.

(2) The shares are directly held by Altitude
 II SF. Altitude II GP serves as sole general partner of Altitude II SF and Maki is the managing
 member of Altitude II GP. Each of Altitude II GP and Maki shares voting and dispositive power
 over the shares held by Altitude II SF. The foregoing amount does not include 178,703 shares
 of Common Stock potentially issuable to Altitude II SF upon the satisfaction of certain earn-out
 conditions.

(3) This percentage is calculated based upon
 41,893,140 shares of Common Stock outstanding as of October 31, 2022, as reported in
 the Issuer's Quarterly Report on Form 10-Q filed with the SEC on November 7,
 2022.

---

| | | | | |
|:---|:---|:---|:---|:---|
| &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 |
| &nbsp;&nbsp;&nbsp;&nbsp;1. | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures II, LLC | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures II, LLC | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures II, LLC | &nbsp;&nbsp;Names of Reporting Persons<br> Altitude Life Science Ventures II, LLC |
| &nbsp;&nbsp;&nbsp;&nbsp;2. | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) |
|  | &nbsp;&nbsp;(a)<br> (b) | &nbsp;&nbsp;◻ ⌧ (1) | &nbsp;&nbsp;◻ ⌧ (1) | &nbsp;&nbsp;◻ ⌧ (1) |
| &nbsp;&nbsp;&nbsp;&nbsp;3. | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only |
| &nbsp;&nbsp;&nbsp;&nbsp;4. | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware | &nbsp;&nbsp;Citizenship or Place of Organization<br> Delaware |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 5. | &nbsp;&nbsp;Sole Voting Power<br> 0 |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 6. | &nbsp;&nbsp;Shared Voting Power<br> 2,826,350 shares (2)  |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 7. | &nbsp;&nbsp;Sole Dispositive Power<br> 0 |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 8. | &nbsp;&nbsp;Shared Dispositive Power<br> 2,826,350 shares (2)  |
| &nbsp;&nbsp;&nbsp;&nbsp;9. | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 2,826,350 shares (2)  | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 2,826,350 shares (2)  | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 2,826,350 shares (2)  | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 2,826,350 shares (2)  |
| &nbsp;&nbsp;&nbsp;&nbsp;10. | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ |
| &nbsp;&nbsp;&nbsp;&nbsp;11. | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 6.7% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 6.7% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 6.7% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 6.7% (3) |
| &nbsp;&nbsp;&nbsp;&nbsp;12. | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> OO | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> OO | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> OO | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> OO |

---

(1) This Schedule 13G is filed by the Reporting
 Persons. The Reporting Persons expressly disclaim status as a "group" for purposes
 of this Schedule 13G.

(2) Includes 1,413,175 shares of Common Stock
 that are directly held by Altitude II and 1,413,175 shares of Common Stock that are directly
 held by Altitude II SF. Altitude II GP serves as sole general partner of Altitude II and
 Altitude II SF, and Maki is the managing member of Altitude II GP. Each of Altitude II GP
 and Maki shares voting and dispositive power over the shares held by Altitude II and Altitude
 II SF. The foregoing amount does not include 178,703 shares of Common Stock potentially issuable
 to Altitude II and 178,703 shares of Common Stock potentially issuable to Altitude II SF
 upon the satisfaction of certain earn-out conditions.

(3) This percentage is calculated based upon
 41,893,140 shares of Common Stock outstanding as of October 31, 2022, as reported in
 the Issuer's Quarterly Report on Form 10-Q filed with the SEC on November 7,
 2022.

---

| | | | | |
|:---|:---|:---|:---|:---|
| &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 | &nbsp;&nbsp;CUSIP No. 28202V108 |
| &nbsp;&nbsp;&nbsp;&nbsp;1. | &nbsp;&nbsp;Names of Reporting Persons<br> David Maki | &nbsp;&nbsp;Names of Reporting Persons<br> David Maki | &nbsp;&nbsp;Names of Reporting Persons<br> David Maki | &nbsp;&nbsp;Names of Reporting Persons<br> David Maki |
| &nbsp;&nbsp;&nbsp;&nbsp;2. | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) | &nbsp;&nbsp;Check the Appropriate Box if a Member of a Group (See Instructions) |
|  | &nbsp;&nbsp;(a)<br> (b) | &nbsp;&nbsp;◻ ⌧ (1) | &nbsp;&nbsp;◻ ⌧ (1) | &nbsp;&nbsp;◻ ⌧ (1) |
| &nbsp;&nbsp;&nbsp;&nbsp;3. | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only | &nbsp;&nbsp;SEC Use Only |
| &nbsp;&nbsp;&nbsp;&nbsp;4. | &nbsp;&nbsp;Citizenship or Place of Organization<br> United States | &nbsp;&nbsp;Citizenship or Place of Organization<br> United States | &nbsp;&nbsp;Citizenship or Place of Organization<br> United States | &nbsp;&nbsp;Citizenship or Place of Organization<br> United States |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 5. | &nbsp;&nbsp;Sole Voting Power<br> 0 |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 6. | &nbsp;&nbsp;Shared Voting Power<br> 2,826,350 shares (2) |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 7. | &nbsp;&nbsp;Sole Dispositive Power<br> 0 |
| &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | &nbsp;&nbsp;Number of<br> Shares<br> Beneficially<br> Owned by<br> Each<br> Reporting<br> Person With | 8. | &nbsp;&nbsp;Shared Dispositive Power<br> 2,826,350 shares (2) |
| &nbsp;&nbsp;&nbsp;&nbsp;9. | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 2,826,350 shares (2) | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 2,826,350 shares (2) | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 2,826,350 shares (2) | &nbsp;&nbsp;Aggregate Amount Beneficially Owned by Each Reporting Person<br> 2,826,350 shares (2) |
| &nbsp;&nbsp;&nbsp;&nbsp;10. | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ | &nbsp;&nbsp;Check if the Aggregate Amount in Row (9) Excludes Certain Shares (See Instructions) ◻ |
| &nbsp;&nbsp;&nbsp;&nbsp;11. | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 6.7% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 6.7% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 6.7% (3) | &nbsp;&nbsp;Percent of Class Represented by Amount in Row (9)<br> 6.7% (3) |
| &nbsp;&nbsp;&nbsp;&nbsp;12. | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> IN | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> IN | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> IN | &nbsp;&nbsp;Type of Reporting Person (See Instructions)<br> IN |

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(1) This Schedule 13G is filed by the Reporting
 Persons. The Reporting Persons expressly disclaim status as a "group" for purposes
 of this Schedule 13G.

(2) Includes 1,413,175 shares of Common Stock
 that are directly held by Altitude II and 1,413,175 shares of Common Stock that are directly
 held by Altitude II SF. Altitude II GP serves as sole general partner of Altitude II and
 Altitude II SF, and Maki is the managing member of Altitude II GP. Each of Altitude II GP
 and Maki shares voting and dispositive power over the shares held by Altitude II and Altitude
 II SF. The foregoing amount does not include 178,703 shares of Common Stock potentially issuable
 to Altitude II and 178,703 shares of Common Stock potentially issuable to Altitude II SF
 upon the satisfaction of certain earn-out conditions.

(3) This percentage is calculated based upon
 41,893,140 shares of Common Stock outstanding as of October 31, 2022, as reported in
 the Issuer's Quarterly Report on Form 10-Q filed with the SEC on November 7,
 2022.

**Item 1.**

(a) Name of Issuer <br> <u>eFFECTOR Therapeutics, Inc.</u>

(b) Address of Issuer's Principal Executive Offices <br> 142 North Cedros Avenue, Suite B <br> <u>Solana Beach, CA 92075</u>

**Item 2.**

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| | |
|:---|:---|
| &nbsp;&nbsp;(a) | &nbsp;&nbsp; Name of Person Filing Altitude Life Science Ventures Fund II, L.P. ("Altitude II") |
|  | &nbsp;&nbsp;Altitude Life Science Ventures Side Fund II, L.P. ("Altitude II SF") |
|  | &nbsp;&nbsp;Altitude Life Science Ventures II, LLC ("Altitude GP") |
|  | &nbsp;&nbsp;David Maki ("Maki") |

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(b) Address of Principal Business Office or, if none, Residence <br> <u>1014 Market Street, Suite 200, Kirkland, WA 98074</u>

(c) Citizenship

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| | | | |
|:---|:---|:---|:---|
| &nbsp;&nbsp;Entities: | &nbsp;&nbsp;Altitude II | &nbsp;&nbsp;- | &nbsp;&nbsp;Delaware |
|  | &nbsp;&nbsp;Altitude II SF | &nbsp;&nbsp;- | &nbsp;&nbsp;Delaware |
|  | &nbsp;&nbsp;Altitude II GP | &nbsp;&nbsp;- | &nbsp;&nbsp;Delaware |
| &nbsp;&nbsp;Individuals: | &nbsp;&nbsp;Maki | &nbsp;&nbsp;- | &nbsp;&nbsp;United States |

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| | |
|:---|:---|
| &nbsp;&nbsp;(d) | &nbsp;&nbsp;Title of Class of Securities |
|  | &nbsp;&nbsp;Common stock, $0.0001 par value per share ("Common Stock") |

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(e) CUSIP Number <br> <u>28202V108</u>

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| | |
|:---|:---|
| **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:** |
|  | Not applicable |

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| | |
|:---|:---|
| **Item 4.** | **Ownership** |
|  | The following information regarding the aggregate number and percentage of the class of securities of the issuer identified in Item 1 is provided as of March 7, 2023: |

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| | | | | | | | |
|:---|:---|:---|:---|:---|:---|:---|:---|
| **Reporting Persons** | **Shares Held<br> Directly** | **Sole <br> Voting<br> Power** | **Shared<br> Voting<br> Power** | **Sole <br> Dispositive<br> Power** | **Shared<br> Dispositive<br> Power** | **Beneficial<br> Ownership** | **Percentage<br> of Class (3)** |
| Altitude II (1) | 1413175 | 0 | 1413175 | 0 | 1413175 | 1413175 | 3.4% |
| Altitude II SF (2) | 1413175 | 0 | 1413175 | 0 | 1413175 | 1413175 | 3.4% |
| Altitude II GP (1) (2) | 0 | 0 | 2826350 | 0 | 2826350 | 2826350 | 6.7% |
| Maki (1) (2) | 0 | 0 | 2826350 | 0 | 2826350 | 2826350 | 6.7% |

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&nbsp;&nbsp;&nbsp;&nbsp;(1) Includes 1,413,175 shares of Common Stock that are directly
held by Altitude II. Altitude II GP serves as sole general partner of Altitude II and Maki is the managing member of Altitude II GP.
Each of Altitude II GP and Maki shares voting and dispositive power over the shares held by Altitude II. The foregoing amount does not
include 178,703 shares of Common Stock potentially issuable to Altitude II upon the satisfaction of certain earn-out conditions.

(2) Includes 1,413,175 shares of Common Stock that are directly
held by Altitude II SF. Altitude II GP serves as sole general partner of Altitude II SF and Maki is the managing member of Altitude II
GP. Each of Altitude II GP and Maki shares voting and dispositive power over the shares held by Altitude II SF. The foregoing amount
does not include 178,703 shares of Common Stock potentially issuable to Altitude II SF upon the satisfaction of certain earn-out conditions.

(3) This percentage is calculated based upon 41,893,140 shares of
Common Stock outstanding as of October 31, 2022, as reported in the Issuer's Quarterly Report on Form 10-Q filed with
the SEC on November 7, 2022.

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| | |
|:---|:---|
| **Item 5.** | **Ownership of Five Percent or Less of a Class** |
|  | 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 Five Percent on Behalf of Another Person** |
|  | Not applicable |
| **Item 7.** | **Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company or Control Person** |
|  | 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 such purpose or effect. |

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**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.

Dated: March 7, 2023

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| | |
|:---|:---|
| **Altitude Life Science Ventures Fund II, L.P.** | **Altitude Life Science Ventures Fund II, L.P.** |
| By: | Altitude Life Science Ventures II, LLC |
| its | General Partner |
| By: | /s/ David Maki |
|  | Name: David Maki |
|  | Title: Managing Member |
| **Altitude Life Science Ventures Side Fund II, L.P.** | **Altitude Life Science Ventures Side Fund II, L.P.** |
| By: | Altitude Life Science Ventures II, LLC |
| its | General Partner |
| By: | /s/ David Maki |
|  | Name: David Maki |
|  | Title: Managing Member |
| **Altitude Life Science Ventures II, LLC** | **Altitude Life Science Ventures II, LLC** |
| By: | /s/ David Maki |
|  | Name: David Maki |
|  | Title: Managing Member |

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| |
|:---|
| /s/ David Maki |
| David Maki |

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| | |
|:---|:---|
|  | &nbsp;&nbsp;**ATTENTION** |
| &nbsp;&nbsp;**Intentional misstatements or omissions of fact constitute Federal Criminal Violations (See 18 U.S.C. 1001).** | &nbsp;&nbsp;**Intentional misstatements or omissions of fact constitute Federal Criminal Violations (See 18 U.S.C. 1001).** |

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**Exhibit(s):**

A Joint Filing Agreement

EXHIBIT A

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 eFFECTOR Therapeutics, Inc. is filed on behalf of each of us.

Dated: March 7, 2023

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| | |
|:---|:---|
| **Altitude Life Science Ventures Fund II, L.P.** | **Altitude Life Science Ventures Fund II, L.P.** |
| By: | Altitude Life Science Ventures II, LLC |
| its | General Partner |
| By: | /s/ David Maki |
|  | Name: David Maki |
|  | Title: Managing Member |
| **Altitude Life Science Ventures Side Fund II, L.P.** | **Altitude Life Science Ventures Side Fund II, L.P.** |
| By: | Altitude Life Science Ventures II, LLC |
| its | General Partner |
| By: | /s/ David Maki |
|  | Name: David Maki |
|  | Title: Managing Member |
| **Altitude Life Science Ventures II, LLC** | **Altitude Life Science Ventures II, LLC** |
| By: | /s/ David Maki |
|  | Name: David Maki |
|  | Title: Managing Member |

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| |
|:---|
| /s/ David Maki |
| David Maki |

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