# EDGAR Filing Document

**Accession Number:** 0001952107
**File Stem:** 0000950170-25-108822
**Filing Date:** 2025-8
**Character Count:** 9582
**Document Hash:** 3c923c97382e0d5b0d46ba6b389e4b70
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000950170-25-108822.hdr.sgml**: 20250814

**ACCESSION NUMBER**: 0000950170-25-108822

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13G/A

**PUBLIC DOCUMENT COUNT**: 1

**FILED AS OF DATE**: 20250814

**DATE AS OF CHANGE**: 20250814

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Dianthus Therapeutics, Inc. /DE/
- **CENTRAL INDEX KEY:** 0001690585
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13G/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-90538
- **FILM NUMBER:** 251218364

**BUSINESS ADDRESS:**
- **STREET 1:** 7 TIMES SQUARE
- **STREET 2:** 43RD FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10036
- **BUSINESS PHONE:** 929-999-4055

**MAIL ADDRESS:**
- **STREET 1:** 7 TIMES SQUARE
- **STREET 2:** 43RD FLOOR
- **CITY:** NEW YORK
- **STATE:** NY
- **ZIP:** 10036

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** Magenta Therapeutics, Inc.
- **DATE OF NAME CHANGE:** 20161121
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** BCLS Fund III Investments, LP
- **CENTRAL INDEX KEY:** 0001952107

**ORGANIZATION NAME:**
- **EIN:** 873064173
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

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

**BUSINESS ADDRESS:**
- **STREET 1:** 200 CLARENDON STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02116
- **BUSINESS PHONE:** 6175162000

**MAIL ADDRESS:**
- **STREET 1:** 200 CLARENDON STREET
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02116

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

## SCHEDULE 13G

### Under the Securities Exchange Act of 1934

**(Amendment No. 2)**

**Issuer:** DIANTHUS THERAPEUTICS, INC.

**Title of Class of Securities:** Common Stock, $0.001 par value per share

**CUSIP Number:** 252828108

**Date of Event Which Requires Filing of this Statement:** 06/30/2025

**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>BCLS Fund III Investments, LP | Names of Reporting Persons<br>BCLS Fund III Investments, LP |
|:---|:---|:---|:---|
| 2. | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [ ] | Check the Appropriate Box if a Member of a Group (See Instructions)<br>(a) [ ] (b) [ ] |
| 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 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 6. | Shared Voting Power<br>2482250 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 7. | Sole Dispositive Power<br>0 |
| Number of<br>Shares<br>Beneficially<br>Owned by<br>Each<br>Reporting<br>Person<br>With | 8. | Shared Dispositive Power<br>2482250 |
| 9. | Aggregate Amount Beneficially Owned by Each Reporting Person<br>2482250 | Aggregate Amount Beneficially Owned by Each Reporting Person<br>2482250 |
| 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>7.5% | Percent of Class Represented by Amount in Row (9)<br>7.5% |
| 12. | Type of Reporting Person (See Instructions)<br>PN | Type of Reporting Person (See Instructions)<br>PN |

---

**Item 1(a). Name of Issuer:**
DIANTHUS THERAPEUTICS, INC.

**Item 1(b). Address of Issuer's Principal Executive Offices:**
7 Times Square, 43rd Floor, New York, New York 10036

**Item 2(a). Name of Person Filing:**
This Schedule 13G is being filed by BCLS Fund III Investments, LP, a Delaware limited partnership (the "Reporting Person").

Bain Capital Life Sciences Investors, LLC, a Delaware limited liability company ("BCLSI"), is the manager of Bain Capital Life Sciences III General Partner, LLC, a Delaware limited liability company ("BCLS Fund III GP"), which is the general partner of Bain Capital Life Sciences Fund III, L.P., a Delaware limited partnership ("BCLS Fund III"), which is the managing member of BCLS Fund III Investments GP, LLC, a Delaware limited liability company (together with the Reporting Person, BCLSI, BCLS Fund III GP and BCLS Fund III, the "Bain Capital Life Sciences Entities"), which is the general partner of the Reporting Person. As a result, BCLSI may be deemed to share voting and dispositive power with respect to the securities held by the Reporting Person.

**Item 2(b). Address of Principal Business Office:**
The principal business address for each of the Bain Capital Life Sciences Entities is 200 Clarendon Street, Boston, Massachusetts 02116.

**Item 2(c). Citizenship:**
Each of the Bain Capital Life Sciences Entities is organized under the laws of the State of Delaware.

**Item 2(d). Title of Class of Securities:**
Common Stock, $0.001 par value per share

**Item 2(e). CUSIP Number:**
252828108

**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:**

As of the close of business on June 30, 2025, the Reporting Person held 1,481,917 shares of Common Stock and a pre-funded warrant to purchase up to 1,000,333 shares of Common Stock, together representing approximately 7.5% of the outstanding Common Stock.
The Reporting Person is prohibited from exercising the pre-funded warrant if, as a result of such exercise, the Reporting Person would beneficially own more than 9.99% of the total number of shares of Common Stock then issued and outstanding immediately after giving effect to the exercise.
The percentage of the outstanding shares of Common Stock held by the Reporting Person is based on (i) 32,176,482 shares of Common Stock outstanding as of June 30, 2025, as reported by the Issuer in its Quarterly Report on Form 10-Q for the quarter ended June 30, 2025, filed with the Securities and Exchange Commission on August 7, 2025 and (ii) 1,000,333 shares of Common Stock issuable upon the exercise of the pre-funded warrant held by the Reporting Person.

**(b) Percent of class:**

See Item 4(a) hereof.

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

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

0

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

See Item 4(a) hereof.

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

0

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

See Item 4(a) hereof.

**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.

**BCLS Fund III Investments, LP**

**Date:** 08/14/2025

**By:** /s/ Ricky Sun

**Name & Title:** Ricky Sun, Partner of Bain Capital Life Sciences Investors, LLC