# EDGAR Filing Document

**Accession Number:** 0001492422
**File Stem:** 0000950157-26-000479
**Filing Date:** 2026-4
**Character Count:** 7736
**Document Hash:** 03939c4366c75f73404170e3104bd653
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0000950157-26-000479.hdr.sgml**: 20260406

**ACCESSION NUMBER**: 0000950157-26-000479

**CONFORMED SUBMISSION TYPE**: 3

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260331

**FILED AS OF DATE**: 20260406

**DATE AS OF CHANGE**: 20260406

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** BIOGEN INC.
- **CENTRAL INDEX KEY:** 0000875045
- **STANDARD INDUSTRIAL CLASSIFICATION:** BIOLOGICAL PRODUCTS (NO DIAGNOSTIC SUBSTANCES) [2836]
- **ORGANIZATION NAME:** 03 Life Sciences
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** 3
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 001-38276
- **FILM NUMBER:** 26842433

**BUSINESS ADDRESS:**
- **STREET 1:** 225 BINNEY STREET
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02142
- **BUSINESS PHONE:** 7814642000

**MAIL ADDRESS:**
- **STREET 1:** 225 BINNEY STREET
- **CITY:** CAMBRIDGE
- **STATE:** MA
- **ZIP:** 02142

**FORMER NAME:**
- **FORMER CONFORMED NAME:** BIOGEN IDEC INC.
- **DATE OF NAME CHANGE:** 20070427

**FORMER NAME:**
- **FORMER CONFORMED NAME:** BIOGEN IDEC INC
- **DATE OF NAME CHANGE:** 20031112

**FORMER NAME:**
- **FORMER CONFORMED NAME:** IDEC PHARMACEUTICALS CORP / DE
- **DATE OF NAME CHANGE:** 19970530
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Apellis Pharmaceuticals, Inc.
- **CENTRAL INDEX KEY:** 0001492422
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 271537290
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 100 FIFTH AVENUE
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02451
- **BUSINESS PHONE:** 617-977-5700

**MAIL ADDRESS:**
- **STREET 1:** 100 FIFTH AVENUE
- **CITY:** WALTHAM
- **STATE:** MA
- **ZIP:** 02451

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

## FORM 3

### INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

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

---

| | | |
|:---|:---|:---|
| **1. Name and Address of Reporting Person**<sup>*</sup><br>BIOGEN INC.<br><sub>(Last) (First) (Middle)</sub><br>225 BINNEY STREET<br><sub>(Street)</sub><br>CAMBRIDGE, MA 02142<br><sub>(City) (State) (Zip)</sub> | **3. Issuer Name and Ticker or Trading Symbol**<br>Apellis Pharmaceuticals, Inc. [ APLS ] | **5. If Amendment, Date of Original Filed (Month/Day/Year)**<br>  |
| **2. Date of Event Requiring Statement (Month/Day/Year)**<br>2026-03-31 | **4. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director   [ ] 10% Owner<br>[ ] Officer (give title below)   [X] Other (specify below)<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 Beneficially Owned

---

|  |  |  |  |
| --- | --- | --- | --- |
| 1. Title of Security | 2. Amount of Securities Beneficially Owned | 3. Ownership Form | 4. Nature of Indirect Beneficial Ownership |
| Common Stock | 0<sup>(1)(2)(3)</sup> | I<sup>(1)(2)(3)</sup> | See footnotes<sup>(1)(2)(3)</sup> |
| Common Stock | 0<sup>(4)</sup> | I<sup>(4)</sup> | See footnotes<sup>(4)</sup> |

---

## Table II - Derivative Securities Beneficially Owned

---

|  |  |  |  |  |  |  |  |
| --- | --- | --- | --- | --- | --- | --- | --- |
| 1. Title of Derivative Security | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 2. Date Exercisable and Expiration Date (Month/Day/Year) | 3. Title and Amount of Underlying Securities | 3. Title and Amount of Underlying Securities | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| 1. Title of Derivative Security | Date Exercisable | Expiration Date | Title | Amount or Number of Shares | 4. Conversion or Exercise Price | 5. Ownership Form | 6. Nature of Indirect Beneficial Ownership |
| Stock Options | <sup>(5)</sup> | <sup>(5)</sup> | Common Stock | 0<sup>(5)</sup> | $0 | I<sup>(1)(2)(3)(5)</sup> | See footnotes<sup>(1)(2)(3)(5)</sup> |

---

### Footnotes:

(1) The reporting person entered into a Tender and Support Agreement, dated March 31, 2026 (the "Tender and Support Agreement") with respect to the shares of common stock, par value $0.0001 per share (the "Common Stock"), of Apellis Pharmaceuticals, Inc. (the "Issuer") held by each of (i) Morningside Venture Investments, Ltd., (ii) Cedric Francois, (iii) Gerald Chan, (iv) Alec Machiels, and (v) Pascal Deschatelets (each, a "Holder" and, collectively, the "Holders").

(2) By virtue of entering into the Tender and Support Agreement, dated March 31, 2026, with each of the Holders, the reporting person on this Form 3 may be deemed to be a member of a "group" for purposes of Section 13(d) of the Securities and Exchange Act of 1934, as amended (the "Exchange Act") with respect to the securities held by parties who continue to be bound by the Tender and Support Agreement, which such "group" beneficially owns (as defined in Section 13(d) of the Exchange Act), in the aggregate, more than 10% of the outstanding Common Stock. Pursuant to the Tender and Support Agreement, the Holders agreed to irrevocably and unconditionally appoint the reporting person, or any person designated by the reporting person, as its proxy and attorney-in-fact to vote such Holders' Common Stock for certain matters as set forth in the Tender and Support Agreement.

(3) The Tender and Support Agreement does not provide the reporting person with a pecuniary interest in the Common Stock and as such the reporting person is not a beneficial owner for purposes of Section 16 of the Exchange Act.

(4) Each of Messrs Chan, Deschatelets, Francois and Machiels holds Restricted Stock Units ("RSUs") in the amount and on the terms reported on each of Messrs Chan, Deschatelets, Francois and Machiels' past and current Form 3 and Form 4 filings with respect to the Issuer, as amended. The Tender and Support Agreement does not provide the reporting person with a pecuniary interest in the Common Stock underlying such RSUs and as such the reporting person is not a beneficial owner for purposes of Section 16 of the Exchange Act.

(5) Each of Messrs Chan, Deschatelets, Francois and Machiels holds options for Common Stock (the "Options"), which are currently outstanding and unexercised as of March 31, 2026, in the amount and on the terms reported on each of Messrs Chan, Deschatelets, Francois and Machiels' past and current Form 3 and Form 4 filings with respect to the Issuer, as amended. The Tender and Support Agreement does not provide the reporting person with a pecuniary interest in the Common Stock underlying such Options and as such the reporting person is not a beneficial owner for purposes of Section 16 of the Exchange Act.

**Signature:** /s/ Wendell Taylor, Secretary, Biogen Inc.  
**Date:** 2026-04-06

### 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.**