# EDGAR Filing Document

**Accession Number:** 0001061983
**File Stem:** 0001061983-26-000071
**Filing Date:** 2026-6
**Character Count:** 7036
**Document Hash:** 9aec723371d77129d93b652326ae2d20
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001061983-26-000071.hdr.sgml**: 20260629

**ACCESSION NUMBER**: 0001061983-26-000071

**CONFORMED SUBMISSION TYPE**: 4

**PUBLIC DOCUMENT COUNT**: 1

**CONFORMED PERIOD OF REPORT**: 20260624

**FILED AS OF DATE**: 20260629

**DATE AS OF CHANGE**: 20260629

**REPORTING-OWNER**: 

**OWNER DATA:**
- **COMPANY CONFORMED NAME:** Lee Sung
- **CENTRAL INDEX KEY:** 0001793200

**ORGANIZATION NAME:**

**FILING VALUES:**
- **FORM TYPE:** 4
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 000-50633
- **FILM NUMBER:** 261137280

**MAIL ADDRESS:**
- **STREET 1:** 7000 MARINA BLVD
- **CITY:** BRISBANE
- **STATE:** CA
- **ZIP:** 94005
**ISSUER**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** CYTOKINETICS INC
- **CENTRAL INDEX KEY:** 0001061983
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 943291317
- **FISCAL YEAR END:** 1231

**BUSINESS ADDRESS:**
- **STREET 1:** 350 OYSTER POINT BOULEVARD
- **STREET 2:** .
- **CITY:** SOUTH SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94080
- **BUSINESS PHONE:** (650) 624-3000

**MAIL ADDRESS:**
- **STREET 1:** 350 OYSTER POINT BOULEVARD
- **CITY:** SOUTH SAN FRANCISCO
- **STATE:** CA
- **ZIP:** 94080

### 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).

[x] 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>Lee Sung<br><sub>(Last) (First) (Middle)</sub><br>350 OYSTER POINT BLVD<br><sub>(Street)</sub><br>SOUTH SAN FRANCISCO, CA 94080<br><sub>(City) (State) (Zip)</sub> | **3. Date of Earliest Transaction (Month/Day/Year)**<br>2026-06-24 | **5. Relationship of Reporting Person(s) to Issuer**<br>(Check all applicable)<br>[ ] Director [ ] 10% Owner<br>[X] Officer (give title below) [ ] Other (specify below)<br>_EVP, Chief Financial Officer_ |
| **2. Issuer Name and Ticker or Trading Symbol**<br>CYTOKINETICS INC [ CYTK ] | **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 | 2026-06-24 |  | M |  | 23370 | A | $48.51 | 86591 | D |  |
| Common Stock | 2026-06-24 |  | M |  | 9307 | A | $44.36 | 95898 | D |  |
| Common Stock | 2026-06-24 |  | M |  | 2817 | A | $44.36 | 98715 | D |  |
| Common Stock | 2026-06-24 |  | M |  | 1113 | A | $48.51 | 99828 | D |  |
| Common Stock | 2026-06-24 |  | M |  | 188 | A | $44.36 | 100016 | D |  |
| Common Stock | 2026-06-24 |  | M |  | 822 | A | $44.36 | 100838 | D |  |
| Common Stock | 2026-06-24 |  | M |  | 1113 | A | $48.51 | 101951 | D |  |
| Common Stock | 2026-06-24 |  | S |  | 38730 | D | $82.30 | 63221 | D |  |

---

## 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 |
| Non-Qualified Stock Option (Right to Buy) | $48.51 | 2026-06-24 |  | M |  |  | 23370 | 2025-06-02 | 2034-05-30 | Common Stock | 23370 | $0 | 30047 | D |  |
| Non-Qualified Stock Option (Right to Buy) | $44.36 | 2026-06-24 |  | M |  |  | 9307 | 2025-04-14 | 2035-03-13 | Common Stock | 9307 | $0 | 32019 | D |  |
| Incentive Stock Option (Right to Buy) | $44.36 | 2026-06-24 |  | M |  |  | 2817 | 2025-04-14 | 2035-03-13 | Common Stock | 2817 | $0 | 6199 | D |  |
| Non-Qualified Stock Option (Right to Buy) | $48.51 | 2026-06-24 |  | M |  |  | 1113 | 2025-06-02 | 2034-05-30 | Common Stock | 1113 | $0 | 28934 | D |  |
| Incentive Stock Option (Right to Buy) | $44.36 | 2026-06-24 |  | M |  |  | 188 | 2025-04-14 | 2035-03-13 | Common Stock | 188 | $0 | 6011 | D |  |
| Non-Qualified Stock Option (Right to Buy) | $44.36 | 2026-06-24 |  | M |  |  | 822 | 2025-04-14 | 2035-03-13 | Common Stock | 822 | $0 | 31197 | D |  |
| Non-Qualified Stock Option (Right to Buy) | $48.51 | 2026-06-24 |  | M |  |  | 1113 | 2025-06-02 | 2034-05-30 | Common Stock | 1113 | $0 | 27821 | D |  |

---

**Signature:** /s/ John O. Faurescu, attorney-in-fact for Mr. Lee  
**Date:** 2026-06-29

### 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.**