RA Capital cashes out Cidara (NASDAQ: CDTX) in Merck tender offer

Rhea-AI Filing Summary

RA Capital Healthcare Fund, advised by RA Capital Management, fully exited its Cidara Therapeutics (CDTX) position in connection with Merck’s acquisition. Pre-funded warrants for 1,286,786 common shares were cashless exercised into common stock immediately before the merger. The Fund then disposed of 4,652,309 Cidara common shares at $221.50 per share in the tender offer. It also disposed of 89,956 Series A Preferred shares, which were exchanged for $15,505.00 per Series A share under the merger terms.

Outstanding stock options covering 22,200 and 5,079 common shares became fully vested and were cancelled at the merger’s effective time in return for cash based on the $221.50 per-share merger price minus the applicable exercise prices. The Form 4 notes that the reported securities are held by the Fund and that RA Capital entities and principals disclaim beneficial ownership except for their pecuniary interests.

SEC Form 4

FORM 4

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

STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940

OMB APPROVAL

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X

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

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^*

RA CAPITAL MANAGEMENT, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

2. Issuer Name and Ticker or Trading Symbol
Cidara Therapeutics, Inc. [ CDTX ]

5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

3. Date of Earliest Transaction (Month/Day/Year)
01/07/2026

4. If Amendment, Date of Original Filed (Month/Day/Year)

6. Individual or Joint/Group Filing (Check Applicable Line)

	Form filed by One Reporting Person
X	Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price
Common Stock	01/07/2026		M(1)		1,286,786	A	$0.0001	4,652,309	I	See footnotes(2)(3)
Common Stock	01/07/2026		D(4)(5)(6)		4,652,309	D	$221.5	0	I	See footnotes(2)(3)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Option (right to buy)	$26.62	01/07/2026		D			22,200	(7)	01/02/2035	Common Stock	22,200	(7)	0	I	See footnotes(2)(8)
Stock Option (right to buy)	$21.31	01/07/2026		D			5,079	(7)	06/17/2035	Common Stock	5,079	(7)	0	I	See Footnotes(2)(8)
Pre-Funded Warrants (Right to Buy)	$0.0001	01/07/2026		M(1)			1,286,786	(9)	(9)	Common Stock	1,286,786	(7)	0	I	See footnotes(2)(3)
Series A Preferred Stock	(10)	01/07/2026		D(4)(5)(6)			89,956	(7)	(10)	Common Stock	6,296,920	$15,505	0	I	See footnotes(2)(3)

1. Name and Address of Reporting Person^*

RA CAPITAL MANAGEMENT, L.P.

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

RA Capital Healthcare Fund LP

(Last) (First) (Middle)

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Kolchinsky Peter

(Last) (First) (Middle)

C/O RA CAPITAL MANAGEMENT, L.P.

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

1. Name and Address of Reporting Person^*

Shah Rajeev M.

(Last) (First) (Middle)

C/O RA CAPITAL MANAGEMENT, L.P.

200 BERKELEY STREET, 18TH FLOOR

(Street)

BOSTON MA 02116

(City) (State) (Zip)

Relationship of Reporting Person(s) to Issuer

X	Director	X	10% Owner
	Officer (give title below)		Other (specify below)

Explanation of Responses:

1. Pursuant to the Merger Agreement (as defined below), Pre-Funded Warrants that were outstanding and unexercised as of immediately prior the effective time of the Merger (as defined below) were treated as being simultaneously cashless exercised in accordance with their terms, subject to any applicable withholding of taxes.

2. RA Capital Management, L.P. (the "Adviser") is the investment manager for RA Capital Healthcare Fund, L.P. (the "Fund"). The general partner of the Adviser is RA Capital Management GP, LLC (the "Adviser GP"), of which Dr. Peter Kolchinsky and Mr. Rajeev Shah are the managing members. Each of the Adviser, the Adviser GP, Dr. Kolchinsky, and Mr. Shah disclaims beneficial ownership of any of the reported securities, except to the extent of its or his respective pecuniary interest therein.

3. Held directly by the Fund.

4. Pursuant to the Agreement and Plan of Merger (the "Merger Agreement"), dated November 13, 2025, by and among Cidara Therapeutics, Inc. (the "Issuer"), Merck Sharp & Dohme LLC ("Merck") and Caymus Purchaser, Inc., a wholly owned subsidiary of Merck ("Purchaser"), on January 7, 2026, Purchaser completed a tender offer to acquire (i) all outstanding shares of common stock of the Issuer, par value $0.0001 per share (each, a "Common Share") and (ii) all outstanding shares of Series A Convertible Voting Preferred Stock of the Issuer, par value $0.0001 per share (each, a "Series A Share"), and thereafter merged with and into the Issuer, with the Issuer continuing as the surviving corporation and a wholly owned subsidiary of Merck (the "Merger").

5. (Continued from Footnote 4) Pursuant to the terms of the Merger Agreement, Common Shares and Series A Shares were tendered and disposed of at the Offer Acceptance Time (as defined in the Merger Agreement) in exchange for the right to receive (i) $221.50 per Common Share (the "Common Share Merger Consideration"), in cash, without interest, subject to any applicable withholding of taxes, and (ii) $15,505.00 per Series A Share (the "Series A Merger Consideration"), in cash, without interest, subject to any applicable withholding of taxes.

6. (Continued from Footnote 5) At the effective time of the Merger, each issued and outstanding Common Share and Series A Share (other than Common Shares (a) held by the Issuer (or in the Issuer's treasury), Merck, Purchaser, any other direct or indirect wholly owned subsidiary of Merck or the Issuer, or by stockholders of the Issuer who have properly exercised and perfected their statutory rights of appraisal, or (b) irrevocably accepted for purchase in the tender offer) was automatically canceled and converted into the right to receive the Common Share Merger Consideration and the Series A Merger Consideration, respectively, without interest and subject to any applicable withholding of taxes.

7. As of immediately prior to and contingent upon the occurrence of the effective time of the Merger, pursuant to the Merger Agreement, each outstanding option became fully vested and exercisable, and to the extent outstanding and unexercised as of immediately before the effective time of the Merger, was cancelled at the effective time of the Merger and converted into the right to receive cash, without interest, subject to any applicable withholding of taxes, in an amount equal to the product of (i) the total number of Common Shares subject to such option immediately prior to the effective time of the Merger multiplied by (ii) the excess of (x) $221.50 per Common Share over (y) the exercise price payable per Common Share under such option.

8. Joshua Resnick is a Partner of the Adviser who serves on the Issuer's board of directors. Under Dr. Resnick's arrangement with the Adviser, Dr. Resnick holds the option for the benefit of the Fund. Dr. Resnick is obligated to turn over to the Adviser any net cash or stock received upon exercise of the option, which will offset advisory fees owed by the Fund to the Adviser. The Reporting Persons therefore disclaim beneficial ownership of the option and underlying common stock.

9. The Pre-Funded Warrants had no expiration date and were exercisable immediately. Notwithstanding the foregoing, the Reporting Persons were not entitled to exercise the Pre-Funded Warrants to the extent that such exercise would cause the aggregate number of Common Shares beneficially owned by the Reporting Persons, their affiliates and any persons who are members of a Section 13(d) group with the Reporting Persons or their affiliates to exceed 9.99% of the total number of issued and outstanding Common Shares of the Issuer following such exercise.

10. Each share of Series A Preferred Stock was convertible at any time at the option of the holder into a number of shares of common stock equal to the quotient of (A) $1,000, plus all declared and unpaid dividends, divided by (B) the Conversion Price of $14.20 per share of common stock, subject to appropriate adjustment in the event of any stock dividend, stock split, combination or other similar recapitalization, rounded down to the nearest whole share of common stock, for no additional consideration; except that the holder did not have the right to convert any portion of the Series A Preferred Stock such that the holder would beneficially own in excess of 9.99% of the shares of common stock outstanding immediately after giving effect to such conversion. The Series A Preferred Stock had no expiration date.

Remarks:

Joshua Resnick, a Partner of the Adviser, serves on the Issuer's board of directors.

	/s/ Peter Kolchinsky, Manager of RA Capital Management, L.P.	01/09/2026
	/s/ Peter Kolchinsky, Manager of RA Capital Healthcare Fund GP, LLC the General Partner of RA Capital Healthcare Fund, L.P.	01/09/2026
	/s/ Peter Kolchinsky, individually	01/09/2026
	/s/ Rajeev Shah, individually	01/09/2026
	** Signature of Reporting Person	Date
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FAQ

What does the RA Capital Form 4 for Cidara Therapeutics (CDTX) report?

The Form 4 reports that RA Capital Healthcare Fund, L.P., advised by RA Capital Management, L.P., exited its Cidara position in connection with Merck’s acquisition. Pre-funded warrants were exercised into common stock and all reported common and Series A Preferred shares, as well as related stock options, were cashed out under the merger terms.

How many Cidara (CDTX) common shares did RA Capital’s fund tender, and at what price?

The Fund disposed of 4,652,309 Cidara Therapeutics common shares in the transaction. Under the merger agreement, each common share was exchanged for $221.50 in cash, without interest, subject to applicable tax withholding.

What happened to RA Capital’s pre-funded warrants in Cidara Therapeutics (CDTX)?

Pre-funded warrants representing 1,286,786 Cidara common shares were treated, under the merger agreement, as being simultaneously cashless exercised immediately prior to the effective time of the merger, resulting in the issuance of the same number of common shares subject to tax withholding.

How were Cidara (CDTX) Series A Preferred shares held by RA Capital’s fund treated in the Merck deal?

The Form 4 shows 89,956 shares of Series A Preferred Stock disposed of. Under the merger agreement, each Series A share was exchanged for $15,505.00 in cash, without interest, subject to applicable tax withholding.

What happened to the stock options reported in the RA Capital Form 4 for Cidara (CDTX)?

Options covering 22,200 and 5,079 Cidara common shares became fully vested immediately prior to the merger’s effective time. Any such options that remained unexercised were then cancelled and converted into a right to receive cash equal to the number of shares under the option multiplied by the excess of $221.50 per share over the option’s exercise price.

Who is Joshua Resnick and how do the options relate to RA Capital in this Cidara (CDTX) filing?

Joshua Resnick is a Partner of RA Capital Management who serves on Cidara’s board. The footnotes state that he holds the options for the benefit of the Fund and must turn over any net cash or stock from option exercises to the Adviser, which offsets advisory fees owed by the Fund.

Do RA Capital and its principals claim full beneficial ownership of the Cidara (CDTX) securities in this Form 4?

No. The footnotes explain that RA Capital Management, L.P., its general partner, and principals Peter Kolchinsky and Rajeev Shah each disclaim beneficial ownership of the reported securities, except to the extent of their respective pecuniary interests. The securities are held directly by RA Capital Healthcare Fund, L.P..