As filed with the Securities and Exchange Commission on July 19, 2017

Registration No. 333-

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

FORM S-1

REGISTRATION STATEMENT 
UNDER THE SECURITIES ACT OF 1933

CYCLACEL PHARMACEUTICALS, INC.

(Exact name of registrant as specified in its charter)

200 Connell Drive, Suite 1500 
Berkeley Heights, NJ 07922 
(908) 517-7330 
(Address, including zip code, and telephone number, including area code, of registrant’s principal executive offices)

Spiro Rombotis 
Chief Executive Officer 
Cyclacel Pharmaceuticals, Inc. 
200 Connell Drive, Suite 1500 
Berkeley Heights, NJ 07922 
(908) 517-7330 
(Name, address, including zip code, and telephone number, including area code, of agent for service)

With copies to:

If any of the securities being registered on this Form are to be offered on a delayed or continuous basis pursuant to Rule 415 under the Securities Act of 1933, check the following box: ¨

If this Form is filed to register additional securities for an offering pursuant to Rule 462(b) under the Securities Act, please check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering:  x  File No. 333-218305

If this Form is a post-effective amendment filed pursuant to Rule 462(c) under the Securities Act, check the following box and list the Securities Act registration statement number of the earlier effective registration statement for the same offering: ¨

If this Form is a registration statement pursuant to General Instruction I.D. or a post-effective amendment thereto that shall become effective upon filing with the Commission pursuant to Rule 462(d) under the Securities Act, check the following box: ¨

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company. See the definitions of  “large accelerated filer,” “accelerated filer,” and “smaller reporting company” in Rule 12b-2 of the Exchange Act. (Check one):

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter). ¨

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ¨

CALCULATION OF REGISTRATION FEE

(1)Estimated solely for the purpose of computing the amount of the registration fee pursuant to Rule 457(o) under the Securities Act of 1933, as amended (the “Securities Act”).

(2)Includes the price of additional shares of common stock and warrants to purchase shares of common stock that the underwriters have the option to purchase to cover over-allotments, if any.

(3)No separate fee is required pursuant to Rule 457(i) under the Securities Act.

This Registration Statement shall become effective upon filing with the Securities and Exchange Commission in accordance with Rule 462(b) promulgated under the Securities Act of 1933, as amended.

EXPLANATORY NOTE AND INCORPORATION OF
CERTAIN INFORMATION BY REFERENCE

This Registration Statement is being filed with the Securities and Exchange Commission (the “Commission”) pursuant to Rule 462(b) under the Securities Act of 1933, as amended. This Registration Statement incorporates by reference the contents of, including all amendments and exhibits thereto and all information incorporated by reference therein, the Registration Statement on Form S-1 (Registration No. 333-218305), which was declared effective by the Commission on July 18, 2017, and is being filed solely for the purpose of registering an increase in the maximum aggregate offering price of $5,060,000. The required opinions and consents are listed on the Exhibit Index attached hereto.

SIGNATURES

Pursuant to the requirements of the Securities Act of 1933, as amended, the Registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized in the City of Berkeley Heights, State of New Jersey, on July 19, 2017.

Pursuant to the requirements of the Securities Act of 1933, as amended, this registration statement has been signed by the following persons in the capacities and as of the dates indicated.

EXHIBIT INDEX

*Filed herewith.