SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(D)

OF THE SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported): March 9, 2016

INTERNATIONAL STEM CELL CORPORATION

(Exact name of registrant as specified in its charter)

5950 Priestly Drive, Carlsbad, California 92008

(Address of principal executive offices, including zip code)

(760) 940-6383

(Registrant’s telephone number, including area code)

(Former name or former address, if changed since last report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

On March 9,2016, International Stem Cell, Inc. (the “Company”), entered into a Securities Purchase Agreement (the “Purchase Agreement”) with three investors, which included two institutional investors and Andrey Semechkin, the Company’s Chief Executive Officer and Co-Chairman providing for the issuance (the “Offering”) of (i) 2,000 shares of Series I-1 convertible preferred stock (the “Series I-1 Preferred Stock”) issuable to the institutional investors at a price of $1,000 per share, (ii) 4,310 shares of Series I-2 convertible preferred stock (the “Series I-2 Preferred Stock”, and together with the Series I-1 Preferred Stock, the “Preferred Stock”) issuable to Andrey Semechkin at a price of $1,000 per share, (iii) Series A Warrants (the “Series A Warrants”) to purchase up to approximately 3.6 million shares of common stock at an initial exercise price of $3.64 per share with a term of five years, (iv) Series B Warrants (the “Series B Warrants”) to purchase up to approximately 3.6 million shares of common stock at an initial exercise price of $1.75 per share with a term of six months and (v) Series C Warrants (the “Series C Warrants”, together with the Series A Warrants and the Series B Warrants, collectively, the “Investor Warrants”) to purchase up to approximately 3.6 million shares of common stock at an initial exercise price of $1.75 per share with a term of twelve months. The closing of the Offering is expected to occur on or about March 15, 2016 (the “Closing Date”), subject to satisfaction of customary closing conditions set forth in the Purchase Agreement. The Purchase Agreement also contains representations, warranties, indemnification and other provisions customary for transactions of this nature.

Rodman & Renshaw, a unit of H.C. Wainwright & Co., LLC. (the “Placement Agent”) is acting as the exclusive placement agent for the Offering pursuant to a placement agency engagement letter, dated as of March 9, 2016, by and between the Placement Agent and the Company (the “Engagement Letter”). Upon the closing of the Offering, pursuant to the Engagement Letter, the Placement Agent will receive a placement agent fee of $200,000 and a warrant to purchase approximately 343,000 shares of common stock (the “Placement Agent Warrant”, together with the Investor Warrants, the “Warrants”) as well as the reimbursement of fees and expenses up to $50,000. Similar to the Series A Warrant, the Placement Warrant will have an initial exercise price of $3.64 per share, be immediately exercisable and will terminate on five years after the date of issuance.

Subject to certain ownership limitations with respect to the Series I-1 Preferred Stock, the Preferred Stock is convertible at any time into shares of Common Stock at an initial conversion price of $1.75 per share. The Preferred Stock is non-voting, is only entitled to dividends in the event that dividends are paid on the Common Stock, and will not have any preferences over the Common Stock, except that the Preferred Stock shall have preferential liquidation rights over the Common Stock. Other than the Series I-1 Preferred Stock having a beneficial ownership limitation, the Series I-1 Preferred Stock and Series I-2 Preferred Stock are substantially identical. The conversion price of the Preferred Stock is subject to certain resets as set forth in the Certificates of Designation, including the date of any future amendment to the certificate of incorporation with respect to a reverse stock split, the effectiveness dates of the registration statements and, in certain instances, the six and twelve month anniversaries of the Closing Date.

The Warrants are immediately exercisable and the exercise price of the Warrants is subject to certain reset adjustments as set forth in the forms of Warrant, including the date of any future amendment to the Company’s certificate of incorporation with respect to a reverse stock split, the effectiveness dates of the registration statements and, in certain instances, the six and twelve month anniversaries of the date of issuance of the Warrants.

The Company has also entered into a registration rights agreement (the “Registration Rights Agreement”) with the institutional investors pursuant to which the Company is obligated to file, within forty-five calendar days of the closing of the Offering, a registration statement to register the resale of (i) 200% of the shares of Common Stock issuable upon conversion of the Preferred Stock sold to the institutional investors, (ii) 100% of the shares of Common Stock issuable upon exercise of the Series A Warrants held by the institutional investors, and (iii) 200% of the shares of Common Stock issuable upon exercise of the Series B Warrants and Series C Warrants held by the institutional investors. Additionally, the Registration Rights Agreement provides for certain monetary penalties if

the registration statements are not filed or declared effective prior to certain dates as set forth in the Registration Rights Agreement.

The foregoing descriptions of the Purchase Agreement, the Registration Rights Agreement, Placement Agent Agreement, the Series I-1 Preferred Stock, the Series I-2 Preferred Stock and the Warrants are subject to, and qualified in their entirety by, such documents attached hereto as Exhibits 10.1, 10.2, 10.3, 3.1, 3.2, 4.1, 4.2, 4.3 and 4.4, respectively, which are incorporated herein by reference.

The shares of Preferred Stock and Warrants described above have not been registered under the Securities Act of 1933, as amended. The issuance and sale of the Preferred Stock and the Warrants by the Company under the Purchase Agreement is exempt from registration pursuant to Section 4(a)(2) of the Securities Act of 1933, as amended and Rule 506(b) promulgated thereunder. The information contained above in Item 1.01 is hereby incorporated by reference into this Item 3.02.

The Company intends to file prior to the Closing Date, the Certificate of Designation of Preferences, Rights and Limitations of Series I-1 Convertible Preferred Stock and the Certificate of Designation of Preferences, Rights and Limitations of Series I-2 Convertible Preferred Stock (together the “Certificates of Designation”) with the Secretary of State of the State of Delaware, establishing and designating the Series I-1 Preferred Stock and the Series I-2 Preferred Stock. Each share of Series I-1 Preferred Stock and Series I-2 Preferred Stock has a stated value of $1,000. Each share of Series I-1 Preferred Stock and Series I-2 Preferred Stock is convertible, at any time at the option of the holder thereof, into a number of shares of Common Stock determined by dividing the stated value by the initial conversion price of $1.75 per share, subject to certain adjustments and subject to a 9.99% blocker provision with respect to the Series I-1 Preferred Stock. The Series I-1 Preferred Stock and the Series I-2 Preferred Stock have no dividend rights, liquidation preferences or other preferences over Common Stock and have no voting rights except as required by law. Copies of the Certificates of Designation are attached hereto as Exhibits 3.1 and 3.2 and incorporated herein by reference. The foregoing descriptions of the Certificates of Designation are qualified in their entirety by reference to Exhibits 3.1 and 3.2 attached hereto.

Prior to the Closing Date, the Company intends to file Certificates of Designation, forms of which are attached hereto as Exhibits 3.1 and 3.2, and incorporated herein by reference. As discussed in Item 3.03, the Certificates of Designation establish and designate the Series I-1 Preferred Stock and the Series I-2 Preferred Stock, and the rights, preferences, privileges and limitations thereof.

On March 10, 2016, the Company issued a press release announcing the Offering. The Company’s press release is attached hereto as Exhibit 99.1 and is incorporated herein by reference.

Safe Harbor Statement

Statements in this report that are not strictly historical in nature constitute “forward-looking statements.” Such statements include, but are not limited to, the Company’s issuance of securities, the amount of proceeds from the Offering and the closing of the Offering. Such forward-looking statements involve known and unknown risks, uncertainties and other factors that may cause actual results to be materially different from any results expressed or implied by such forward-looking statements. All forward-looking statements are qualified in their entirety by this cautionary statement. The Company is providing this information as of this date and does not undertake any obligation to update any forward-looking statements contained in this report as a result of new information, future events or otherwise.

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

Dated: March 9, 2016