UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-Q/A

(Amendment No. 1)

For the quarterly period ended March 31, 2015

For the transition period from              to             

Commission File Number: 001-36721

Coherus BioSciences, Inc.

(Exact name of registrant as specified in its charter)

201 Redwood Shores Parkway, Suite 200

Redwood City, California 94065

(650) 649-3530

(Address, including zip code, and telephone number, including area code, of Registrant’s principal executive offices)

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days.    Yes  x    No  ¨

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files).    Yes  x    No  ¨

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

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act).    Yes  ¨    No  x

As of April 30, 2015, 37,841,347 shares of the registrant’s common stock were outstanding.

EXPLANATORY NOTE

Coherus BioSciences, Inc., or the “Company”, is filing this amendment (the “Form 10-Q/A”) to our Quarterly Report on Form 10-Q for the quarter ended March 31, 2015 (the “Form 10-Q”), filed with the U.S. Securities and Exchange Commission on May 11, 2015, solely to amend Item 6 Exhibit Index of the Form 10-Q and re-file the agreements identified as Exhibit 10.2(a) and 10.2(b) to the Form 10-Q. The Company has made no further changes to the Form 10-Q.

This Form 10-Q/A should be read in conjunction with the original Form 10-Q, which continues to speak as of the date of the Form 10-Q. Except as specifically noted above, this Form 10-Q/A does not modify or update disclosures in the Form 10-Q. Accordingly, this Form 10-Q/A does not reflect events occurring after the filing of the Form 10-Q or modify or update any related or other disclosures.

2

ITEM 6. EXHIBITS

3

SIGNATURES

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

4

INDEX TO EXHIBITS

5