UNITED STATES SECURITIES AND EXCHANGE COMMISSION ATYR PHARMA, INC. (Exact name of registrant as specified in its charter) Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2019 or ☐ TRANSITION REPORT UNDER SECTION 13 OF 15(d) OR THE EXCHANGE ACT OF 1934 From the transition period from to Commission File Number 001-37378 Indicate by check mark whether the registrant is a large accelera ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 Form 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2018 ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number: 001-37378 ATYR PHARMA, INC. (Exact Name of Registrant as Specified in its Charter) (State or other jurisdiction of incorporation Delaware 20- ...