The Food and Drug Administration (FDA) has granted Orphan Drug designation to efzofitimod (ATYR1923) for the treatment of systemic sclerosis.

Efzofitimod is a potential first-in-class selective modulator of neuropilin-2 that is designed to downregulate innate and adaptive immune responses in inflammatory disease states. The investigational drug is a fusion protein comprised of the immunomodulatory domain of histidyl-tRNA synthetase fused to the FC region of a human antibody. In preclinical studies, efzofitimod was found to prevent inflammation and fibrosis in multiple animal models of systemic sclerosis and idiopathic pulmonary fibrosis.

“The data we have presented in animal models of [systemic sclerosis] along with the positive findings reported from our recent phase 1b/2a study in pulmonary sarcoidosis patients suggest that efzofitimod has the potential to be a new treatment option that resolves inflammation and subsequent fibrosis in those living with [systemic sclerosis-associated ILD],” said Sanjay S. Shukla, MD, MS, President and CEO of aTyr. “We look forward to exploring the potential expansion of our efzofitimod clinical program into other forms of ILD with high unmet need where this novel therapeutic may be able to improve patient outcomes.”

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The Company plans to initiate a registrational study evaluating efzofitimod in pulmonary sarcoidosis in the third quarter of 2022.


  1. aTyr Pharma announces FDA Orphan Drug designation for efzofitimod (ATYR1923) for treatment of systemic sclerosis. News release. aTyr Pharma, Inc. Accessed April 13, 2022.
  2. R&D: Efzofitimod (ATYR1923). aTyr Pharma, Inc. Accessed April 13, 2022.

This article originally appeared on MPR