About Us

aTyr’s mission is to translate novel biological pathways into innovative therapeutics for improved patient outcomes.

Our focus is on the extracellular functionality and signaling pathways of tRNA synthetases. Built on more than a decade of foundational science, we have built a global intellectual property estate directed to all 20 human tRNA synthetases and certain associated signaling pathways, with over 300 protein compositions patented.

Our lead clinical product candidate, efzofitimod (ATYR1923), is a selective modulator of Neuropilin-2 (NRP2) that downregulates innate and adaptive immune responses in uncontrolled inflammatory disease states. We are developing efzofitimod as a potential disease-modifying therapy for patients with severe inflammatory lung diseases with high unmet medical need. This includes interstitial lung disease (ILD), a group of rare immune-mediated disorders that can cause progressive fibrosis of the lung. We selected pulmonary sarcoidosis, a major form of ILD, as our first clinical indication. Close to 200,000 people in the United States lives with pulmonary sarcoidosis, which occurs in more than 90% of sarcoidosis cases, and efzofitimod has been granted orphan drug designation for the treatment of sarcoidosis.

We recently reported positive results from a Phase 1b/2a multi-center clinical trial of efzofitimod in patients with pulmonary sarcoidosis. The study was designed primarily to evaluate the safety, tolerability, and immunogenicity of multiple doses of efzofitimod and secondarily to assess preliminary clinical activity by investigating effects on steroid-sparing, established clinical endpoints and certain biomarkers. The study met its primary safety endpoint, with efzofitimod determined to be safe and well-tolerated at all doses with no drug-related serious adverse events or signal of immunogenicity. Additionally, the study demonstrated consistent dose response for efzofitimod on key efficacy endpoints and improvements compared to placebo, including measures of steroid reduction, lung function, sarcoidosis symptom measures and inflammatory biomarkers. The results of the study provide clinical proof-of-concept for efzofitimod, as well as validation for our tRNA synthetase biology platform and NRP2 as a target. The results support advancement of efzofitimod in pulmonary sarcoidosis and we expect to initiate a registrational trial in 2022. The results also support expansion to investigate efzofitimod in other forms of ILD with high unmet need, such as chronic hypersensitivity pneumonitis and connective tissue disease-related ILD.

Our lead preclinical candidate, ATYR2810, is a fully humanized monoclonal antibody that specifically and functionally blocks the interaction between NRP2 and one of its primary ligands, VEGF. NRP2 is highly expressed on certain tumors and increased NRP2 expression is associated with resistance to current therapies, metastasis and worsened overall survival in some cancers. The role of NRP2 and VEGF signaling in the tumor microenvironment and its importance in the progression of certain aggressive cancers is becoming increasingly validated. ATYR2810 is in preclinical development for the potential treatment of certain aggressive solid tumors where NRP2 is implicated.

We are also advancing our preclinical pipeline of tRNA synthetases and NRP2 targeting antibodies through internal research efforts and academic collaborations. We recently identified new receptor targets for two tRNA synthetases which may have utility treatment of cancer, fibrosis and inflammation.

Our Values

Patients First

We are guided by our focus on patients


We are data-driven and embrace the unfamiliar


We achieve quality results with a foundation of trust, honesty and consistency with our words, plans and actions

Courage and Humility

We are a passionate team that acts with determination and mutual respect


We are efficient with our time and resources, learning and adapting to an always changing environment