UNITY Biotechnology’s first lead candidate, UBX0101, was designed to treat osteoarthritis. It was unusual amongst senolytic small molecules as an inhibitor of the p53/MDM2 protein interaction. Disruption of this protein interaction triggers the destruction of senescent cells.

The U.S. FDA cleared an Investigational New Drug (IND) application for UBX0101, and UNITY initiated a Phase I clinical trial in osteoarthritis of the knee in the second quarter of 2018. The drug was delivered locally via intra-articular injection. Initial results from the Phase I study were positive, with clinically significant improvements in patients with osteoarthritis.

Unfortunately, as of August 2020, following disappointing results from the Phase II osteoarthritis human trial, UNITY discontinued the development of UBX0101. The company stated its intention to complete collection of the Phase 2 24-week data, as well as that from the ongoing Phase 1b high-dose, repeat-dose study in the second half of 2020; it is not clear if these were publicly reported. In any event, the drug’s development was abandoned.