UNITY Biotechnology: using repurposed chemotherapeutic drugs like navitoclax to selectively drive senescent cells into apoptosis by suppressing on the mechanisms that prevents that fate. They also have antibodies and immunotherapies in their backlog of patents, but if they haven't got it to work by now, not likely to be a direction they take in favor of the drugs.
Oisin Biotechnologies: programmed gene therapy that assesses p16 levels in the cell and then induces caspase expression and apoptosis if it looks senescent.
SIWA Therapeutics: monoclonal antibodies.
Everon Biosciences: small molecule drugs and related immunotherapies.
There is a lot of money sloshing into the field of senescent cell clearance at the moment, and given that the target market is ultimately every adult human for a treatment undertaken every few years, I think there is plenty of room for more players.