Sunesis tanks as it pulls plug on vecabrutinib program

Shares of US drug developer Sunesis Pharmaceuticals (Nasdaq: SNSS) plunged 43% to $0.35 by close of trading Tuesday, after it revealed it will not advance its non-covalent BTK inhibitor vecabrutinib into the planned Phase II portion of the Phase Ib/ii trial in adults with relapsed/refractory chronic lymphocytic leukemia (CLL) and other B-cell malignancies.

The decision was made after assessing the totality of the data including the 500mg cohort, the highest dose studied in the trial, and the stock fell a further 5% pre-market today.

“Although vecabrutinib continues to exhibit an excellent safety profile, there is insufficient evidence of activity in BTK-inhibitor resistant B-cell malignancies to advance the drug into the planned Phase II portion of the trial. One partial remission was observed after 11 treatment cycles in a CLL patient treated in Cohort 5 (300 mg BID) and a number of patients treated across the dose range explored (25mg to 500mg BID) saw stable disease; however, no other remissions have been observed,” said Dayton Misfeldt, interim chief executive of Sunesis. “We will complete the Phase Ib and evaluate the best path forward for vecabrutinib. We are grateful for the patients and their families who participated in this trial, as well as the investigators and research staff at our trial sites.”