Shares of Celldex Therapeutics (NASDAQ: CLDX) were tanking 34.1% as of 11:56 a.m. EDT on Monday. The big decline came after Celldex announced interim results from a phase 1b study of CDX-0159 in treating patients with chronic inducible urticaria (CIndU), severe hives that affect around 0.5% of the population.
Celldex reported that eight of the 10 patients who were assessed for at least 15 days after treatment with CDX-0159 experienced a complete response. One of the patients experienced a partial response. That sounds like great news, so why did the biotech stock sink?
It could be that investors are concerned about the safety profile for CDX-0159. Celldex stated that the drug “was generally well-tolerated.” However, the company also said that one patient experienced a severe reaction with a “brief loss of consciousness, followed by shaking and sweating.” This patient was treated with antihistamines and steroids, and recovered quickly.