
Shares of drug developer Compass Therapeutics CMPX.O fall 14.5% to $1.62
CMPX says its experimental biliary tract cancer drug, tovecimig, when combined with chemotherapy, showed an overall response rate (ORR) of 17.1% in patients compared to 5.3% who received chemotherapy alone
ORR is the proportion of patients whose tumors reduced in size or disappeared over a predefined period of time
Brokerage Leerink Partners says this response rate is lower than expected, and lower than what was seen in previous trials
Other treatments, such as Enhertu by AstraZeneca AZN.L and Pemazyre by Incyte INCY.O, have shown higher response rates in similar patient populations, brokerage says
Including sessions moves, CMPX stock up 31% YTD