Piper Jaffray analyst Steven Breazzano said the rucaparib response rates in platinum resistant and platinum refractory patients of 25% and 0%, respectively, reported by Clovis Oncology (CLVS) are lower than some may have been expecting and "seemingly negative on the surface." However, he continues to believe rucaparib will be approved in BRCA patients who have received 2+ lines of therapy, which is an earlier and broader patient population than assigned to competitor AstraZeneca's (AZN) Lynparza, he tells investors. The ultimate market potential and key to success is the maintenance setting, for which TESARO's (TSRO) niraparib is still best-positioned, adds Breazzano, who keeps a Neutral rating on Clovis shares.

Bearish flow noted in AstraZeneca with 3,362 puts trading, or 1.7x expected. Most active are 4/26 weekly 70 puts and May-24 70 calls, with total volume in those strikes near 3,600 contracts. The Put/Call Ratio is 1.72, while ATM IV is up nearly 2 points on the day. Earnings are expected on April 25th.