H.C. Wainwright analyst Debjit Chattopadhyay views the selloff today in shares of Global Blood Therapeutics as a buying opportunity. The analyst highlights "key mechanistic differences "between senicapoc and sildenafil, which he notes are often highlighted to further the bear argument of potentially increased risk of vaso-occlusive crisis with Global Blood's potential sickle cell disease treatment voxelotor. Unlike both senicapoc and sildenafil, 12-weeks treatment with voxelotor has translated into numerically fewer VOC events in Phase 2, Chattopadhyay tells investors in a research note titled "It's Deja Vu All Over Again." The analyst thinks Sarepta Therapeutics' (SRPT) Exnodys 51 approval "saga could serve as a good reference for voxelotor." While admitting he's not privy to the ongoing discussions between the FDA and Global Blood, Chattopadhyay continues to believe the agency is likely to embrace alternative endpoints over VOC as key secondary endpoints to the proposed confirmatory study for voxelotor. He continues to expect a potential rolling new drug application submission during mid-2019, with one-year safety data to be included as data matures. The analyst keeps a Buy rating on Global Blood Therapeutics with a $125 price target. The stock in late morning trading is down 9.5%, or $4.38, to $41.58 after STAT's Adam Feuerstein wrote the company's FDA filing plan "is riskier than you think."