Citi analyst Yigal Nochomovitz recommends using this morning's selloff in shares of Puma Biotechnology (PBYI) as a buying opportunity. The stock in pre-market trading is down 24%, or $9.25, to $28.80. The Roche (RHHBY) press release does not provide any numbers on magnitude of benefit or any details on benefit in subgroups, Nochomovitz tells investors in a research note after the Aphinity trial met its endpoint. The analyst adds that today's press release does not definitively state Roche will be filing on the data, rather noting that, "These data will be discussed with health authorities across the world, including the US FDA with the hope to convert the current US accelerated approval to a full approval." It is hard to ignore the word choice of "hope" as opposed to "expectation," Nochomovitz contends. He continues to expect Puma's neratinib to receive FDA approval by the action date in July for extended adjuvant. The analyst said he sees "significant upside" in the shares. Further, Nochomovitz thinks Puma's breast cancer opportunities outside of adjuvant can justify the current valuation without any extended adjuvant revenue. He has a Buy rating on Puma with an $88 price target.