The release of study abstracts for next month's American Society of Clinical Oncology, or ASCO, conference drove significant moves tonight in drugmakers including Incyte (INCY), but Piper Jaffray urged caution on the company's data, saying its "not sure what other investors are seeing that we aren't."

PIPER REACTS TO ASCO ABSTRACTS: Weighing in on tonight's study abstracts, Piper Jaffray analyst Joshua Schimmer argues that Nektar (NKTR), Lion Bio (LBIO), bluebird (BLUE) and oncolytic therapies look like early winners but says he's "more cautious" on Incyte despite the stock's sharp move higher. Explaining his reaction to Incyte, Schimmer says "it takes about 5 minutes of cross checking" to see that, across most tumor types, the responses from epacadostat in combination with Merck's (MRK) PD-1 product are generally what one would expect from a PD-1 therapy alone. The high responses in melanoma are an exception but the analyst cautions they are "very preliminary and likely to fall" over time, adding that while Incyte is one of his "favorite" names in biotech, he doesn't view its current valuation favorably.

Turning to his winners for the night, Schimmer calls the Lion Bio results "not bad" and says bluebird's data is "looking good." On oncolytics, the analyst argues that Amgen's (AMGN) study of Imlygic in combination with ipilimumab "showed meaningful improvement" over ipilimumab alone on several metrics, which he says bodes well for the numerous oncolytic products on the horizon.

PRICE ACTION: Shares of Incyte are up 9.76% to $132.25 in after-hours trading, while bluebird has pared its earlier dip and is down just 0.2%. Among other movers after tonight's wave of abstracts, CytRx (CYTR) is up 16.9%, Leap (LPTX) is up 13.2%, and NewLink Genetics (NLNK) is down 13.4%.