Let's take a look at today's top stories in biotech and health care. Keep an eye out for AstraZeneca (NYSE:AZN)Clovis Oncology (NASDAQ:CLVS), and Incyte Corporation (NASDAQ:INCY)

Will AstraZeneca and Clovis get an ASCO lift today?
Shares of Clovis Oncology shot up close to 9% in after-hours trading yesterday after an abstract for the company's epidermal growth factor receptor, or EGFR, inhibitor called CO-1686 was posted for the upcoming American Society of Clinical Oncology, or ASCO, meeting. CO-1686 is being studied in a mid-stage trial as a potential first-line treatment in non-small cell lung cancer, or NSCLC, patients expressing certain EGFR mutations and as a second or later-line treatment for those who become resistant to EGFR-directed therapy. Although the abstract didn't provide many details, we did learn that some patients treated with CO-1686 showed partial responses or stable disease. The company will provide a more detailed update at ASCO.

Given the limited data release, I suspect that what really got investors excited was AstraZeneca's abstract for its own EGFR inhibitor, dubbed "AZD9291." In AZD9291's early stage trial, 51% of evaluable patients showed significant reductions in tumor burden following treatment. Even more encouraging is the fact that 64% of patients with a specific EGFR mutation responded to treatment, showing that the drug may work particularly well in certain sub-populations.

Should you join the AstraZeneca or Clovis oncology party today? My take is that you might want to take a pass. Clovis shares have repeatedly shot higher in reaction to positive clinical developments in the past, only to give back their gains in short order once day traders hit the exits. Moreover, Clovis sports a $1.73 billion market cap and lacks any form of significant revenue. In this moody market, that particular combination hasn't proven to be a recipe for success, evinced by Clovis' 15% downturn year-to-date. 

Turning to AstraZeneca, I also don't see this intriguing clinical development as a buying signal either. AstraZeneca shares are already up over 35% year-to-date on the back of the highly uncertain Pfizer deal. In short, AstraZeneca could see a rapid reversal if it continues to rebuff a potential takeover. So, you might want to tread lightly with this stock for the time being. 

How far will Incyte fall today?
Shares of Incyte Corporation fell 12.77% in after-hours trading yesterday after the company posted an abstract at ASCO discussing its flagship drug Jakafi as a potential second-line pancreatic cancer treatment .  Jakafi is currently approved as a therapy for myelofibrosis, seeing sales of $69.7 million in the first-quarter of this year for this indication. Although these are decent sales numbers, Jakafi's real value lies in its ability to become a more widely applicable cancer treatment.

Investors are thus downbeat on Incyte today because the abstract notes that Jakafi failed to show a significant clinical benefit in terms of either overall survival or progression free-survival. These data stem from an ongoing mid-stage trial testing Jakafi in advanced pancreatic cancer patients that have failed first-line treatment with gemcitabine.

Looking ahead, you need to understand that Incyte is currently trading at 25 times revenue, meaning that the market is probably assigning at least some value to a label expansion for Jakafi. Now that Jakafi looks like it may not be expanded to pancreatic cancer, the market might rethink this valuation. As such, you probably don't want to try to catch this falling knife today.   

George Budwell has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.