Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of Clovis Oncology (NASDAQ:CLVS) are trading 14% higher today after the development-stage biotech announced the presentation of data at an upcoming American Society of Clinical Oncology (ASCO) meeting. Also driving today's gains was the news that AstraZeneca (NYSE:AZN) will also present data on a very similar drug at the same meeting.

So what: Clovis announced last night that it would present five abstracts on the progress in phase 1 and phase 2 studies of CO-1686, an oral targeted covalent inhibitor of the epidermal growth factor receptor (EGFR) to be used in treating non-small-cell lung cancer. AstraZeneca's development-stage cancer drug AZN9291 also aims to treat the same type of lung cancer, and its more detailed data revealed that 51% of the 177 patients involved in a study had their tumors shrink during treatment.

AZN9291 was granted "breakthrough therapy" status by the FDA to speed its arrival to the market, but some analysts have pointed out that Clovis' CO-1686 appears to be a safer treatment than AstraZeneca's drug, as AZN9291 appears to produce higher rates of adverse response.

Now what: AstraZeneca's own projections anticipate up to $3 billion in revenue from AZN9291, so a safer alternative could easily steal much of its thunder. Clovis has no real revenue to speak of yet, but if it can capture even half of that $3 billion market opportunity, it would pull in nearly enough revenue to drop to a price-to-sales ratio of less than one. AstraZeneca, in comparison, has a price-to-sales ratio of nearly 4, although it does have a broader range of drugs both on the market and in its pipeline.

Clovis' shares have experienced a lot of volatility since it doubled last year on positive CO-1686 data, and there's bound to be more in store before the company can move this exciting drug through its final trials. I'd be cautious here, but there may be enough reason for optimism to put a speculative toe in the water -- just make sure you understand what Clovis' and AstraZeneca's data really means first.

Alex Planes 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.