Get ready for the clinical trial season for anticancer therapies. The American Society for Clinical Oncology meeting is in May, and everyone who's going to present new trial data is starting to work on their PowerPoint slides. ASCO (famously) embargos the presentations themselves, but the run-up to the meeting is out there in plain sight.

For example, Bayer and Onyx will be talking about their drug, sorafenib. Promising interim data was released today - well, a summary was, anyway - which means that this will be an eagerly awaited ASCO talk. Meanwhile, Schering AG and Novartis were planning to make a big splash with one of their therapies, PTK-787, but the bad news came out on that one almost simultaneously. They'll still be presenting, but the mood will be quite a bit more somber.

All these trials have surrogate endpoints and real endpoints. The real ones are the ones that matter, but you have to wait until the end of the trial for them. Surrogates are designed to be read out more quickly. In the case of these drugs, the surrogate marker is whether the drug seems able to delay progression of the cancer. As time goes on, you'll get actual survival rates, which are the real story, but investors are desperate for news and will take whatever they can get. For their part, the companies will use good surrogate data as a signal to go ahead and start putting the FDA package together, which saves time. Competition in this area is such that time equals money even more than usual.

The problem with surrogate markers is that you can get fooled. It's possible for a drug to look like it's delaying cancer progression, but in the end to not have much effect on survival rates. (Just to really drive everyone nuts, the opposite situation is possible, too.) That's where AstraZeneca's Iressa ran into trouble. As the long-term data starting coming in, it became clear that the drug really didn't help with survival. And if your drug doesn't do that, the patients and insurance companies would like to know, quite correctly, just why they should pay for it.