Dendreon Clinical Trial Primer: What You Need to Know About Today’s Provenge Data

Dendreon said it made history a couple weeks ago, when its drug for stimulating the immune system to fight cancer cells was found to be the first of its kind to help men with prostate cancer live longer. Today, we’ll find out just how strong the medical evidence is to support that claim.

The Seattle biotech company (NASDAQ: [[ticker:DNDN]]) plans to release detailed results on its experimental drug, sipuleucel-T, (Provenge) from a clinical trial of 512 men with terminal prostate cancer. Data from the trial, called IMPACT, will be presented at the American Urological Association in Chicago at 2:20 pm Central time//12:20 pm Pacific.

Dendreon, of course, has already seen the data, but researchers, investors, and patient advocates haven’t. All we outsiders know is that the company’s CEO, Mitchell Gold, has characterized the data as “consistent” with results from prior clinical trials, and that there was no gray zone for interpretation. He called the findings “unambiguous” and a “clear hit.”

If doctors interpret the data the same way, this would be a big step forward for prostate cancer treatment. About 30,000 men in the U.S. die each year of the disease, and given the high price something like Provenge is bound to command, analysts predict this drug could exceed $1 billion in annual sales. Dendreon is so pumped about this result that it hung a banner on its building in Seattle’s Belltown neighborhood that looks to be 30 feet tall by at least 40 feet wide after it announced success on April 14. It says “Congratulations Dendreon. Global Impact Starts Here,” with a blue ribbon for prostate cancer patients.

Before we get too far ahead of ourselves in counting up the dollars and the Nobel Prizes, I figured many readers could use a reminder of what is in the public domain about Provenge and what to watch for in the data.

The biggest trial to support the effect of Provenge to date is called 9901. That study, of 127 men, produced results in 2005. It showed that men with terminal prostate cancer lived a median time of 25.9 months if they were randomly assigned to get Provenge, compared with a median of 21.4 months if they got a placebo. Median means that half lived less that than amount of time, and half lived longer. (Statisticians prefer to use medians because averages can be warped by individual outliers who might die immediately or live 10 years for some other reason).

The findings from this study meant that men lived a median time of 4.5 months longer, or 21 percent longer, if they got Provenge. This result

Author: Luke Timmerman

Luke is an award-winning journalist specializing in life sciences. He has served as national biotechnology editor for Xconomy and national biotechnology reporter for Bloomberg News. Luke got started covering life sciences at The Seattle Times, where he was the lead reporter on an investigation of doctors who leaked confidential information about clinical trials to investors. The story won the Scripps Howard National Journalism Award and several other national prizes. Luke holds a bachelor’s degree in journalism from the University of Wisconsin-Madison, and during the 2005-2006 academic year, he was a Knight Science Journalism Fellow at MIT.