Washington Editor

Poor interim statistical analysis of a Phase III trial of Provenge in prostate cancer patients caused Seattle-based Dendreon Corp.’s stock to dive Friday.

In response to the disappointing news, Christopher Henney, Dendreon’s CEO, held a conference call Friday, saying, “I want to stress that this is an immature database. We have not found a great deal that we can use [from the analysis]. We did find, however, that it was not strongly positive and I felt that it was important that we communicate that.”

Dendreon’s stock (NASDAQ:DNDN) closed Friday at $5, down $3.05 or nearly 38 percent.

Provenge, formerly APC8015, is a therapeutic vaccine being studied as a treatment for both advanced and early stage prostate cancer.

The interim analysis appears to indicate that Provenge will not meet its primary endpoint time to disease progression in a Phase III study of 127 men with hormone-resistant prostate cancer, an advanced form of the disease. Two other Phase III studies are under way one evaluating 120 men with advanced disease and a second looking at early stage disease. (See BioWorld Today, Aug. 13, 2001, and Jan. 27, 2000.)

“The administrative analysis was designed to yield information helpful to us in business decision making,” Henney said. “It was not designed to yield efficacy information. We asked the statistician to predict for us whether there would be a twofold difference between the two arms in terms of time to disease progression. We did not ask about safety of the product or the secondary endpoint time to disease-related pain.

“What we received is inconclusive, ambiguous information,” Henney said. “The summary was a possible positive outcome rather than a probable one. Obviously, we need more definitive information and the best way to achieve that is to let the database mature.”

Henney and other company officials agreed that the data likely will be ready sometime mid- to late-year.

As for the future, Bill Tanner, managing director at SG Cowen Securities Corp. in Boston, said: “I don’t think we are going to know until we get the full data later in the year. I think that if it looks like Provenge is a non-starter, then the uphill climb becomes a lot more steep.”

Provenge is designed to jumpstart the immune system by relying on the individual patient’s dendritic cells to stimulate an immune reaction to cancer. Dendreon isolates the patient’s dendritic cells specialized immune cells that serve as watchdogs by identifying foreign proteins from peripheral blood. The cells are then activated with a recombinant prostate tumor vaccine in order to trigger an immune reaction to a prostate-specific antigen known as prostate alkaline phosphatase, which is found in most prostate cancer cells.

In Phase II trials, Provenge provided a median delay in disease progression of more than 300 days. In men receiving placebo, disease progression time occurred between 90 and 120 days. Some men experienced tumor regression or stabilization measured by changes in serum PSA levels over time and tumor shrinkage seen on X-rays. (See BioWorld Today, Jan. 27, 2000.)

Other than the prostate cancer treatment, Dendreon is working on Mylovenge, a treatment for multiple myeloma, currently in three Phase II trials. In Phase I, Dendreon is studying APC8024, a vaccine designed to trigger T-cell immunity of the antigen Her2-neu for women with breast cancer.

Dendreon and the pharmaceutical division of Tokyo-based Kirin Brewery Co. Ltd. have a licensing and development agreement for Provenge and Mylovenge, giving Kirin rights and options to the Asian marketplace with Dendreon retaining rights in North America and Europe. Initially signed in 1998, the deal was expanded last summer, triggering a $10 million payment to Dendreon. (See BioWorld Today, Aug. 13, 2001.)