Nothing like a new use for aging or troubled drugs to make a marketer’s day. The combination of the two Pfizer pills “work through different mechanisms of action, but there is a synergistic effect that inhibits the growth of prostate cancer cells,” Xi Cheng, assistant research professor at Rutgers, the State University of New Jersey, who conducted the study, tells Reuters.

The Rutgers team found that the combination of low doses of Lipitor and Celebrex had a more potent impact on tumor growth than a higher dose of either agent when used separately. The combo was administered to cultured mice tumors in order to measure the transition of early prostate cancer to its more aggressive and potentially fatal stage, according to Zheng, who adds that Pfizer played no role in study, which was funded by the NIH.

In the early stage of the disease, prostate cancer cells depend on androgen hormones, such as testosterone, to grow. Treatment involves either decreasing the production of the hormone or blocking its action. The objective of the Rutgers study was to indefinitely delay the transition to androgen-independence, prolonging the time during which the cancer would be responsive to low-toxicity, anti-hormone therapy, Reuters writes. Zheng says it appears that a cell signaling pathway for tumor cell growth is inhibited by the combination of the two compounds.

Human clinical trials are being planned. Of course, the results are unlikely to be available before Lipitor patent protection evaporates in 2010 or 2011. But the prospect of a cancer cocktail must be tantalizing, nonetheless, especially given concerns over cardiovascular side effects that have plagued Celebrex for the past few years.