* Picoplatin suggests lower colon-cancer nerve-damage risk

* Side effects include lower platelets, white blood cells

* Suggests greater ability to cut prostate-cancer marker

* CEO aims for pivotal trials next year vs both cancers

* Shares down less than 1 percent

By Ransdell Pierson

NEW YORK, May 28 (Reuters) - Poniard Pharmaceuticals Inc PARD.O said on Thursday that its experimental drug picoplatin showed favorable results in mid-stage trials against advanced colorectal cancer and advanced prostate cancer, setting the stage for possible late-stage studies in 2010.

The tiny U.S. biotechnology company has already said it plans later this year to seek U.S. regulatory approval of the medicine as a treatment for small-cell lung cancer. Picoplatin is meant to be as effective as current platinum-based cancer drugs, including Sanofi-Aventis' SASY.PA blockbuster Eloxatin (oxaliplatin), but with considerably less nerve toxicity.

The Phase II colorectal cancer trial described on Thursday involved 101 patients with advanced cancer who had not received prior chemotherapy.

One group received Eloxatin along with two other standard treatments, 5-fluorouracil and leucovorin. The three drugs, known as the FOLFOX regimen, are the current gold standard of treatment against metastatic colorectal cancer.

Another group of patients instead received picoplatin every four weeks alongside 5-fluorouracil and leucovorin.

Symptoms worsened within seven months among the average patient taking the Eloxatin regimen, which Poniard said was similar to the 6.8 months for those taking the picoplatin combination.

About three-fourths of patients in both groups achieved disease control, as judged by stable disease or reduction in tumor size.

Poniard said only 29 percent of patients receiving the picoplatin combination experienced neurotoxicity -- such as uncomfortable tingling of fingers and toes -- compared with 60 percent of those treated with the Eloxatin regimen.

Moreover, none of the picoplatin-treated patients experienced severe neurotoxicity, compared with 16 percent of those taking Eloxatin, Poniard said.

“This data suggests activity (against cancer) is retained, but toxicity is improved by substituting picoplatin for Eloxatin,” said Dr. Richard Goldberg, a University of North Carolina oncologist who is a consultant for Poniard.

But the picoplatin-treated patients showed a greater incidence of blood abnormalities, such as lowered levels of infection-fighting white blood cells and platelets -- sticky blood cells that promote clotting.

Poniard said one episode of fever was associated with reduced white blood cells. No bleeding complications -- often seen with reduced platelet counts -- were reported.

The other mid-stage study described on Thursday involved 32 patients with metastatic prostate cancer who had not received prior chemotherapy.

All patients received intravenous picoplatin every three weeks in combination with Taxotere (docetaxel), a leading prostate cancer treatment sold by Sanofi-Aventis, and daily doses of the steroid prednisone.

Some 78 percent of patients who could be evaluated were able to reduce their level of a protein called PSA, or prostate specific antigen, by at least 50 percent for at least four weeks. The protein is considered a marker for prostate cancer, or prostate cancer risk.

By contrast, Poniard said only about 45 percent of similar patients receiving Taxotere by itself would be expected to reduce their PSA levels to such a degree.

PSA levels began to rise again within 8.5 months in the average patient. That is somewhat better than the 6 months one would expect for Taxotere as a stand-alone treatment, said Dr. William Oh, a Harvard oncologist who is a consultant for Poniard.

“Taxotere is the only drug for (advanced) prostate cancer that has been shown to improve survival, so if picoplatin is able in larger trials to further extend survival, that would be an important advance,” Oh said.

Poniard Chief Executive Jerry McMahon said favorable data from the colorectal and prostate cancer trials could help his company attract a partner that could help finance costly larger trials for the medicine.

“Our hope -- a lot depending on partnering -- is that we would begin pivotal trials next year in both colorectal and prostate cancer,” McMahon said in an interview.

Poniard shares were down less than 1 percent at $4.45 in morning trading, after rising sharply in premarket activity. (Reporting by Ransdell Pierson; Editing by Steve Orlofsky and Lisa Von Ahn)