By Lisa Seachrist

Washington Editor

Allergan Ligand Retinoid Therapeutics (ALRT) put an early end to a pivotal Phase III clinical trial of its topical retinoid treatment for Kaposi's sarcoma (KS) in light of highly significant improvement seen among treated patients as compared to controls.

The trial conducted in Europe showed that 42 percent of the patients treated with Panretin — a topical gel formulation of 9-cis retinoic acid — saw their KS lesions shrink or disappear compared with only 7 percent of the placebo-treated patients.

"These positive interim results are the first confirmation of those obtained in earlier Phase I/II studies," said John Gibson, senior vice president of development at Allergan.

ALRT will have the results of another pivotal Phase III trial conducted in the U.S. by the end of the third quarter or early in the first quarter of this year. Based on the outcome of that trial, the company expects to file a new drug application (NDA) for Panretin topical gel at the end of the year or early in 1998.

"We expect to be able to analyze and announce the final results of the North American Phase III trial early in the fourth quarter of this year," said Marvin Rosenthale, president of ALRT, "and, if the results are positive, to file an NDA within two to three months."

ALRT's stock (NASDAQ:ALRI) was up 12 percent, closing Wednesday at $20.375 on the news.

ALRT is a joint venture undertaken by Allergan Inc., of Irvine, Calif., and Ligand Pharmaceuticals Inc., in San Diego, to develop retinoid therapies for various cancers, skin and eye diseases. Panretin is this venture's lead product.

The European trial, which was conducted by Allergan, was designed to pit Panretin against a placebo gel in a total of 270 patients. Early Phase I/II studies showed that in 12 weeks, Panretin shrank or eliminated 27 percent of the KS treated lesions compared to 16 percent of the untreated lesions. Based on that data, the study was powered to detect a 25 percent response with Panretin in a background of 10 percent response with placebo.

"In the earlier study, we used patients as their own controls," said Mary Kenny, associate director of media relations for Ligand. "The researchers saw evidence that people were using Panretin on lesions that were supposed to be controls. The effectiveness of the treatment turned out to be much less than the pivotal trial."

For the pivotal trial, patients treated their lesions either with a 0.1 percent Panretin Topical Gel or a placebo gel for 12 weeks. After that time, all patients were given the option to switch to Panretin. The study was halted after Panretin was shown to give a 42 percent response rate compared to a 7 percent rate for placebo in 82 patients. Another 50 patients are completing the 12-week treatment trial.

An interim check on the placebo activity for the U.S. pivotal trial, which has a similar design to the European trial and is being conducted by Ligand, showed that the 9 percent of the control group experienced improvement in lesions. No interim check on the drug activity is planned for that study, and the company expects to complete a full analysis on the 268 patients by the end of this year.

"This study is pretty much on track," Kenny said. "We don't expect that the European results will affect this study."

ALRT also is developing Oral Panretin for the treatment of renal cell carcinoma, non-Hodgkin's lymphoma, multiple myeloma, prostate, breast and ovarian cancers. *