By Lisa Seachrist

Washington Editor

WASHINGTON — Genentech Inc. halted development of insulin-like growth factor 1 (IGF-1) for the treatment of Type I and Type II diabetes after determining the drug would require extensive clinical trials to be proven safe and effective.

The South San Francisco company has IGF-1 in Phase III studies as an adjunct to insulin for glucose control in Type I diabetes and in Phase II trials in Type II diabetes. The company decided to abandon development of the drug for the treatment of diabetes over concerns it may increase the incidence of diabetic retinopathy.

"It is important to note that we didn't make this decision as a result of any adverse events in our trials," said Kathleen Rinehart, manager of corporate communications at Genentech. "Essentially, we came to the conclusion that there is a potential concern about diabetic retinopathy and the only way to answer that concern is with lengthy clinical trials."

Diabetic retinopathy is characterized by an excessive buildup of blood vessels in the retina. It is the leading cause of blindness in diabetics. Animal research has linked IGF-1 to an overgrowth of these blood vessels. (See BioWorld Today, June 17, 1997, p. 1.) And, Rinehart noted, the company realized from the outset retinopathy would be an issue with the use of IGF-1.

Because retinopathy is a long-term sequela of diabetes, both the company and the FDA concluded that establishing IGF-1's safety with respect to the condition would require a pivotal trial with extensive follow-up. Genentech decided the cost of such a trial made further development of the molecule for glucose control too risky. The company will continue to develop the drug for other indications.

"We haven't abandoned the development of IGF-1," Rinehart said. "We have decided that we won't proceed in this indication. However, the company remains committed to the development of potential drugs in the areas of endocrinology and metabolic disorders."

Rinehart noted the decision came as part of a routine review of the company's clinical program. "Genentech has such an extensive pipeline that good management requires that we review our programs on a regular basis," she said.

Joyce Lonergan, an analyst with Cowen & Co., in New York, told BioWorld Today, "It takes a lot of guts to make a decision to drop development in Phase III."

"This decision shows that they really know when to turn there resources to other projects," Lonergan said. "I am very thrilled that they made this decision."

Lonergan noted diabetes trials are very big and the market is very competitive so it makes sense to decide to move ahead with other products. In the diabetes area, Genentech is developing nerve growth factor for the treatment of peripheral neuropathy.

The company's stock (NYSE: GNE) closed Friday at $57.625, unchanged. *