By Mary Welch

Fresh on the heels of positive Phase III results for pegvisomant, a novel growth hormone receptor antagonist, Sensus Drug Development Corp. sold 19.9 percent of its stock to Pharmacia & Upjohn (P&U) for an undisclosed amount.

P&U, based in Bridgewater, N.J., may acquire the remainder of the privately held company later.

"We have nothing else to add about our deal with Pharmacia & Upjohn," said Donald Payne, chief financial officer of Austin, Texas-based Sensus. "But I would say that we're delighted with the Phase III results, and expect to file a [new drug application] by the end of the year."

Paul Fitzhenry, spokesman for P&U, said the purchase is conditional, "dependent on the FDA timetables." Sensus was attractive to P&U because it "brings a product to the market in the very near term, and it adds a product to our growth-hormone business, without significant cost in either research and development or sales and marketing," Fitzhenry said.

P&U markets genotropin, a growth hormone with sales of $395 million in 1998. It is approved in the U.S. for growth hormone deficiency in children and adults. Elsewhere, it is approved for chronic renal insufficiency and children with short stature associated with Turner's Syndrome. Genotropin, launched in 1987, is the world's most widely used recombinant human growth hormone.

Tom Brakel, an analyst with Mehta Partners LLP in New York, believes P&U will pay about $25 million for Sensus. "That's my ballpark guess," he said. Brakel estimated U.S. sales of pegvisomant between $25 million and $50 million.

"This disease largely starts from benign tumors, so the first line of treatment is probably surgery," he said. "Now, if the hormone levels rebound or become inappropriate, the person is a candidate for drug therapy for the rest of his or her life. The other drugs currently on the market have side effects. So, there's room for a better drug, and the Sensus product could be called upon to play an important role in the treatment of these patients."

The trial took place at 16 medical centers in the U.S. and Europe, and involved 111 patients suffering from acromegaly, a serious, debilitating disease that affects about 400,000 people worldwide. The condition is caused by increased secretion of growth hormone as a result of a tumor in the pituitary gland, which results in abnormally high levels of IGF-I, followed by the onset of clinical disease symptoms.

Acromegaly is characterized by enlarged hands, feet and facial bones. The heart and other internal organs are also affected, and complications can include cardiovascular disease, high blood pressure, arthritis and diabetes. Left uncontrolled, acromegaly may result in premature death.

Patients in the active treatment groups received 10, 15 or 20 milligrams per day for 12 weeks. Pegvisomant (also known as B2036-PEG) was found to be well tolerated, with no major adverse events reported. All three dosage groups achieved statistical significance in meeting the primary endpoint, with 89 percent of those in the 20 milligrams-per-day dose group normalizing their IGF-1 levels, Payne said.

"The primary endpoint was a decrease in the IGF-I levels, and we saw significant clinical support that pegvisomant did that," he said. "This trial confirms the successful results that we saw in our open-label extension of our Phase II trial. It also showed statistical significance in another endpoint, which was the relief of clinical symptoms. We believe the trial demonstrated the superior ability of pegvisomant to treat this patient population over the other current treatments."

Current treatments involve removing the tumor and radiation therapy along with other drugs that have a different mechanism of action, he said.

Until recently, pegvisomant was known by the trade name Trovert.

"It turned out there was a similar name in Europe, so we couldn't use Trovert," Payne said, adding that another trade name will be assigned soon.

Robert Davis, executive vice president of Sensus, explained how the drug works.

"The growth hormone binds to the receptor, and produces IGF-I but only on one side," he said. "So, no signal is given to secrete the growth hormone. It doesn't occur. Pegvisomant, in the end, blocks the action of growth hormone as well as the consequent production of IGF-I."

Pegvisomant has been given orphan drug status by the FDA and in Japan. The regulatory agency also designated it for "fast track" review. Sensus said the drug could be on the market next year. It also is in Phase II studies for diabetes-related retinopathy, with results expected to be released around July 1. And it is in Phase II studies for insulin sensitivity.

The company anticipates starting studies on diabetes-related kidney diseases next year, as well as trials for breast and prostate cancer.

Sensus was founded in 1993 with technology from Ohio University's Edison Biotechnology Institute in Athens, Ohio. The company licensed worldwide rights from Genentech Inc., of South San Francisco. As part of that deal, Genentech received royalties and equity in Sensus. (See BioWorld Today, Feb. 27, 1995, p. 2.)

Last summer, Sensus filed for an initial public offering, which later was withdrawn. Early this year, the company raised $23.4 million in a private equity financing. (See BioWorld Today, Jan. 26, 1999, p. 1.)