Allelix Biopharmaceuticals Inc. was given approval to start Phase IItrials of its parathyroid hormone product in the U.S., but is going towait until it gets the go-ahead in Canada before starting trials for thetreatment of osteoporosis.

Graham Strachan, president and CEO of the Toronto-based company,said he anticipates starting Phase II trials of ALX1-11 in bothcountries in April. The U.S. arm of the trial, at 11 or 12 centers, isexpected to include 175 to 200 postmenopausal women withosteoporosis. In Canada, about 50 women will be enrolled at aboutfive sites.

The study will be double-blind, placebo-controlled and test threedose levels of ALX1-11, or recombinant human parathyroid hormone(PTH). Treatment will run for about nine months followed by threemonths of analysis.

"We hope to see it demonstrate increases in bone mass and density,"Strachan told BioWorld, adding that animal work showed that itrebuilt bone mass up to 10 percent in one year. Studies of a synthetichuman parathyroid hormone fragment tested in humans alsodemonstrated increases in bone mineral density, he said.

Osteoporosis is a degenerative bone disease that increases the risk ofbone fractures. PTH is a protein that plays a role in regulating bonemineral metabolism and stabilizing calcium levels in the body.

PTH was being developed with Glaxo Canada Inc. through a jointventure of the two companies, formed in 1993. That followed a five-year research and development collaboration on PTH. But Glaxowithdrew from the venture late last year.

"We reacquired all rights," Strachan said. "They [Glaxo] were quitesatisfied that the molecule works and is safe. They just have adifferent strategy."

The companies were going to share the costs of taking PTH throughPhase II trials, at which point Glaxo would have the option toundertake worldwide clinical and commercial development.

"We have all the material on hand for Phase II," Strachan said. "Weestimate the additional cost [without Glaxo] through Phase II willprobably be about $10 million."

But, he said, "we're in discussions with several companies aboutpartnering."

Strachan said "we ought to be able to look for a somewhat betterdeal" than Allelix had with Glaxo. "We have an attractive moleculehere. It seems to be effective. It's a question of demonstrating that itworks."

The North American study will compare the efficacy and dose-response relationship of ALX1-11 at three dose levels with placeboin terms of increasing bone mineral density. It also will compare theefficacy of the three doses in terms of effects on total body bonemineral density and biochemical markers of bone turnover.

"It's quite different than other osteoporotic agents," which aredesigned to prevent further bone loss, Strachan said. "[PTH] isthought to stimulate osteoclast to produce new bone cells. PTHcatalyzes the regrowth of bone. It seems to be unique in that ability."n

-- Jim Shrine

(c) 1997 American Health Consultants. All rights reserved.