By Don Long

Transcend Therapeutics Inc. stopped a Phase III trial of Procysteine for acute respiratory distress syndrome (ARDS) after preliminary analysis of the suspended trial failed to explain the higher death rate among patients receiving the drug than among those receiving placebo.

The Cambridge, Mass.-based company said it will unblind the study and carry out a complete analysis of safety and efficacy data.

In late March, on the advice of an independent safety monitoring board, the company suspended the 213-patient study and conducted a preliminary review examining the baseline characteristics of the two groups, said Hector Gomez, president and CEO of Transcend. (See BioWorld Today, March 23, 1998, p. 1.)

"The purpose was to assess the comparability of the two groups," he said. "But we found nothing that could explain the difference in mortality." Gomez said he had no theories concerning the "very unexpected" Phase III results.

Previous History Says Compound's Safe

"Our previous history says that this is a safe compound," he added. A report of the full analysis will not be finished until the third quarter of this year, Gomez said.

Procysteine neutralizes tissue-damaging toxic molecules, called reactive oxygen species (ROS), by delivering the amino acid cysteine into cells, thus boosting cellular production of glutathione, an ROS-neutralizing peptide.

Because Procysteine is administered intravenously or in the emergency room via catheter, it offers a much less invasive therapy than the current treatment which consists of forcing highly-oxygenated air into the lungs through a tube inserted into a patient's nose or mouth.

Analysis of the unblinded Phase III data stalls two trials of oral Procysteine. A Phase II trial for treatment of amyotrophic lateral sclerosis (ALS) had been planned, along with a Phase II trial for treatment of atherosclerosis. The company had completed Phase I trials for both treatments without producing any problems with safety.

While Transcend is developing Procysteine i.v. for its use in treating ARDS in all countries other than Japan, partner Boehringer Ingelheim GmbH, of Ingelheim, Germany is responsible for the drug's Japanese development and holds a worldwide license for its use and sale for all pharmaceutical applications.

In March, when the Phase III trial first was suspended, Transcend's stock (NASDAQ:TSND) plunged 61 percent. The company's shares closed Friday at $3.156, down $0.53. *

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