ConjuChem Biotechnologies Inc. discontinued dosing in a Phase II trial of its growth hormone product, DAC:GRF in HIV lipodystrophy, pending an investigation into the death of a patient.

The company's stock (TSX:CJB) nosedived on the news, falling C57 cents, or 28.8 percent, to close at C$1.41 (US$1.25).

It's too early to know whether the cause of death might be linked to ConjuChem's product, the company said. The patient was being treated at a clinical site in Argentina.

"Right now, we're working closely with the family and health authorities in Argentina to conduct an autopsy," said Mark Perrin, president and CEO of the Montreal-based firm. From there, "we'll be getting data as fast as we can."

ConjuChem finished enrolling 192 patients in the study last month. The goal was to evaluate the change in insulin-like growth factor-1 (IGF-1) levels from baseline to week 12, with patients receiving weekly injections of DAC:GRF, a chemically modified version of growth hormone-releasing factor. DAC:GRF was designed using ConjuChem's Drug Affinity Complex (DAC) platform, which allows the GRF peptide to bond covalently with human serum albumin for a longer half-life. The idea is to provoke the natural release of growth hormone without the multiple daily injections required by most existing GRF products.

It is not the company's first setback with its DAC program. Last fall, ConjuChem said it was halting development of DAC:GLP-1, a Type II diabetes drug, after Phase II results revealed toxicity issues related to the diluent used to administer the drug. Its stock fell by more than 50 percent that day, closing at C78 cents. (See BioWorld Today, Oct. 3, 2005.)

But Perrin said the problems seem to be unrelated to the DAC technology.

"Side effects in [the DAC:GLP-1] trial were nausea and vomiting, which were very specific to the GLP class of drugs," he told BioWorld Today. Though the patient death in the DAC-GRF Phase II study still is under investigation, "it looks like it was quite specific to GRF."

The trial in HIV lipodystrophy was the only ongoing study of DAC:GRF, and Perrin said the news is not expected to interfere with development of the company's other drugs.

After the toxicity issues emerged during the DAC:GLP-1 study, ConjuChem opted to abandon that program - at least temporarily - in favor of a compound created using its newer DAC technology, PC-DAC (Pre-formed Conjugate-Drug Affinity Complex), which involves the conjugation of a DAC peptide ex vivo with recombinant albumin.

The preformed formulation is aimed at providing the same efficacy as the earlier compound but without the side effects, and early results have been promising. Preliminary data from a Phase I/II study reported earlier this year showed that treatment with PC-DAC:Exendin-4 was able to reduce glucose levels in patients for more than one week while appearing well-tolerated.

"We're moving aggressively to start a multiple-dose trial for that compound in the fourth quarter," Perrin said.