Washington Editor

A fusion inhibitor for HIV patients being developed by Trimeris Inc. and Hoffmann-La Roche Inc. produced better than expected results in a Phase III trial.

In response, Trimeris’ stock (NASDAQ:TRMS) shot up $11.25 Thursday, or 28.7 percent, to close at $50.50.

The drug, T-20, is injected subcutaneously twice daily in conjunction with approved HIV products. It works by inhibiting fusion of HIV with host cells before the virus enters the cell and starts the replication process. Most HIV drugs work inside the cell and target enzymes involved in replication of the virus.

In the study, T-20, given in combination with an individualized antiretroviral treatment regimen, met the primary endpoint of decreasing the amount of virus in the blood as compared to the individualized treatment regimen alone.

“This is very good news, as you can imagine. It is a defining moment for a biotech company to have data of this sort in a Phase III trial that meets comfortably the primary endpoint,” Dani Bolognesi, CEO of Durham, N.C.-based Trimeris, told BioWorld Today. “As this moves forward in the regulatory path, we anticipate very good things. It validates the target and validates the franchise that we are developing in this area. We are doing more in the fusion inhibitor arena and in a way, we are now ushering in a new class of antiviral agents that will be a new paradigm in the way you treat HIV disease.”

Indeed, Sharon Seiler, vice president, senior biotechnology analyst with Punk, Ziegel & Co. in New York, told BioWorld Today that the Phase III results are “robust.”

“There probably are some manufacturing constraints with T-20 because it is a peptide that has to be injected twice a day. So, Trimeris and Roche really have looked to the salvage market [patients who are not well served by products currently on the market], but I think ultimately this is an important proof of concept. Adding an entry inhibitor drug to the classes of drugs already available can provide important benefits,” Seiler said. “When more convenient entry inhibitor drugs are available, they will likely become standard of care, even in early stage patients.”

Bolognesi expects to file for regulatory approval early in the second half of this year based on this Phase III trial, referred to as TORO 1, and a second Phase III called TORO 2. The second trial, being conducted overseas, should be complete in four to five weeks.

Given its FDA fast-track designation, T-20 likely would be approved late this year or early next year, Seiler said.

“There have not been safety issues with this drug, and at least initially, it [will be] indicated for a population that does not have a lot of alternatives,” she said. “I think the FDA, even though they’ve had a spotty record, has been very quick to approve new drugs for HIV.”

She anticipates first-year North American sales to top $146 million.

As per its co-development agreement with Roche, of Nutley, N.J., Trimeris would split revenues 50-50 from T-20 sales in North America. Trimeris would receive royalties on overseas sales. So far, Bolognesi said, Roche has paid Trimeris roughly $12 million in up-front and milestone payments. The next milestone would be paid to Trimeris upon FDA clearance. (See BioWorld Today, June 20, 2001.)

The agreement between Trimeris and Roche also applies to T-1249, another HIV fusion inhibitor, which is in Phase I/II trials, about two to two and a half years behind T-20 in development, Bolognesi said.

TORO 1 (T-20 vs. Optimized Regimen Only, previously known as T20-301) evaluated 491 patients with HIV-1 who were treatment experienced and/or had documented resistance to each of the three classes of currently available antiretrovirals.

Patients who received T-20 achieved a reduction in HIV levels of 1.697 log10 copies/mL compared to 0.763 log10 copies/mL for those who were randomized to the control arm. The primary efficacy endpoint for the study, the difference in the magnitude of decrease in HIV between the two arms, was 0.934 log10 copies/mL and was statistically significant (p<0.0001).

The company said while most patients in the T-20 arm experienced injection-site reactions, only 3 percent dropped out of the study as a consequence. Some other adverse events were insomnia, headache, peripheral neuropathy and dizziness.

TORO 1 and 2 are randomized, open-label trials that enrolled a total of 1,000 patients at 112 centers worldwide.