West Coast Editor

Shares of Incyte Corp. took a hit after the firm disclosed data from a Phase IIb trial that showed its once-daily oral HIV drug Reverset worked against the virus, but apparently not as well as investors had hoped.

"It's excellent news," said Pam Murphy, Wilmington, Del.-based Incyte's vice president of corporate communications and investor relations.

Still, Incyte's stock (NASDAQ:INCY) ended Monday at $7.42, down $1.34, or 15.3 percent, after trading as low as $6.52.

Although declining to speculate on why the stock fell, Murphy said, "The issue with Study 203, which we have said over and over again, was that it was conducted to accomplish some very specific objectives." She added that the trial "accomplished all of those objectives swimmingly."

Incyte wanted to established a sustainable and clinically relevant potency of the Reverset dose in treatment-experienced patients, while demonstrating safety over a longer period of time than 10 days (the duration of an earlier trial), while identifying subgroups that might respond especially well to the drug.

"We wanted to pick a dose for Phase III," Murphy said, noting that Study 203 was not strong on "p" values but was engineered to show "meaningful benefit" with Reverset over placebo.

Tested in 199 patients at 25 sites, the nucleoside analogue reverse transcriptase inhibitor yielded significant antiviral benefit at the highest of three doses, 200 mg, which brought a 54 percent response rate, compared with a 40 percent rate in placebo patients. Incyte is planning a Phase III study using that dose.

"We hope to complete all our discussions with the agency this summer and fall and be in position to launch the Phase III by year end," Murphy said.

Study 203 was designed to measure knockdown of HIV in treatment-experienced patients failing their current treatments. Results from the first two stages of the trial were offered at the International AIDS Society Conference on HIV Pathogenesis and Treatment in Rio de Janeiro, Brazil.

Specifically, at two weeks when Reverset was added to therapy, patients gained a 0.7 log drop in viral load overall as compared to placebo patients (who showed no change), and a 1.1 log drop in the subset of patients not using in their background treatment regimen 3TC and FTC. London-based GlaxoSmithKline plc's 3TC and FTC, also known as Emtriva, from Foster City, Calif.-based Gilead Sciences Inc. are both used as first-line treatments.

At 16 weeks in the overall group, when the 200-mg dose of Reverset was used as add-on therapy in either an optimized or non-optimized regimen, patients given the Incyte drug came up with a 1.2 log drop in viral load vs. a 0.8 log drop for placebo patients and a 1.4 log drop in viral load in the subset of patients not also getting 3TC or FTC, vs. a 0.5 log drop for placebo patients.

The overall group gained a 54 percent response rate vs. a 40 percent response rate as compared to placebo, with response defined as more than a 1.0 log drop in viral load. In patients not getting 3TC or FTC as background, the difference was 80 percent vs. 25 percent on placebo.

At 16 weeks in the non-optimized group, patients given the 200-mg dose got a 0.6 log drop in viral load as compared to non-optimized placebo patients, who achieved a 0.1 log reduction, and a 1.5 log drop in the subset of patients not getting 3TC or FTC, as compared to a 0.3 log increase in the non-optimized placebo patients.

"We were surprised at how robust the data were in the patients that were not taking 3TC and FTC," Murphy said. "That's a real clear benefit. It doesn't limit Reverset in any way, it just clarifies how the drug will be used."

The 100-mg and 50-mg daily doses gained viral load decreases of 0.3 to 0.4 log during the two week add-on phase and viral load decreases of 0.8 to 0.9 log at week 16, following the optimized background phase of the study.

Incyte signed a collaborative licensing agreement in September 2003 with Atlanta-based Pharmasset Inc., giving Incyte exclusive rights in the U.S., Europe and certain other markets to develop, manufacture and market Reverset. Data last year from a Phase II study of Reverset dosed once daily for 10 days showed that, of 30 treatment-na ve patients, those who got the drug had a 98 percent reduction in the amount of HIV found in their blood. (See BioWorld Today, Nov. 3, 2004.)

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