By Frances Bishopp

Arris Pharmaceutical Inc. reported clinical study results from a Phase IIa study of its lead product, APC-366, a tryptase inhibitor for asthma, reached statistical significance in the achievement of the study's primary endpoint: the late airway response, showing a more than 25 percent reduction as compared to placebo.

The Phase IIa study took place in the U.K. and had 16 patients who were dosed with both placebo and with APC-366 using a double-blind cross-over study. The patients had mild asthma and were dosed with either the placebo or a nebulized formulation of APC-366 three times daily for four days.

An allergen challenge was performed after the 10th dose on day four of the study to evaluate the effects of the treatment. The trial evaluated the subjects' response to allergen challenge and measured late airway responses by the area under the curve over a period of time from three to nine hours, post allergen challenge.

John Walker, president and CEO of Arris, told BioWorld Today that his South San Francisco-based company, which went public in 1993, has been talking about tryptase as a target for "mass cell-mediated inflammation" for a long time, with the first clinical indication to be asthma.

"We have assembled a tremendous amount of data, in vitro and in vivo studies in multiple species, that have demonstrated the important role that tryptase plays in this allergic inflammatory response," Walker said.

"We are the first and to my knowledge the only people who have examined tryptase in its role in humans, and as a result we have a lead position on a new chemical based on a new modality for the treatment of these inflammatory disorders," Walker said.

Arris is developing APC-366 with Bayer AG, of Leverkusen, Germany.

Arris is also running a second Phase IIa study of APC-366 for bronchial hyperresponsiveness and plans to begin a Phase IIb study of APC-366 in a dry powder inhaler later this year.

Arris' stock (NASDAQ:ARRS) closed Thursday at $13, up $1. *