Placebo results that were better than expected resulted in the failure ofIsis Pharmaceuticals Inc.'s ISIS 2105 to show statistical significancein Phase II trials to treat genital warts caused by humanpapillomavirus.Isis officials said despite the results, they saw antiviral activity fromthe compound (afovirsen) and plan to take it forward as a surgicaladjuvant in patients undergoing cryotherapy, or freezing of wartsbefore their removal. The news was released after the market closed onThursday. Isis (NASDAQ:ISIP) stock was up 25 cents Friday, closingat $5.50 per share.The Phase II trial results involved ISIS 2105 as an adjuvant to surgeryand as a primary therapy.In the adjuvant therapy, single doses of 0.3 or 1 mg were administeredto each wart at the time of surgery. The wart recurrence rate was 10percent in the placebo group and 6 percent in each of the single-dosegroups. By patients, 15 percent of placebos had recurrence of wartsafter six months vs. 11 percent of treated patients."We had anticipated a far higher recurrence rate among placebo-treated patients," Daniel Kisner, Isis' president and chief operatingofficer, told BioWorld. "Surgical literature would suggest 40 percent[of placebos] should have recurrence."Some Patients BenefittedIn the multidose primary therapy trials, doses of 2.0 and 2.7 mg perwart were injected twice weekly. "We saw significant clearing of wartsin a small number of patients after eight weeks," Kisner said. "Theselate-onset responses are probably not sufficient to pursue it as aprimary therapy at this point."Isis will take the compound forward in placebo-controlled Phase IIstudy with 35 to 50 patients who have a total of 150 to 200 warts,Kisner said. Patients will be randomized to treatment groups ofpatients undergoing cryotherapy with two doses of ISIS 2105 orplacebo. The trial will measure patient response rate, time to responseand wart recurrence rate."The fact that we don't have statistically significant results in thesurgical adjuvant study is not terribly surprising to us," said Kisner,who was surprised, however, at the 10 percent placebo recurrence rate."We are going to focus on multiple-dose surgical adjuvant setting.From a commercial perspective this makes great sense." The majorityof patients are treated with some form of surgery. n

-- Jim Shrine

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