CARLSBAD, Calif. -- The first clinical trial of an antisensecompound injected into humans has turned up no significantside effects in the first 50 healthy subjects given the drug, IsisPharmaceuticals Inc. reported Tuesday.
But the first evidence of whether Isis 2105 is effective intreating genital warts won't be known until around the end ofthe year after it's tested in about 45 patients who have genitalwarts. Isis last March became the first company to test anantisense compound in an FDA-approved clinical trial. In asecond part of the Phase I study, Isis 2105 is being given inescalating doses to more healthy participants and those withwarts.
Some participants in the first trial group did experienceredness and swelling at the injection site, which subsided after24 hours, Daniel L. Kisner, Isis' executive vice president, toldBioWorld. However, the company is unsure if this was theresult of the drug or a placebo used as a control in the study."In no case did we see anything that looked like a dose-limitingtoxicity," he said.
Antisense drugs, which specifically bind to messenger RNAmolecules that code for disease-causing proteins, are seen aspotential tools to interfere with the disease process.
Beyond Isis 2105, Isis has 13 other antisense compounds, twoor three of which could be the basis for investigational newdrug (IND) filings in 1993, Kisner said. Among the candidatesare potential treatments to halt blindness fromcytomegalovirus in AIDS patients, a topical ointment for herpessimplex and an HIV treatment.
If Isis 2105 continues to generate positive clinical data, thedrug could enter Phase II clinicals in early 1993 and be thebasis for a product licensing application (PLA) in about two tofour years, Kisner said.
Isis also claims to be making continuing headway on thetechnical challenge of scaling up production of antisensecompounds -- and driving down their costs.
It can now produce about a kilogram of pharmaceutical-gradeantisense compound per year, more than enough to meet itsclinical testing needs, Kisner said. "If you realize that a coupleof years ago no one could make more than a couple milligramsof this stuff, you'd realize that's progress."
With more efficient production equipment expected next year,Isis hopes to ramp up daily output of each bench-top device tobetween 50 and 100 milligrams, he said. In terms ofproduction costs, "we don't really know what the floor is,"Kisner said.
With Isis 2105, "our guess is that our cost of goods for an entirecourse of therapy (to treat one wart) is somewhere between $5and $15." However, the injectable 2105 may require much lessantisense compound than antisense drugs deliveredintravenously or as ointments.
"I wouldn't say that the cost of oligonucleotides is no longer anissue, but we're making progress," Kisner said.
Isis tapped the buoyant 1991 IPO market and then made twomore stock offerings last year, raising $70 million in total. Isisstock (NASDAQ:ISIP) closed Tuesday up 25 cents at $8.25 ashare, still below its IPO price of $10.
It closed out the first quarter ended March 31 with $52.4million in cash or equivalents. However, its costs -- and losses -- have climbed during the past year. Isis posted a $5 millionfirst-quarter loss, which company officials said was larger dueto two in-licensing agreements. They predict that Isis' 1992loss should come in under $20 million, even as the companyexpands its operations.
-- Ray Potter Senior Editor
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