Texas Biotechnology Corp. resubmitted to the FDA its new drug application (NDA) for Novastan (argatroban) as an anticoagulant for heparin-induced thrombocytopenia (HIT) syndrome for those who require anticoagulation.

Last May, the FDA sent Houston-based Texas Biotechnology a ¿not-approvable¿ letter. (See BioWorld Today, May 12, 1998, p. 1.)

David McWilliams, president, said the death rate for HIT is about 25 percent. The company ¿didn¿t feel it was ethical to have a placebo-controlled trial, so we filed [the resubmitted NDA] using a historic trial which looked at patients with HIT that were not in the trial. These patients were theoretically supposed to be similar to those in the trial.¿

According to McWilliams, the hospitals¿ records had been ¿adjusted,¿ and some of the sicker patients ¿ who should have been included in the historic trial ¿ were excluded.

Since receiving the letter from the FDA, Texas Biotechnology and its development partner, SmithKline Beecham plc, of London, collected new historical data on 193 patients, about the same number as that in the original historic trial. In addition, a Phase III trial that was ongoing at the time of the original 1997 submission was completed, and that data is now included in the resubmission. In total, some 564 patients were given Novastan in the two Phase III trials.

As with the original submission, Novastan is a fast-track drug, meaning the FDA will rule within six months.

Novastan is a small-molecule inhibitor of thrombin, an enzyme involved in blood clotting which Texas Biotechnology licensed from Genentech Inc., of South San Francisco. HIT is an immune-mediated disease caused by the development of antibodies to a complex of heparin and platelet factor 4. Essentially, it is an allergic reaction to heparin.

Texas Biotechnology¿s stock (AMEX: TXB) closed Monday at $5, unchanged. ¿ Mary Welch