Delavirdine Filed In USA; NNRTI Role Reviewed

Pharmacia & Upjohn has filed its New Drug Application in the USA for Rescriptor (delavirdine) a non-nucleoside reverse transcriptase inhibitor, for the treatment of HIV infection. If approved, delavirdine could be the second NNRTI to reach the market after Boehringer Ingelheim's Viramune (nevirapine; Marketletters passim), which was launched in the USA earlier this year.

At the XI International Conference on AIDS in Vancouver earlier this month, Peter Carberry from P&U presented updated results of a study originally presented in January, which found that combining delavirdine with Glaxo Wellcome's Retrovir (zidovudine) or Bristol-Myers Squibb's Videx (didanosine), produces a sustained reduction in viral burden and increases in CD4 count in HIV patients.

Several dose groups were included in the two-part study. For patients in the first part (protocol 21) with early infection (CD4 cell counts of 200-500/mm3), the groups were: zidovudine at standard doses or zidovudine with one of three doses of delavirdine (200mg, 300mg or 400mg tid). Those with more established infection (CD4 counts 0-300/mm3) entered protocol 017 and were randomized to didanosine at standard doses or didanosine plus delavirdine 400mg tid. 60% of those enrolled were zidovudine naive.