A Phase I Concentration-Targeted Multidose Study of Atevirdine Mesylate ( U-87201E ), AZT, and ddI or ddC

To determine the safety, toxicity, pharmacokinetic profile, and antiretroviral activity of atevirdine mesylate ( U-87201E ) in HIV-infected patients. Per 06/04/93 amendment, to also evaluate the interactive effects of didanosine ( ddI ) or zalcitabine ( dideoxycytidine; ddC ) with zidovudine ( AZT ) on the pharmacokinetics of U-87201E and to assess the effects of the triple combination therapies on immunologic and virologic parameters. Since the use of non-nucleoside reverse transcriptase inhibitors such as U-87201E has been associated with the rapid development of resistant HIV isolates, an initial evaluation of this drug in patients was made in combination with AZT. Because of the inability to detect resistance after 6 weeks of combined AZT/U-87201E therapy, this protocol will initially investigate U-87201E administered alone and then investigate the effect of this drug with AZT and ddI or ddC. Since the use of non-nucleoside reverse transcriptase inhibitors such as U-87201E has been associated with the rapid development of resistant HIV isolates, an initial evaluation of this drug in patients was made in combination with AZT. Because of the inability to detect resistance after 6 weeks of combined AZT/U-87201E therapy, this protocol will initially investigate U-87201E administered alone and then investigate the effect of this drug with AZT and ddI or ddC. Ten patients are treated at each of three targeted concentration ranges of U-87201E. Patients in the second cohort are enrolled immediately after patients in the first cohort are accrued; patients in the third cohort are enrolled when 5 of 10 patients in the second cohort have tolerated that dose for at least 4 weeks. The MTD will be the dose below that which produces dose-limiting grade 3 or 4 toxicity in five out of 10 patients. At least two women and five antiretroviral naive patients must be enrolled in each dose concentration range. Patients receive at least 8 weeks of monotherapy with U-87201E, with possible extension to at least 24 weeks with the same dose of U-87201E alone or in combination with zidovudine plus either ddI or ddC. Patients are followed weekly for at least 8 weeks and, if applicable, at weeks 10, 12, 16, 20, and 24 and monthly thereafter, up to 1 month following the last dose. Patients on combination therapy will have an indwelling venous catheter inserted for the first 2 days of combination therapy. Per 10/15/93 amendment, if no MTD is established with the first three cohorts, then 10 additional patients will be enrolled at a fourth concentration.