sc-52151 and HIV-Infections

SC-52151, an HIV-1 protease inhibitor, was developed as an ethanol-based elixir and subsequently as a self-emulsifying drug delivery system (SEDDS) to improve bioavailability. To evaluate formulation and treatment regimen effects, we conducted a four-arm, phase I/II study using the highest previously tested daily dose, 2250 mg. Forty-nine patients received the elixir or SEDDS at a dosage of 750 mg three times daily or 1125 mg twice daily for 14 days. One patient developed hypertriglyceridemia, and one had fever and dyspnea. The SEDDS formulation compared with the elixir resulted in a larger area under the concentration-time curve (AUC, p < 0.001), peak (Cmax, p = 0.041) and trough (Cmin, p = 0.025). Twice-daily administration compared with administration three times daily produced a higher cumulative AUC (p = 0.008). Both SEDDS regimens produced mean plasma concentrations above the 90% inhibitory concentration (IC90) for HIV. A mean decline of 0.03 log10 RNA copies (SEDDS) and an increase of 0.15 log10 (elixir) were observed. Although SC-52151 was well tolerated and the SEDDS formulation resulted in plasma concentrations above the IC90 for viral replication, no antiviral activity was produced.

Topics: Adult; CD4 Lymphocyte Count; Female; HIV Infections; HIV Protease Inhibitors; Humans; Male; Middle Aged; RNA, Viral; Urea

Protease inhibitors block HIV by binding with its protease enzyme and it is hoped that they will be more potent and less toxic than nucleoside analogs. The companies Hoffmann-La Roche, Merck, Abbott, Searle, Agouron, Kyoto and Upjohn all have tested protease inhibitors in human trials. The drugs include L-524, ABT-538, AG- 1343, saquinavir, SC-52151, and SC-55389a. The protease inhibitors from Merck, Roche, and Abbott have shown higher anti-viral activity than any previous anti-HIV drug. Vertex, Burroughs Wellcome, and Kissei have conducted animal studies of VX-478, which shows promise in inhibiting the virus, with no toxicity. Other companies developing protease inhibitors include DuPont-Merck, Ciba-Geigy, Hoechst-Bayer, Nippon Mining, Parke-Davis, and Smith-Kline Beecham. Companies increasingly are combining protease inhibitors with nucleoside analogs, mainly AZT, in their large-scale efficacy studies in an effort to produce a strong and sustained anti-HIV effect. Potential cross-resistance to many of these compounds remains a major research issue. It is likely that at least one of the three leading companies in the field -- Merck, Abbott, or Roche -- will file for Food and Drug Administration approval in 1995. The National Drug Development Task Force is expected to announce the creation of a new task force on protease inhibitors.

Topics: Animals; Blood Proteins; CD4 Lymphocyte Count; Clinical Trials as Topic; Drug Industry; Drug Resistance; Drug Therapy, Combination; HIV Infections; HIV Protease Inhibitors; Humans; Isoquinolines; Oligopeptides; Protein Binding; Pyrones; Quinolines; Rats; Saquinavir; Technology, Pharmaceutical; Urea; Warfarin; Zidovudine