A phase I/II study of 2'-deoxy-3'-thiacytidine (lamivudine) in patients with advanced human immunodeficiency virus infection.

In a phase I/II trial assessing the toxicity, pharmacokinetics, and activity of the (-)enantiomer of 2'-deoxy-3'-thiacytidine (3TC, lamivudine), 97 patients with AIDS or advanced human immunodeficiency virus (HIV) disease were administered 3TC at 0.5-20.0 mg/kg/day. The cohort's median entry CD4 cell count was 128/mm3 (range, 7-357). A toxic dose was not reached, although some patients reported mild headache, insomnia, and abdominal symptoms, and there was a general downward trend in neutrophil counts at the highest doses. Although subjective and difficult to interpret, increases in energy and appetite were noted, particularly in patients receiving > or = 8.0 mg/kg/day. Immunologic and virologic parameters showed evidence of at least transient anti-HIV activity at those higher doses. Although further studies of 3TC as monotherapy are needed, its favorable toxicity profile, evidence of at least transient clinical activity, and results of in vitro resistance experiments support further clinical testing in combination therapy.

Acyclovir for prevention of cytomegalovirus infection and disease after allogeneic marrow transplantation.

Patients undergoing allogeneic bone marrow transplantation who are seropositive for cytomegalovirus are vulnerable to serious cytomegalovirus infection, presumably because of reactivation of latent endogenous virus and severe immunosuppression. We administered intravenous acyclovir from 5 days before to 30 days after allogeneic marrow transplantation for hematologic neoplasms in an effort to prevent cytomegalovirus infection and disease in patients seropositive for cytomegalovirus before transplantation. Eighty-six patients seropositive for both cytomegalovirus and herpes simplex virus before transplantation received acyclovir, whereas 65 patients seropositive only for cytomegalovirus served as controls (acyclovir is the standard prophylactic agent against herpes simplex virus in this setting). The probability that cytomegalovirus infection would develop within the first 100 days after transplantation was 0.70 among acyclovir recipients and 0.87 among control patients at medians of 62 and 40 days after transplantation, respectively (P = 0.0001 by log-rank test). Invasive cytomegalovirus disease developed in 19 acyclovir recipients (22 percent) and 25 control patients (38 percent) (P = 0.008). Survival within the first 100 days after transplantation was better among acyclovir recipients (P = 0.002). Acyclovir prophylaxis was associated with a relative risk of 0.5 or less for the development of cytomegalovirus infection or disease or for death within the first 100 days after transplantation (P less than or equal to 0.04), in proportional-hazards regression analysis. We conclude that prophylaxis with intravenous acyclovir significantly reduced the risk of both cytomegalovirus infection and cytomegalovirus disease in seropositive patients after allogeneic bone marrow transplantation and that it was also associated with significantly improved survival.

Serum is an acceptable specimen for measuring acyclovir levels.

Acyclovir levels to date have been performed on plasma rather than serum samples. To determine if serum was an acceptable specimen, acyclovir levels were measured on simultaneously collected plasma and serum samples by radioimmunoassay. Eighty-two paired samples from 20 patients containing between 0.39 and 115.3 microM acyclovir were studied. Least squares regression, orthogonal regression, and two-way analysis of variance with replication all indicated an acceptably high degree of correlation. We concluded that serum is a suitable specimen for measuring acyclovir levels.