Phase I studies of hypericin, the active compound in St. John's Wort, as an antiretroviral agent in HIV-infected adults. AIDS Clinical Trials Group Protocols 150 and 258.

BACKGROUND

Hypericin, the active compound in St. John's Wort, has antiretroviral activity in vitro. Many HIV-infected persons use St. John's wort.

OBJECTIVE

To evaluate the safety and antiretroviral activity of hypericin in HIV-infected patients.

DESIGN

Phase I study.

SETTING

Four clinical research units.

PATIENTS: 30 HIV-infected patients with CD4 counts less than 350 cells/mm3.

INTERVENTION: Intravenous hypericin, 0.25 or 0.5 mg/kg of body weight twice weekly or 0.25 mg/kg three times weekly, or oral hypericin, 0.5 mg/kg daily.

MEASUREMENTS: Safety was assessed at weekly visits. Antiretroviral activity was assessed by changes in HIV p24 antigen level, HIV titer, HIV RNA copies, and CD4 cell counts.

RESULTS

Of the 30 patients who were enrolled, 16 discontinued treatment early because of toxic effects. Severe cutaneous phototoxicity was observed in 11 of 23 (48% [95% CI, 27% to 69%]) evaluable patients, and dose escalation could not be completed. Virologic markers and CD4 cell count did not significantly change.

CONCLUSIONS

Hypericin caused significant phototoxicity and had no antiretroviral activity in the limited number of patients studied.