A Pilot Study of 566C80 for the Salvage Treatment of Toxoplasmic Encephalitis in Patients Infected With the Human Immunodeficiency Virus (HIV) Who Have Failed or Are Intolerant of Pyrimethamine-Sulfadiazine

Inclusion Criteria Patients must have the following: * Presumptive diagnosis of AIDS. * Cerebral toxoplasmosis. * Expected survival of at least four weeks without therapy. * Willing and able to give informed consent. Prior Medication: Allowed: * Pyrimethamine-sulfonamide. * Clindamycin-sulfonamide. Exclusion Criteria Co-existing Condition: Patients with the following conditions or symptoms are excluded: * Significant emotional disorder or psychosis. * Evidence of significant malabsorption, ileus or significant emesis at entry which would inhibit drug absorption. * Other known central nervous system lesions such as lymphoma, tuberculoma, cryptococcoma, active neurosyphilis. Unwilling or unable to take 566C80 with a meal, enteral supplements (eg: * Ensure Plus) or pulverized form through a nasogastric tube. * Active drug or alcohol abuse sufficient in the investigator's opinion to prevent compliance with the study regimen. Concurrent Medication: Excluded: * Drugs with potential anti-toxoplasmosis activity including sulfone, sulfonamide, trimethoprim, pyrimethamine and clindamycin during the acute therapy phase of the trial. * First three weeks of treatment: * Retrovir (zidovudine) or any investigational agent including antiretroviral agents (eg: * ddI,ddC). Patients with the following are excluded: * Significant emotional disorder or psychosis. * Evidence of significant malabsorption, ileus or significant emesis at entry which would inhibit drug absorption. * Othe…