OBJECTIVES: I. Evaluate the efficacy of tin mesoporphyrin in patients with acute porphyria attacks who are also treated with a standard course of heme arginate.

II. Evaluate the safety and tolerability of tin mesoporphyrin when administered to these patients.

PROTOCOL OUTLINE: This is an randomized, unblinded, multicenter study. Patients are randomized to receive heme arginate alone or both heme arginate and tin mesoporphyrin.

Patients receive a single intravenous dose of tin mesoporphyrin immediately before the first dose of heme arginate. Heme arginate is administered daily for 4 days.

Patients are followed at 3 and 6 days after treatment.

PROTOCOL ENTRY CRITERIA:

--Disease Characteristics--

Documented acute intermittent porphyria, variegate porphyria, or hereditary coproporphyria

No chronic or subacute symptoms (present for longer than 2 weeks)

--Prior/Concurrent Therapy--

At least 3 weeks since prior treatment with heme arginate or tin mesoporphyrin

--Patient Characteristics--

Renal: Urinary porphobilinogen at least 40 mg/24 hr

Other:

• Not pregnant
• Fertile female patients must use effective contraception during and 6 months before study
• No evidence that symptoms are due to another acute illness
• No acute hemorrhagic disorder such as: Gastrointestinal bleeding Intracerebral hemorrhage
• No known sensitivity to heme preparation or tin mesoporphyrin
• No other medical condition that might increase risk to patient