Posted On: 12/16/2016 9:00:30 PM
Post# of 72436
Any trial conducted after approval would be Phase 4, but the primary objective is usually long-term safety at the therapeutic dosage used in Phase 3, not efficacy at a different dosage. If CTIX wants to see the efficacy at dosage > 400 mg, they need to run another Phase 3.
Ziagen has 83% bioavailability. Since 300 mg of Ziagen is bioequivalent to 350 mg of Prurisol, Prurisol has 71% bioavailability. Ziagen is often prescribed for 600 mg per day, so there's:
600 mg of Ziagen * 0.83 = 498 mg of abacavir in circulation
400 mg of Prurisol * 0.71 = 284 mg of abacavir in circulation
We already know that 200 mg is working. I think 400 mg is the sweet spot for efficacy without the nasty side effects. Anything higher could have side effects similar to Ziagen.
Ziagen has 83% bioavailability. Since 300 mg of Ziagen is bioequivalent to 350 mg of Prurisol, Prurisol has 71% bioavailability. Ziagen is often prescribed for 600 mg per day, so there's:
600 mg of Ziagen * 0.83 = 498 mg of abacavir in circulation
400 mg of Prurisol * 0.71 = 284 mg of abacavir in circulation
We already know that 200 mg is working. I think 400 mg is the sweet spot for efficacy without the nasty side effects. Anything higher could have side effects similar to Ziagen.
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