A drug we didn’t know we needed
STUDY TYPE: Pharmacokinetic equivalence study
FUNDING: Vanda Pharmaceuticals
On February 20, 2026, the FDA approved a new psychiatric medication without any clinical trials. The drug is milsaperidone (Bysanti), an antipsychotic approved for adults with schizophrenia or acute bipolar I manic or mixed episodes.
Milsaperidone is an active metabolite of iloperidone (Fanapt), and vice versa. In other words, the two convert into each other at a steady rate, so that when you give one of them you are effectively given both.
To prove that point, Vanda Pharmaceuticals submitted pharmacokinetic data showing exactly that:
The lines overlap at low and high doses, after a single dose and at steady state.
The company is due to lose its patent on Fanapt in 2027 or 2028, and this new approval will extend that patent on a virtually identical drug to 2044.
In a press release, Vanda cited no advantages of this clone, other than patent extension that will allow them to conduct trials in major depression (and the fact that it rests on “100,000 patient-years of real-world experience with Fanapt”).
Historical Precedence
The FDA laid the ground for these kinds of approvals in 1984, through the 505(b)(2) New Drug Application pathway, which allows approval of drugs that convert into known entities. However, only around 25% have been approved on pharmacokinetics alone, and this is the first I’m aware of like that in psychiatry.
Within psychiatry, some XR formulations were approved without new clinical trials, like like Aplenzin (bupropion hydrobromide), which created a more expensive version of Wellbutrin by pairing it with a hydrobromide salt. That approval was also suspect, as bromides were taken off the market in the 1970’s due to risks of cancer, thyroid problems, infertility, and intoxication (bromism). By my calculations, the full dose of Aplenzin is enough to raise these risks.
Unlike Aplenzin, with Bysanti the generic version does not appear in the drug name, giving the false impression that it is a new drug.
Practice Implications
- Milsaperidone (Bysanti) is a branded drug that is identical to the soon-to-be-generic iloperidone.
- Iloperidone has no data in bipolar depression, bipolar maintenance. In schizophrenia, it ranks low for efficacy and poor for tolerability.
—Chris Aiken, MD
Director, Psych Partners
Editor in Chief, Carlat Psychiatry Report
What’s Your Take? Share in Comments
- Am I missing something? Do you see an advantage with this approval?
One comment
Ben Wise, MD
April 6, 2026 at 2:17 pm
As always sir, appreciate you being on top of what the reps are up to.