Japan's health ministry has asked doctors to stop starting new patients on avacopan, a vasculitis drug sold by Kissei Pharmaceutical, and, for patients already on it, to consider stopping or switching to alternative treatment as the general rule. Kissei set out the request in a notice dated October 22, 2026, after a ministry panel met the previous day.
What the panel concluded
The Second Committee on Drugs of the Pharmaceutical Affairs Council met on October 21. It heard the Pharmaceuticals and Medical Devices Agency report the ministry's findings from its review of the written response Kissei submitted under a reporting order from the health minister. The order asked the company to verify the reliability of the international Phase III trial data, which has been questioned in the US and Europe, and the drug's safety.
According to Kissei, the deliberations confirmed there may be problems with the reliability of the materials submitted at the approval review. They also found it difficult to judge that the drug's therapeutic benefit outweighs its risks. The panel added that the disease is a serious rare one, and that any treatment change for patients already on the drug must be decided individually, given their condition and other options.
The ministry's three requests
The ministry issued a notice to medical institutions the same day, asking for the following "for the time being":
| Patient group | Request |
|---|---|
| New patients | Refrain from starting avacopan |
| Patients now on avacopan | As a rule, consider stopping or switching to alternative treatment, based on each patient's condition, effect, other options and the impact of a change |
| Patients who continue on avacopan | Keep to proper use under the May 21 safety bulletin (blue letter) |
Avacopan is approved in Japan for microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA), both designated intractable diseases. Kissei says authorities are still reviewing the clinical trial data behind the approval, along with the drug's benefits and risks.
The earlier steps
This follows two earlier actions by Kissei. On May 15, 2026 it began asking healthcare professionals to prescribe with caution. On May 21 it revised the Japanese package insert for serious liver injury and issued a safety bulletin, known as a blue letter.
Kissei says it will pass the ministry's position to medical institutions promptly and has a drug information line for clinicians and patients. In the US, the drug is currently supplied to patients with severe, active MPA or GPA.
Financial impact
Kissei says it is examining the effect on its results and will disclose it promptly if it becomes clear that the matter will affect them. The notice gives no sales figure for the drug and no estimate of the impact.