More than 60 years after it first became available as a 50-mg tablet, an oral suspension formulation of mercaptopurine has been approved by the Food and Drug Administration.
The oral suspension formulation (20 mg/mL) – approved on April 28 for the treatment of patients with acute lymphoblastic leukemia as part of a combination regimen – will make it possible to more accurately dose pediatric patients with ALL, according to the FDA announcement of the approval.
Mercaptopurine, a nucleoside metabolic inhibitor, was initially approved in 1953, in a 50-mg tablet formulation. Until now, this has been the only formulation available, which the FDA statement points out is not an ideal dosage form for children under age 6. Compounded formulations provided by local pharmacies or splitting the 50-mg tablets have been used to dose children, but "a suspension offers the advantage of more accurately delivering the desired dose to children with a wide range of weights using a consistent administration schedule," and will make it possible to be more flexible in adjusting the dose, the FDA statement said.
Approval of the suspension was based on a clinical pharmacology study that evaluated the bioequivalence of mercaptopurine tablets with the oral suspension in healthy adults. The starting dose of mercaptopurine in multiagent combination chemotherapy maintenance regimens is 1.5 to 2.5 mg/kg (50-75 mg/m2) as a single daily dose.
The suspension is manufactured by NOVA Laboratories in the United Kingdom, and it will be distributed in the United States by Rare Disease Therapeutics under the trade name Purixan. The prescribing information is available here.
Serious adverse events associated with this product should be reported to the FDA’s MedWatch program at 800-332-1088 or www.fda.gov/medwatch/.