The U.S. Food and Drug Administration (FDA) approved emapalumab, an anti-interferon gamma monoclonal antibody, for the treatment of adults and children with primary hemophagocytic lymphohistiocytosis (HLH) that was refractory or relapsed or progressed following conventional HLH therapy.
The approval, which also included patients who could not tolerate conventional therapy, was based on results from a multicenter, open-label, single-arm trial, which included 27 pediatric patients who received emapalumab at a starting dose of 1 mg/kg every three days. All participants received dexamethasone as background HLH treatment, at doses ranging between 5 to 10 mg/m2 per day. Before administration of emapalumab, patients also received prophylaxis for herpes zoster, Pneumocystis jirovecii, and fungal infections.
At the end of the treatment period, the overall response rate (defined as a complete response [CR] or partial response [PR] or improvement in HLH), was 63 percent. Responses included seven CRs and eight PRs, and two patients who experienced an improvement in HLH (defined as ≥3 HLH abnormalities improved by at least 50 percent from baseline).
The most common adverse events (AEs; occurring in ≥20% of patients) were infections, hypertension, infusion-related reactions, and pyrexia.
Emapalumab also received priority-review, breakthrough-therapy designation, and orphan-product designation.
Source: FDA news release, November 20, 2018.