On 17 August 2017, the US Food and Drug Administration (FDA) approved inotuzumab ozogamicin (BESPONSA, Wyeth Pharmaceuticals Inc., a subsidiary of Pfizer Inc.) for the treatment of adults with relapsed or refractory B-cell precursor acute lymphoblastic leukaemia (ALL).
The approval was based on data from INO-VATE ALL (NCT01564784), a randomised (1:1), open label, international, multicentre study in 326 patients with Philadelphia chromosome-negative or Philadelphia chromosome-positive relapsed or refractory B-cell precursor ALL. Patients were required to have ≥5% bone marrow blasts and to have received one or two previous induction chemotherapy regimens for ALL. Patients with Philadelphia chromosome positive B cell precursor ALL were required to have disease that failed treatment with at least one tyrosine kinase inhibitor and standard chemotherapy.
Patients were randomised to receive inotuzumab ozogamicin (n=164) or investigator’s choice of chemotherapy (n=162). Of the initial 218 randomised patients, 35.8% of those who received inotuzumab ozogamicin experienced complete remission (CR) for a median 8.0 months and 89.7% of those patients achieved minimal residual disease (MRD)-negativity. Of the patients who received chemotherapy, 17.4% experienced CR for a median 4.9 months and 31.6% of those patients achieved MRD-negativity.
The most common adverse reactions occurring in greater than 20% of patients were thrombocytopenia, neutropenia, infection, anaemia, leukopenia, fatigue, haemorrhage, pyrexia, nausea, headache, febrile neutropenia, transaminases increased, abdominal pain, gamma-glutamyltransferase increased, and hyperbilirubinemia. The most common (≥2%) adverse reactions reported as the reason for permanent discontinuation were infection, thrombocytopenia, hyperbilirubinemia, transaminases increased, and haemorrhage.
For the first cycle, the recommended dose of inotuzumab ozogamicin for all patients is 1.8 mg/m2 per cycle, administered as three divided doses on day 1 (0.8 mg/m2), day 8 (0.5 mg/m2), and day 15 (0.5 mg/m2). The recommended dosing for subsequent cycles depends on response to treatment. Details are available in the full prescribing information here.
FDA previously granted Orphan Drug and Breakthrough Therapy designations to inotuzumab ozogamicin for the treatment of ALL, as well as priority review.
Healthcare professionals should report all serious adverse events suspected to be associated with the use of any medicine and device to FDA’s MedWatch Reporting System.