The FDA has approved obinutuzumab, an engineered monoclonal antibody designed to attach to CD20, in combination with chemotherapy, followed by obinutuzumab alone in those who responded, for people with previously untreated advanced follicular lymphoma (stage II bulky, III, or IV).
The approval is based on results from the phase III GALLIUM study (NCT01332968), which showed superior progression-free survival (PFS) for patients who received this obinutuzumab-based regimen compared with those who received a rituximab-based regimen as first-line therapy. Follicular lymphoma, the most common indolent form of non-Hodgkin lymphoma, is incurable and becomes harder to treat each time it returns.
The obinutuzumab-based regimen significantly reduced the risk of disease worsening or death compared to rituximab by 28 percent (PFS as assessed by independent review committee; HR=0.72; 95% CI 0.56-0.93; p=0.0118). Safety was evaluated based on 1,385 patients with previously untreated follicular lymphoma (86%) or marginal zone lymphoma (14%).
The most common grade 3-5 side effects (occurring in at least 5% of patients) observed more frequently in the obinutuzumab arm were low white blood cell count, infusion reactions, low white blood cell count with fever, and low platelet count.
The most common side effects (occurring in at least 20% of patients) observed at least 2 percent more frequently in the obinutuzumab arm included infusion reactions, low white blood cell count, upper respiratory tract infection, cough, constipation, and diarrhea.
The supplemental Biologics License Application for obinutuzumab, based on the GALLIUM data, was granted Priority Review, a designation given to medicines that the FDA has determined to have the potential to provide significant improvements in the treatment, prevention, or diagnosis of a disease.
With this approval, obinutuzumab is available in the U.S. for three different indications across two common types of blood cancer. Other indications for obinutuzumab include: with the chemotherapy drug, chlorambucil, to treat chronic lymphocytic leukemia (CLL) in adults who have not had previous CLL treatment; with the chemotherapy drug, bendamustine, followed by obinutuzumab alone for follicular lymphoma in adults who did not respond to a rituximab-containing regimen, or whose follicular lymphoma returned after such treatment; and with chemotherapy, followed by obinutuzumab alone in those who responded, to treat stage II bulky, III, or IV follicular lymphoma in adults who have not had previous treatment.