Health Canada has expanded the approved use of obinutuzumab (Gazyva®).
The anti-CD20 monoclonal antibody is now approved for use in combination with chemotherapy to treat patients with previously untreated follicular lymphoma (FL) that is advanced (stage II bulky, stage III, or stage IV).
In patients who respond to this treatment, obinutuzumab monotherapy can be given as maintenance.
Health Canada previously approved obinutuzumab for the following indications:
- In combination with chlorambucil to treat patients with previously untreated chronic lymphocytic leukemia
- First in combination with bendamustine, then as monotherapy, in FL patients who relapsed after or are refractory to a rituximab-containing regimen.
Phase 3 results
Health Canada’s latest approval of obinutuzumab is based on results from the phase 3 GALLIUM study, which were published in NEJM in October 2017. The following are updated data from the product monograph.
GALLIUM included 1385 patients with previously untreated non-Hodgkin lymphoma, and 1202 of these patients had previously untreated, advanced FL.
Half of the FL patients (n=601) were randomized to receive obinutuzumab plus chemotherapy (followed by obinutuzumab maintenance for up to 2 years), and half were randomized to rituximab plus chemotherapy (followed by rituximab maintenance for up to 2 years).
The different chemotherapies used were CHOP (cyclophosphamide, doxorubicin, vincristine, and prednisone), CVP (cyclophosphamide, vincristine, and prednisone), and bendamustine.
At a median observation time of 41.1 months, the overall response rate was 91% in the obinutuzumab arm and 88% in the rituximab arm. The complete response rates were 28% and 27%, respectively.
The median progression-free survival was not reached in either arm. The hazard ratio, for obinutuzumab compared to rituximab, was 0.72 (95% CI, 0.56-0.93, P=0.0118).
The estimated 3-year progression-free survival was 78.9% in the rituximab arm and 83.4% in the obinutuzumab arm.
Safety was evaluated based on all 1385 patients in the study, 86% of whom had FL and 14% of whom had marginal zone lymphoma.
Serious adverse events (AEs) occurred in 50% of patients in the obinutuzumab arm and 43% in the rituximab arm. Fatal AEs occurred in 5% and 4%, respectively. Infections and second malignancies were the leading causes of these deaths.
During the monotherapy period, the most common AEs (≥ 5%) in patients treated with obinutuzumab were cough (21%), neutropenia (19%), upper respiratory tract infection (15%), viral upper respiratory tract infection (15%), diarrhea (13%), arthralgia (10%), fatigue (9%), sinusitis (9%), infusion reactions (8%), pneumonia (8%), herpes zoster (8%), lower respiratory tract infection (7%), pyrexia (7%), back pain (6%), headache (6%), urinary tract infection (6%), nausea (6%), bronchitis (5%), and vomiting (5%).
Grade 3-4 AEs (≥1%) in patients treated with obinutuzumab included neutropenia (17%), pneumonia (3%), and febrile neutropenia (2%). There were 2 deaths due to pneumonia in the obinutuzumab arm.