SAN DIEGO Among patients with previously untreated follicular lymphoma, obinutuzumab-based induction and maintenance chemoimmunotherapy significantly improved progression-free survival compared with rituximab-based therapy, according to a study presented during the plenary session of the American Society of Hematology (ASH) 58th Annual Meeting and Exposition.1

“There is significant benefit with rituximab-based induction plus maintenance in patients with previously-untreated, advanced-stage, symptomatic follicular lymphoma,” said principal investigator Robert E. Marcus, MBBS, FRCP, FRCPath, Kings College Hospital, London, United Kingdom. “Obinutuzumab, a glycol-engineered type 2 anti-CD20 monoclonal antibody, has been shown to prolong progression-free survival when combined with bendamustine in rituximab-refractory indolent non-Hodgkin lymphoma.”

For this cohort of the open-label, phase 3 GALLIUM study (ClinicalTrials.gov Identifier: NCT01332968), researchers enrolled 1202 patients with previously untreated, grade 1-3a, follicular lymphoma to compare the efficacy and safety of obinutuzumab-based and rituximab-based regimens.

Participants were randomly assigned 1:1 to rituximab or obinutuzumab with CHOP (cyclophosphamide, doxorubicin, vincristine, prednisone) or CVP (cyclophosphamide, bortezomib, prednisone) chemotherapy. Patients with a complete or partial response at the end of induction received rituximab or obinutuzumab maintenance every 2 months for 2 years or until disease progression.

After a median follow-up of 34.5 months, results showed that obinutuzumab-based therapy reduced the risk of progression or death by 34% compared with rituximab-based therapy (hazard ratio, 0.66; 95% CI, 0.51-0.85; P = .0012), leading to an approximately 1.5 times longer median progression-free survival with obinutuzumab vs rituximab.

The 3-year progression-free survival rates per investigator assessment were 80.0% (95% CI, 75.9-83.6) with obinutuzumab-chemotherapy and 73.3% (95% CI, 68.8-77.2) with rituximab-chemotherapy.

“Obinutuzumab-chemotherapy plus maintenance is superior to rituximab-chemotherapy plus maintenance in untreated follicular lymphoma patients in this interim efficacy analysis,” said Dr Marcus. “The progression-free survival results are supported by other time-to-event endpoints.”

The study did not, however, demonstrate a significant difference in overall survival between the 2 treatment arms (hazard ratio, 0.75; 95% CI, 0.49-1.17; P = .21).

Obinutuzumab-based therapy was associated with a higher frequency of grade 3 to 5 and serious adverse events, including infusion-related reaction, cytopenias, and infections vs rituximab-based therapy.

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“Non-fatal adverse events were higher in the obinutuzumab arm,” Dr Marcus added. “Fatal adverse events were more common in patients on bendamustine in both arms.

“Obinutuzumab-based therapy significantly improves outcome compared with rituximab-based therapy and should now be considered as a first-line treatment for follicular lymphoma,” Dr Marcus concluded.

Reference

  1. Marcus RE, Davies AJ, Ando K, et al. Obinutuzumab-based induction and maintenance prolongs progression-free survival (PFS) in patients with previously untreated follicular lymphoma: Primary results of the randomized phase 3 GALLIUM study. Paper presented at: American Society of Hematology (ASH) 58th Annual Meeting and Exposition; December 3-6, 2016; San Diego, CA.