ASH 2017 | 10-year updated PRIMA study results for FL patients receiving rituximab maintenance 

The 59^th Annual Meeting & Exposition of the American Society of Hematology (ASH) took place in Atlanta, GA, on December 9–12, 2017. On Sunday December 10^th, abstract #486 was presented during this session titled “Long Term Follow-up of the PRIMA Study: Half of Patients Receiving Rituximab Maintenance Remain Progression Free at 10 Years” by Gilles Andre Salles, Hospices Civils de Lyon - Université de Lyon, Pierre-Bénite, France and colleagues.

The Primary RItuximab and MAintenance (PRIMA) study aimed to evaluate the benefit of rituximab (R) maintenance in patients with follicular lymphoma (FL) after response to a first line R-chemotherapy induction. This study was based on previous evidence suggesting that rituximab maintenance provides significant clinical benefit to FL patients. The ASH oral presentation provided the 10-year updated results of the PRIMA trial. This article is based on data presented at the live session, which may supersede information in the pre-published ASH Abstract.

Study Highlights

• Patients with FL were randomized firstly to an R-chemotherapy induction regime and then randomized to either observation or to receive R-maintenance (375 mg/m²) every 8 weeks for 2 years
• A total of 607 patients were available for follow-up with a median of 9.7 years
• Median progression-free survival (PFS): 4.1 observation vs 5 years R-maintenance (P < 0.0001; HR=0.61, 95% CI, 0.52–0.73)
• 10-year estimated disease-free progression: 35% observation vs 51% R-maintenance
• R-maintenance was shown to be favorable across all major sub-groups including age, FLIPI Index and response to induction
• Time-to-next-treatment median time was not reached for the R-maintenance group vs 6 years with observation (P < 0.001; HR=0.66, 95% CI 0.55–0.78)
• The overall survival (OS) was not significantly different between the two arms: 80% R-maintenance vs 80% observation (P = 0.795; HR=1.04, 95% CI 0.77–1.40)
• No new safety signals emerged from this study

The 10-year updated results showed that R-maintenance after induction immunochemotherapy had enduring PFS benefit compared with observation. Although the OS survival was not significantly different between the two groups, patients with high tumor burden had an 80% chance of survival at ten years. Gillies Salles concluded that “with more than half of the patients responding to rituximab chemo and having received rituximab maintenance with a free-of-disease recurrence at 10 years, should we really continue to say that follicular lymphoma is an incurable disease?”

Watch the full interview with Gilles Salles discussing the results of the PRIMA study here.