Relapsed/Refractory MCL with bendamustine-rituximab: Measurement of response and prediction by FDG-PET

This article was recently written and published by Dominick Lamonica from the State University of New York, Buffalo along with his colleagues in Journal of Nuclear Medicine in July 2016, describing data from a phase II clinical trial in patients (n=45) with relapsed/refractory mantle cell lymphoma (MCL) who had undergone prespecified ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) at screening and had six cycles of bendamustine-rituximab (BR) therapy.

The key findings were as follows:

• The complete data was available for 32 out of 45 patients and it was reported that 24 patients attained complete metabolic responses (CMR) after 6 cycles of BR
• The patients attaining CMR demonstrated an overall response rate of 96% by the International Working Group (IWG) criteria, with 62.5% achieving a complete response
• CMR was found to be associated with greater 1 year progression-free survival (91.5%) compared to those (12.5%) without CMR, longer median duration of response (20.6 months compared with 7.8 months) and improved overall survival at 1 year.
• FDG-PET data from patients with refractory or advanced disease demonstrated CMR in more than half of the patients

Conclusions

Patients with relapsed/refractory MCL who have undergone FDG-PET and received BR indicated CMR predicted an improved 1-year survival, duration of response and overall survival.

18F-Fluorodeoxyglucose (FDG) PET for measurement of response and prediction of outcome to relapsed/refractory mantle cell lymphoma (MCL) therapy with bendamustine-rituximab (BR)

Abstract

In a single-arm, phase 2 clinical trial, bendamustine-rituximab (BR) demonstrated an overall response rate (ORR) of 82% among 45 patients with relapsed/refractory mantle cell lymphoma (MCL), with manageable tolerability. A prespecified ¹⁸F-fluorodeoxyglucose positron emission tomography (FDG-PET) analysis was conducted to assess the predictive value of the metabolic response to BR compared with the response by International Working Group (IWG) criteria.

METHODS:

Adult patients with relapsed/refractory MCL underwent FDG-PET at screening and following 6 cycles of BR therapy. Scans were reviewed by a central facility and scored using the 5-point Deauville scale, comparing uptake to the liver and mediastinum in up to 6 lesions, to determine metabolic response rates, indicated by negative posttreatment scans. Metabolic responses were compared with study outcomes assessed by IWG criteria.

RESULTS:

Complete FDG-PET data were available for 32 of 45 patients. All patients had positive baseline scans, with baseline scores ranging from 4 to 5. Complete metabolic responses (CMR) were observed in 24 (75%) patients after 6 cycles of BR. Patients attaining a CMR had a 96% ORR by IWG criteria, with 62.5% achieving a complete response (CR). Of the 8 patients not attaining a CMR, 6 responded to BR but none achieved a CR. CMR was associated with greater 1-y progression-free survival of 91.5% compared with 12.5% without CMR; longer median duration of response (DOR) of 20.6 months compared with 7.8 months; and improved overall survival (OS) at 1 year. FDG-PET data from patients with refractory or advanced disease demonstrated CMR in more than half.

CONCLUSION:

Compared with positive end-of-treatment FDG-PET, negative scans, indicating a CMR, were predictive of improved 1-year survival, DOR, and OS for patients with relapsed/refractory MCL receiving BR.