Rituximab response in follicular lymphoma is associated with the rs20575 polymorphism in TRAILR1 extrinsic apoptosis trigger.

OBJECTIVE: Rituximab in combination with chemotherapy has been proven to increase progression-free and overall survival in follicular lymphoma (FL), but there is considerable interindividual variability in the response. Extrinsic pathway apoptosis triggered by death receptors seems to be involved in the mechanism of action of monoclonal antibodies. This study aimed to assess the association between TRAILR1/TRAIL polymorphisms (rs20575, rs20576, rs2230229, rs12488654) and rituximab response and the relationship with FASL rs763110, previously found to be associated with rituximab response.

PATIENTS AND METHODS: Polymorphisms were determined in a study cohort of 125 FL patients treated with rituximab as first-line treatment and correlated with response, which was scored according to the International Working Group Consensus Revised as complete response, partial response, stable disease, and progressive disease.

RESULTS: No significant association with response was found for rs20576, rs2230229, and rs12488654 polymorphisms. In contrast, rs20575 GC/GG carriers were more partial/nonresponders (88.2%) than complete responders (72.5%), showing a trend toward statistical significance (P=0.064). In a multivariable setting, we found that female sex [odds ratio=0.355, 95% confidence interval (CI): 0.137-0.922, P=0.033] and the TRAILR1 rs20575 CC genotype (odds ratio=0.162, 95% CI: 0.035-0.757, P=0.021) were independent positive predictive factors of complete clinical response to rituximab, constructing a parsimonious model with good calibration [χ of 5.719 (d.f.=6, P=0.455)] and discrimination (C-statistic=0.739, 95% CI: 0.636-0.842).

CONCLUSION: After studying the pharmacogenetic role of TRAILR1/TRAIL polymorphisms in rituximab-treated FL patients, we found that the rs20575 CC genotype is an independent predictive factor of better rituximab response, indicating the possible involvement of death receptors in anti-CD20 mechanisms of action.