Elderly Men May Need Higher Rituximab Dose for DLBCL

the Cancer Therapy Advisor take:

Survival for elderly men with diffuse large B-cell lymphoma (DLBCL) who are receiving standard therapy appears to be lower than that of elderly women on the same treatment regimen. According to research presented at the 2014 American Society of Clinical Oncology (ASCO) Annual Meeting, this difference in survival may be due to sex-related differences in clearance rate of rituximab.

Elderly men, for example, have faster rituximab clearance rates than elderly women, thereby shortening their exposure time to the treatment.

Researchers found that boosting the rituximab dose from 375 mg/m2 to 500 mg/m2 improved progression-free survival (PFS) and overall survival (OS) so that it was comparable to that seen in elderly women with DLBCL. Both groups received treatment with rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone (R-CHOP-14).

For this study, dubbed SEXIE-R-CHOP 14, the researchers randomly assigned 268 evaluable patients aged 60 to 80 years receive treatment. A total of 148 men received rituximab 500 mg/m2 instead of 375 mg/m2 and 120 women received rituximab 375 mg/m2.

Event-free survival (EFS) at 3 years was 68% for women and 65% in men. PFS at 3 years was also 68% for women but 74% for men. Also at 3 years, OS was 72% for women and 80% for men, according to the study data. Further, multivariable analysis showed significantly improved PFS, EFS, and OS in men receiving a higher dose, as compared with women.

The researchers speculate that younger men and women, who also have faster rituximab clearance rates than elderly women, may also benefit from higher rituximab doses.

Experts concluded that these study results should spur reevaluation of rituximab and its use in clinical practice.