SALT LAKE CITY — Because several studies have suggested it fails to increase overall survival (OS) despite prolonging progression-free survival (PFS), use of maintenance rituximab (MR) following chemoimmunotherapy in follicular lymphoma (FL) remains controversial.
A study published in the journal Blood examined real-world outcomes of FL patients receiving MR following induction therapy. To do that, they extracted data from the electronic health record of the VHA, the largest nationwide integrated health system in the United States.1
A study team led by researchers from the George E. Wahlen VAMC in Salt Lake City focused on FL patients diagnosed from 2006-2014 and treated at the VHA, identifying them by linking information from the VA Clinical Cancer Registry (VACCR) to administrative, lab and pharmacy data, and clinical and radiology notes in the VHA Corporate Data Warehouse (CDW).
Veterans diagnosed with Grades 1-3a and Stages II-IV, had no evidence of prior malignancy, received continuous hematology/oncology care in the VHA from time of diagnosis through first-line (1L) treatment were eligible for analysis. Patients were included if they received rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP); rituximab plus cyclophosphamide, vincristine and prednisone (RCVP); bendamustine and rituximab (BR); or single-agent rituximab (R).
Excluded were patients who had evidence of progressive disease (PD) upon their first post-induction imaging response assessment (by CT and/or PET/CT) following the completion of 1L therapy.
With radiology reports retrievable for 80% of patients, potential participants were classified as PD, stable disease (SD), partial response (PR) or complete response (CR). The study included patients who survived three months following the completion of 1L therapy and did not receive 2L therapy.
Overall, 905 FL patients met inclusion criteria. Of participants, median age was 65 years, 860 (95%) were male, 791 (87%) were non-Hispanic white, 697 (77%) had Grade 1-2 FL at time of diagnosis and 754 (83%) had Stage III-IV disease.
At 1L, 243 (27%) had a Hb < 12, 237 (26%) had an LDH &rt; ULN, and 511 (56%) had a CCI of &rt; 1. The majority of patients received R-CHOP (324, 36%) as 1L. 248 (27%) received RCVP, 190 (21%) received BR, and 143 (16%) received single agent rituximab, while. 320 patients (35%) received MR.
Results indicated that the patients and disease characteristics for patients who received MR were comparable to those patients who did not receive MR with one exception: MR patients were less likely to have hemoglobin levels less than 12. The five-year overall survival (OS) of all patients was 76%, and the median follow-up was 3.9 years.
“This is the first study in the US that details patient and disease specific prognostic features, treatment practices, and outcomes, using EHR data in a real world nationwide cohort of FL patients,” study authors wrote. “Our cohort’s average age and five-year OS were comparable to those reported in SEER. Patient comorbidities (CCI) and recognized FL prognostic factors (age, Hb, LDH) were significantly associated with a worse survival. In a multivariate model that adjusted for these patient and disease specific risk factors, MR was associated with an improvement in OS. Our report, in addition to those previously mentioned, provide additional evidence that MR improves OS in real-world patient populations.”
1Halwani, A.S., Rasmussen, K., Patil, V., Burningham, Z., Low, C., Reyes, C. M., Masaquel, A., Henderson, K., Delong-Sieg, E., & Sauer, B.C. (2017). Maintenance Rituximab after First-Line Treatment in Veterans with Follicular Lymphoma Is Associated with Prolonged Overall Survival. Blood, 130(Suppl 1), 1489. Accessed April 16, 2018. Retrieved from http://www.bloodjournal.org/content/130/Suppl_1/1489.
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