OBJECTIVES

: Complete response (CR) has been proposed as a surrogate end point for survival in first-line follicular lymphoma (FL) treatment trials. However, its prognostic value beyond initial treatment is still unknown. The objective of this study is to compare CR vs non-CR status as estimators of survival for patients (pts) with relapsed/refractory (r/r) FL.

METHODS

: We performed a systematic literature review (SLR) on clinical outcomes in pts with r/r FL after two prior therapies. Clinical trials and observational studies were searched through Embase, PubMed, and Cochrane Central Register from 1998 to 2020. Eligible studies for meta-analysis were studies reporting Kaplan-Meier (K-M) curve of OS or PFS stratified by responding category (CR, non-CR including partial response [PR], stable disease [SD], and progressive disease [PD]). Data were extracted using digitizing software; hazard ratios (HRs) comparing OS or PFS curves by CR vs each of non-CR status were calculated as previously described by Tierney JF et al. (2007). A pooled HR was calculated based on the method previously described by Parmar MKB et al. (1998).

RESULTS

: Of the 3747 publications screened through SLR, 88 studies were reviewed, among which 4 reported K-M curve stratified by responding status. The four studies included in the meta-analysis appear heterogeneous in terms of received treatment regimens, patient baseline characteristics, responses to prior regimens, and response measurement time. The survival rates were numerically longer in pts achieving CR than for those pts achieving non-CR (OS: HR 0-0.89 comparing CR vs PR and HR 0.17-0.38 comparing CR vs SD/PD). On meta-analyses of OS, pooled HRs comparing CR vs non-CR status were estimated to be 0.21-0.25.

CONCLUSIONS

: These findings suggest that achieving a CR in r/r FL associates with substantial overall survival benefit. New treatments targeting the r/r FL could aim at increasing the CR rates.