A systematic review and meta-analysis published in JAMA Oncology indicates that minimal residual disease (MRD) status is strongly associated with progression-free survival (PFS) in patients with chronic lymphocytic leukemia (CLL). The findings suggest that assessing MRD status could improve clinical trial efficiency and potentially accelerate drug registration.
The meta-analysis, which included 2765 patients from 11 prospective clinical trials, demonstrated that undetectable MRD at a threshold of 0.01% was associated with a hazard ratio (HR) of 0.28 (95% CI, 0.20-0.39; P < .001) for PFS. While median PFS was not reached in either the undetectable MRD group (n = 1265) or the detectable MRD group (n = 1075), the estimated 24-month PFS rates were 91.9% (95% CI, 88.8%-95.2%) and 75.3% (95% CI, 64.7%-87.6%), respectively (P < .001).
Impact Across Treatment Settings
The association between undetectable MRD and improved PFS was consistent across different treatment settings. In the frontline setting, the HR was 0.24 (95% CI, 0.18-0.33). For relapsed or refractory disease, the HR was 0.34 (95% CI, 0.16-0.71). Studies using time-limited therapy also showed a significant association (HR, 0.28; 95% CI, 0.19-0.40).
According to Fausto Alfredo Rios-Olais, MD, hematology fellow at the Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán in Mexico City, Mexico, and coauthors, "These findings may have implications for clinical trial design and provide a rationale for using MRD as an end point for accelerated drug registration."
Study Details
The investigators conducted searches of PubMed, Embase, Scopus, and Web of Science to identify relevant clinical studies in CLL. The analysis included data from several randomized, phase 3 trials, including MURANO, E1912, HELIOS, CLL-11, GENUINE, GLOW, CLL-14, CLL-13, and iLLUMINATE, as well as from the phase 2 non-randomized GREEN and M13-982 studies.
MRD and Response Criteria
Data from two trials reporting MRD-associated PFS according to standard response criteria indicated that patients achieving a complete response (CR) with undetectable MRD (n = 427) had the longest PFS. Similar PFS was observed in patients with undetectable MRD and a partial response (PR; n = 292) and those with a CR but detectable MRD (n = 95). The shortest PFS was seen in patients with a PR and detectable MRD (n = 215).
Conclusion
"The findings of this systematic review and meta-analysis suggest that assessing MRD status as an end point in clinical trials and as a surrogate of PFS may improve trial efficiency and potentially allow for accelerated drug registration," the authors concluded.
