Association between treatment (tx) response and PFS and OS in R/R chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL): A 12-month landmark (LM) meta-analysis.

7047 Background: Despite advances in tx for CLL/SLL, CRs are rarely observed after tx in the R/R setting, thus impacting long-term outcomes. We evaluated the association between response after tx and survival outcomes in patients (pt) with R/R CLL/SLL. Methods: Adults with R/R CLL/SLL and ≥ 1 prior line of therapy (LOT) from 6 clinical trials (initiated after 01/01/2012 and completed before 12/31/2022) were sourced from the Medidata Enterprise Data Store. Cox models adjusted for potential prognostic factors were used to assess pt-level associations between achieving and maintaining a CR or CR with incomplete bone marrow recovery (CRi) by 12 mo after start of tx (LM date) and PFS and OS. In separate LM analyses (LMA), associations between achieving and maintaining CR/CRi, PR/nodular PR (nPR) by LM, or non-CR/non-PR (ie, those not achieving or maintaining CR/CRi or PR/nPR or not evaluated by LM), and PFS and OS were assessed. Results: Of 1604 pts (CLL, 97.7%; SLL, 2.3%; age ≥ 65 y, 61.8%; male, 66.6%; ECOG PS 0–1/2, 93.2%/6.8%; median IQR follow-up, 3.4 y 2.2–4.1; median IQR LOT, 2 1–3; study tx, BTKi 40.4%, BCL2i 40.1%, anti-CD20 mAb 12.5%, and PI3Ki 9.9%), 15.1% and 61.7% achieved a best overall response of CR/CRi and PR/nPR, respectively (ORR, 76.8%); 6.8% of pts had no response recorded in follow-up. A total of 1178 pts without progression, death, or censoring before LM were included in PFS LMA. Median (95% CI) PFS from LM was 64.4 mo (61.7–not reached NR) for CR/CRi, 43.3 mo (38.8–54.7) for PR/nPR, and 23.9 mo (18.3–50.6) for non-CR/non-PR. Pts who achieved and maintained CR/CRi had significantly longer PFS versus both non-CR/CRi and PR/nPR pts, with adjusted HR of 0.62 ( P = 0.01) and 0.64 ( P = 0.02), respectively (Table). For OS LMA, 1404 pts without death or censoring before LM were included. Median (95% CI) OS from LM was NR for CR/CRi and PR/nPR groups and 62.9 mo (51.2–NR) for non-CR/non-PR. At 24 mo from LM, 90% (85%–95%) CR/CRi, 87% (84%–89%) PR/nPR, and 72% (67%–77%) non-CR/non-PR pts were still alive. CR/CRi pts or PR/nPR pts had significantly longer PFS and OS versus non-CR/non-PR pts. Conclusions: We demonstrated that achieving and maintaining CR/CRi by 12 mo after start of tx was associated with significantly improved PFS versus achieving and maintaining PR/nPR, which was also better than not achieving/maintaining any response. These findings support the potential utility of durable CR/CRi as an informative early endpoint for assessing the value of tx in pts with R/R CLL/SLL. Adjusted HR (95% CI) Table: see text