Hematology · Medical Literature
[Comment] Beyond MURANO: sequencing therapy in relapsed chronic lymphocytic leukaemia
Abstract
The treatment landscape of chronic lymphocytic leukaemia has undergone a revolution in the past decade. Highly effective targeted therapies have shifted the treatment paradigm from continuous disease control towards fixed-duration combination approaches capable of inducing deep and durable remissions. Following studies such as CLL13, MURANO, AMPLIFY, and most recently CLL17, time-restricted therapy is also increasingly becoming the preferred front-line strategy for many patients.1–4As front-line treatment evolves, decisions at relapse have become increasingly complex.
Clinical relevance
In the evolving CLL treatment landscape—where fixed-duration front-line regimens informed by CLL13, MURANO, AMPLIFY, and CLL17 are increasingly standard—how should therapy be optimally sequenced at relapse, and does the addition of the noncovalent BTK inhibitor pirtobrutinib to fixed-duration venetoclax–rituximab improve outcomes in patients with previously treated CLL/SLL compared to venetoclax–rituximab alone? __SNAPSHOT__ {"studyDesign":"Expert Commentary (Comment) contextualizing the phase 3 BRUIN CLL-322 randomized controlled trial (open-label, multicenter, 1:1 randomized, controlled, phase 3 trial), published simultaneously in The Lancet. Only the abstract of the Commentary is available; the BRUIN CLL-322 trial article is the primary data source referenced.","setting":"152 sites across 22 countries comprising community hospitals and academic centers (BRUIN CLL-322 trial, referenced within the Commentary).","sampleSize":"n=639 (PVR arm: n=321; VR arm: n=318) in the BRUIN CLL-322 trial referenced by the Commentary.","population":"Adults with relapsed or refractory CLL or small lymphocytic lymphoma (SLL) requiring treatment per iwCLL 2018 criteria, with at least 1 prior line of therapy. Approximately 80% had prior covalent BTK inhibitor exposure; patients with prior noncovalent BTK inhibitor or BCL2 inhibitor exposure were excluded. Enrollment of covalent BTKi-naive patients was capped at approximately 20%. Median age 67–68 years; majority male (~68–70%).","intervention":"Fixed-duration pirtobrutinib (noncovalent BTK inhibitor) plus venetoclax–rituximab (PVR): pirtobrutinib administered for 28 cycles including a 3-cycle pirtobrutinib–rituximab lead-in before venetoclax initiation; venetoclax for 25 cycles; rituximab for 6 cycles.","comparator":"Fixed-duration venetoclax–rituximab (VR): venetoclax for 25 cycles; rituximab for 6 cycles.","primaryOutcome":"Progression-free survival (PFS) as assessed by an independent review committee (IRC) per iwCLL 2018 criteria.","followUp":"Median follow-up 27.3 months (data cutoff February 2, 2026); overall survival data immature at time of analysis.","fundingSource":"Industry (Eli Lilly and Company sponsored BRUIN CLL-322; the Commentary is published in The Lancet; funding of the Commentary itself is not reported in the available abstract)."}
Key findings
The BRUIN CLL-322 trial, which is the central data source discussed in this Commentary, demonstrated a statistically significant improvement in IRC-assessed PFS with fixed-duration PVR versus VR. The hazard ratio for progression or death was 0.547 (95% CI 0.400–0.748; p=0.0001), representing a 45.3% relative reduction in risk. Median PFS was not reached in the PVR arm versus 39.7 months in the VR arm. The 24-month PFS rate was 86.9% (PVR) versus 71.8% (VR), an absolute difference of 15.1 percentage points (calculated). NNT to prevent one progression or death event at 24 months: approximately 7 patients (calculated from absolute risk reduction of ~15.1%). PFS benefit was consistent across prespecified subgroups including patients with prior covalent BTKi exposure, those who discontinued due to disease progression, and those with high-risk genomic features (TP53 aberrations, del(17p), unmutated IGHV, complex karyotype). Overall survival data were immature. Notably, the 24-month PFS rate of 71.8% in the VR control arm was substantially lower than the 85–86% historically reported in the MURANO trial, reflecting the higher-risk, predominantly post-covalent-BTKi population enrolled in BRUIN CLL-322. Safety: grade ≥3 treatment-emergent adverse events occurred in 78.8% (PVR) versus 73.0% (VR). Treatment discontinuation due to related adverse events was similar (5.4% vs 5.1%). Grade ≥3 tumor lysis syndrome was lower with PVR (0.9%) versus VR (3.9%), attributed to the cytoreductive lead-in effect of pirtobrutinib–rituximab before venetoclax initiation. Rates of atrial fibrillation or flutter were low and similar (3.5% vs 2.6%). Hypertension was slightly more frequent with PVR (12.0% vs 7.4%). Grade 5 treatment-related events occurred in 0.3% (PVR) vs 1.3% (VR). For context, the MURANO final analysis (7-year follow-up) reported a PFS rate of 23% and OS rate of 70% in the VenR arm; VenR retreatment in 25 patients achieved a 72% ORR, 32% uMRD, and median second PFS of approximately 23 months. In CLL17 (untreated patients), fixed-duration venetoclax–obinutuzumab and venetoclax–ibrutinib each demonstrated noninferiority to continuous ibrutinib (3-year PFS: 81.1%, 79.4%, and 81.0%, respectively).
Practice implications
This Commentary by Kater and Seymour contextualizes the BRUIN CLL-322 trial results within the rapidly evolving CLL treatment landscape. The trial established that fixed-duration PVR provides a statistically significant and likely clinically meaningful PFS benefit over VR alone in relapsed/refractory CLL, particularly in the now-dominant clinical scenario of patients who have received prior covalent BTKi therapy. The absolute 15.1-percentage-point improvement in 24-month PFS and the NNT of approximately 7 suggest meaningful clinical benefit; however, overall survival data remain immature, and OS is the definitive endpoint for judging benefit in a largely incurable disease. The Commentary underscores that the VR control arm performed substantially worse than historical MURANO populations, confirming that modern relapsed CLL—now predominantly post-BTKi—is a higher-risk disease state and that historical benchmarks from MURANO may no longer apply to contemporary patients. The findings are most applicable to patients with relapsed/refractory CLL after at least one prior line including a covalent BTKi, without prior exposure to noncovalent BTKi or venetoclax. Patients with prior venetoclax or noncovalent BTKi exposure were excluded and are not represented. The Commentary also situates these relapse-setting findings against the front-line paradigm shift demonstrated by CLL17 (fixed-duration noninferiority to continuous ibrutinib) and AMPLIFY, highlighting that as more patients receive fixed-duration front-line regimens, rational sequencing at relapse becomes increasingly critical and more complex. IMPORTANT LIMITATION: Only the abstract of the Commentary is available; the full text and its complete clinical reasoning, nuanced sequencing recommendations, and any additional data references cannot be evaluated. Clinical decisions should be informed by the full Commentary and the peer-reviewed BRUIN CLL-322 trial publication. __LIMITATIONS__ Only the abstract of the Commentary (not a primary trial) is available; the full text, with complete expert analysis and referenced evidence, was not accessible for this review.,The Commentary is an expert opinion piece, not a primary study; its conclusions represent interpretation rather than new data generation.,BRUIN CLL-322 (the referenced index trial) is open-label; blinding of participants and investigators was not possible, introducing potential ascertainment bias.,Overall survival data were immature at the time of analysis (median follow-up 27.3 months); PFS is a surrogate endpoint, and OS benefit has not yet been established.,Patients with prior noncovalent BTKi or venetoclax exposure were excluded, limiting generalizability to patients who have already received these agents—a gap that will grow as triplet front-line regimens become more widely used.,Approximately 20% of BRUIN CLL-322 patients were covalent BTKi-naive, meaning findings are primarily informative for post-BTKi patients but the trial was not exclusively restricted to this group.,Industry funding (Eli Lilly) of BRUIN CLL-322 introduces potential sponsorship bias.,No head-to-head comparison of PVR versus continuous noncovalent BTKi monotherapy or MRD-guided approaches is available.,Long-term treatment-free survival, quality of life, and the feasibility of subsequent therapies after PVR failure have not been reported.,Generalizability to frail, elderly, or comorbid patients may be limited given trial enrollment criteria and the predominantly academic/specialist trial infrastructure. __BOTTOM_LINE_CATEGORY__ potentially_practice_informing __BOTTOM_LINE__ Fixed-duration pirtobrutinib plus venetoclax–rituximab (PVR) demonstrated a statistically significant and potentially clinically meaningful 45% relative reduction in progression or death versus VR alone (HR 0.547; p=0.0001) in predominantly post-covalent-BTKi relapsed/refractory CLL, with manageable toxicity and a lower rate of grade ≥3 tumor lysis syndrome. Overall survival data are immature, and findings are not applicable to patients with prior venetoclax or noncovalent BTKi exposure. PVR represents a promising new fixed-duration option in the relapsed/refractory setting, but regulatory approval and OS maturity are required before it can be considered a confirmed new standard of care.