A Bayesian framework to study tumor subclone-specific expression by combining bulk DNA and single-cell RNA sequencing data.

Genetic and gene expression heterogeneity is an essential hallmark of many tumors, allowing the cancer to evolve and to develop resistance to treatment. Currently, the most commonly used data types for studying such heterogeneity are bulk tumor/normal whole-genome or whole-exome sequencing (WGS, WES); and single-cell RNA sequencing (scRNA-seq), respectively. However, tools are currently lacking to link genomic tumor subclonality with transcriptomic heterogeneity by integrating genomic and single-cell transcriptomic data collected from the same tumor. To address this gap, we developed scBayes, a Bayesian probabilistic framework that uses tumor subclonal structure inferred from bulk DNA sequencing data to determine the subclonal identity of cells from single-cell gene expression (scRNA-seq) measurements. Grouping together cells representing the same genetically defined tumor subclones allows comparison of gene expression across different subclones, or investigation of gene expression changes within the same subclone across time (i.e., progression, treatment response, or relapse) or space (i.e., at multiple metastatic sites and organs). We used simulated data sets, in silico synthetic data sets, as well as biological data sets generated from cancer samples to extensively characterize and validate the performance of our method, as well as to show improvements over existing methods. We show the validity and utility of our approach by applying it to published data sets and recapitulating the findings, as well as arriving at novel insights into cancer subclonal expression behavior in our own data sets. We further show that our method is applicable to a wide range of single-cell sequencing technologies including single-cell DNA sequencing as well as Smart-seq and 10x Genomics scRNA-seq protocols.

Pirtobrutinib after a Covalent BTK Inhibitor in Chronic Lymphocytic Leukemia.

BACKGROUND: Patients with chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) have poor outcomes after the failure of covalent Bruton's tyrosine kinase (BTK) inhibitor treatment, and new therapeutic options are needed. Pirtobrutinib, a highly selective, noncovalent (reversible) BTK inhibitor, was designed to reestablish BTK inhibition. METHODS: We conducted a phase 1-2 trial in which patients with relapsed or refractory B-cell cancers received pirtobrutinib. Here, we report efficacy results among patients with CLL or SLL who had previously received a BTK inhibitor as well as safety results among all the patients with CLL or SLL. The primary end point was an overall response (partial response or better) as assessed by independent review. Secondary end points included progression-free survival and safety. RESULTS: A total of 317 patients with CLL or SLL received pirtobrutinib, including 247 who had previously received a BTK inhibitor. Among these 247 patients, the median number of previous lines of therapy was 3 (range, 1 to 11), and 100 patients (40.5%) had also received a B-cell lymphoma 2 (BCL2) inhibitor such as venetoclax. The percentage of patients with an overall response to pirtobrutinib was 73.3% (95% confidence interval [CI], 67.3 to 78.7), and the percentage was 82.2% (95% CI, 76.8 to 86.7) when partial response with lymphocytosis was included. The median progression-free survival was 19.6 months (95% CI, 16.9 to 22.1). Among all 317 patients with CLL or SLL who received pirtobrutinib, the most common adverse events were infections (in 71.0%), bleeding (in 42.6%), and neutropenia (in 32.5%). At a median duration of treatment of 16.5 months (range, 0.2 to 39.9), some adverse events that are typically associated with BTK inhibitors occurred relatively infrequently, including hypertension (in 14.2% of patients), atrial fibrillation or flutter (in 3.8%), and major hemorrhage (in 2.2%). Only 9 of 317 patients (2.8%) discontinued pirtobrutinib owing to a treatment-related adverse event. CONCLUSIONS: In this trial, pirtobrutinib showed efficacy in patients with heavily pretreated CLL or SLL who had received a covalent BTK inhibitor. The most common adverse events were infections, bleeding, and neutropenia. (Funded by Loxo Oncology; BRUIN ClinicalTrials.gov number, NCT03740529.).

Fixed-Duration Pirtobrutinib plus Venetoclax with or without Rituximab in Relapsed/Refractory CLL: Phase 1b BRUIN Trial.

Pirtobrutinib is a highly selective, non-covalent (reversible) Bruton tyrosine kinase inhibitor (BTKi). Patients with relapsed or refractory (R/R) chronic lymphocytic leukemia (CLL) were treated with fixed-duration pirtobrutinib plus venetoclax (PV) or pirtobrutinib plus venetoclax and rituximab (PVR) in this phase 1b trial (NCT03740529). Prior covalent BTKi therapy was allowed, but not prior venetoclax. Patients were assigned to receive PV (n=15) or PVR (n=10) for 25 cycles. Median age was 66 years (range, 39-78). Median prior lines of therapy was 2 (range, 1-4), and 17 (68%) patients had received prior covalent BTKi. At the data-cutoff date (May 5, 2023), median time on study was 27.0 months for PV and 23.3 months for PVR. Overall response rates were 93.3% (95% CI:68.1-99.8%) for PV and 100% (95% CI:69.2-100.0%) for PVR, with 10 complete responses (PV:7; PVR:3). After 12 cycles of treatment, 85.7% (95% CI:57.2-98.2%) of PV and 90.0% (95% CI:55.5-99.7%) of PVR patients achieved undetectable minimal residual disease assessed in peripheral blood by clonoSEQ® assay at a sensitivity of <1x10-4. Progression-free survival at 18 months was 92.9% (95% CI: 59.1-99.0) for PV patients and 80.0% (95% CI: 40.9-94.6) for PVR patients. No DLTs were observed in either treatment combination during the 5-week assessment period. The most common grade ≥3 adverse events for all patients included neutropenia (52%) and anemia (16%). Adverse events led to dose reduction in 3 patients and discontinuation in 2. In conclusion, fixed-duration PV or PVR was well tolerated and had promising efficacy in patients with R/R CLL, including patients previously treated with a covalent BTKi.

Mutational profile of previously treated chronic lymphocytic leukemia patients progressing on acalabrutinib or ibrutinib.

Chronic lymphocytic leukemia (CLL) progression during Bruton tyrosine kinase (BTK) inhibitor treatment is typically characterized by emergent B-cell receptor pathway mutations. Using peripheral blood samples from relapsed/refractory CLL patients in ELEVATE-RR (NCT02477696) (median 2 prior therapies), we report clonal evolution data for patients progressing on acalabrutinib or ibrutinib (median follow-up 41 months). Paired (baseline and progression) samples were available for 47 (excluding 1 Richter) acalabrutinib-treated and 30 (excluding 6 Richter) ibrutinib-treated patients. At progression, emergent BTK mutations were observed in 31 (66%) acalabrutinib-treated and 11 (37%) ibrutinib-treated patients (median variant allele fraction [VAF]: 16.1% vs 15.6%). BTK C481S mutations were most common in both groups; T474I (n = 9; 8 co-occurring with C481) and the novel E41V mutation within the pleckstrin homology domain of BTK (n = 1) occurred with acalabrutinib, while neither mutation occurred with ibrutinib. L528W and A428D co-mutations presented in one ibrutinib-treated patient. Pre-existing TP53 mutations were present in 25 (53.2%) acalabrutinib-treated and 16 (53.3%) ibrutinib-treated patients at screening. Emergent TP53 mutations occurred with acalabrutinib and ibrutinib (13% vs 7%; median VAF: 6.0% vs 37.3%, respectively). Six acalabrutinib-treated patients and one ibrutinib-treated patient had emergent TP53/BTK co-mutations. Emergent PLCG2 mutations occurred in 3 (6%) acalabrutinib-treated and 6 (20%) ibrutinib-treated patients. One acalabrutinib-treated patient and 4 ibrutinib-treated patients had emergent BTK/PLCG2 co-mutations. While common BTK C481 mutations were observed with both treatments, patterns of mutation and co-mutation frequency, mutation VAF, and uncommon BTK variants varied with acalabrutinib (T474I and E41V) and ibrutinib (L528W, A428D) in this patient population.

Follow-up from the A041202 study shows continued efficacy of ibrutinib regimens for older adults with CLL.

ABSTRACT: A041202 (NCT01886872) is a phase 3 study comparing bendamustine plus rituximab (BR) with ibrutinib and the combination of ibrutinib plus rituximab (IR) in previously untreated older patients with chronic lymphocytic leukemia (CLL). The initial results showed that ibrutinib-containing regimens had superior progression-free survival (PFS) and rituximab did not add additional benefits. Here we present an updated analysis. With a median follow-up of 55 months, the median PFS was 44 months (95% confidence interval [CI], 38-54) for BR and not yet reached in either ibrutinib-containing arm. The 48-month PFS estimates were 47%, 76%, and 76% for BR, ibrutinib, and IR, respectively. The benefit of ibrutinib regimens over chemoimmunotherapy was consistent across subgroups of patients defined by TP53 abnormalities, del(11q), complex karyotype, and immunoglobulin heavy chain variable region (IGHV). No significant interaction effects were observed between the treatment arm and del(11q), the complex karyotype, or IGHV. However, a greater difference in PFS was observed among the patients with TP53 abnormalities. There was no difference in the overall survival. Notable adverse events with ibrutinib included atrial fibrillation (afib) and hypertension. Afib was observed in 11 patients (pts) on BR (3%) and 67 pts on ibrutinib (18%). All-grade hypertension was observed in 95 pts on BR (27%) and 263 pts on ibrutinib (55%). These data show that ibrutinib regimens prolong PFS compared with BR for older patients with treatment-naïve CLL. These benefits were observed across subgroups, including high-risk groups. Strikingly, within the ibrutinib arms, there was no inferior PFS for patients with abnormalities in TP53, the highest risk feature observed in CLL. These data continue to demonstrate the efficacy of ibrutinib in treatment-naïve CLL.

Detailed safety profile of acalabrutinib vs ibrutinib in previously treated chronic lymphocytic leukemia in the ELEVATE-RR trial.

ELEVATE-RR demonstrated noninferior progression-free survival and lower incidence of key adverse events (AEs) with acalabrutinib vs ibrutinib in previously treated chronic lymphocytic leukemia. We further characterize AEs of acalabrutinib and ibrutinib via post hoc analysis. Overall and exposure-adjusted incidence rate was assessed for common Bruton tyrosine kinase inhibitor-associated AEs and for selected events of clinical interest (ECIs). AE burden scores based on previously published methodology were calculated for AEs overall and selected ECIs. Safety analyses included 529 patients (acalabrutinib, n = 266; ibrutinib, n = 263). Among common AEs, incidences of any-grade diarrhea, arthralgia, urinary tract infection, back pain, muscle spasms, and dyspepsia were higher with ibrutinib, with 1.5- to 4.1-fold higher exposure-adjusted incidence rates. Incidences of headache and cough were higher with acalabrutinib, with 1.6- and 1.2-fold higher exposure-adjusted incidence rate, respectively. Among ECIs, incidences of any-grade atrial fibrillation/flutter, hypertension, and bleeding were higher with ibrutinib, as were exposure-adjusted incidence rates (2.0-, 2.8-, and 1.6-fold, respectively); incidences of cardiac events overall (the Medical Dictionary for Regulatory Activities system organ class) and infections were similar between arms. Rate of discontinuation because of AEs was lower for acalabrutinib (hazard ratio, 0.62; 95% confidence interval, 0.41-0.93). AE burden score was higher for ibrutinib vs acalabrutinib overall and for the ECIs atrial fibrillation/flutter, hypertension, and bleeding. A limitation of this analysis is its open-label study design, which may influence the reporting of more subjective AEs. Overall, event-based analyses and AE burden scores demonstrated higher AE burden overall and specifically for atrial fibrillation, hypertension, and hemorrhage with ibrutinib vs acalabrutinib. This trial was registered at www.clinicaltrials.gov as #NCT02477696.

Ventricular arrhythmias and sudden death events following acalabrutinib initiation.

Acalabrutinib, a next-generation Bruton's tyrosine kinase inhibitor (BTKi), associates with dramatic efficacy against B-cell malignancies. Recently, unexplained ventricular arrhythmias (VAs) with next-generation BTKi-therapy have been reported. Yet, whether acalabrutinib associates with VAs in long-term follow-up is unknown. Leveraging a large-cohort of 290 consecutive B-cell malignancy patients treated with acalabrutinib from 2014 to 2020, we assessed the incidence of VAs. The primary-endpoint was incident VA development (ventricular fibrillation, ventricular tachycardia, and symptomatic premature ventricular contractions). Probability-scores were assessed to determine likelihood of acalabrutinib-association. Incident rates as function of time-on-therapy were calculated. Weighted average observed incidence rates were compared with expected population rates using relative-risks. Absolute excess risk (AER) for acalabrutinib-associated VAs was estimated. Over 1063 person-years of follow-up, there were 8 cases of incident-VAs, including 6 in those without coronary disease (CAD) or heart failure (HF) and 1 sudden-death; median time-to-event 14.9 months. Among those without prior ibrutinib-use, CAD, or HF, the weighted average incidence was 394 per 100 000 person years compared with a reported incidence of 48.1 among similar-aged non-BTKi-treated subjects (relative risk, 8.2; P < .001; AER, 346). Outside of age, no cardiac or electrocardiographic variables associated with VA development. Collectively, these data suggest VAs may be a class-effect of BTKi therapies.

Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma, Version 2.2024, NCCN Clinical Practice Guidelines in Oncology

Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are essentially different manifestations of the same disease that are similarly managed. A number of molecular and cytogenetic variables with prognostic implications have been identified. Undetectable minimal residual disease at the end of treatment with chemoimmunotherapy or venetoclax-based combination regimens is an independent predictor of improved survival among patients with previously untreated or relapsed/refractory CLL/SLL. The selection of treatment is based on the disease stage, presence or absence of del(17p) or TP53 mutation, immunoglobulin heavy chain variable region mutation status, patient age, performance status, comorbid conditions, and the agent's toxicity profile. This manuscript discusses the recommendations outlined in the NCCN Guidelines for the diagnosis and management of patients with CLL/SLL.

Racial disparities in chronic lymphocytic leukemia/small lymphocytic lymphoma accounting for small molecule inhibitors: A real-world cohort analysis.

Kaplan-Meier curve depicting overall survival from CLL treatment start by race. For patients with CLL, no overall survival difference was observed between races in this real-world US database.

Disruption of Nurse-like Cell Differentiation as a Therapeutic Strategy for Chronic Lymphocytic Leukemia.

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia, but, despite advances in treatment, many patients still experience relapse. CLL cells depend on interactions with supportive cells, and nurse-like cells (NLCs) are the major such cell type. However, little is known about how NLCs develop. Here, we performed DNA methylation analysis of CLL patient-derived NLCs using the 850K Illumina array, comparing CD14+ cells at day 1 (monocytes) versus day 14 (NLCs). We found a strong loss of methylation in AP-1 transcription factor binding sites, which may be driven by MAPK signaling. Testing of individual MAPK pathways (MEK, p38, and JNK) revealed a strong dependence on MEK/ERK for NLC development, because treatment of patient samples with the MEK inhibitor trametinib dramatically reduced NLC development in vitro. Using the adoptive transfer Eµ-TCL1 mouse model of CLL, we found that MEK inhibition slowed CLL progression, leading to lower WBC counts and to significantly longer survival time. There were also lower numbers of mouse macrophages, particularly within the M2-like population. In summary, NLC development depends on MEK signaling, and inhibition of MEK leads to increased survival time in vivo. Hence, targeting the MEK/ERK pathway may be an effective treatment strategy for CLL.

Safety of Extended Pirtobrutinib Exposure in Relapsed and/or Refractory B-Cell Malignancies.

INTRODUCTION: Pirtobrutinib, a highly selective, noncovalent (reversible) Bruton tyrosine kinase inhibitor, has demonstrated promising efficacy in B-cell malignancies and is associated with low rates of discontinuation and dose reduction. Pirtobrutinib is administered until disease progression or toxicity, necessitating an understanding of the safety profile in patients with extended treatment. METHODS: Here we report the safety of pirtobrutinib in patients with relapsed/refractory B-cell malignancies with extended (≥12 months) drug exposure from the BRUIN trial. Assessments included median time-to-first-occurrence of adverse events (AEs), dose reductions, and discontinuations due to treatment-emergent AEs (TEAEs) and select AEs of interest (AESIs). RESULTS: Of 773 patients enrolled, 326 (42%) received treatment for ≥12 months. In the extended exposure cohort, the median time-on-treatment was 19 months. The most common all-cause TEAEs were fatigue (32%) and diarrhea (31%). TEAEs leading to dose reduction occurred in 23 (7%) and discontinuations in 11 (3%) extended exposure patients. One patient had a fatal treatment-related AE (COVID-19 pneumonia). Infections (73.0%) were the most common AESI with a median time-to-first-occurrence of 7.4 months. Majority of TEAEs and AESIs occurred during the first year of therapy. CONCLUSIONS: Pirtobrutinib therapy continues to demonstrate an excellent safety profile amenable to long-term administration without evidence of new or worsening toxicity signals.

The impact of increasing karyotypic complexity and evolution on survival in patients with CLL treated with ibrutinib.

Complex karyotype, defined as ≥3 cytogenetic abnormalities, is prognostic of survival in patients treated with ibrutinib or venetoclax in relapsed/refractory (RR) chronic lymphocytic leukemia (CLL). Recent studies re-evaluating this dichotomous variable have shown that higher numbers of cytogenetic abnormalities (ie, ≥5) have a worse overall survival in patients treated with chemoimmunotherapy. We sought to determine if increasing karyotypic complexity, treated as a continuous variable, was prognostic of survival for patients treated with ibrutinib for CLL. We conducted a retrospective analysis of all patients with CLL treated with single-agent ibrutinib or in combination with an anti-CD20 antibody at our institution. We included 456 patients with both treatment-naive and RR disease. Median number of prior therapies was 2 (range, 0-13), 30% of patients had presence of del(17p), and 75% expressed unmutated IGHV. Fifty percent had ≥3 cytogenetic abnormalities, including 30% with ≥5. In a multivariable analysis, increasing karyotypic complexity was an independent predictor of shorter progression-free survival (hazard ratio, 1.07; 95% confidence interval, 1.04-1.10; P < .0001) and overall survival (hazard ratio, 1.09; 95% confidence interval, 1.05-1.12; P < .0001). Furthermore, we found that presence of clonal evolution determined by cytogenetic analysis at progression was prognostic of subsequent survival (P = .02). This solidifies karyotypic complexity as an important prognostic factor for patients with CLL treated with ibrutinib. Further research should consider sequential karyotypic analysis as a determination of risk of progression and death in patients with CLL.

Acalabrutinib in treatment-naive chronic lymphocytic leukemia.

Acalabrutinib has demonstrated significant efficacy and safety in relapsed chronic lymphocytic leukemia (CLL). Efficacy and safety of acalabrutinib monotherapy were evaluated in a treatment-naive CLL cohort of a single-arm phase 1/2 trial (ACE-CL-001). Adults were eligible for enrollment if chemotherapy was declined or deemed inappropriate due to comorbidities (N = 99). Patients had a median age of 64 years and 47% had Rai stage III/IV disease. Acalabrutinib was administered orally 200 mg once daily, or 100 mg twice daily until progression or intolerance. A total of 99 patients were treated; 57 (62%) had unmutated immunoglobulin heavy-chain variable gene, and 12 (18%) had TP53 aberrations. After median follow-up of 53 months, 85 patients remain on treatment; 14 discontinued treatment, mostly because of adverse events (AEs) (n = 6) or disease progression (n = 3). Overall response rate was 97% (90% partial response; 7% complete response), with similar outcomes among all prognostic subgroups. Because of improved trough BTK occupancy with twice-daily dosing, all patients were transitioned to 100 mg twice daily. Median duration of response (DOR) was not reached; 48-month DOR rate was 97% (95% confidence interval, 90-99). Serious AEs were reported in 38 patients (38%). AEs required discontinuation in 6 patients (6%) because of second primary cancers (n = 4) and infection (n = 2). Grade ≥3 events of special interest included infection (15%), hypertension (11%), bleeding events (3%), and atrial fibrillation (2%). Durable efficacy and long-term safety of acalabrutinib in this trial support its use in clinical management of symptomatic, untreated patients with CLL.

Refining prognosis in chronic lymphocytic leukemia with normal Fluorescence in situ hybridization results.

Fluorescence in situ hybridization (FISH) to detect the recurrent cytogenetics abnormalities deletion 13q, trisomy 12, deletion 11q, and deletion 17p is important for prognostication in chronic lymphocytic leukemia (CLL). A subset of patients are negative for each of these abnormalities (normal 12/13/11/17 FISH), and outcomes are heterogenous within this group. To elucidate variables important for prognostication in this subgroup we conducted a retrospective analysis of 280 treatment-naïve CLL patients with normal standard CLL FISH results. In a multivariable model, advanced Rai stage (p = 0.04, hazard ratio [HR] 1.24 (95% confidence interval [CI] 1.01-1.53)), unmutated immunoglobulin heavy chain gene (IGHV) (p < 0.0001, HR 5.59 (95% CI 3.63-8.62)) and IGH rearrangement by FISH (p = 0.02, HR 2.56 (95% CI 1.20-5.48)) were significantly associated with shorter time to first treatment. In a multivariable model for overall survival, increasing age at 5-year increments (p < 0.0001, HR 1.55 (95% CI 1.25-1.93)), unmutated IGHV (p = 0.01, HR 5.28 (95% CI 1.52-18.35)) and gain of REL (p = 0.01, HR 4.08 (5% CI 1.45-11.49)) were significantly associated with shorter survival. Our study identifies variables important for refining prognosis for CLL patients with normal standard CLL FISH results.

Patient characteristics that predict Richter's transformation in patients with chronic lymphocytic leukemia treated with ibrutinib.

Chronic lymphocytic leukemia (CLL) transformation to aggressive lymphoma, known as Richter's Transformation (RT), has a dismal prognosis. There are limited data evaluating risk of RT in patients treated with ibrutinib. We performed a retrospective analysis to determine prognostic variables associated with development of RT and overall survival (OS) at progression after treatment with ibrutinib. We identified 559 patients with CLL treated with ibrutinib from 2010-2019. After a median follow-up of 44.5 months from ibrutinib start, 179 patients progressed and were included in our analysis. After a median follow-up of 20.8 months from progression, 54 out of 179 patients developed RT. Progression on treatment (hazard ratio [HR] 4.01 [1.60-10.00], p = .003), higher LDH (HR 1.80 for 2-fold increase [1.33-2.43], p = .0001), and lymphadenopathy without lymphocytosis (HR 2.88 [1.15-7.20], p = .02) were independent prognostic variables for the development of RT at progression. Progression with lymphadenopathy without lymphocytosis continued to be an independent prognostic variable of worse OS post-progression. In a subset analysis of 50 patients who obtained a PET-CT at progression, the median SUVmax for patients who would develop RT was 15.2 (n = 30, range: 4.0-46.3) versus those patients who did not develop RT with a SUVmax of 7.7 (n = 20, range: 2.3-27.2) (p = .0030). Median OS from date of RT was 4.0 months, suggesting that prognosis for RT remains poor. A lymph node biopsy to rule out RT should be considered in patients who received ibrutinib who progress on treatment, have an elevated LDH, or progress with lymphadenopathy without lymphocytosis.

Pirtobrutinib in relapsed or refractory B-cell malignancies (BRUIN): a phase 1/2 study.

BACKGROUND: Covalent Bruton's tyrosine kinase (BTK) inhibitors are efficacious in multiple B-cell malignancies, but patients discontinue these agents due to resistance and intolerance. We evaluated the safety and efficacy of pirtobrutinib (working name; formerly known as LOXO-305), a highly selective, reversible BTK inhibitor, in these patients. METHODS: Patients with previously treated B-cell malignancies were enrolled in a first-in-human, multicentre, open-label, phase 1/2 trial of the BTK inhibitor pirtobrutinib. The primary endpoint was the maximum tolerated dose (phase 1) and overall response rate (ORR; phase 2). This trial is registered with ClinicalTrials.gov, NCT03740529. FINDINGS: 323 patients were treated with pirtobrutinib across seven dose levels (25 mg, 50 mg, 100 mg, 150 mg, 200 mg, 250 mg, and 300 mg once per day) with linear dose-proportional exposures. No dose-limiting toxicities were observed and the maximum tolerated dose was not reached. The recommended phase 2 dose was 200 mg daily. Adverse events in at least 10% of 323 patients were fatigue (65 [20%]), diarrhoea (55 [17%]), and contusion (42 [13%]). The most common adverse event of grade 3 or higher was neutropenia (32 [10%]). There was no correlation between pirtobrutinib exposure and the frequency of grade 3 treatment-related adverse events. Grade 3 atrial fibrillation or flutter was not observed, and grade 3 haemorrhage was observed in one patient in the setting of mechanical trauma. Five (1%) patients discontinued treatment due to a treatment-related adverse event. In 121 efficacy evaluable patients with chronic lymphocytic leukaemia (CLL) or small lymphocytic lymphoma (SLL) treated with a previous covalent BTK inhibitor (median previous lines of treatment 4), the ORR with pirtobrutinib was 62% (95% CI 53-71). The ORR was similar in CLL patients with previous covalent BTK inhibitor resistance (53 [67%] of 79), covalent BTK inhibitor intolerance (22 [52%] of 42), BTK C481-mutant (17 [71%] of 24) and BTK wild-type (43 [66%] of 65) disease. In 52 efficacy evaluable patients with mantle cell lymphoma (MCL) previously treated with covalent BTK inhibitors, the ORR was 52% (95% CI 38-66). Of 117 patients with CLL, SLL, or MCL who responded, all but eight remain progression-free to date. INTERPRETATION: Pirtobrutinib was safe and active in multiple B-cell malignancies, including patients previously treated with covalent BTK inhibitors. Pirtobrutinib might address a growing unmet need for alternative therapies for these patients. FUNDING: Loxo Oncology.

Acalabrutinib monotherapy in patients with relapsed/refractory chronic lymphocytic leukemia: updated phase 2 results.

Therapeutic targeting of Bruton tyrosine kinase (BTK) has dramatically improved survival outcomes for patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). Acalabrutinib is an oral, highly selective BTK inhibitor that allows for twice-daily dosing due to its selectivity. In this phase 1b/2 study, 134 patients with relapsed/refractory CLL or SLL (median age, 66 years [range, 42-85 years]; median prior therapies, 2 [range, 1-13]) received acalabrutinib 100 mg twice daily for a median of 41 months (range, 0.2-58 months). Median trough BTK occupancy at steady state was 97%. Most adverse events (AEs) were mild or moderate, and were most commonly diarrhea (52%) and headache (51%). Grade ≥3 AEs (occurring in ≥5% of patients) were neutropenia (14%), pneumonia (11%), hypertension (7%), anemia (7%), and diarrhea (5%). Atrial fibrillation and major bleeding AEs (all grades) occurred in 7% and 5% of patients, respectively. Most patients (56%) remain on treatment; the primary reasons for discontinuation were progressive disease (21%) and AEs (11%). The overall response rate, including partial response with lymphocytosis, with acalabrutinib was 94%; responses were similar regardless of genomic features (presence of del(11)(q22.3), del(17)(p13.1), complex karyotype, or immunoglobulin variable region heavy chain mutation status). Median duration of response and progression-free survival (PFS) have not been reached; the estimated 45-month PFS was 62% (95% confidence interval, 51% to 71%). BTK mutation was detected in 6 of 9 patients (67%) at relapse. This updated and expanded study confirms the efficacy, durability of response, and long-term safety of acalabrutinib, justifying its further investigation in previously untreated and treated patients with CLL/SLL. This trial was registered at www.clinicaltrials.gov as #NCT02029443.

NCCN Guidelines® Insights: Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma, Version 3.2022.

The treatment landscape of chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) has significantly evolved in recent years. Targeted therapy with Bruton's tyrosine kinase (BTK) inhibitors and BCL-2 inhibitors has emerged as an effective chemotherapy-free option for patients with previously untreated or relapsed/refractory CLL/SLL. Undetectable minimal residual disease after the end of treatment is emerging as an important predictor of progression-free and overall survival for patients treated with fixed-duration BCL-2 inhibitor-based treatment. These NCCN Guidelines Insights discuss the updates to the NCCN Guidelines for CLL/SLL specific to the use of chemotherapy-free treatment options for patients with treatment-naïve and relapsed/refractory disease.

Management of relapsed/refractory Chronic Lymphocytic Leukemia.

The therapeutic landscape for chronic lymphocytic leukemia (CLL) has changed dramatically over the past decade as our understanding of the biology of CLL has advanced, allowing the development of oral therapies targeting key drivers of CLL. Currently, inhibitors of Bruton's Tyrosine Kinase and the BH3 mimetic venetoclax are standards of care for both frontline and relapsed/refractory CLL. Sequencing of available therapies, therefore, has become a major challenge of therapy. In this review, we will focus on the current landscape for the treatment of relapsed/refractory CLL. We will also discuss important considerations when sequencing these available treatments. The recent advances in this disease are significant steps forward, and raise new questions of how these available drugs should be given as well as how we can continue to improve the treatment of CLL.

Acalabrutinib with or without obinutuzumab versus chlorambucil and obinutuzmab for treatment-naive chronic lymphocytic leukaemia (ELEVATE TN): a randomised, controlled, phase 3 trial.

BACKGROUND: Acalabrutinib is a selective, covalent Bruton tyrosine-kinase inhibitor with activity in chronic lymphocytic leukaemia. We compare the efficacy of acalabrutinib with or without obinutuzumab against chlorambucil with obinutuzumab in patients with treatment-naive chronic lymphocytic leukaemia. METHODS: ELEVATE TN is a global, phase 3, multicentre, open-label study in patients with treatment-naive chronic lymphocytic leukaemia done at 142 academic and community hospitals in 18 countries. Eligible patients had untreated chronic lymphocytic leukaemia and were aged 65 years or older, or older than 18 years and younger than 65 years with creatinine clearance of 30-69 mL/min (calculated by use of the Cockcroft-Gault equation) or Cumulative Illness Rating Scale for Geriatrics score greater than 6. Additional criteria included an Eastern Cooperative Oncology Group performance status score of 2 or less and adequate haematologic, hepatic, and renal function. Patients with significant cardiovascular disease were excluded, and concomitant treatment with warfarin or equivalent vitamin K antagonists was prohibited. Patients were randomly assigned (1:1:1) centrally via an interactive voice or web response system to receive acalabrutinib and obinutuzumab, acalabrutinib monotherapy, or obinutuzumab and oral chlorambucil. Treatments were administered in 28-day cycles. To reduce infusion-related reactions, acalabrutinib was administered for one cycle before obinutuzumab administration. Oral acalabrutinib was administered (100 mg) twice a day until progressive disease or unacceptable toxic effects occurred. In the acalabrutinib-obinutuzumab group, intravenous obinutuzumab was given on days 1 (100 mg), 2 (900 mg), 8 (1000 mg), and 15 (1000 mg) of cycle 2 and on day 1 (1000 mg) of cycles 3-7. In the obinutuzumab-chlorambucil group, intravenous obinutuzumab was given on days 1 (100 mg), 2 (900 mg), 8 (1000 mg), and 15 (1000 mg) of cycle 1 and on day 1 (1000 mg) of cycles 2-6. Oral chlorambucil was given (0·5 mg/kg) on days 1 and 15 of each cycle, for six cycles. The primary endpoint was progression-free survival between the two combination-therapy groups, assessed by independent review committee. Crossover to acalabrutinib was allowed in patients who progressed on obinutuzumab-chlorambucil. Safety was assessed in all patients who received at least one dose of treatment. Enrolment for this trial is complete, and the study is registered at ClinicalTrials.gov, NCT02475681. FINDINGS: Between Sept 14, 2015, and Feb 8, 2017, we recruited 675 patients for assessment. 140 patients did not meet eligibility criteria, and 535 patients were randomly assigned to treatment. 179 patients were assigned to receive acalabrutinib-obinutuzumab, 179 patients were assigned to receive acalabrutinib monotherapy, and 177 patients were assigned to receive obinutuzumab-chlorambucil. At median follow-up of 28·3 months (IQR 25·6-33·1), median progression-free survival was longer with acalabrutinib-obinutuzumab and acalabrutinib monotherapy, compared with obinutuzumab-chlorambucil (median not reached with acalabrutinib and obinutuzumab vs 22·6 months with obinutuzumab, hazard ratio [HR] 0·1; 95% CI 0·06-0·17, p<0·0001; and not reached with acalabrutinib monotherapy vs 22·6 months with obinutuzumab, 0·20; 0·13-0·3, p<0·0001). Estimated progression-free survival at 24 months was 93% with acalabrutinib-obinutuzumab (95% CI 87-96%), 87% with acalabrutinib monotherapy (81-92%), and 47% with obinutuzumab-chlorambucil (39-55%). The most common grade 3 or higher adverse event across groups was neutropenia (53 [30%] of 178 patients in the acalabrutinib-obinutuzumab group, 17 [9%] of 179 patients in the acalabrutinib group, and 70 [41%] of 169 patients in the obinutuzumab-chlorambucil group). All-grade infusion reactions were less frequent with acalabrutinib-obinutuzumab (24 [13%] of 178 patients) than obinutuzumab-chlorambucil (67 [40%] of 169 patients). Grade 3 or higher infections occurred in 37 (21%) patients given acalabrutinib-obinutuzumab, 25 (14%) patients given acalabrutinib monotherapy, and 14 (8%) patients given obinutuzumab-chlorambucil. Deaths occurred in eight (4%) patients given acalabrutinib-obinutuzumab, 12 (7%) patients given acalabrutinib, and 15 (9%) patients given obinutuzumab-chlorambucil. INTERPRETATION: Acalabrutinib with or without obinutuzumab significantly improved progression-free survival over obinutuzumab-chlorambucil chemoimmunotherapy, providing a chemotherapy-free treatment option with an acceptable side-effect profile that was consistent with previous studies. These data support the use of acalabrutinib in combination with obinutuzumab or alone as a new treatment option for patients with treatment-naive symptomatic chronic lymphocytic leukaemia. FUNDING: Acerta Pharma, a member of the AstraZeneca Group, and R35 CA198183 (to JCB).