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.

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.

Poor outcomes for trial-ineligible patients receiving polatuzumab for relapsed/refractory diffuse large B-cell lymphoma in routine care: An Australian Lymphoma and Related Diseases Registry project.

Polatuzumab vedotin (Pola) is an approved therapy in combination with rituximab and bendamustine for relapsed or refractory diffuse large B-cell lymphoma (RR-DLBCL) based on positive results of the landmark phase II randomised G029365 trial. However, trial results for many approved novel therapies in RR-DLBCL have not been replicated in routine care cohorts, as RR-DLBCL patient populations are heterogeneous and trial eligibility is increasingly restrictive. We evaluated outcomes from pola ± bendamustine and rituximab in patients with RR-DLBCL enrolled in a compassionate access program with no alternative treatment options identified via the Australasian Lymphoma and Related Diseases Registry according to their eligibility for the original phase II published study. Of 58 eligible patients, 74% met the criteria deeming them ineligible for the G029365 original study at the time of pola's commencement. Median progression-free survival and overall survival in our cohort were 2.3 and 3.5 months, respectively. In contrast to the landmark trial cohort, more of our patients ceased therapy prior to completion, the majority due to progressive disease and only 8/58 received any subsequent treatment. Dismal outcomes in this Australian real-world population demonstrate trial eligibility is challenging to meet, and newer treatments can be difficult to deliver in routine care. Clinically applicable results from therapeutic studies require trial cohorts to reflect representative clinical populations wherever possible, and more research is required to address the benefit of novel agents in the increasing majority who are ineligible for modern studies.

Primary gastric diffuse large B-cell lymphoma: A multicentre retrospective study.

Primary gastric diffuse large B-cell lymphoma (PG-DLBCL) accounts for the majority of extra-nodal DLBCL. Even so, literature is lacking on early, localised presentations. We studied a cohort of patients with stage I disease, diagnosed between 2006 and 2018, from six centres between Australia, Canada and Denmark. Our goal was to characterise outcomes, review treatment and investigate the role of interim positron emission tomography (iPET). Thirty-seven eligible patients were identified. The median duration of follow-up was 42.2 months. All received chemoimmunotherapy with 91.9% (n = 34) given rituximab, cyclophosphamide, doxorubicin, vincristine and prednisolone (R-CHOP). 35.1% (n = 13) underwent consolidative radiotherapy. Eighteen patients were H. pylori positive and 11 had the documentation of H. pylori eradication therapy. The 4-year progression-free survival and overall survival of R-CHOP was 88% (95% CI: 71-95) and 91% (95% CI: 75-97) respectively. All patients who achieved a partial metabolic response or complete metabolic response on iPET went on to achieve complete response at the end of treatment. R-CHOP-based therapy with iPET assessment appears to offer favourable outcomes, with radiotherapy and H. pylori eradication therapy implemented on a case-by-case basis.

Impact and utility of follicular lymphoma GELF criteria in routine care: an Australasian Lymphoma Alliance study.

Follicular Lymphoma (FL) treatment initiation is largely determined by tumor burden and symptoms. In the pre-rituximab era, the Group d'Etude des Lymphomes Folliculaires (GELF) developed widely adopted criteria to identify high tumor burden FL patients to harmonize clinical trial populations. The utilization of GELF criteria (GELFc) in routine therapeutic decision-making is poorly described. This multicenter retrospective study evaluated patterns of GELFc at presentation and GELFc utilization in therapeutic decision-making in newly diagnosed, advanced stage rituximab-era FL. Associations between GELFc, treatment given, and patient survival were analyzed in 300 eligible cases identified between 2002-2019. 163 (54%) had ≥1 GELFc at diagnosis. The presence or cumulative number of GELFc did not predict PFS in patients undergoing watch-and-wait (WW) or those receiving systemic treatment. Of interest, in patients with ≥1 GELFc, 16/163 (10%) underwent initial watch-and-wait (comprising 22% of the watchand- wait cohort). In those receiving systemic therapy +/- radiotherapy, 74/215 (34%) met no GELFc. Our data suggest clinicians are using adjunctive measures to make decisions regarding treatment initiation in a significant proportion of patients. By restricting FL clinical trial eligibility only to those meeting GELFc, reported outcomes may not be applicable to a significant proportion of patients treated in routine care settings.

Durable Responses With Mosunetuzumab in Relapsed/Refractory Indolent and Aggressive B-Cell Non-Hodgkin Lymphomas: Extended Follow-Up of a Phase I/II Study.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.Mosunetuzumab is a CD20xCD3 T-cell-engaging bispecific antibody administered as an off-the-shelf, fixed-duration treatment in an outpatient setting. We report an updated analysis of the durability of response, by investigator assessment, after an overall median follow-up of 3.5 years in patients with relapsed/refractory indolent or aggressive B-cell non-Hodgkin lymphoma (iNHL/aNHL) from the dose-escalation stage of a phase I/II study of mosunetuzumab (ClinicalTrials.gov identifier: NCT02500407). Across dose levels, 65.7% of patients with iNHL and 36.4% with aNHL achieved a complete or partial response to mosunetuzumab. Median duration of response (DoR) in patients with iNHL for all responders was 23.2 months (95% CI, 13.8 to not estimable [NE]), but was not reached in complete responders (95% CI, 21.0 to NE). After a median time on study of 38.9 months, no relapses were observed beyond 26 months in complete responders. In patients with aNHL, median DoR for all responders was 7.8 months (95% CI, 4.6 to 22.8). Among 12 complete responders who progressed postmosunetuzumab treatment and were retreated with mosunetuzumab, 83.3% had an objective response and 58.3% achieved a second complete response. Our study reports the longest follow-up using bispecific antibodies in patients with B-cell non-Hodgkin lymphoma and demonstrates that mosunetuzumab can mediate durable remissions with time-limited treatment.

International Prognostic Score for Nodular Lymphocyte-Predominant Hodgkin Lymphoma.

PURPOSE: Nodular lymphocyte-predominant Hodgkin lymphoma (NLPHL) is a rare cancer, and large international cooperative efforts are needed to evaluate the significance of clinical risk factors and immunoarchitectural patterns (IAPs) for all stages of pediatric and adult patients with NLPHL. METHODS: Thirty-eight institutions participated in the Global nLPHL One Working Group retrospective study of NLPHL cases from 1992 to 2021. We measured progression-free survival (PFS), overall survival (OS), transformation rate, and lymphoma-specific death rate. We performed uni- and multivariable (MVA) Cox regression stratified by management to select factors for the lymphocyte-predominant international prognostic score (LP-IPS) validated by five-fold cross-validation. RESULTS: We identified 2,243 patients with a median age of 37 years (IQR, 23-51). The median follow-up was 6.3 years (IQR, 3.4-10.8). Most had stage I to II (72.9%) and few B symptoms (9.9%) or splenic involvement (5.4%). IAP was scored for 916 (40.8%). Frontline management included chemotherapy alone (32.4%), combined modality therapy (30.5%), radiotherapy alone (24.0%), observation after excision (4.6%), rituximab alone (4.0%), active surveillance (3.4%), and rituximab and radiotherapy (1.1%). The PFS, OS, transformation, and lymphoma-specific death rates at 10 years were 70.8%, 91.6%, 4.8%, and 3.3%, respectively. On MVA, IAPs were not associated with PFS or OS, but IAP E had higher risk of transformation (hazard ratio [HR], 1.81; P < .05). We developed the LP-IPS with 1 point each for age ≥45 years, stage III-IV, hemoglobin <10.5 g/dL, and splenic involvement. Increasing LP-IPS was significantly associated with worse PFS (HR, 1.52) and OS (HR, 2.31) and increased risk of lymphoma-specific death (HR, 2.63) and transformation (HR, 1.41). CONCLUSION: In this comprehensive study of all ages of patients with NLPHL, we develop the LP-IPS to identify high-risk patients and inform upcoming prospective clinical trials evaluating de-escalation of therapy for patients with low LP-IPS scores (<2).

The value of bispecific antibodies in relapsed and refractory DLBCL.

Diffuse large B-cell lymphoma (DLBCL) may be cured with anti-CD20 based chemoimmunotherapy in the majority of cases, however, relapsed/refractory disease occurs in 30-40% patients, and despite significant recent therapeutic advances, continues to represent an unmet clinical need. Bispecific antibodies represent a novel class of therapy currently in development for relapsed/refractory B-cell lymphoma. This review discusses the background clinical need, mechanism of action, and clinical data including efficacy and toxicity for bispecific antibodies in DLBCL, focusing on the most advanced class in development; CD20 targeting T-cell engaging antibodies. Emerging possibilities for future use of bispecific antibodies is also discussed, including novel and cytotoxic combination regimens in relapsed and first-line settings.

CAR T cells and time-limited ibrutinib as treatment for relapsed/refractory mantle cell lymphoma: the phase 2 TARMAC study.

ABSTRACT: CD19-directed chimeric antigen receptor T cells (CAR-T) achieve high response rates in patients with relapsed/refractory mantle cell lymphoma (MCL). However, their use is associated with significant toxicity, relapse concern, and unclear broad tractability. Preclinical and clinical data support a beneficial synergistic effect of ibrutinib on apheresis product fitness, CAR-T expansion, and toxicity. We evaluated the combination of time-limited ibrutinib and CTL019 CAR-T in 20 patients with MCL in the phase 2 TARMAC study. Ibrutinib commenced before leukapheresis and continued through CAR-T manufacture for a minimum of 6 months after CAR-T administration. The median prior lines of therapy was 2; 50% of patients were previously exposed to a Bruton tyrosine kinase inhibitor (BTKi). The primary end point was 4-month postinfusion complete response (CR) rate, and secondary end points included safety and subgroup analysis based on TP53 aberrancy. The primary end point was met; 80% of patients demonstrated CR, with 70% and 40% demonstrating measurable residual disease negativity by flow cytometry and molecular methods, respectively. At 13-month median follow-up, the estimated 12-month progression-free survival was 75% and overall survival 100%. Fifteen patients (75%) developed cytokine release syndrome; 12 (55%) with grade 1 to 2 and 3 (20%) with grade 3. Reversible grade 1 to 2 neurotoxicity was observed in 2 patients (10%). Efficacy was preserved irrespective of prior BTKi exposure or TP53 mutation. Deep responses correlated with robust CAR-T expansion and a less exhausted baseline T-cell phenotype. Overall, the safety and efficacy of the combination of BTKi and T-cell redirecting immunotherapy appears promising and merits further exploration. This trial was registered at www.ClinicalTrials.gov as #NCT04234061.

Death from mantle cell lymphoma limits sequential therapy, particularly after first relapse: Patterns of care and outcomes in a series from Australia and the United Kingdom.

Mantle cell lymphoma (MCL) is a B-cell non-Hodgkin lymphoma characterised by a heterogeneous clinical course. Patients can often receive sequential treatments, yet these typically yield diminishing periods of disease control, raising questions about optimal therapy sequencing. Novel agents, such as chimeric antigen receptor T-cell therapies and bispecific antibodies, show promise in relapsed MCL, but are often reserved for later treatment lines, which may underserve patients with aggressive disease phenotypes who die early in the treatment journey. To assess the problem of patient attrition from lymphoma-related death limiting sequential treatment, we performed a multicentre retrospective cohort analysis of 389 patients treated at Australian and UK centres over a 10-year period. Deaths from MCL increased after each treatment line, with 7%, 23% and 26% of patients dying from uncontrolled MCL after first, second and third lines respectively. Patients with older age at diagnosis and early relapse after induction therapy were at particular risk of death after second-line treatment. This limitation of sequential treatment by lymphoma-related death provides support for the trial of novel therapies in earlier treatment lines, particularly in high-risk patient populations.

Australia and New Zealand consensus position statement: use of COVID-19 therapeutics in patients with haematological malignancies.

Despite widespread vaccination rates, we are living with high transmission rates of SARS-CoV-2. Although overall hospitalisation rates are falling, the risk of serious infection remains high for patients who are immunocompromised because of haematological malignancies. In light of the ongoing pandemic and the development of multiple agents for treatment, representatives from the Haematology Society of Australia and New Zealand and infectious diseases specialists have collaborated on this consensus position statement regarding COVID-19 management in patients with haematological disorders. It is our recommendation that both patients with haematological malignancies and treating specialists be educated regarding the preventive and treatment options available and that patients continue to receive adequate vaccinations, keeping in mind the suboptimal vaccine responses that occur in haematology patients, in particular, those with B-cell malignancies and on B-cell-targeting or depleting therapy. Patients with haematological malignancies should receive treatment for COVID-19 in accordance with the severity of their symptoms, but even mild infections should prompt early treatment with antiviral agents. The issue of de-isolation following COVID-19 infection and optimal time to treatment for haematological malignancies is discussed but remains an area with evolving data. This position statement is to be used in conjunction with advice from infectious disease, respiratory and intensive care specialists, and current guidelines from the National COVID-19 Clinical Evidence Taskforce and the New Zealand Ministry of Health and Cancer Agency Te Aho o Te Kahu COVID-19 Guidelines.

High-Dose Methotrexate as CNS Prophylaxis in High-Risk Aggressive B-Cell Lymphoma.

PURPOSE: CNS progression or relapse is an uncommon but devastating complication of aggressive B-cell lymphoma. There is no consensus regarding the optimal approach to CNS prophylaxis. This study was designed to determine whether high-dose methotrexate (HD-MTX) is effective at preventing CNS progression in patients at high risk of this complication. PATIENTS AND METHODS: Patients age 18-80 years with aggressive B-cell lymphoma and high risk of CNS progression, treated with curative-intent anti-CD20-based chemoimmunotherapy, were included in this international, retrospective, observational study. Cause-specific hazard ratios (HRs) and cumulative risks of CNS progression were calculated according to use of HD-MTX, with time to CNS progression calculated from diagnosis for all patients (all-pts) and from completion of frontline systemic lymphoma induction therapy, for patients in complete response at completion of chemoimmunotherapy (CR-pts). RESULTS: Two thousand four hundred eighteen all-pts (HD-MTX; n = 425) and 1,616 CR-pts (HD-MTX; n = 356) were included. CNS International Prognostic Index was 4-6 in 83.4% all-pts. Patients treated with HD-MTX had a lower risk of CNS progression (adjusted HR, 0.59 [95% CI, 0.38 to 0.90]; P = .014), but significance was not retained when confined to CR-pts (adjusted HR, 0.74 [95% CI, 0.42 to 1.30]; P = .29), with 5-year adjusted risk difference of 1.6% (95% CI, -1.5 to 4.4; all-pts) and 1.4% (95% CI, -1.5 to 4.1; CR-pts). Subgroups were underpowered to draw definitive conclusions regarding the efficacy of HD-MTX in individual high-risk clinical scenarios; however, there was no clear reduction in CNS progression risk with HD-MTX in any high-risk subgroup. CONCLUSION: In this large study, high-risk patients receiving HD-MTX had a 7.2% 2-year risk of CNS progression, consistent with the progression risk in previously reported high-risk cohorts. Use of HD-MTX was not associated with a clinically meaningful reduction in risk of CNS progression.

Marginal zone lymphoma: 2023 update on diagnosis and management.

DISEASE OVERVIEW: Marginal zone lymphomas (MZL) are collectively the second most common type of indolent lymphoma. DIAGNOSIS: Three subtypes of MZL are recognized: splenic, extranodal, and nodal. The diagnosis is secured following biopsy of an involved nodal or extranodal site demonstrating a clonal B-cell infiltrate with CD5 and CD10 negative immunophenotype most common. Some cases will features IgM paraprotein, but MYD88 L256P mutations are less frequent than in Waldenstrom macroglobulinemia. Prognostication Several prognostic models have been developed, including the MALT-IPI and the MZL-IPI. The latter is broadly applicable across MZL subtypes and incorporates elevated serum LDH, anemia, lymphopenia, thrombocytopenia and nodal or disseminated subtypes as independent predictors of outcome. TREATMENT: We discuss suggested approach to therapy for both early and advanced-stage disease, with reference to chemo-immunotherapy, radiotherapy, and emerging treatments in relapsed/refractory disease such as BTK inhibitors.

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.).

Time to progression of disease and outcomes with second-line BTK inhibitors in relapsed/refractory mantle cell lymphoma.

Time to progression of disease (POD) after first-line (1L) therapy is prognostic in mantle cell lymphoma (MCL), although studies have included a broad range of 1L, second-line (2L), and subsequent lines of therapy. The purpose of this study was to evaluate the factors predicting outcomes in patients with relapsed/refractory (R/R) MCL exclusively initiating 2L Bruton's tyrosine kinase inhibitors (BTKis) after 1L rituximab-containing therapy. Patients were accrued from 8 international centers (7 main, 1 validation cohort). Multivariable models evaluating the association between time to POD and clinical/pathologic factors were constructed and converted into nomograms and prognostic indexes predicting outcomes in this population. A total of 360 patients were included, including 160 in the main cohort and 200 in the validation cohort. Time to POD, Ki67 ≥ 30%, and MCL International Prognostic Index (MIPI) were associated with progression-free survival (PFS2) and overall survival (OS2) from the start of 2L BTKis. C-indexes were consistently ≥0.68 in both cohorts. Web/application-based calculators based on nomograms and prognostic indexes to estimate PFS2 and OS2 were constructed. The 2L BTKi MIPI identifies 3 groups with distinct 2-year PFS2, including high risk (14%), intermediate risk (50%), and low risk (64%). Time to POD, Ki67, and MIPI are associated with survival outcomes in patients with R/R MCL receiving 2L BTKis. Simple clinical models incorporating these variables may assist in planning for alternative therapies such as chimeric antigen receptor T-cell therapy, allogeneic stem cell transplantation, or novel agents with alternative mechanisms of action.

Pirtobrutinib in Covalent Bruton Tyrosine Kinase Inhibitor Pretreated Mantle-Cell Lymphoma.

PURPOSE: Pirtobrutinib is a highly selective, noncovalent (reversible) Bruton tyrosine kinase inhibitor (BTKi). We report the safety and efficacy of pirtobrutinib in patients with covalent Bruton tyrosine kinase inhibitor (cBTKi) pretreated mantle-cell lymphoma (MCL), a population with poor prognosis. METHODS: Patients with cBTKi pretreated relapsed/refractory (R/R) MCL received pirtobrutinib monotherapy in a multicenter phase I/II trial (BRUIN; ClinicalTrials.gov identifier: NCT03740529). Efficacy was assessed in the first 90 consecutively enrolled patients who met criteria for inclusion in the primary efficacy cohort. The primary end point was overall response rate (ORR). Secondary end points included duration of response (DOR) and safety. RESULTS: The median patient age was 70 years (range, 46-87), the median prior lines of therapy was 3 (range, 1-8), 82.2% had discontinued a prior cBTKi because of disease progression, and 77.8% had intermediate- or high-risk simplified MCL International Prognostic Index score. The ORR was 57.8% (95% CI, 46.9 to 68.1), including 20.0% complete responses (n = 18). At a median follow-up of 12 months, the median DOR was 21.6 months (95% CI, 7.5 to not reached). The 6- and 12-month estimated DOR rates were 73.6% and 57.1%, respectively. In the MCL safety cohort (n = 164), the most common treatment-emergent adverse events (TEAEs) were fatigue (29.9%), diarrhea (21.3%), and dyspnea (16.5%). Grade ≥3 TEAEs of hemorrhage (3.7%) and atrial fibrillation/flutter (1.2%) were less common. Only 3% of patients discontinued pirtobrutinib because of a treatment-related adverse event. CONCLUSION: Pirtobrutinib is a first-in-class novel noncovalent (reversible) BTKi and the first BTKi of any kind to demonstrate durable efficacy after prior cBTKi therapy in heavily pretreated R/R MCL. Pirtobrutinib was well tolerated with low rates of treatment discontinuation because of toxicity.

Mosunetuzumab monotherapy is active and tolerable in patients with relapsed/refractory diffuse large B-cell lymphoma.

As part of a phase 1 or 2 study, this single-arm expansion cohort established the efficacy and safety of mosunetuzumab monotherapy in patients with relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL) (received ≥2 previous lines of therapy). Intravenous mosunetuzumab was administered with cycle (C) 1 step-up dosing for cytokine release syndrome (CRS) mitigation: C1 day (D) 1: 1 mg; C1D8 2 mg; C1D15 and C2D1: 60 mg; C3 + D1: 30 mg. Hospitalization was not mandatory. Patients with complete response (CR) completed treatment after C8; those with partial response or stable disease continued treatment for a total of 17 cycles. The primary end point was CR rate (best response), assessed against a historical control CR rate (20%) by independent review facility. Eighty-eight patients (73.9% de novo DLBCL; 26.1% transformed follicular lymphoma) were enrolled; all had received previous anthracycline and anti-CD20 therapy. Overall response and CR rates were 42.0% (95% confidence interval [CI], 31.6-53.1) and 23.9% (95% CI, 15.4-34.1), respectively; CR rate did not reach statistical significance vs the historical control (P = .36). Median time to first response was 1.4 months. Median progression-free survival was 3.2 months (95% CI, 2.2-5.3). The CR rate in 26 patients who received previous chimeric antigen receptor T-cell (CAR-T) therapy was 12%. CRS was one of the most common adverse events (26.1% of patients); predominantly grade 1 to 2 and primarily in C1. Four patients (4.5%) discontinued mosunetuzumab owing to adverse events. Mosunetuzumab demonstrated notable efficacy and a manageable safety profile in patients with R/R DLBCL, including those previously treated with CAR-Ts. This trial was registered at www.clinicaltrials.gov as #NCT02500407.