Classic Hodgkin lymphoma (cHL) is the cancer type most susceptible to antibodies targeting programmed cell death protein 1 (PD1) and is characterized by scarce Hodgkin and Reed-Sternberg cells (HRSCs), perpetuating a unique tumor microenvironment (TME). Although anti-PD1 effects appear to be largely mediated by cytotoxic CD8+ T cells in solid tumors, HRSCs frequently lack major histocompatibility complex expression, and the mechanism of anti-PD1 efficacy in cHL is unclear. Rapid clinical responses and high interim complete response rates to anti-PD1 based first-line treatment were recently reported for patients with early-stage unfavorable cHL treated in the German Hodgkin Study Group phase 2 NIVAHL trial. To investigate the mechanisms underlying this very early response to anti-PD1 treatment, we analyzed paired biopsies and blood samples obtained from NIVAHL patients before and during the first days of nivolumab first-line cHL therapy. Mirroring the rapid clinical response, HRSCs had disappeared from the tissue within days after the first nivolumab application. The TME already shows a reduction in type 1 regulatory T cells and PD-L1+ tumor-associated macrophages at this early time point of treatment. Interestingly, a cytotoxic immune response and a clonal T-cell expansion were not observed in the tumors or peripheral blood. These early changes in the TME were distinct from alterations found in a separate set of cHL biopsies at relapse during anti-PD1 therapy. We identify a unique very early histologic response pattern to anti-PD1 therapy in cHL that is suggestive of withdrawal of prosurvival factors, rather than induction of an adaptive antitumor immune response, as the main mechanism of action.

This phase 2 study evaluated isatuximab as monotherapy or combined with dexamethasone in relapsed/refractory multiple myeloma (RRMM). Patients had RRMM refractory to an immunomodulatory drug (IMiD) and a proteasome inhibitor (PI) or had received ≥3 prior lines of therapy incorporating an IMiD and PI. Patients received isatuximab either as monotherapy (20 mg/kg on days 1, 8, 15, and 22 [once weekly] of cycle 1 followed by 20 mg/kg on days 1 and 15 of subsequent cycles; Isa group) or in combination with dexamethasone (40 mg/d [20 mg/d in patients aged ≥75 years] once weekly; Isa-dex group). Treated patients (N = 164) had received a median of 4 (range, 2-10) prior treatment lines. Patients received a median of 5 (1-24) and 7 (1-22) treatment cycles; at data cutoff, 13 (11.9%) of 109 and 15 (27.3%) of 55 patients remained on treatment in the Isa and Isa-dex arms, respectively. Overall response rate (primary efficacy end point) was 23.9% in the Isa arm and 43.6% in the Isa-dex arm (odds ratio, 0.405; 95% confidence interval, 0.192-0.859; P = .008). Median progression-free survival and overall survival were 4.9 and 18.9 months for Isa, and 10.2 and 17.3 months for Isa-dex. Infusion reactions (mostly grade 1/2) and hematologic abnormalities were the most common adverse events. There was a similar incidence of grade 3 or higher infections in both groups (22.0% and 21.8%). In conclusion, addition of dexamethasone to isatuximab increased response rates and survival outcomes with no detrimental effect on safety. This trial was registered at www.clinicaltrials.gov as #NCT01084252.

There is a Blood Commentary on this article in this issue.

Steroid-refractory chronic graft-versus-host disease (cGVHD) is a therapeutic challenge. Sclerotic skin manifestations are especially difficult to treat. We conducted a randomized phase 2 clinical trial (#NCT01688466) to determine the safety, efficacy, and preferred dose of pomalidomide in persons with moderate to severe cGVHD unresponsive to corticosteroids and/or subsequent lines of therapy. Thirty-four subjects were randomized to receive pomalidomide 0.5 mg per day orally (n = 17; low-dose cohort) or 2 mg per day at a starting dose of 0.5 mg per day increasing to 2 mg per day over 6 weeks (n = 17; high-dose cohort). The primary endpoint was overall response rate (ORR) at 6 months according to the 2005 National Institutes of Health cGVHD Response Criteria. Thirty-two patients had severe sclerotic skin and received a median of 5 (range, 2-10) previous systemic therapies. ORR was 47% (95% confidence interval, 30-65) in the intention-to-treat analyses. All were partial responses, with no difference in ORR between the cohorts. ORR was 67% (45%-84%) in the 24 evaluable subjects at 6 months. Nine had improvement in National Institutes of Health joint/fascia scores (P = .018). Median change from the baseline in body surface area involvement of skin cGVHD was -7.5% (-10% to 35%; P = .002). The most frequent adverse events were lymphopenia, infection, and fatigue. Eight subjects in the high-dose cohort had dose decreases because of adverse events. There was 1 death in the low-dose cohort from bacterial pneumonia. Our data indicate antifibrotic effects of pomalidomide and possible association with increases in concentrations of blood regulatory T-cell and interleukin-2. Pomalidomide 0.5 mg per day is a safe and effective therapy for advanced corticosteroid-refractory cGVHD.

This open-label phase 2 study (CONTRALTO) assessed the safety and efficacy of BCL-2 inhibitor venetoclax (VEN) plus rituximab (R), and VEN plus bendamustine (B) and R, vs B + R (BR) alone in relapsed/refractory (R/R) follicular lymphoma. Patients in the chemotherapy-free arm (arm A: VEN + R) received VEN 800 mg/d plus R 375 mg/m2 on days 1, 8, 15, and 22 of cycle 1 and day 1 of cycles 4, 6, 8, 10, and 12. After a safety run-in with VEN 600 mg, patients in the chemotherapy-containing cohort were randomized to either VEN + BR (arm B; VEN 800 mg/d for 1 year + 6 cycles of BR [B 90 mg/m2 on days 1 and 2 and R 375 mg/m2 on day 1]) or 6 cycles of BR (arm C). Overall, 163 patients were analyzed (9 in the safety run-in and 52, 51, and 51 in arms A, B, and C, respectively). Complete metabolic/complete response rates were 17% (arm A), 75% (arm B), and 69% (arm C). Of patients in arm B, only 61% received ≥90% of the planned B dose vs 96% of patients in arm C. More frequent hematologic toxicity resulted in more reduced dosing/treatment discontinuation in arm B vs arm C. Rates of grade 3/4 adverse events were 51.9%, 93.9%, and 60.0% in arms A, B, and C, respectively. VEN + BR led to increased toxicity and lower dose intensity of BR than in arm C, but efficacy was similar. Optimizing dose and schedule to maintain BR dose intensity may improve efficacy and tolerability of VEN + BR, while VEN + R data warrant further study. This study was registered at www.clinicaltrials.gov as #NCT02187861.

Bruton tyrosine kinase (BTK) inhibition is an effective treatment approach for patients with Waldenström macroglobulinemia (WM). The phase 3 ASPEN study compared the efficacy and safety of ibrutinib, a first-generation BTK inhibitor, with zanubrutinib, a novel highly selective BTK inhibitor, in patients with WM. Patients with MYD88L265P disease were randomly assigned 1:1 to treatment with ibrutinib or zanubrutinib. The primary end point was the proportion of patients achieving a complete response (CR) or a very good partial response (VGPR) by independent review. Key secondary end points included major response rate (MRR), progression-free survival (PFS), duration of response (DOR), disease burden, and safety. A total of 201 patients were randomized, and 199 received ≥1 dose of study treatment. No patient achieved a CR. Twenty-nine (28%) zanubrutinib patients and 19 (19%) ibrutinib patients achieved a VGPR, a nonstatistically significant difference (P = .09). MRRs were 77% and 78%, respectively. Median DOR and PFS were not reached; 84% and 85% of ibrutinib and zanubrutinib patients were progression free at 18 months. Atrial fibrillation, contusion, diarrhea, peripheral edema, hemorrhage, muscle spasms, and pneumonia, as well as adverse events leading to treatment discontinuation, were less common among zanubrutinib recipients. Incidence of neutropenia was higher with zanubrutinib, although grade ≥3 infection rates were similar in both arms (1.2 and 1.1 events per 100 person-months). These results demonstrate that zanubrutinib and ibrutinib are highly effective in the treatment of WM, but zanubrutinib treatment was associated with a trend toward better response quality and less toxicity, particularly cardiovascular toxicity.

Newly diagnosed multiple myeloma (NDMM) patients treated with immunomodulatory drugs are at high risk of venous thromboembolism (VTE), but data are lacking from large prospective cohorts. We present thrombosis outcome data from Myeloma IX (n = 1936) and Myeloma XI (n = 4358) phase 3 randomized controlled trials for NDMM that treated transplant-eligible and transplant-ineligible patients before and after publication of thrombosis prevention guidelines. In Myeloma IX, transplant-eligible patients randomly assigned to cyclophosphamide, vincristine, doxorubicin, and dexamethasone (CVAD) induction had higher risk of VTE compared with patients treated with cyclophosphamide, thalidomide, and dexamethasone (CTD) (22.5% [n = 121 of 538] vs 16.1% [n = 89 of 554]; adjusted hazard ratio [aHR],1.46; 95% confidence interval [95% CI], 1.11-1.93). For transplant-ineligible patients, those randomly assigned to attenuated CTD (CTDa) induction had a higher risk of VTE compared with those treated with melphalan and prednisolone (MP) (16.0% [n = 68 of 425] vs 4.1% [n = 17 of 419]; aHR, 4.25; 95% CI, 2.50-7.20). In Myeloma XI, there was no difference in risk of VTE (12.2% [n = 124 of 1014] vs 13.2% [n = 133 of 1008]; aHR, 0.92; 95% CI, 0.72-1.18) or arterial thrombosis (1.2% [n = 12 of 1014] vs 1.5% [n = 15 of 1008]; aHR, 0.80; 95% CI, 0.37-1.70) between transplant-eligible pathways for patients treated with cyclophosphamide, lenalidomide, and dexamethasone (CRD) or CTD. For transplant-ineligible patients, there was no difference in VTEs between attenuated CRD (CRDa) and CTDa (10.4% [n = 95 of 916] vs 10.7% [n = 97 of 910]; aHR, 0.97; 95% CI, 0.73-1.29). However, arterial risk was higher with CRDa than with CTDa (3.1% [n = 28 of 916] vs 1.6% [n = 15 of 910]; aHR, 1.91; 95% CI, 1.02-3.57). Thrombotic events occurred almost entirely within 6 months of treatment initiation. Thrombosis was not associated with inferior progression-free survival (PFS) or overall survival (OS), apart from inferior OS for patients with arterial events (aHR, 1.53; 95% CI, 1.12-2.08) in Myeloma XI. The Myeloma XI trial protocol incorporated International Myeloma Working Group (IMWG) thrombosis prevention recommendations and compared with Myeloma IX, more patients received thromboprophylaxis (80.5% vs 22.3%) with lower rates of VTE for identical regimens (CTD, 13.2% vs 16.1%; CTDa, 10.7% vs 16.0%). However, thrombosis remained frequent in spite of IMWG-guided thromboprophylaxis, suggesting that new approaches are needed.

EPOCH (etoposide, prednisone, vincristine, cyclophosphamide, and doxorubicin) is a preferred regimen for HIV-non-Hodgkin lymphomas (HIV-NHLs), which are frequently Epstein-Barr virus (EBV) positive or human herpesvirus type-8 (HHV-8) positive. The histone deacetylase (HDAC) inhibitor vorinostat disrupts EBV/HHV-8 latency, enhances chemotherapy-induced cell death, and may clear HIV reservoirs. We performed a randomized phase 2 study in 90 patients (45 per study arm) with aggressive HIV-NHLs, using dose-adjusted EPOCH (plus rituximab if CD20+), alone or with 300 mg vorinostat, administered on days 1 to 5 of each cycle. Up to 1 prior cycle of systemic chemotherapy was allowed. The primary end point was complete response (CR). In 86 evaluable patients with diffuse large B-cell lymphoma (DLBCL; n = 61), plasmablastic lymphoma (n = 15), primary effusion lymphoma (n = 7), unclassifiable B-cell NHL (n = 2), and Burkitt lymphoma (n = 1), CR rates were 74% vs 68% for EPOCH vs EPOCH-vorinostat (P = .72). Patients with a CD4+ count <200 cells/mm3 had a lower CR rate. EPOCH-vorinostat did not eliminate HIV reservoirs, resulted in more frequent grade 4 neutropenia and thrombocytopenia, and did not affect survival. Overall, patients with Myc+ DLBCL had a significantly lower EFS. A low diagnosis-to-treatment interval (DTI) was also associated with inferior outcomes, whereas preprotocol therapy had no negative impact. In summary, EPOCH had broad efficacy against highly aggressive HIV-NHLs, whereas vorinostat had no benefit; patients with Myc-driven DLBCL, low CD4, and low DTI had less favorable outcomes. Permitting preprotocol therapy facilitated accruals without compromising outcomes. This trial was registered at www.clinicaltrials.gov as #NCT0119384.

Altered mitochondrial function occurs in sickle cell disease (SCD), due in part to low nitric oxide (NO) bioavailability. Arginine, the substrate for NO production, becomes acutely deficient in SCD patients with vaso-occlusive pain episodes (VOE). To determine if arginine improves mitochondrial function, 12 children with SCD-VOE (13.6 ± 3 years; 67% male; 75% hemoglobin-SS) were randomized to 1 of 3 arginine doses: (1) 100 mg/kg IV 3 times/day (TID); (2) loading dose (200 mg/kg) then 100 mg/kg TID; or (3) loading dose (200 mg/kg) followed by continuous infusion (300 mg/kg per day) until discharge. Platelet-rich plasma mitochondrial activity, protein expression, and protein-carbonyls were measured from emergency department (ED) presentation vs discharge. All VOE subjects at ED presentation had significantly decreased complex-V activity compared to a steady-state cohort. Notably, complex-V activity was increased at discharge in subjects from all 3 arginine-dosing schemes; greatest increase occurred with a loading dose (P < .001). Although complex-IV and citrate synthase activities were similar in VOE platelets vs steady state, enzyme activities were significantly increased in VOE subjects after arginine-loading dose treatment. Arginine also decreased protein-carbonyl levels across all treatment doses (P < .01), suggesting a decrease in oxidative stress. Arginine therapy increases mitochondrial activity and reduces oxidative stress in children with SCD/VOE. This trial was registered at www.clinicaltrials.gov as #NCT02536170.

Granulocytic myeloid-derived suppressor cells (G-MDSCs) promote tumor growth and immunosuppression in multiple myeloma (MM). However, their phenotype is not well established for accurate monitoring or clinical translation. We aimed to provide the phenotypic profile of G-MDSCs based on their prognostic significance in MM, immunosuppressive potential, and molecular program. The preestablished phenotype of G-MDSCs was evaluated in bone marrow samples from controls and MM patients using multidimensional flow cytometry; surprisingly, we found that CD11b+CD14-CD15+CD33+HLADR- cells overlapped with common eosinophils and neutrophils, which were not expanded in MM patients. Therefore, we relied on automated clustering to unbiasedly identify all granulocytic subsets in the tumor microenvironment: basophils, eosinophils, and immature, intermediate, and mature neutrophils. In a series of 267 newly diagnosed MM patients (GEM2012MENOS65 trial), only the frequency of mature neutrophils at diagnosis was significantly associated with patient outcome, and a high mature neutrophil/T-cell ratio resulted in inferior progression-free survival (P < .001). Upon fluorescence-activated cell sorting of each neutrophil subset, T-cell proliferation decreased in the presence of mature neutrophils (0.5-fold; P = .016), and the cytotoxic potential of T cells engaged by a BCMA×CD3-bispecific antibody increased notably with the depletion of mature neutrophils (fourfold; P = .0007). Most interestingly, RNA sequencing of the 3 subsets revealed that G-MDSC-related genes were specifically upregulated in mature neutrophils from MM patients vs controls because of differential chromatin accessibility. Taken together, our results establish a correlation between the clinical significance, immunosuppressive potential, and transcriptional network of well-defined neutrophil subsets, providing for the first time a set of optimal markers (CD11b/CD13/CD16) for accurate monitoring of G-MDSCs in MM.

Lenalidomide, bortezomib, and dexamethasone (RVd) followed by autologous stem cell transplantation (ASCT) is standard frontline therapy for transplant-eligible patients with newly diagnosed multiple myeloma (NDMM). The addition of daratumumab (D) to RVd (D-RVd) in transplant-eligible NDMM patients was evaluated. Patients (N = 207) were randomized 1:1 to D-RVd or RVd induction (4 cycles), ASCT, D-RVd or RVd consolidation (2 cycles), and lenalidomide or lenalidomide plus D maintenance (26 cycles). The primary end point, stringent complete response (sCR) rate by the end of post-ASCT consolidation, favored D-RVd vs RVd (42.4% vs 32.0%; odds ratio, 1.57; 95% confidence interval, 0.87-2.82; 1-sided P = .068) and met the prespecified 1-sided α of 0.10. With longer follow-up (median, 22.1 months), responses deepened; sCR rates improved for D-RVd vs RVd (62.6% vs 45.4%; P = .0177), as did minimal residual disease (MRD) negativity (10-5 threshold) rates in the intent-to-treat population (51.0% vs 20.4%; P < .0001). Four patients (3.8%) in the D-RVd group and 7 patients (6.8%) in the RVd group progressed; respective 24-month progression-free survival rates were 95.8% and 89.8%. Grade 3/4 hematologic adverse events were more common with D-RVd. More infections occurred with D-RVd, but grade 3/4 infection rates were similar. Median CD34+ cell yield was 8.2 × 106/kg for D-RVd and 9.4 × 106/kg for RVd, although plerixafor use was more common with D-RVd. Median times to neutrophil and platelet engraftment were comparable. Daratumumab with RVd induction and consolidation improved depth of response in patients with transplant-eligible NDMM, with no new safety concerns. This trial was registered at www.clinicaltrials.gov as #NCT02874742.

Patients undergoing treatment of acute lymphoblastic leukemia (ALL) are at risk for thrombosis, caused in part by the use of l-asparaginase (L-ASP). Antithrombin (AT) replacement has been suggested to prevent venous thromboembolism (VTE) and thus may increase exposure to ASP. We report herein the results of the prophylactic replacement strategy in the pediatrics-inspired prospective GRAALL-2005 study. Between 2006 and 2014, 784 adult patients with newly diagnosed Philadelphia- ALL were included. The incidence rate of VTE was 16%, with 69% of cases occurring during induction therapy. Most patients received AT supplementation (87%). After excluding patients who did not receive L-ASP or who developed thrombosis before L-ASP, AT supplementation did not have a significant impact on VTE. Administration of fibrinogen concentrates was associated with an increased risk of VTE, whereas transfusion of fresh frozen plasma had no effect. Heparin prophylaxis was associated with an increased risk of VTE. Prophylactic measures were not associated with an increased risk of grade 3 to 4 bleeding complications. The rate of VTE recurrence after L-ASP reintroduction was 3% (1 of 34). In ALL patients receiving L-ASP therapy, the use of fibrinogen concentrates may increase the risk of thrombosis and should be restricted to rare patients with hypofibrinogenemia-induced hemorrhage. VTE developed despite extensive AT supplementation, which suggests the need for additional prophylactic measures. Although this large descriptive study was not powered to demonstrate the efficacy of these prophylactic measures, it provides important insight to guide future trial design. This trial was registered at www.clinicaltrials.gov as #NCT00327678.

This phase 2 study was designed to compare systemic decitabine exposure, demethylation activity, and safety in the first 2 cycles with cedazuridine 100 mg/decitabine 35 mg vs standard decitabine 20 mg/m2 IV. Adults with International Prognostic Scoring System intermediate-1/2- or high-risk myelodysplastic syndromes (MDS) or chronic myelomonocytic leukemia (CMML) were randomized 1:1 to receive oral cedazuridine/decitabine or IV decitabine in cycle 1, followed by crossover to the other treatment in cycle 2. All patients received oral cedazuridine/decitabine in subsequent cycles. Cedazuridine and decitabine were given initially as separate capsules in a dose-confirmation stage and then as a single fixed-dose combination (FDC) tablet. Primary end points: mean decitabine systemic exposure (geometric least-squares mean [LSM]) of oral/IV 5-day area under curve from time 0 to last measurable concentration (AUClast), percentage long interspersed nuclear element 1 (LINE-1) DNA demethylation for oral cedazuridine/decitabine vs IV decitabine, and clinical response. Eighty patients were randomized and treated. Oral/IV ratios of geometric LSM 5-day AUClast (80% confidence interval) were 93.5% (82.1-106.5) and 97.6% (80.5-118.3) for the dose-confirmation and FDC stages, respectively. Differences in mean %LINE-1 demethylation between oral and IV were ≤1%. Clinical responses were observed in 48 patients (60%), including 17 (21%) with complete response. The most common grade ≥3 adverse events regardless of causality were neutropenia (46%), thrombocytopenia (38%), and febrile neutropenia (29%). Oral cedazuridine/decitabine (100/35 mg) produced similar systemic decitabine exposure, DNA demethylation, and safety vs decitabine 20 mg/m2 IV in the first 2 cycles, with similar efficacy. This study is registered at www.clinicaltrials.gov as #NCT02103478.

Essential thrombocythemia (ET) is characterized by abnormal megakaryopoiesis and enhanced thrombotic risk. Once-daily low-dose aspirin is the recommended antithrombotic regimen, but accelerated platelet generation may reduce the duration of platelet cyclooxygenase-1 (COX-1) inhibition. We performed a multicenter double-blind trial to investigate the efficacy of 3 aspirin regimens in optimizing platelet COX-1 inhibition while preserving COX-2-dependent vascular thromboresistance. Patients on chronic once-daily low-dose aspirin (n = 245) were randomized (1:1:1) to receive 100 mg of aspirin 1, 2, or 3 times daily for 2 weeks. Serum thromboxane B2 (sTXB2), a validated biomarker of platelet COX-1 activity, and urinary prostacyclin metabolite (PGIM) excretion were measured at randomization and after 2 weeks, as primary surrogate end points of efficacy and safety, respectively. Urinary TX metabolite (TXM) excretion, gastrointestinal tolerance, and ET-related symptoms were also investigated. Evaluable patients assigned to the twice-daily and thrice-daily regimens showed substantially reduced interindividual variability and lower median (interquartile range) values for sTXB2 (ng/mL) compared with the once-daily arm: 4 (2.1-6.7; n = 79), 2.5 (1.4-5.65, n = 79), and 19.3 (9.7-40; n = 85), respectively. Urinary PGIM was comparable in the 3 arms. Urinary TXM was reduced by 35% in both experimental arms. Patients in the thrice-daily arm reported a higher abdominal discomfort score. In conclusion, the currently recommended aspirin regimen of 75 to 100 once daily for cardiovascular prophylaxis appears to be largely inadequate in reducing platelet activation in the vast majority of patients with ET. The antiplatelet response to low-dose aspirin can be markedly improved by shortening the dosing interval to 12 hours, with no improvement with further reductions (EudraCT 2016-002885-30).

Although no therapies are approved for light chain (AL) amyloidosis, cyclophosphamide, bortezomib, and dexamethasone (CyBorD) is considered standard of care. Based on outcomes of daratumumab in multiple myeloma (MM), the phase 3 ANDROMEDA study (NCT03201965) is evaluating daratumumab-CyBorD vs CyBorD in newly diagnosed AL amyloidosis. We report results of the 28-patient safety run-in. Patients received subcutaneous daratumumab (DARA SC) weekly in cycles 1 to 2, every 2 weeks in cycles 3 to 6, and every 4 weeks thereafter for up to 2 years. CyBorD was given weekly for 6 cycles. Patients had a median of 2 involved organs (kidney, 68%; cardiac, 61%). Patients received a median of 16 (range, 1-23) treatment cycles. Treatment-emergent adverse events were consistent with DARA SC in MM and CyBorD. Infusion-related reactions occurred in 1 patient (grade 1). No grade 5 treatment-emergent adverse events occurred; 5 patients died, including 3 after transplant. Overall hematologic response rate was 96%, with a complete hematologic response in 15 (54%) patients; at least partial response occurred in 20, 22, and 17 patients at 1, 3, and 6 months, respectively. Renal response occurred in 6 of 16, 7 of 15, and 10 of 15 patients, and cardiac response occurred in 6 of 16, 6 of 13, and 8 of 13 patients at 3, 6, and 12 months, respectively. Hepatic response occurred in 2 of 3 patients at 12 months. Daratumumab-CyBorD was well tolerated, with no new safety concerns versus the intravenous formulation, and demonstrated robust hematologic and organ responses. This trial was registered at www.clinicaltrials.gov as #NCT03201965.

As part of a randomized, prospective clinical trial in large cell lymphoma, we conducted serial fluorodeoxyglucose positron emission tomography (FDG-PET) at baseline, after 2 cycles of chemotherapy (interim PET [i-PET]), and at end of treatment (EoT) to identify biomarkers of response that are predictive of remission and survival. Scans were interpreted in a core laboratory by 2 imaging experts, using the visual Deauville 5-point scale (5-PS), and by calculating percent change in FDG uptake (change in standardized uptake value [ΔSUV]). Visual scores of 1 through 3 and ΔSUV ≥66% were prospectively defined as negative. Of 524 patients enrolled in the parent trial, 169 agreed to enroll in the PET substudy and 158 were eligible for final analysis. In this selected population, all had FDG-avid disease at baseline; by 5-PS, 55 (35%) remained positive on i-PET and 28 (18%) on EoT PET. Median ΔSUV on i-PET was 86.2%. With a median follow-up of 5 years, ΔSUV, as continuous variable, was associated with progression-free survival (PFS) (hazard ratio [HR] = 0.99; 95% confidence interval [CI], 0.97-1.00; P = .02) and overall survival (OS) (HR, 0.98; 95% CI, 0.97-0.99; P = .03). ΔSUV ≥66% was predictive of OS (HR, 0.31; 95% CI, 0.11-0.85; P = .02) but not PFS (HR, 0.47; 95% CI, 0.19-1.13; P = .09). Visual 5-PS on i-PET did not predict outcome. ΔSUV, but not visual analysis, on i-PET predicted OS in DLBCL, although the low number of events limited the statistical analysis. These data may help guide future clinical trials using PET response-adapted therapy. This trial was registered at www.clinicaltrials.gov as #NCT00118209.

Effective treatment options are limited for patients with acute myeloid leukemia (AML) who cannot tolerate intensive chemotherapy. Adults age ≥18 years with newly diagnosed AML ineligible for intensive chemotherapy were enrolled in this international phase 3 randomized double-blind placebo-controlled trial. Patients (N = 211) were randomized 2:1 to venetoclax (n = 143) or placebo (n = 68) in 28-day cycles, plus low-dose cytarabine (LDAC) on days 1 to 10. Primary end point was overall survival (OS); secondary end points included response rate, transfusion independence, and event-free survival. Median age was 76 years (range, 36-93 years), 38% had secondary AML, and 20% had received prior hypomethylating agent treatment. Planned primary analysis showed a 25% reduction in risk of death with venetoclax plus LDAC vs LDAC alone (hazard ratio [HR], 0.75; 95% confidence interval [CI], 0.52-1.07; P = .11), although not statistically significant; median OS was 7.2 vs 4.1 months, respectively. Unplanned analysis with additional 6-month follow-up demonstrated median OS of 8.4 months for the venetoclax arm (HR, 0.70; 95% CI, 0.50-0.98; P = .04). Complete remission (CR) plus CR with incomplete blood count recovery rates were 48% and 13% for venetoclax plus LDAC and LDAC alone, respectively. Key grade ≥3 adverse events (venetoclax vs LDAC alone) were febrile neutropenia (32% vs 29%), neutropenia (47% vs 16%), and thrombocytopenia (45% vs 37%). Venetoclax plus LDAC demonstrates clinically meaningful improvement in remission rate and OS vs LDAC alone, with a manageable safety profile. Results confirm venetoclax plus LDAC as an important frontline treatment for AML patients unfit for intensive chemotherapy. This trial was registered at www.clinicaltrials.gov as #NCT03069352.

Inhibition of the B-cell receptor pathway, and specifically of Bruton tyrosine kinase (BTK), is a leading therapeutic strategy in B-cell malignancies, including chronic lymphocytic leukemia (CLL). Target occupancy is a measure of covalent binding to BTK and has been applied as a pharmacodynamic parameter in clinical studies of BTK inhibitors. However, the kinetics of de novo BTK synthesis, which determines occupancy, and the relationship between occupancy, pathway inhibition and clinical outcomes remain undefined. This randomized phase 2 study investigated the safety, efficacy, and pharmacodynamics of a selective BTK inhibitor acalabrutinib at 100 mg twice daily (BID) or 200 mg once daily (QD) in 48 patients with relapsed/refractory or high-risk treatment-naïve CLL. Acalabrutinib was well tolerated and yielded an overall response rate (ORR) of partial response or better of 95.8% (95% confidence interval [CI], 78.9-99.9) and an estimated progression-free survival (PFS) rate at 24 months of 91.5% (95% CI, 70.0-97.8) with BID dosing and an ORR of 79.2% (95% CI, 57.9-92.9) and an estimated PFS rate at 24 months of 87.2% (95% CI, 57.2-96.7) with QD dosing. BTK resynthesis was faster in patients with CLL than in healthy volunteers. BID dosing maintained higher BTK occupancy and achieved more potent pathway inhibition compared with QD dosing. Small increments in occupancy attained by BID dosing relative to QD dosing compounded over time to augment downstream biological effects. The impact of BTK occupancy on long-term clinical outcomes remains to be determined. This trial was registered at www.clinicaltrials.gov as #NCT02337829.