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.

Acalabrutinib ± obinutuzumab versus obinutuzumab + chlorambucil in treatment-naïve chronic lymphocytic leukemia: Elevate-TN four-year follow up

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Background: Early results from ELEVATE-TN (NCT02475681) at a median follow-up of 28.3 mo demonstrated superior efficacy of acalabrutinib (A) ± obinutuzumab (O) compared with O + chlorambucil (Clb) in patients (pts) with treatment-naïve (TN) chronic lymphocytic leukemia (CLL) (Sharman et al. Lancet 2020;395:1278-91). Results from a 4-year update are reported here. Methods: Pts received A±O or O+Clb. Crossover to A monotherapy was permitted in pts who progressed on O+Clb. Investigator-assessed (INV) progression-free survival (PFS), INV overall response rate (ORR), overall survival (OS), and safety were evaluated. Results: 535 pts (A+O, n=179; A, n=179; O+Clb, n=177) were randomized with a median age of 70 y; 63% had unmutated IGHV and 9% del(17p). At a median follow-up of 46.9 mo (range, 0.0–59.4; data cutoff: Sept 11, 2020), the median PFS was not reached (NR) for A+O and A pts vs 27.8 mo for O+Clb pts (both P<0.0001). In pts with unmutated IGHV, the median PFS was NR (A+O and A) vs 22.2 mo among O+Clb pts (both P<0.0001). In pts with del(17p), the median PFS was NR (A+O and A) vs 17.7 mo for O+Clb ( P<0.005). Estimated 48-mo PFS rates were 87% for A+O, 78% for A, and 25% for O+Clb. Median OS was NR in any treatment arm with a trend towards significance in the A+O group (A+O vs O+Clb, P=0.0604); estimated 48-mo OS rates were 93% (A+O), 88% (A), and 88% (O+Clb). ORR was significantly higher with A+O (96.1%; 95% CI 92.1–98.1) vs O+Clb (82.5%; 95% CI 76.2–87.4; P<0.0001); ORR with A was 89.9% (95% CI 84.7–93.5; P=0.035 vs O+Clb). Complete response/complete response with incomplete hematologic recovery (CR/CRi) rates were higher with A+O (26.8%/3.9%) vs O+Clb (12.4%/0.6%); 10.6%/0.6% had CR/CRi with A. Common adverse events (AEs) and AEs of interest are shown in the Table. Overall treatment discontinuation rates were 25.1% (A+O), 30.7% (A), and 22.6% (O+Clb); the most common reasons were AEs (12.8%, 12.3%, 14.7%, respectively) and progressive disease (4.5%, 7.8%, 1.7%). Most pts (77.4%) completed O+Clb treatment. Conclusions: With a median follow-up of 46.9 mo (̃4y), the efficacy and safety of A+O and A monotherapy was maintained, with an increase in CR since the interim analysis (from 21% to 27% [A+O] and from 7% to 11% [A]) and low rates of discontinuation.[Table: see text]

Randomized, phase III study of early intervention with venetoclax and obinutuzumab versus delayed therapy with venetoclax and obinutuzumab in newly diagnosed asymptomatic high-risk patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL): EVOLVE CLL/SLL study (SWOG S1925, NCT#04269902)

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Background: Currently, asymptomatic patients with CLL/SLL are observed without treatment until development of symptoms or cytopenias. Historically, early intervention studies with chemoimmunotherapy have not resulted in an overall survival (OS) benefit and have resulted in toxicity. The introduction of targeted therapies, such as venetoclax and obinutuzumab (VO), have provided tolerable/efficacious options for CLL patients. In the CLL14 study, symptomatic CLL patients receiving frontline therapy with VO had longer progression-free survival (PFS) and deeper remissions [more minimal residual disease-undetectable (MRDu)] compared with those receiving chlorambucil and obinutuzumab (Fischer 2019). The CLL-International Prognostic Index (CLL-IPI; Table) is a validated prognostic model to predict which patients are highest risk for a shorter time to first therapy and shorter OS. We aim to use VO as early intervention in asymptomatic, high-risk patients with CLL to potentially lengthen OS and thus alter the natural history of the disease. Methods: On 12/14/20, we activated the S1925 study for adult patients with CLL or SLL, who were diagnosed within 12 months of enrollment. Eligible patients have a CLL-IPI score ≥ 4 (Table) or complex cytogenetics (≥3 cytogenetic abnormalities) and do not meet any criteria for initiation of treatment by the International Working Group for CLL (IWCLL; Hallek 2018) guidelines. Enrolled patients are randomized in a 2:1 manner to early versus delayed (at the time IWCLL indication for treatment is met) therapy with VO. VO is administered for a fixed duration of 12 months as previously described (Fischer 2019). The primary endpoint is OS. We hypothesize that early intervention with VO will improve the rate of 6-year OS from 60% to 80%. This design requires 222 eligible patients for 88% power (2-sided α=0.05) for the primary comparison. To allow for 10% ineligibility, we will enroll 247 patients. Estimated accrual time is 4 years. Secondary endpoints include: rates of response, PFS, and relapse-free survival; safety; time to 2nd CLL-directed therapy; and quality of life (FACT-Leukemia total score). The primary translational objective is to evaluate the prognostic association between OS and peripheral blood MRD status at 15 months after treatment initiation by flow cytometry. Additional exploratory objectives include the association of other clinical outcomes, baseline prognostic factors, and IWCLL-defined response with MRD status at multiple timepoints. Currently, enrollment is open. Clinical trial information: NCT04269902. [Table: see text]

Event free survival in adults with relapsed ALL who underwent front-line therapy with CALGB 10403

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Background: CALGB 10403 is a pediatric-inspired ALL regimen that has recently been shown to have improved survival rates in adolescents and young adults with ALL when compared to historical outcomes with traditional adult ALL regimens (Stock et. al, 2019). Methods: This is a retrospective cohort study of ALL patients who received induction CALGB 10403 at Stanford University (both on and off trial), achieved CR1, and subsequently relapsed. Primary outcome of interest was event free survival from time of diagnosis. Events were defined as relapse or death. Secondary outcomes were overall survival and event free survival from first relapse. Patients were censored at time of last clinical follow up. Results: 25 patients met inclusion criteria and received front-line CALGB 10403 from April 2010 to September 2018. At the time of initial diagnosis median age was 30 years (range 18 – 39 years). 68% of patients were male. 48% of patients were overweight and 40% were obese. 76% of patients had precursor B cell ALL while 24% had T cell ALL. 12% had CNS disease at diagnosis. 36% of patients had WBC greater than 30k. 12% of patients had CRLF2 rearrangement. 12% of patients were MRD positive after first induction. 20% of patients received rituximab. Median event free survival time from diagnosis was 20 months (range 3 – 79 months) and median overall survival time was 53 months. Blinatumomab was the most common salvage therapy after 1st relapse, followed by inotuzumab. 15 patients (60%) achieved CR2, of which 4 (27%) were MRD positive after 2nd induction. 15 patients (60%) went to HSCT. Of the patients who achieved CR2, 8 relapsed for a second time. Median event free survival time after first relapse was 23 months. Survival 1 year after relapse was 60%. 11 of the 25 patients were alive at last follow up. Median follow up time of survivors was 6 years. Conclusions: This is a descriptive retrospective cohort study of adult patients in a real world setting who received CALGB 10403 induction and subsequently relapsed. Compared to other studies of relapsed ALL patients who were induced with traditional chemotherapy (Fielding et. al, 2007), survival 1 year after relapse was much higher (60% vs. 22%). As CALGB 10403 becomes an increasingly common induction regimen for AYA and adults with ALL, further outcomes study is required.[Table: see text]

Up to seven years of follow-up in the RESONATE-2 study of first-line ibrutinib treatment for patients with chronic lymphocytic leukemia

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Background: Ibrutinib, a once-daily Bruton’s tyrosine kinase inhibitor, is the only targeted therapy with significant progression-free survival (PFS) and overall survival (OS) benefit in multiple randomized phase 3 studies versus established therapies in patients (pts) with previously untreated chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). Extended long-term follow-up data for the RESONATE-2 study of first-line ibrutinib vs chlorambucil in older pts with CLL/SLL are reported. Methods: In the phase 3 RESONATE-2 study, older pts (≥65 years [y]) with previously untreated CLL/SLL and without del(17p) (N=269) were randomly assigned 1:1 to once-daily single-agent ibrutinib 420 mg until disease progression (PD) or unacceptable toxicity (n=136) or chlorambucil 0.5–0.8 mg/kg up to 12 cycles (n=133). Outcomes included PFS, OS, overall response rate (ORR), and safety. Long-term responses were investigator-assessed per 2008 iwCLL criteria. Results: With up to 7y of follow-up (median, 74.9 months; range, 0.1–86.8), significant PFS benefit was sustained for pts treated with ibrutinib vs chlorambucil (hazard ratio [HR] 0.160 [95% confidence interval (CI): 0.111–0.230]). At 6.5y, PFS was 61% in pts treated with ibrutinib vs 9% in pts treated with chlorambucil. This PFS benefit was observed across all subgroups, including in ibrutinib-treated pts with high-risk genomic features of unmutated IGHV (HR 0.109 [95% CI: 0.063–0.189]) or del(11q) (HR 0.033 [95% CI: 0.010–0.107]). OS at 6.5y was 78% with ibrutinib treatment. ORR was 92% for ibrutinib-treated pts with complete response (CR/CRi) rate increasing to 34% with this follow-up. Ongoing rates of grade ≥3 adverse events (AEs) of interest remained low for hypertension (5–6y interval: 5%, n=4; 6–7y: 4%, n=3) and atrial fibrillation (5–6y: 1%, n=1; 6–7y: 1%, n=1); no grade ≥3 major hemorrhage occurred in 5–7y. Dose reductions due to grade ≥3 AEs occurred in 1% (n=1) of pts during the 5–6y and 6–7y intervals. Across full follow-up, 31 pts had dose reductions due to any-grade AEs of whom 22/31 (71%) had resolution or improvement the AE. Primary reason for discontinuations in 5–7y was PD (5–6y: 5%, n=4; 6–7y: 6%, n=4). Any-grade AEs leading to discontinuations were seen in 3% (n=2) of pts from 5–6y and none in 6–7y. With over 7y of follow-up, 47% of pts remain on single-agent ibrutinib. Conclusions: Extended long-term data from RESONATE-2 demonstrate the sustained PFS and OS benefit of first-line ibrutinib treatment for pts with CLL, including for pts with high-risk genomic features. Responses continue to deepen over time. Rates of grade ≥3 AEs of interest continued to be low at up to 7y follow-up and further discontinuations and dose reductions due to AEs were rare; most AEs leading to dose reduction resolved or improved. Ibrutinib remains well tolerated with no new safety signals observed. Clinical trial information: NCT01722487, NCT01724346.

Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma, Version 4.2020, NCCN Clinical Practice Guidelines in Oncology

Chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL) are characterized by a progressive accumulation of leukemic cells in the peripheral blood, bone marrow, and lymphoid tissues. Treatment of CLL/SLL has evolved significantly in recent years because of the improved understanding of the disease biology and the development of novel targeted therapies. In patients with indications for initiating treatment, the selection of treatment should be based on the disease stage, patient's age and overall fitness (performance status and comorbid conditions), and cytogenetic abnormalities. This manuscript discusses the recommendations outlined in the NCCN Guidelines for the diagnosis and management of patients with CLL/SLL.

NCCN Guidelines Insights: Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma, Version 2.2019

Chronic lymphocytic leukemia (CLL) is generally characterized by an indolent disease course. Histologic transformation (also known as Richter's transformation) to more aggressive lymphomas, such as diffuse large B-cell lymphoma or Hodgkin lymphoma, occurs in approximately 2% to 10% of patients and is associated with a poor prognosis. These NCCN Guidelines Insights discuss the recommendations for the diagnosis and management of patients with histologic transformation.

Toxicity burden in older patients with chronic lymphocytic leukemia (CLL) receiving bendamustine with rituximab (BR) or ibrutinib (IB) regimens: Alliance A041202

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Background: IB is a Bruton’s tyrosine kinase inhibitor that showed superior progression-free survival compared with BR in CLL patients (pts) 65 years or older in a randomized phase 3 trial (Woyach et al, NEJM 2018). Pts receiving IB had higher rates of atrial fibrillation (AFIB) and hypertension (HTN); BR pts had higher rates of hematologic toxicity. Differences in treatment duration for BR (6 cycles) and IB (until progression) complicated adverse event (AE) comparisons. Here we use an exploratory approach to compare toxicity burden between arms and provide assessment of AFIB, HTN and infections (INF). Methods: AEs were reported for each of cycles 1-6 and then every 3 cycles until progression or nonprotocol CLL therapy. Only grade (gr) 3-4 AEs were reported thereafter until death. A simple global AE score was calculated for each pt by summing grades of all gr 1-4 AEs and dividing by the number of cycles over which AEs were submitted. Results: 537 pts began therapy (176 BR, 361 IB). 68% on BR completed all 6 cycles. At a median follow-up of 38 months, 64% remained on IB. Treatment discontinuation for AE occurred in 10% and 14% of BR and IB pts. Overall, median AE score was 1.8 (interquartile range (IQR) 0.9-3.3) and 3.8 (IQR 2.3-5.9) in BR and IB arms (p < 0.01). For cycles 1-6, median AE score was 6.2 (IQR 3.8-9.0) and 4.8 (IQR 3.0-7.2) in BR and IB arms (p < 0.01). In the IB arm, median AE score post 6 cycles decreased significantly to 3.4 (IQR 1.9-5.6) (p < 0.01). Gr 3 or higher cumulative rates of AFIB, HTN, and INF over time appear in the table. 100 pts (26/176 BR, 74/361 IB) had 137 severe INF (39% respiratory: 16 BR, 37 IB; 25% skin: 3 BR, 31 IB; 12% GU: 3 BR, 13 IB; 25% other: 12 BR, 22 IB). There were 7 gr 5 INF (3 BR, 4 IB), none confirmed fungal. Conclusions: There was no difference in treatment discontinuation rates for AE. Overall toxicity burden was significantly higher for IB, although IB toxicity burden decreased after 6 cycles. Toxicity burden was significantly higher in cycles 1-6 for pts receiving BR. Risk of severe AFIB, HTN, and INF is highest in the first year of IB. A simple AE score provides valuable information, especially when evaluating regimens of varying length. Clinical trial information: NCT01886872 . Support: U10CA180821, U10CA180882, U24CA196171; https://acknowledgments.alliancefound.org ; Pharmacyclics; ClinicalTrials.gov Identifier: NCT01886872. [Table: see text]

Idelalisib, a selective inhibitor of phosphatidylinositol 3-kinase-δ, as therapy for previously treated indolent non-Hodgkin lymphoma

Idelalisib (GS-1101, CAL-101), an oral inhibitor of phosphatidylinositol 3-kinase-δ, was evaluated in a phase I study in 64 patients with relapsed indolent non-Hodgkin lymphoma (iNHL). Patients had a median (range) age of 64 (32-91) years, 34 (53%) had bulky disease (≥1 lymph nodes ≥5 cm), and 37 (58%) had refractory disease. Patients had received a median (range) of 4 (1-10) prior therapies. Eight dose regimens of idelalisib were evaluated; idelalisib was taken once or twice daily continuously at doses ranging from 50 to 350 mg. After 48 weeks, patients still benefitting (n = 19; 30%) enrolled into an extension study. Adverse events (AEs) occurring in 20% or more patients (total%/grade ≥3%) included diarrhea (36/8), fatigue (36/3), nausea (25/3), rash (25/3), pyrexia (20/3), and chills (20/0). Laboratory abnormalities included neutropenia (44/23), anemia (31/5), thrombocytopenia (25/11), and serum transaminase elevations (48/25). Twelve (19%) patients discontinued therapy due to AEs. Idelalisib induced disease regression in 46/54 (85%) of evaluable patients achieving an overall response rate of 30/64 (47%), with 1 patient having a complete response (1.6%). Median duration of response was 18.4 months, median progression-free survival was 7.6 months. Idelalisib is well tolerated and active in heavily pretreated, relapsed/refractory patients with iNHL. These trials were registered at clinicaltrials.gov as NCT00710528 and NCT01090414.

Southwest Oncology Group Study S0530: a phase 2 trial of clofarabine and cytarabine for relapsed or refractory acute lymphocytic leukaemia

Clofarabine and cytarabine target different steps in DNA synthesis and replication, are synergistic in vivo, and have non-overlapping toxicities, making this combination a potentially promising treatment for acute lymphocytic leukaemia. Thirty-seven patients were treated. The median age was 41 years, 44% of patients were either in ≥2nd relapse or had refractory disease and 59% of patients had poor risk cytogenetics. Six out of 36 patients (17%) achieved a complete remission with or without complete count recovery; median overall survival was 3 months. Nucleoside transporter expression did not predict outcome. This regimen lacked sufficient activity to warrant further testing.

International standardized approach for flow cytometric residual disease monitoring in chronic lymphocytic leukaemia

The eradication of minimal residual disease (MRD) in chronic lymphocytic leukaemia (CLL) predicts for improved outcome. However, the wide variety of MRD techniques makes it difficult to interpret and compare different clinical trials. Our aim was to develop a standardized flow cytometric CLL-MRD assay and compare it to real-time quantitative allele-specific oligonucleotide (RQ-ASO) Immunoglobulin heavy chain gene (IgH) polymerase chain reaction (PCR). Analysis of 728 paired blood and marrow samples demonstrated high concordance (87%) for patients off-therapy. Blood analysis was equally or more sensitive than marrow in 92% of samples but marrow analysis was necessary to detect MRD within 3 months of alemtuzumab therapy. Assessment of 50 CLL-specific antibody combinations identified three (CD5/CD19 with CD20/CD38, CD81/CD22 and CD79b/CD43) with low inter-laboratory variation and false-detection rates. Experienced operators demonstrated an accuracy of 95.7% (specificity 98.8%, sensitivity 91.1%) in 141 samples with 0.01-0.1% CLL. There was close correlation and 95% concordance with RQ-ASO IgH-PCR for detection of CLL above 0.01%. The proposed flow cytometry approach is applicable to all sample types and therapeutic regimes, and sufficiently rapid and sensitive to guide therapy to an MRD-negativity in real time. These techniques may be used as a tool for assessing response and comparing the efficacy of different therapeutic approaches.

Pilot study of the efficacy of a thrombin inhibitor for use during cardiopulmonary bypass

Heparin is normally used for anticoagulation during cardiopulmonary bypass (CPB), but its use is contraindicated in patients with a history of heparin-induced thrombocytopenia, heparin-provoked thrombosis, or both. Heparin therapy can also be ineffective due to heparin resistance. A short-acting, oligonucleotide-based thrombin inhibitor (thrombin aptamer) may potentially serve as a substitute for heparin in these and other clinical situations. We tested a novel thrombin aptamer in a canine CPB pilot study to determine its anticoagulant efficacy, the resultant changes in coagulation variables, and the aptamer's clearance mechanisms and pharmacokinetics. Seven dogs were studied initially: Four received varied doses of the aptamer (to establish the pharmacokinetic profile) and 3 received heparin. Subsequently, 4 other dogs underwent CPB, receiving a constant infusion of the aptamer before CPB (to characterize the baseline coagulation status), with partial CPB and hemodilution, during 60 minutes of total CPB, and, finally, after a 2-hour recovery period. At a 0.5 mg.kg-1.min-1 dose, the activated clotting time rose with aptamer infusion from 106 +/- 12 seconds to 187 +/- 8 seconds (+/- 1 standard deviation) (p = 0.014), increased further with hemodilution (to 259 +/- 41 seconds; p = 0.017), and was even more prolonged during total CPB (> 1,500 seconds; p < 0.001). This later increase in the activated clotting time paralleled a rise in the plasma concentration of the thrombin aptamer during total CPB, as determined by high-performance liquid chromatography.(ABSTRACT TRUNCATED AT 250 WORDS)