Accurate identification of patients likely to achieve long-progression-free survival (PFS) after chemoimmunotherapy is essential given the availability of less toxic alternatives, such as ibrutinib. ...Fludarabine, cyclophosphamide, and rituximab (FCR) achieved a high response rate, but continued relapses were seen in initial reports. We reviewed the original 300 patient phase 2 FCR study to identify long-term disease-free survivors. Minimal residual disease (MRD) was assessed posttreatment by a polymerase chain reaction-based ligase chain reaction assay (sensitivity 0.01%). At the median follow-up of 12.8 years, PFS was 30.9% (median PFS, 6.4 years). The 12.8-year PFS was 53.9% for patients with mutated immunoglobulin heavy chain variable (IGHV) gene (IGHV-M) and 8.7% for patients with unmutated IGHV (IGHV-UM). 50.7% of patients with IGHV-M achieved MRD-negativity posttreatment; of these, PFS was 79.8% at 12.8 years. A plateau was seen on the PFS curve in patients with IGHV-M, with no relapses beyond 10.4 years in 42 patients (total follow-up 105.4 patient-years). On multivariable analysis, IGHV-UM (hazard ratio, 3.37 2.18-5.21; P < .001) and del(17p) by conventional karyotyping (hazard ratio, 7.96 1.02-61.92; P = .048) were significantly associated with inferior PFS. Fifteen patients with IGHV-M had 4-color MRD flow cytometry (sensitivity 0.01%) performed in peripheral blood, at a median of 12.8 years posttreatment (range, 9.5-14.7). All were MRD-negative. The high rate of very long-term PFS in patients with IGHV-M after FCR argues for the continued use of chemoimmunotherapy in this patient subgroup outside clinical trials; alternative strategies may be preferred in patients with IGHV-UM, to limit long-term toxicity.
•FCR-treated chronic lymphocytic leukemia patients with mutated IGHV gene achieve long-term PFS, with a plateau on the PFS curve.•MRD-negativity posttreatment is highly predictive of long-term PFS, particularly in patients with mutated IGHV gene.
Targeted therapies for chronic lymphocytic leukemia (CLL) include venetoclax, the oral inhibitor of B-cell lymphoma-2, and inhibitors of kinases in the B-cell receptor signaling pathway, like Bruton ...tyrosine kinase and phosphatidylinositol 3 kinase. Randomized clinical trials clearly demonstrated improved progression-free survival with targeted therapy over chemoimmunotherapy in first-line and treatment of relapsed/refractory CLL. Comparative trials of venetoclax-based vs other targeted therapies have not been conducted. Differentiating features and considerations with targeted therapies include goals of treatment and therapeutic approach as well as side effect and toxicity profiles. With targeted therapy options for first-line and relapsed CLL, it is ever more important to develop sound rationale and strategy for selecting first-line and treatment of relapsed disease and for long-term management of the disease, including therapeutic sequencing. Fixed-duration therapy with a treatment-free remission is a particularly appealing prospect, since it avoids continuous exposure to treatment and potential for toxicity. We discuss rationale and practical application of venetoclax in first-line and treatment of relapsed and refractory CLL. Venetoclax is highly active at achieving deep remission for most treated patients with CLL, including those with high-risk disease such as del(17p) CLL.
Summary Background Deletion of chromosome 17p (del17p) in patients with chronic lymphocytic leukaemia confers very poor prognosis when treated with standard chemo-immunotherapy. Venetoclax is an oral ...small-molecule BCL2 inhibitor that induces chronic lymphocytic leukaemia cell apoptosis. In a previous first-in-human study of venetoclax, 77% of patients with relapsed or refractory chronic lymphocytic leukaemia achieved an overall response. Here we aimed to assess the activity and safety of venetoclax monotherapy in patients with relapsed or refractory del(17p) chronic lymphocytic leukaemia. Methods In this phase 2, single-arm, multicentre study, we recruited patients aged 18 years and older with del(17p) relapsed or refractory chronic lymphocytic leukaemia (as defined by 2008 Modified International Workshop on Chronic Lymphocytic Leukemia guidelines) from 31 centres in the USA, Canada, UK, Germany, Poland, and Australia. Patients started once daily venetoclax with a weekly dose ramp-up schedule (20, 50, 100, 200, 400 mg) over 4–5 weeks. Patients were then given daily 400 mg continuous dosing until disease progression or discontinuation for another reason. The primary endpoint was the proportion of patients achieving an overall response, assessed by an independent review committee. Activity and safety analyses included all patients who received at least one dose of study drug (per protocol). This study is registered with ClinicalTrials.gov , number NCT01889186 . Follow-up is ongoing, and patients are still receiving treatment. Findings Between May 27, 2013, and June 27, 2014, 107 patients were enrolled into the study. At a median follow-up of 12·1 months (IQR 10·1–14·2), an overall response by independent review was achieved in 85 (79·4%; 95% CI 70·5–86·6) of 107 patients. The most common grade 3–4 adverse events were neutropenia (43 40%), infection (21 20%), anaemia (19 18%), and thrombocytopenia (16 15%). Serious adverse events occurred in 59 (55%) patients, irrespective of their relationship to treatment, with the most common (≥5% of patients) being pyrexia and autoimmune haemolytic anaemia (seven 7% each), pneumonia (six 6%), and febrile neutropenia (five 5%). 11 patients died in the study within 30 days of the last dose of venetoclax; seven due to disease progression and four from an adverse event (none assessed as treatment related). Interpretation Results of this trial show that venetoclax monotherapy is active and well tolerated in patients with relapsed or refractory del(17p) chronic lymphocytic leukaemia, providing a new therapeutic option for this very poor prognosis population. Additionally, in view of the distinct mechanism-of-action of venetoclax, combinations or sequencing with other novel targeted agents should be investigated to further advance treatment of del(17p) chronic lymphocytic leukaemia. Funding AbbVie and Genentech.
To define the efficacy of venetoclax with extended follow-up and identify clinical or biological treatment effect modifiers, updated data for previously treated patients with chronic lymphocytic ...leukemia (CLL) or small lymphocytic lymphoma (SLL) enrolled in 4 early-phase trials were pooled. Rates of response, complete remission (CR/CRi), and undetectable minimal residual disease (U-MRD) were analyzed for all patients (n = 436) and for those patients who were planned to receive 400 mg/day monotherapy (n = 347). Univariate and multiple regression analyses were performed to identify the pretreatment factors associated with response rates and duration of response (DoR). Objective responses were documented in 75% of all patients, including 22% CR/CRi. Overall, 27% and 16% of the patients achieved U-MRD in blood and marrow, respectively. Estimated median progression-free survival (PFS), DoR, and time to progression were 30.2, 38.4, and 36.9 months, respectively. Similar efficacy outcomes were observed within the 400 mg/day monotherapy subset. For those who achieved CR/CRi, the 3-year PFS estimate was 83%. DoR was superior for patients achieving CR/CRi or U-MRD in landmark analyses. In multiple regression analyses, bulky lymphadenopathy (≥5 cm) and refractoriness to B-cell receptor inhibitor (BCRi) therapy were significantly associated with lower CR rate and shorter DoR. Fewer prior therapies were associated with higher CR rate, but not DoR. Chromosome 17p deletion and/or TP53 mutation and NOTCH1 mutation were consistently associated with shorter DoR, but not probability of response. Thus, both pretreatment factors and depth of response correlated with DoR with venetoclax. Patients without bulky lymphadenopathy, BCRi-refractory CLL, or an adverse mutation profile had the most durable benefit.
•Patients with relapsed CLL achieving complete remission or undetectable MRD on venetoclax treatment have the most durable responses.•Less durable responses are associated with bulky adenopathy, TP53 aberrations, NOTCH1 mutations, and prior refractoriness to BCRis.
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B-cell receptor (BCR) signaling is a critical pathway in the pathogenesis of several B-cell malignancies, including chronic lymphocytic leukemia (CLL), and can be targeted by inhibitors of ...BCR-associated kinases, such as Bruton tyrosine kinase (Btk). PCI-32765, a selective, irreversible Btk inhibitor, is a novel, molecularly targeted agent for patients with B-cell malignancies, and is particularly active in patients with CLL. In this study, we analyzed the mechanism of action of PCI-32765 in CLL, using in vitro and in vivo models, and performed correlative studies on specimens from patients receiving therapy with PCI-32765. PCI-32765 significantly inhibited CLL cell survival, DNA synthesis, and migration in response to tissue homing chemokines (CXCL12, CXCL13). PCI-32765 also down-regulated secretion of BCR-dependent chemokines (CCL3, CCL4) by the CLL cells, both in vitro and in vivo. In an adoptive transfer TCL1 mouse model of CLL, PCI-32765 affected disease progression. In this model, PCI-32765 caused a transient early lymphocytosis, and profoundly inhibited CLL progression, as assessed by weight, development, and extent of hepatospenomegaly, and survival. Our data demonstrate that PCI-32765 effectively inhibits CLL cell migration and survival, possibly explaining some of the characteristic clinical activity of this new targeted agent.
Purpose Oral targeted therapies represent a significant advance for the treatment of patients with chronic lymphocytic leukemia (CLL); however, their high cost has raised concerns about affordability ...and the economic impact on society. Our objective was to project the future prevalence and cost burden of CLL in the era of oral targeted therapies in the United States. Methods We developed a simulation model that evaluated the evolving management of CLL from 2011 to 2025: chemoimmunotherapy (CIT) as the standard of care before 2014, oral targeted therapies for patients with del(17p) and relapsed CLL from 2014, and for first-line treatment from 2016 onward. A comparator scenario also was simulated where CIT remained the standard of care throughout. Disease progression and survival parameters for each therapy were based on published clinical trials. Results The number of people living with CLL in the United States is projected to increase from 128,000 in 2011 to 199,000 by 2025 (55% increase) due to improved survival; meanwhile, the annual cost of CLL management will increase from $0.74 billion to $5.13 billion (590% increase). The per-patient lifetime cost of CLL treatment will increase from $147,000 to $604,000 (310% increase) as oral targeted therapies become the first-line treatment. For patients enrolled in Medicare, the corresponding total out-of-pocket cost will increase from $9,200 to $57,000 (520% increase). Compared with the CIT scenario, oral targeted therapies resulted in an incremental cost-effectiveness ratio of $189,000 per quality-adjusted life-year. Conclusion The increased benefit and cost of oral targeted therapies is projected to enhance CLL survivorship but can impose a substantial financial burden on both patients and payers. More sustainable pricing strategies for targeted therapies are needed to avoid financial toxicity to patients.
Deep remission and prolonged disease-free survival can be achieved with first-line chemoimmunotherapy (CIT), such as combined fludarabine, cyclophosphamide, and rituximab, in the majority of patients ...with chronic lymphocytic leukemia (CLL). More modest results are reported with less intense regimens like obinutuzumab plus chlorambucil. Clinical assessment has limited sensitivity in detecting residual disease responsible for subsequent relapse, even including morphologic bone marrow (BM) evaluation. Multicolor flow cytometry and polymerase chain reaction (PCR)-based methods can detect minimal residual disease (MRD) to a sensitivity of ≥1:10 000 (10−4). Achieving BM MRD-negative complete remission (CR) is associated with superior progression-free survival (PFS) and overall survival; MRD status is the single best posttreatment predictor of long-term outcomes after CIT. Newer oral B-cell receptor signaling pathway inhibitors are highly effective at controlling disease, but best monotherapy responses are typically partial remission, and patients must remain on treatment to maintain disease control. Therapeutic progress is still needed for CLL. We propose that targeting MRD provides opportunity to realize this progress. Achieving BM MRD-negative CR is a prerequisite for long-term unmaintained disease-free survival and potential for cure. We review available methodologies for detecting MRD and correlations with posttreatment outcomes. We discuss the potential utility of MRD to direct individualized therapy. Finally, we discuss the importance of MRD-negative status as a surrogate marker for longer PFS in clinical studies to allow more rapid determination of clinical benefit.
In lymphocytes, the phosphoinositide 3′-kinase (PI3K) isoform p110δ (PI3Kδ) transmits signals from surface receptors, including the B-cell receptor (BCR). CAL-101, a selective inhibitor of PI3Kδ, ...displays clinical activity in CLL, causing rapid lymph node shrinkage and a transient lymphocytosis. Inhibition of pro-survival pathways, the presumed mechanism of CAL-101, does not explain this characteristic pattern of activity. Therefore, we tested CAL-101 in assays that model CLL-microenvironment interactions in vitro. We found that CAL-101 inhibits CLL cell chemotaxis toward CXCL12 and CXCL13 and migration beneath stromal cells (pseudoemperipolesis). CAL-101 also down-regulates secretion of chemokines in stromal cocultures and after BCR triggering. CAL-101 reduces survival signals derived from the BCR or from nurse-like cells, and inhibits BCR- and chemokine-receptor–induced AKT and MAP kinase (ERK) activation. In stromal cocultures, CAL-101 sensitizes CLL cells toward bendamustine, fludarabine, and dexamethasone. These results are corroborated by clinical data showing marked reductions in circulating CCL3, CCL4, and CXCL13 levels, and a surge in lymphocytosis during CAL-101 treatment. Thus, CAL-101 displays a dual mechanism of action, directly decreasing cell survival while reducing interactions that retain CLL cells in protective tissue microenvironments. These data provide an explanation for the clinical activity of CAL-101, and a roadmap for future therapeutic development.
Bruton tyrosine kinase (BTK) is a validated target for treatment of B-cell malignancies, and oral inhibitors of BTK have emerged as a standard of care for these diseases. Acalabrutinib is a second ...generation, highly selective, potent, covalent BTK inhibitor that exhibits minimal off-target activity in
in vitro
assays, providing the potential to improve tolerability over the first-in-class BTK inhibitor, ibrutinib. Acalabrutinib was approved for the treatment of relapsed/refractory mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL) in the US in 2017 and 2019, respectively. Acalabrutinib is also undergoing trials for other B-cell malignancies, both as monotherapy and in combinations. In this review, we discuss results from clinical trials evaluating the efficacy and safety of acalabrutinib in patients with CLL, MCL, and Waldenstrom’s macroglobulinemia. Recent phase 3 data showed that acalabrutinib improved progression-free survival (PFS) compared with rituximab plus idelalisib or rituximab plus bendamustine in patients with relapsed/refractory CLL, and acalabrutinib with or without obinutuzumab improved PFS compared with chlorambucil plus obinutuzumab in patients with treatment-naïve CLL. Overall, acalabrutinib had a tolerable safety profile, with most adverse events being grade 1/2 severity (most commonly headache and diarrhea) and a low rate of discontinuation due to adverse events.
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