Cancer immunotherapy based on genetically redirecting T cells has been used successfully to treat B cell malignancies
. In this strategy, the T cell genome is modified by integration of viral vectors ...or transposons encoding chimaeric antigen receptors (CARs) that direct tumour cell killing. However, this approach is often limited by the extent of expansion and persistence of CAR T cells
. Here we report mechanistic insights from studies of a patient with chronic lymphocytic leukaemia treated with CAR T cells targeting the CD19 protein. Following infusion of CAR T cells, anti-tumour activity was evident in the peripheral blood, lymph nodes and bone marrow; this activity was accompanied by complete remission. Unexpectedly, at the peak of the response, 94% of CAR T cells originated from a single clone in which lentiviral vector-mediated insertion of the CAR transgene disrupted the methylcytosine dioxygenase TET2 gene. Further analysis revealed a hypomorphic mutation in this patient's second TET2 allele. TET2-disrupted CAR T cells exhibited an epigenetic profile consistent with altered T cell differentiation and, at the peak of expansion, displayed a central memory phenotype. Experimental knockdown of TET2 recapitulated the potency-enhancing effect of TET2 dysfunction in this patient's CAR T cells. These findings suggest that the progeny of a single CAR T cell induced leukaemia remission and that TET2 modification may be useful for improving immunotherapies.
In a phase 1 trial, idelalisib (GS-1101, CAL-101), a selective inhibitor of the lipid kinase PI3Kδ, was evaluated in 54 patients with relapsed/refractory chronic lymphocytic leukemia (CLL) with ...adverse characteristics including bulky lymphadenopathy (80%), extensive prior therapy (median 5 range 2-14 prior regimens), treatment-refractory disease (70%), unmutated IGHV (91%), and del17p and/or TP53 mutations (24%). Patients were treated at 6 dose levels of oral idelalisib (range 50-350 mg once or twice daily) and remained on continuous therapy while deriving clinical benefit. Idelalisib-mediated inhibition of PI3Kδ led to abrogation of Akt phosphorylation in patient CLL cells and significantly reduced serum levels of CLL-related chemokines. The most commonly observed grade ≥3 adverse events were pneumonia (20%), neutropenic fever (11%), and diarrhea (6%). Idelalisib treatment resulted in nodal responses in 81% of patients. The overall response rate was 72%, with 39% of patients meeting the criteria for partial response per IWCLL 2008 and 33% meeting the recently updated criteria of PR with treatment-induced lymphocytosis.1,2 The median progression-free survival for all patients was 15.8 months. This study demonstrates the clinical utility of inhibiting the PI3Kδ pathway with idelalisib. Our findings support the further development of idelalisib in patients with CLL. These trials were registered at clinicaltrials.gov as #NCT00710528 and #NCT01090414.
•Idelalisib was evaluated in 54 patients with heavily pretreated chronic lymphocytic leukemia, and target inhibition was documented in vivo.•Oral idelalisib therapy demonstrated a favorable safety profile and rapidly induced durable disease control in the majority of patients.
Patients with chronic lymphocytic leukemia (CLL) may be more susceptible to Coronavirus disease 2019 (COVID-19) due to age, disease, and treatment-related immunosuppression. We aimed to assess risk ...factors of outcome and elucidate the impact of CLL-directed treatments on the course of COVID-19. We conducted a retrospective, international study, collectively including 941 patients with CLL and confirmed COVID-19. Data from the beginning of the pandemic until March 16, 2021, were collected from 91 centers. The risk factors of case fatality rate (CFR), disease severity, and overall survival (OS) were investigated. OS analysis was restricted to patients with severe COVID-19 (definition: hospitalization with need of oxygen or admission into an intensive care unit). CFR in patients with severe COVID-19 was 38.4%. OS was inferior for patients in all treatment categories compared to untreated (p < 0.001). Untreated patients had a lower risk of death (HR = 0.54, 95% CI:0.41-0.72). The risk of death was higher for older patients and those suffering from cardiac failure (HR = 1.03, 95% CI:1.02-1.04; HR = 1.79, 95% CI:1.04-3.07, respectively). Age, CLL-directed treatment, and cardiac failure were significant risk factors of OS. Untreated patients had a better chance of survival than those on treatment or recently treated.
The Bruton tyrosine kinase (BTK) inhibitor ibrutinib is effective in patients with chronic lymphocytic leukemia (CLL). Reasons for discontinuing therapy with this drug and outcomes following ...discontinuation have not been evaluated outside of clinical trials with relatively short follow-up.
To determine features associated with discontinuation of ibrutinib therapy and outcomes.
A total of 308 patients participating in 4 sequential trials of ibrutinib at The Ohio State University Comprehensive Cancer Center were included. These clinical trials accrued patients included in this analysis from May 2010 until April 2014, and data were locked in June 2014.
Patients were evaluated for time to therapy discontinuation, reasons for discontinuation, and survival following discontinuation. For patients who discontinued therapy because of disease progression, targeted deep sequencing was performed in samples at baseline and time of relapse.
With a median follow-up of 20 months, 232 patients remained on therapy, 31 had discontinued because of disease progression, and 45 had discontinued for other reasons. Disease progression includes Richter's transformation (RT) or progressive CLL. Richter's transformation appeared to occur early and CLL progressions later (cumulative incidence at 12 months, 4.5% 95% CI, 2.0%-7.0% and 0.3% 95% CI, 0%-1.0%, respectively). Median survival following RT was 3.5 months (95% CI, 0.3-6.0 months) and 17.6 months (95% CI, 4.7 months-"not reached") following CLL progression. Sequencing on peripheral blood from 8 patients with RT revealed 2 with mutations in BTK, and a lymph node sample showed no mutations in BTK or PLCG2. Deep sequencing on 11 patients with CLL progression revealed BTK or PLCG2 mutations in all. These mutations were not identified before treatment in any patient.
This single-institution experience with ibrutinib confirms it to be an effective therapy and identifies, for the first time, baseline factors associated with ibrutinib therapy discontinuation. Outcomes data show poor prognosis after discontinuation, especially for those patients with RT. Finally, sequencing data confirm initial reports associating mutations in BTK and PLCG2 with progression and clearly show that CLL progressions are associated with these mutations, while RT is likely not.
clinicaltrials.gov Identifiers:NCT01105247, NCT01217749, NCT01589302, and NCT01578707.
The safety and efficacy of ibrutinib (420 mg) in chronic lymphocytic leukemia (CLL) were evaluated in a phase 2 study; 51 patients had TP53 aberration (TP53 cohort) and 35 were enrolled because of ...age 65 years or older (elderly cohort). Both cohorts included patients with treatment-naive (TN) and relapsed/refractory (RR) CLL. With the median follow-up of 4.8 years, 49 (57.0%) of 86 patients remain on study. Treatment was discontinued for progressive disease in 20 (23.3%) patients and for adverse events in 5 (5.8%). Atrial fibrillation occurred in 18 (20.9%) patients for a rate of 6.4 per 100 patient-years. No serious bleeding occurred. The overall response rate at 6 months, the primary study endpoint, was 95.8% for the TP53 cohort (95% confidence interval, 85.7%-99.5%) and 93.9% for the elderly cohort (95% confidence interval, 79.8%-99.3%). Depth of response improved with time: at best response, 14 (29.2%) of 48 patients in the TP53 cohort and 9 (27.3%) of 33 in the elderly cohort achieved a complete response. Median minimal residual disease (MRD) in peripheral blood was 3.8 × 10−2 at 4 years, with MRD-negative (<10−4) remissions in 5 (10.2%) patients. In the TP53 cohort, the estimated 5-year progression-free survival (PFS) was 74.4% in TN-CLL compared with 19.4% in RR-CLL (P = .0002), and overall survival (OS) was 85.3% vs 53.7%, respectively (P = .023). In the elderly cohort, the estimated 5-year PFS and OS in RR-CLL were 64.8% and 71.6%, respectively, and no event occurred in TN-CLL. Long-term administration of ibrutinib was well tolerated and provided durable disease control for most patients. This trial was registered at www.clinicaltrials.gov as #NCT01500733.
•With 5-year median follow-up, continuous single-agent ibrutinib therapy was well tolerated with deepening of response.•Previously untreated patients, even those with TP53 aberration, achieved durable responses.
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Important advances in understanding the pathogenesis of chronic lymphocytic leukaemia in the past two decades have led to the development of new prognostic tools and novel targeted therapies that ...have improved clinical outcome. Chronic lymphocytic leukaemia is the most common type of leukaemia in developed countries, and the median age at diagnosis is 72 years. The criteria for initiating treatment rely on the Rai and Binet staging systems and on the presence of disease-related symptoms. For many patients with chronic lymphocytic leukaemia, treatment with chemotherapy and anti-CD20 monoclonal antibodies is the standard of care. The impressive efficacy of kinase inhibitors ibrutinib and idelalisib and the BCL-2 antagonist venetoclax have changed the standard of care in specific subsets of patients. In this Seminar, we review the recent progress in the management of chronic lymphocytic leukaemia and highlight new questions surrounding the optimal disease management.
Summary Background Patients with chronic lymphocytic leukaemia (CLL) with TP53 aberrations respond poorly to first-line chemoimmunotherapy, resulting in early relapse and short survival. We ...investigated the safety and activity of ibrutinib in previously untreated and relapsed or refractory CLL with TP53 aberrations. Methods In this investigator-initiated, single-arm phase 2 study, we enrolled eligible adult patients with active CLL with TP53 aberrations at the National Institutes of Health Clinical Center (Bethesda, MD, USA). Patients received 28-day cycles of ibrutinib 420 mg orally once daily until disease progression or the occurrence of limiting toxicities. The primary endpoint was overall response to treatment at 24 weeks in all evaluable patients. This study is registered with ClinicalTrials.gov , number NCT01500733 , and is fully enrolled. Findings Between Dec 22, 2011, and Jan 2, 2014, we enrolled 51 patients; 47 had CLL with deletion 17p13.1 and four carried a TP53 mutation in the absence of deletion 17p13.1. All patients had active disease requiring therapy. 35 enrolled patients had previously untreated CLL and 16 had relapsed or refractory disease. Median follow-up was 24 months (IQR 12·9–27·0). 33 previously untreated patients and 15 patients with relapsed or refractory CLL were evaluable for response at 24 weeks. 32 (97%; 95% CI 86–100) of 33 previously untreated patients achieved an objective response, including partial response in 18 patients (55%) and partial response with lymphocytosis in 14 (42%). One patient had progressive disease at 0·4 months. 12 (80%; 95% CI 52–96) of the 15 patients with relapsed or refractory CLL had an objective response: six (40%) achieved a partial response and six (40%) a partial response with lymphocytosis; the remaining three (20%) patients had stable disease. Grade 3 or worse treatment-related adverse events were neutropenia in 12 (24%) patients (grade 4 in one 2% patient), anaemia in seven (14%) patients, and thrombocytopenia in five (10%) patients (grade 4 in one 2% patient). Grade 3 pneumonia occurred in three (6%) patients, and grade 3 rash in one (2%) patient. Interpretation The activity and safety profile of single-agent ibrutinib in CLL with TP53 aberrations is encouraging and supports its consideration as a novel treatment option for patients with this high-risk disease in both first-line and second-line settings. Funding Intramural Research Program of the National Heart, Lung, and Blood Institute and the National Cancer Institute, Danish Cancer Society, Novo Nordisk Foundation, National Institutes of Health Medical Research Scholars Program, and Pharmacyclics Inc.
The observation that BRCA1- and BRCA2-deficient cells are sensitive to inhibitors of poly(ADP-ribose) polymerase (PARP) has spurred the development of cancer therapies that use these inhibitors to ...target deficiencies in homologous recombination
. The cytotoxicity of PARP inhibitors depends on PARP trapping, the formation of non-covalent protein-DNA adducts composed of inhibited PARP1 bound to DNA lesions of unclear origins
. To address the nature of such lesions and the cellular consequences of PARP trapping, we undertook three CRISPR (clustered regularly interspersed palindromic repeats) screens to identify genes and pathways that mediate cellular resistance to olaparib, a clinically approved PARP inhibitor
. Here we present a high-confidence set of 73 genes, which when mutated cause increased sensitivity to PARP inhibitors. In addition to an expected enrichment for genes related to homologous recombination, we discovered that mutations in all three genes encoding ribonuclease H2 sensitized cells to PARP inhibition. We establish that the underlying cause of the PARP-inhibitor hypersensitivity of cells deficient in ribonuclease H2 is impaired ribonucleotide excision repair
. Embedded ribonucleotides, which are abundant in the genome of cells deficient in ribonucleotide excision repair, are substrates for cleavage by topoisomerase 1, resulting in PARP-trapping lesions that impede DNA replication and endanger genome integrity. We conclude that genomic ribonucleotides are a hitherto unappreciated source of PARP-trapping DNA lesions, and that the frequent deletion of RNASEH2B in metastatic prostate cancer and chronic lymphocytic leukaemia could provide an opportunity to exploit these findings therapeutically.
Autologous T cells expressing a CD19-specific chimeric antigen receptor (CD19.CAR) are active against B-cell malignancies, but it is unknown whether allogeneic CD19.CAR T cells are safe or effective. ...After allogeneic hematopoietic stem cell transplantation (HSCT), infused donor-derived virus-specific T cells (VSTs) expand in vivo, persist long term, and display antiviral activity without inducing graft-vs-host disease; therefore, we determined whether donor VSTs, engineered to express CD19.CAR, retained the characteristics of nonmanipulated allogeneic VSTs while gaining antitumor activity. We treated 8 patients with allogeneic (donor-derived) CD19.CAR-VSTs 3 months to 13 years after HSCT. There were no infusion-related toxicities. VSTs persisted for a median of 8 weeks in blood and up to 9 weeks at disease sites. Objective antitumor activity was evident in 2 of 6 patients with relapsed disease during the period of CD19.CAR-VST persistence, whereas 2 patients who received cells while in remission remain disease free. In 2 of 3 patients with viral reactivation, donor CD19.CAR-VSTs expanded concomitantly with VSTs. Hence CD19.CAR-VSTs display antitumor activity and, because their number may be increased in the presence of viral stimuli, earlier treatment post-HSCT (when lymphodepletion is greater and the incidence of viral infection is higher) or planned vaccination with viral antigens may enhance disease control. This study is registered at clinicaltrials.gov as #NCT00840853.
•Allogeneic CD19-CAR VSTs are well tolerated by patients with relapsed B-cell malignancies post-HSCT.•At periods of CD19-CAR VST persistence, these cells demonstrate antitumor activity.
Therapy targeting Bruton's tyrosine kinase (BTK) with ibrutinib has transformed the treatment of chronic lymphocytic leukaemia. However, patients who are refractory to or relapse after ibrutinib ...therapy have poor outcomes. Venetoclax is a selective, orally bioavailable inhibitor of BCL-2 active in previously treated patients with relapsed or refractory chronic lymphocytic leukaemia. In this study, we assessed the activity and safety of venetoclax in patients with chronic lymphocytic leukaemia who are refractory to or relapse during or after ibrutinib therapy.
In this interim analysis of a multicentre, open-label, non-randomised, phase 2 trial, we enrolled patients aged 18 years or older with a documented diagnosis of chronic lymphocytic leukaemia according to the 2008 International Workshop on Chronic Lymphocytic Leukemia (IWCLL) criteria and an Eastern Cooperative Oncology Group performance score of 2 or lower. All patients had relapsed or refractory disease after previous treatment with a BCR signalling pathway inhibitor. All patients were screened for Richter's transformation and cases confirmed by biopsy were excluded. Eligible patients received oral venetoclax, starting at 20 mg per day with stepwise dose ramp-up over 5 weeks to 400 mg per day. Patients with rapidly progressing disease received an accelerated dosing schedule (to 400 mg per day by week 3). The primary endpoint was overall response, defined as the proportion of patients with an overall response per investigator's assessment according to IWCLL criteria. All patients who received at least one dose of venetoclax were included in the activity and safety analyses. This study is ongoing; data for this interim analysis were collected per regulatory agencies' request as of June 30, 2017. This trial is registered with ClinicalTrials.gov, number NCT02141282.
Between September, 2014, and November, 2016, 127 previously treated patients with relapsed or refractory chronic lymphocytic leukaemia were enrolled from 15 sites across the USA. 91 patients had received ibrutinib as the last BCR inhibitor therapy before enrolment, 43 of whom were enrolled in the main cohort and 48 in the expansion cohort recruited later after a protocol amendment. At the time of analysis, the median follow-up was 14 months (IQR 8–18) for all 91 patients, 19 months (9–27) for the main cohort, and 12 months (8–15) for the expansion cohort. 59 (65%, 95% CI 53–74) of 91 patients had an overall response, including 30 (70%, 54–83) of 43 patients in the main cohort and 29 (60%, 43–72) of 48 patients in the expansion cohort. The most common treatment-emergent grade 3 or 4 adverse events were neutropenia (46 51% of 91 patients), thrombocytopenia (26 29%), anaemia (26 29%), decreased white blood cell count (17 19%), and decreased lymphocyte count (14 15%). 17 (19%) of 91 patients died, including seven because of disease progression. No treatment-related deaths occurred.
The results of this interim analysis show that venetoclax has durable clinical activity and favourable tolerability in patients with relapsed or refractory chronic lymphocytic leukaemia whose disease progressed during or after discontinutation of ibrutinib therapy. The durability of response to venetoclax will be assessed in the final analysis in 2019.
AbbVie, Genentech.
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