Deregulation and epigenetic modification of BCL2-family genes cause resistance to venetoclax in hematologic malignancies.

The BCL2 inhibitor venetoclax has been approved to treat different hematological malignancies. Because there is no common genetic alteration causing resistance to venetoclax in chronic lymphocytic leukemia (CLL) and B-cell lymphoma, we asked if epigenetic events might be involved in venetoclax resistance. Therefore, we employed whole-exome sequencing, methylated DNA immunoprecipitation sequencing, and genome-wide clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 screening to investigate venetoclax resistance in aggressive lymphoma and high-risk CLL patients. We identified a regulatory CpG island within the PUMA promoter that is methylated upon venetoclax treatment, mediating PUMA downregulation on transcript and protein level. PUMA expression and sensitivity toward venetoclax can be restored by inhibition of methyltransferases. We can demonstrate that loss of PUMA results in metabolic reprogramming with higher oxidative phosphorylation and adenosine triphosphate production, resembling the metabolic phenotype that is seen upon venetoclax resistance. Although PUMA loss is specific for acquired venetoclax resistance but not for acquired MCL1 resistance and is not seen in CLL patients after chemotherapy-resistance, BAX is essential for sensitivity toward both venetoclax and MCL1 inhibition. As we found loss of BAX in Richter's syndrome patients after venetoclax failure, we defined BAX-mediated apoptosis to be critical for drug resistance but not for disease progression of CLL into aggressive diffuse large B-cell lymphoma in vivo. A compound screen revealed TRAIL-mediated apoptosis as a target to overcome BAX deficiency. Furthermore, antibody or CAR T cells eliminated venetoclax resistant lymphoma cells, paving a clinically applicable way to overcome venetoclax resistance.

Richter transformation in chronic lymphocytic leukemia (CLL)-a pooled analysis of German CLL Study Group (GCLLSG) front line treatment trials.

Richter transformation (RT) is defined as development of aggressive lymphoma in patients (pts) with CLL. The incidence rates of RT among pts with CLL range from 2 to 10%. The aim of this analysis is to report the frequency, characteristics and outcomes of pts with RT enrolled in trials of the GCLLSG. A total of 2975 pts with advanced CLL were reviewed for incidence of RT. Clinical, laboratory, and genetic data were pooled. Time-to-event data, starting from time of CLL diagnosis, of first-line therapy or of RT diagnosis, were analyzed by Kaplan-Meier methodology. One hundred and three pts developed RT (3%): 95 pts diffuse large B-cell lymphoma (92%) and eight pts Hodgkin lymphoma (8%). Median observation time was 53 months (interquartile range 38.1-69.5). Median OS from initial CLL diagnosis for pts without RT was 167 months vs 71 months for pts with RT (HR 2.64, CI 2.09-3.33). Median OS after diagnosis of RT was 9 months. Forty-seven pts (46%) received CHOP-like regimens for RT treatment. Three pts subsequently underwent allogeneic and two pts autologous stem cell transplantation. Our findings show that within a large cohort of GCLLSG trial participants, 3% of the pts developed RT after receiving first-line chemo- or chemoimmunotherapy. This dataset confirms the ongoing poor prognosis and high mortality associated with RT.

Management of chronic lymphocytic leukemia (CLL) in the elderly: a position paper from an international Society of Geriatric Oncology (SIOG) Task Force.

Chronic lymphocytic leukemia (CLL) mainly affects older people: the median age at diagnosis is > 70 years. Elderly patients with CLL are heterogeneous with regard both to the biology of their disease and aging. Following the diagnosis of CLL in an elderly individual, careful risk assessment is essential when treatment options are evaluated. This includes not only clinical staging and evaluation of disease-specific prognostic biomarkers such as 17p deletion and TP53 mutation, but also of comorbidities, physical capacity, nutritional status, cognitive capacity, ability to perform activities of daily living and social support. Comorbidity scoring and geriatric assessment tools are helpful in achieving such multidimensional evaluation in a systematic manner. The introduction of new drugs including novel monoclonal antibodies and kinase inhibitors offers enhanced opportunities for the treatment of elderly patients with CLL. This position paper of a Task Force of the International Society of Geriatric Oncology (SIOG) reviews currently available evidence relevant to such patients. All types of elderly patient (i.e. chronological age > 65-70 years) are considered, from robust (fit) to vulnerable (unfit) to the terminally ill. Among the topics covered are the following: (i) the relationship between chronological age, prognosis and survival, (ii) assessment of biological aging, (iii) biological age as a determinant of treatment feasibility and tolerance and (iv) tailoring of both first and further-line treatment to the circumstances of the individual patient.

Effect of first-line treatment on second primary malignancies and Richter's transformation in patients with CLL.

This study aimed to assess the frequency of and the contributing factors for second primary malignancies (SPMs) and Richter's transformations (RTs) following first-line treatment of chronic lymphocytic leukemia within four phase II/III trials of the GCLLSG evaluating fludarabine (F) vs F+cyclophosphamide (FC), chlorambucil vs F, FC without or with rituximab, and bendamustine+R (BR). Among 1458 patients, 239 (16.4%) experienced either an SPM (N=191) or a RT (N=75). Solid tumors (N=115; 43.2% of all second neoplasias) appeared most frequently, followed by RTs (N=75; 28.2%). Patients showed a 1.23-fold increased risk of solid tumors in comparison to the age-matched general population from the German cancer registry. Age>65 (hazard ratio (HR) 2.1; P<0.001), male sex (HR 1.7; P=0.01), co-morbidities (HR 1.6; P=0.01) and number of subsequent treatments⩾1 (HR 12.1; P<0.001) showed an independent adverse prognostic impact on SPM-free survival. Serum thymidine kinase>10 U/l at trial enrollment (HR 3.9; P=0.02), non-response to first-line treatment (HR 3.6; P<0.001) and number of subsequent treatments⩾1 (HR 30.2; P<0.001) were independently associated with increased risk for RT.

[Chronic lymphocytic leukemia : treatment concepts in transition]. / Chronische lymphatische Leukämie : Therapiekonzepte im Wandel.

BACKGROUND: Chronic lymphocytic leukemia (CLL) is the most common leukemia in the Western hemisphere and mainly affects elderly patients. No curative treatment is currently available for this disease. TREATMENT: Advanced disease is treated according to the patients' fitness and comorbidity burden as well as according the presence of high risk genetic factors in CLL cells. The detection of del(17p) and/or TP53 gene mutations reflects a very unfavorable prognosis and refractoriness to chemotherapy (very high risk CLL). In physically fit patients without high comorbidity burden and without very high risk prognostic factors, chemoimmunotherapy containing fludarabine, cyclophosphamide, and the CD20 antibody rituximab (FCR) is standard therapy because this regimen has been shown to improve overall survival. In patients with significant comorbidity burden, a less intense chemoimmunotherapy regimen should be administered consisting of the alkylating agent chlorambucil plus CD20 antibody. In very high risk patients, kinase inhibitors blocking the signaling transduction pathway of the B cell receptor have been approved since 2014. The same substances are also approved in relapsed CLL. However, in relapsed CLL repetitive administration of chemoimmunotherapy is still an alternative treatment option, especially if the first remission was longer lasting (> 24 months). Allogeneic hematopoietic stem cell transplantation in very high risk CLL or early relapsed disease has become less important than in the past. In some patients considering the risk of the transplantation versus the risk of failing to respond to the new treatment option, this procedure might still be the treatment of choice in order to achieve long-lasting remissions. CONCLUSION: In the choice of treatment for patients with CLL, several factors must be considered. Because of the broad spectrum of treatment options, therapy within a clinical study is still the best treatment option.

ERIC recommendations on TP53 mutation analysis in chronic lymphocytic leukemia.

Recent evidence suggests that - in addition to 17p deletion - TP53 mutation is an independent prognostic factor in chronic lymphocytic leukemia (CLL). Data from retrospective analyses and prospective clinical trials show that ∼5% of untreated CLL patients with treatment indication have a TP53 mutation in the absence of 17p deletion. These patients have a poor response and reduced progression-free survival and overall survival with standard treatment approaches. These data suggest that TP53 mutation testing warrants integration into current diagnostic work up of patients with CLL. There are a number of assays to detect TP53 mutations, which have respective advantages and shortcomings. Direct Sanger sequencing of exons 4-9 can be recommended as a suitable test to identify TP53 mutations for centers with limited experience with alternative screening methods. Recommendations are provided on standard operating procedures, quality control, reporting and interpretation. Patients with treatment indications should be investigated for TP53 mutations in addition to the work-up recommended by the International workshop on CLL guidelines. Patients with TP53 mutation may be considered for allogeneic stem cell transplantation in first remission. Alemtuzumab-based regimens can yield a substantial proportion of complete responses, although of short duration. Ideally, patients should be treated within clinical trials exploring new therapeutic agents.

Addition of rituximab to fludarabine and cyclophosphamide in patients with chronic lymphocytic leukaemia: a randomised, open-label, phase 3 trial.

BACKGROUND: On the basis of promising results that were reported in several phase 2 trials, we investigated whether the addition of the monoclonal antibody rituximab to first-line chemotherapy with fludarabine and cyclophosphamide would improve the outcome of patients with chronic lymphocytic leukaemia. METHODS: Treatment-naive, physically fit patients (aged 30-81 years) with CD20-positive chronic lymphocytic leukaemia were randomly assigned in a one-to-one ratio to receive six courses of intravenous fludarabine (25 mg/m(2) per day) and cyclophosphamide (250 mg/m(2) per day) for the first 3 days of each 28-day treatment course with or without rituximab (375 mg/m(2) on day 0 of first course, and 500 mg/m(2) on day 1 of second to sixth courses) in 190 centres in 11 countries. Investigators and patients were not masked to the computer-generated treatment assignment. The primary endpoint was progression-free survival (PFS). Analysis was by intention to treat. This study is registered with ClinicalTrials.gov, number NCT00281918. FINDINGS: 408 patients were assigned to fludarabine, cyclophosphamide, and rituximab (chemoimmunotherapy group) and 409 to fludarabine and cyclophosphamide (chemotherapy group); all patients were analysed. At 3 years after randomisation, 65% of patients in the chemoimmunotherapy group were free of progression compared with 45% in the chemotherapy group (hazard ratio 0·56 [95% CI 0·46-0·69], p<0·0001); 87% were alive versus 83%, respectively (0·67 [0·48-0·92]; p=0·01). Chemoimmunotherapy was more frequently associated with grade 3 and 4 neutropenia (136 [34%] of 404 vs 83 [21%] of 396; p<0·0001) and leucocytopenia (97 [24%] vs 48 [12%]; p<0·0001). Other side-effects, including severe infections, were not increased. There were eight (2%) treatment-related deaths in the chemoimmunotherapy group compared with ten (3%) in the chemotherapy group. INTERPRETATION: Chemoimmunotherapy with fludarabine, cyclophosphamide, and rituximab improves progression-free survival and overall survival in patients with chronic lymphocytic leukaemia. Moreover, the results suggest that the choice of a specific first-line treatment changes the natural course of chronic lymphocytic leukaemia. FUNDING: F Hoffmann-La Roche.