Minimal residual disease-driven treatment intensification with sequential addition of ibrutinib to venetoclax in R/R CLL.

Undetectable measurable residual disease (uMRD) is achievable in patients with chronic lymphocytic leukemia (CLL) with the BCL2-inhibitor venetoclax alone or combined with the Bruton's tyrosine kinase inhibitor ibrutinib. This phase 2, multicenter, MRD-driven study was designed to discontinue treatment upon reaching uMRD4 (<10-4) in patients with relapsed/refractory CLL receiving venetoclax monotherapy or after the addition of ibrutinib. Primary end point of the study was proportion of uMRD4 with venetoclax ± ibrutinib. Secondary end points were overall response rate, partial response, complete response, progression-free survival, duration of response, overall survival, and safety of venetoclax ± ibrutinib. Patients with uMRD4 at Cycle 12 Day 1 discontinued venetoclax. MRD+ patients added ibrutinib and continued both drugs up to Cycle 24 Day 28/uMRD4/progression/toxicity. After Cycle 24 Day 28, MRD+ patients continued ibrutinib. Thirty-eight patients (29% with TP53 aberrations; 79% with unmutated IGHV) started venetoclax. Overall response rate with venetoclax was 36 (95%) of 38 patients (20 complete; 16 partial response). Seventeen patients (45%) with uMRD4 at Cycle 12 Day 1 discontinued venetoclax. Nineteen (55%) MRD+ subjects added ibrutinib. After a median of 7 months (range, 3-10 months) of combined treatment, 16 (84%) of 19 achieved uMRD4, thus stopping both drugs. Two MRD+ patients at Cycle 24 Day 28 continued ibrutinib until progression/toxicity. After a median follow-up of 36.5 months, median progression-free survival was not reached; 10 patients progressed (4 restarted venetoclax, 3 without treatment need, 2 developed Richter transformation, and 1 dropped out). Seven (22%) of 32 patients remain uMRD4 after 3 years of follow-up. Neutropenia was the most frequent grade 3 to 4 adverse event; no grade 5 events occurred on study. This sequential MRD-guided approach led to uMRD4 in 33 (87%) of 38 patients, with venetoclax monotherapy or combined with ibrutinib, delivering treatment combination only in a fraction, and ultimately identifying the few patients benefiting from continuous therapy. This trial was registered at www.clinicaltrials.gov as # NCT04754035.

Patients' preferences for chronic lymphocytic leukemia treatment: The CHOICE study.

Chronic lymphocytic leukemia (CLL) therapies differ in efficacy, side effects, route, frequency, and duration of administration. We assessed patient preferences for treatment attributes and evaluated associations with disease stage, treatment line, and socio-demographic characteristics in a cross sectional, observational study conducted at 16 Italian hematology centers. Study visits occurred between February and July 2020; 401 adult patients with CLL (201 Watch and Wait (W&W), 200 treated) participated in a discrete choice experiment (DCE), composed of 8 choices between pairs of treatment profiles with different levels of 5 attributes of currently available CLL treatments (length of response, route and duration of administration, risk of side effects including diarrhea, infections, or organ damage). Health-related quality of life was assessed with the EQ-5D-5L, EORTC QLQ-C30 and QLQ CLL-16. Previously treated patients had longer disease duration (7 vs. 5 years), higher prevalence of serious comorbidities (45.5% vs. 36.2%) and high-risk molecular markers (unmutated IGHV 55.6% vs. 17.1%; TP53 mutation 15.2% vs. 4.0%). Health-related quality of life scores were similar between groups. In the DCE, W&W patients rated "possible occurrence of infections" highest (relative importance [RI] = 36.2%), followed by "treatment and relevant duration" (RI = 28.0%) and "progression-free survival (PFS)" (RI = 16.9%). Previously treated patients rated "treatment and relevant duration" highest (RI = 33.3%), followed by "possible occurrence of infections" (RI = 28.8%), "possible occurrence of organ damage" (RI = 19.4%), and "PFS" (RI = 9.8%). Concern over infection was rated highest overall; unexpectedly PFS was not among the most important criteria in either group, suggesting that the first COVID-19 pandemic wave may have influenced patient preferences and concerns about CLL therapy options.

Ibrutinib as first line therapy in chronic lymphocytic leukemia patients over 80 years old: A retrospective real-life multicenter Italian cohort.

Although chronic lymphocytic leukemia (CLL) predominantly affects the elderly, limited data exists about the outcomes of over 80-year-old patients, usually underrepresented in clinical trials. We conducted a multicenter study enrolling 79 consecutive CLL patients ≥80 years at the time of frontline therapy, all treated with ibrutinib. Nearly 48% of cases exhibited unmutated IGHV genes, 32% 17p deletion, and 39.2% TP53 mutations; 63.3% displayed a cumulative illness rating scale (CIRS) > 6. The overall response rate on ibrutinib, computed in 74/79 patients (5 patients excluded for early withdrawal), was 89.9%. After a median follow-up of 28.9 months, the median progression-free survival (PFS) and overall survival (OS) were 42.5 and 51.8 months, respectively. CIRS>6 and temporary discontinuation of ibrutinib lasting for 7-30 days were the only parameters associated with a significantly shorter PFS and were both relevant in predicting a shorter PFS compared to patients with CIRS≤6 and therapy discontinuation ≤7 days. The most common grade≥3 adverse events were infections (25.5%), neutropenia (10.1%), and anemia (2.5%). Eighteen patients (22.8%) experienced a cardiovascular event, including grade-2 atrial fibrillation (n = 9; 11%), grade-2 hypertension (n = 5; 6%), heart failure (n = 3; 3%), and acute coronary syndrome (n = 1; 1%). Mild bleeding events were observed in 27 patients (34.2%). Ibrutinib was permanently discontinued in 26 patients due to progressive disease (n = 11, including 5 Richter's syndromes), secondary malignancies (n = 6), infections (n = 3), cardiac failure (n = 3), severe bleeding (n = 2), and sudden death (n = 1). In conclusion, our analyses confirmed the overall effectiveness and favorable safety profile of the ibrutinib-single agent therapeutic approach in CLL patients ≥80 years.

Preexisting and treatment-emergent autoimmune cytopenias in patients with CLL treated with targeted drugs.

Autoimmune cytopenias (AICs) affect 5% to 9% of patients with chronic lymphocytic leukemia (CLL). Targeted drugs-ibrutinib, idelalisib, and venetoclax-have a prominent role in the treatment of CLL, but their impact on CLL-associated AICs is largely unknown. In this study, we evaluated the characteristics and outcome of preexisting AICs and described the incidence, quality, and management of treatment-emergent AICs during therapy with targeted drugs in patients with CLL. We collected data from 572 patients treated with ibrutinib (9% in combination with an anti-CD20 monoclonal antibody), 143 treated with idelalisib-rituximab, and 100 treated with venetoclax (12% in combination with an anti-CD20 monoclonal antibody). A history of preexisting AICs was reported in 104 (13%) of 815 patients. Interestingly, 80% of patients whose AICs had not resolved when treatment with a targeted drug was started experienced an improvement or a resolution during therapy. Treatment-emergent AICs occurred in 1% of patients during ibrutinib therapy, in 0.9% during idelalisib therapy, and in 7% during venetoclax therapy, with an estimated incidence rate of 5, 6, and 69 episodes per 1000 patients per year of exposure in the 3 treatment groups, respectively. The vast majority of patients who developed treatment-emergent AICs had unfavorable biological features such as an unmutated IGHV and a del(17p) and/or TP53 mutation. Notably, despite AICs, 83% of patients were able to continue the targeted drug, in some cases in combination with additional immunosuppressive agents. Overall, treatment with ibrutinib, idelalisib, or venetoclax seems to have a beneficial impact on CLL-associated AICs, inducing an improvement or even a resolution of preexisting AICs in most cases and eliciting treatment-emergent AICs in a negligible portion of patients.

The immunomodulatory molecule TIGIT is expressed by chronic lymphocytic leukemia cells and contributes to anergy.

T-cell immunoreceptor with Ig and ITIM domains (TIGIT) is an inhibitory checkpoint receptor that negatively regulates Tcell responses. CD226 competes with TIGIT for binding to the CD155 ligand, delivering a positive signal to the T cell. Here we studied the expression of TIGIT and CD226 in a cohort of 115 patients with chronic lymphocytic leukemia (CLL) and report expression of TIGIT and CD226 by leukemic cells. By devising a TIGIT/CD226 ratio, we showed that CLL cells favoring TIGIT over CD226 are typical of a more indolent disease, while those favoring CD226 are characterized by a shorter time to first treatment and shorter progression-free survival after first treatment. TIGIT expression was inversely correlated to the B-cell receptor (BCR) signaling capacity, as determined by studying BTK phosphorylation, cell proliferation and interleukin- 10 production. In CLL cells treated with ibrutinib, in which surface IgM and BCR signaling capacity are temporarily increased, TIGIT expression was downmodulated, in line with data indicating transient recovery from anergy. Lastly, cells from patients with Richter syndrome were characterized by high levels of CD226, with low to undetectable TIGIT, in keeping with their high proliferative drive. Together, these data suggest that TIGIT contributes to CLL anergy by downregulating BCR signaling, identifying novel and actionable molecular circuits regulating anergy and modulating CLL cell functions.

High rate of durable responses with undetectable minimal residual disease with front-line venetoclax and rituximab in young, fit patients with chronic lymphocytic leukemia and an adverse biological profile: results of the GIMEMA phase II LLC1518 - VERITAS study.

The GIMEMA phase II LLC1518 VERITAS trial investigated the efficacy and safety of front-line, fixed-duration venetoclax and rituximab (VenR) in combination in young (≤65 years), fit patients with chronic lymphocytic leukemia and unmutated IGHV and/or TP53 disruption. Treatment consisted of the venetoclax ramp-up, six monthly courses of the VenR combination, followed by six monthly courses of venetoclax as a single agent. A centralized assessment of minimal residual disease (MRD) was performed by allele-specific oligonucleotide polymerase chain reaction assay on the peripheral blood and bone marrow at the end of treatment (EOT) and during the follow-up. The primary endpoint was the complete remission rate at the EOT. Seventy-five patients were enrolled; the median age was 54 years (range, 38-65), 96% had unmutated IGHV, 12% had TP53 disruption, and 4% had mutated IGHV with TP53 disruption. The overall response rate at the EOT was 94.7%, with a complete remission rate of 76%. MRD was undetectable in the peripheral blood of 69.3% of patients and in the bone marrow of 58.7% of patients. The 12-month MRD-free survival in the 52 patients with undetectable MRD in the peripheral blood at the EOT was 73.1%. After a median follow-up of 20.8 months, no cases of disease progression were observed. Three patients had died, two due to COVID-19 and one due to tumor lysis syndrome. The first report of the VERITAS study shows that front-line VenR was associated with a high rate of complete remissions and durable response with undetectable MRD in young patients with chronic lymphocytic leukemia and unfavorable genetic characteristics. ClinicalTrials.gov identifier: NCT03455517.

Lymphadenopathy as a predictor of progression during venetoclax treatment in chronic lymphocytic leukemia. A campus chronic lymphocytic leukemia study.

Clinical or biological parameters useful to predict progression during treatment in real-life setting with ibrutinib, idelalisib and venetoclax in relapsed/refractory chronic lymphocytic leukemia (CLL) are still debated. We conducted a multi-center retrospective study on CLL patients treated with ibrutinib and/or idelalisib who were switched to venetoclax for progression or due to adverse events to identify any clinical and/or biological parameters useful to predict progression during treatment with venetoclax. Of all the 128 evaluable patients, 81 had received ibrutinib prior to switching to venetoclax, 35 had received idelalisib and 12 both. When comparing the three subgroups, we did not notice any statistical difference in terms of clinical or biological features. No variable at baseline and at different time points during the follow-up (at 6, 12, 18 and 24 months) was found to predict progression nor to have significance for Progression Free Survival (PFS) in the ibrutinib group and in the idelalisib group and in subgroups according to the line of treatment. Analyzing the data of the venetoclax treatment, after a median follow up of 14.3 months, median PFS was not reached and estimated 3-year PFS was 54%. Of the 128 patients treated with venetoclax, 28 (22%) experienced progressive disease. At multivariate analysis for predictive factors for progression, lymph node diameter >56.5 mm before starting treatment emerged as an independent risk factor for progression. The lymph node predictive role for progression during venetoclax treatment could be a new parameter that deserves to be investigate in future studies.

Beyond ibrutinib: novel BTK inhibitors for the treatment of chronic lymphocytic leukemia.

PURPOSE OF THE REVIEW: Ibrutinib was the first Bruton tyrosine kinase inhibitor (BTKi) approved for clinical use, contributing to a dramatic change in the treatment landscape of chronic lymphocytic leukemia (CLL). This review provides an overview of next-generation BTKi that have been recently approved or are being investigated for the treatment of CLL, specifically highlighting differences and similarities compared to ibrutinib. RECENT FINDINGS: Acalabrutinib presented comparable response rates to ibrutinib with lower rates of adverse events and is currently approved for the treatment of CLL. Zanubrutinib displayed excellent response rates with a lower incidence of BTKi-related adverse events, but major rates of neutropenia, and its approval is awaited. With the aim of overcoming drug resistance, noncovalent BTKi have been developed. Of all the explored agents to date, pirtobrutinib has shown promising results with manageable toxicities. SUMMARY: For the treatment of CLL, several effective therapeutic strategies to target BTK are or will soon be available: these drugs present different safety profiles, thus making it possible to tailor the treatment choice according to patient's characteristics. Importantly, noncovalent BTKi will provide a therapeutic chance also for those relapsed/refractory CLL patients who are BTKi-resistant and are considered an unmet clinical need.

Efficacy of idelalisib and rituximab in relapsed/refractory chronic lymphocytic leukemia treated outside of clinical trials. A report of the Gimema Working Group.

Because the efficacy of new drugs reported in trials may not translate into similar results when used in the real-life, we analyzed the efficacy of idelalisib and rituximab (IR) in 149 patients with relapsed/refractory chronic lymphocytic leukemia treated at 34 GIMEMA centers. Median progression-free survival (PFS) and overall survival were 22.9 and 44.5 months, respectively; performance status (PS) ≥2 and ≥3 previous lines of therapy were associated with shorter PFS and overall survival (OS). 48% of patients were on treatment at 12 months; the experience of the centers (≥5 treated patients) and PS 0-1 were associated with a significantly longer treatment duration (p = 0.015 and p = 0.002, respectively). TP53 disruption had no prognostic significance. The overall response rate to subsequent treatment was 49.2%, with median OS of 15.5 months and not reached in patients who discontinued, respectively, for progression and for toxicity (p < 0.01). Treatment breaks ≥14 days were recorded in 96% of patients and adverse events mirrored those reported in trials. In conclusion, this real-life analysis showed that IR treatment duration was longer at experienced centers, that the ECOG PS and ≥3 lines of previous therapy are strong prognostic factor and that the overall outcome with this regimen was superimposable to that reported in a randomized trial.

Comparison of ibrutinib and idelalisib plus rituximab in real-life relapsed/resistant chronic lymphocytic leukemia cases.

OBJECTIVES: To compare the capacity of ibrutinib (IB) and idelalisib-rituximab (IDELA-R) of prolonging overall survival (OS) as in CLL patients, previously treated with chemotherapy only. METHODS: A real-life cohort of 675 cases has been identified and investigated in the database of the groups participating in the study. RESULTS: At an unadjusted univariate analysis, a significant death risk reduction was observed favoring IB (IDELA-R vs IB HR = 0.5, 95% CI = 0.36-0.71) although with some limitations due to the non-randomized and retrospective nature of the study and to the lower number of patients in the IDELA-R group (112 cases) related to the current prescribing practice. To overcome the potential problem of confounding by indication, we adjusted the association between the type of therapy and mortality for all variables significantly associated with OS at Cox univariate analysis. Furthermore, those variables, differently distributed between the two study groups, were introduced into the multivariate Cox model to improve the effectiveness of the analysis. By introducing all these variables into the multiple Cox regression model, we confirmed the protective effect of IB vs IDELA-R (HR = 0.67, 95% CI = 0.45-0.98, P = .04) independent of potential confounders. CONCLUSIONS: Although our analysis presents some constraints, that is, the unavailability of additional potential confounders, and the retrospective nature of the study, this observation may be of help for the daily clinical practice, particularly in the absence of randomized trials comparing the two schedules.

HIF-1α is over-expressed in leukemic cells from TP53-disrupted patients and is a promising therapeutic target in chronic lymphocytic leukemia.

In chronic lymphocytic leukemia (CLL), the hypoxia-inducible factor 1 (HIF-1) regulates the response of tumor cells to hypoxia and their protective interactions with the leukemic microenvironment. In this study, we demonstrate that CLL cells from TP53-disrupted (TP53 dis) patients have constitutively higher expression levels of the α-subunit of HIF-1 (HIF-1α) and increased HIF-1 transcriptional activity compared to the wild-type counterpart. In the TP53 dis subset, HIF-1α upregulation is due to reduced expression of the HIF-1α ubiquitin ligase von Hippel-Lindau protein (pVHL). Hypoxia and stromal cells further enhance HIF-1α accumulation, independently of TP53 status. Hypoxia acts through the downmodulation of pVHL and the activation of the PI3K/AKT and RAS/ERK1-2 pathways, whereas stromal cells induce an increased activity of the RAS/ERK1-2, RHOA/RHOA kinase and PI3K/AKT pathways, without affecting pVHL expression. Interestingly, we observed that higher levels of HIF-1A mRNA correlate with a lower susceptibility of leukemic cells to spontaneous apoptosis, and associate with the fludarabine resistance that mainly characterizes TP53 dis tumor cells. The HIF-1α inhibitor BAY87-2243 exerts cytotoxic effects toward leukemic cells, regardless of the TP53 status, and has anti-tumor activity in Em-TCL1 mice. BAY87-2243 also overcomes the constitutive fludarabine resistance of TP53 dis leukemic cells and elicits a strongly synergistic cytotoxic effect in combination with ibrutinib, thus providing preclinical evidence to stimulate further investigation into use as a potential new drug in CLL.

Biological and clinical implications of BIRC3 mutations in chronic lymphocytic leukemia.

BIRC3 is a recurrently mutated gene in chronic lymphocytic leukemia (CLL) but the functional implications of BIRC3 mutations are largely unexplored. Furthermore, little is known about the prognostic impact of BIRC3 mutations in CLL cohorts homogeneously treated with first-line fludarabine, cyclophosphamide, and rituximab (FCR). By immunoblotting analysis, we showed that the non-canonical nuclear factor-κB pathway is active in BIRC3-mutated cell lines and in primary CLL samples, as documented by the stabilization of MAP3K14 and by the nuclear localization of p52. In addition, BIRC3-mutated primary CLL cells are less sensitive to flu-darabine. In order to confirm in patients that BIRC3 mutations confer resistance to fludarabine-based chemoimmunotherapy, a retrospective multicenter cohort of 287 untreated patients receiving first-line FCR was analyzed by targeted next-generation sequencing of 24 recurrently mutated genes in CLL. By univariate analysis adjusted for multiple comparisons BIRC3 mutations identify a poor prognostic subgroup of patients in whom FCR treatment fails (median progression-free survival: 2.2 years, P<0.001) similar to cases harboring TP53 mutations (median progression-free survival: 2.6 years, P<0.0001). BIRC3 mutations maintained an independent association with an increased risk of progression with a hazard ratio of 2.8 (95% confidence interval 1.4-5.6, P=0.004) in multivariate analysis adjusted for TP53 mutation, 17p deletion and IGHV mutation status. If validated, BIRC3 mutations may be used as a new molecular predictor to select high-risk patients for novel frontline therapeutic approaches.

Frontline treatment with the combination obinutuzumab ± chlorambucil for chronic lymphocytic leukemia outside clinical trials: Results of a multinational, multicenter study by ERIC and the Israeli CLL study group.

In recent years, considerable progress has been made in frontline therapy for elderly/physically unfit patients with CLL. The combination of obinutuzumab and chlorambucil (O-Clb) has been shown to prolong progression free survival (PFS, median PFS-31.5 months) and overall survival (OS) compared to chlorambucil alone. More recently, obinutuzumab given in combination with either ibrutinib or venetoclax improved PFS but not OS when compared to O-Clb. In this retrospective multinational, multicenter co-operative study, we evaluated the efficacy and safety of frontline treatment with O ± Clb in unfit patients with CLL, in a "real-world" setting. Patients with documented del (17p13.1)/TP53 mutation were excluded. A total of 437 patients (median age, 75.9 years; median CIRS score, 8; median creatinine clearance, 61.1 mL/min) were included. The clinical overall response rate was 80.3% (clinical complete and partial responses in 38.7% and 41.6% of patients, respectively). Median observation time was 14.1 months and estimated median PFS was 27.6 months (95% CI, 24.2-31.0). In a multivariate analysis, high-risk disease [del (11q22.3) and/or IGHV-unmutated], lymph nodes of diameter > 5 cm, obinutuzumab monotherapy and reduced cumulative dose of obinutuzumab, were all independently associated with shorter PFS. The median OS has not yet been reached and estimated 2-year OS is 88%. In conclusion, in a "real-world" setting, frontline treatment with O-Clb achieves PFS comparable to that reported in clinical trials. Inferior outcomes were noted in patients with del (11q22.3) and/or unmutated IGHV and those treated with obinutuzumab-monotherapy. Thus, O-Clb can be still considered as legitimate frontline therapy for unfit CLL patients with low-risk disease.

Efficacy of bendamustine and rituximab as first salvage treatment in chronic lymphocytic leukemia and indirect comparison with ibrutinib: a GIMEMA, ERIC and UK CLL FORUM study.

We performed an observational study on the efficacy of ben-damustine and rituximab (BR) as first salvage regimen in chronic lymphocytic leukemia (CLL). In an intention-to-treat analysis including 237 patients, the median progression-free survival (PFS) was 25 months. The presence of del(17p), unmutated IGHV and advanced stage were associated with a shorter PFS at multivariate analysis. The median time-to-next treatment was 31.3 months. Front-line treatment with a chemoimmunotherapy regimen was the only predictive factor for a shorter time to next treatment at multivariate analysis. The median overall survival (OS) was 74.5 months. Advanced disease stage (i.e. Rai stage III-IV or Binet stage C) and resistant disease were the only parameters significantly associated with a shorter OS. Grade 3-5 infections were recorded in 6.3% of patients. A matched-adjusted indirect comparison with ibrutinib given second-line within Named Patient Programs in the United Kingdom and in Italy was carried out with OS as objective end point. When restricting the analysis to patients with intact 17p who had received chemoimmunotherapy in first line, there was no difference in OS between patients treated with ibrutinib (63% alive at 36 months) and patients treated with BR (74.4% alive at 36 months). BR is an efficacious first salvage regimen in CLL in a real-life population, including the elderly and unfit patients. BR and ibrutinib may be equally effective in terms of OS when used as first salvage treatment in patients without 17p deletion.

CD200 included in a 4-marker modified Matutes score provides optimal sensitivity and specificity for the diagnosis of chronic lymphocytic leukaemia.

CD200, a transmembrane type Ia glycoprotein belonging to the immunoglobulin superfamily, has been shown to have a differential expression in B-cell neoplasms. Here, we retrospectively assessed the diagnostic relevance of CD200 on 427 patients with B-cell chronic neoplasms in leukemic phase (median age, 69 y; range, 35-97 y). The final diagnosis based on the investigator's assessment was chronic lymphocytic leukaemia (CLL) in 75% of cases and non-CLL in 25% of cases. Sensitivity and specificity for the diagnosis of CLL (vs non-CLL) were calculated for the following markers: CD200, CD5, CD22, CD23, CD79b, FMC7, and SmIg. CD23 was the only marker without a statistically significant difference between the investigator assessment and the flowcytometric analysis. The other markers were unable-when individually evaluated-to discriminate between CLL and non-CLL, requiring the integration into a scoring system. The modified score no. 1 (addition of CD200) showed superimposable sensitivity and specificity compared with the Matutes score. The substitution of CD79b (modified score no. 2), surface membrane immunoglobulins (SmIg) (modified score no. 3), and CD79b and FMC7 (modified score no. 4) with CD200 showed that only the modified score no. 4 had both higher sensitivity and higher specificity compared with standard Matutes score. In conclusion, this work defines a simplified score, compared with the classical Matutes score, for the differential diagnosis of chronic B-cell leukaemia-which only requires 4 markers instead of 5 (CD5, CD23, CD200, and SmIg).