IKAROS gain of function disease: Allogeneic hematopoietic cell transplantation experience and expanded clinical phenotypes

IKAROS, encoded by IKZF1, is a tumor suppressor and a key hematopoietic transcription factor responsible for lymphoid and myeloid differentiation. IKZF1 mutations result in inborn errors of immunity presenting with increased susceptibility to infections, immune dysregulation, and malignancies. In particular, patients carrying IKZF1 gain-of-function (GOF) mutations mostly exhibit symptoms of immune dysregulation and polyclonal plasma cell proliferation. Herein, we describe seven new IKAROS GOF cases from two unrelated families, presenting with novel infectious, immune dysregulation and hematologic diseases. Two of the patients underwent allogeneic hematopoietic cell transplantation (HCT) due to poorly responsive complications. HCT was well-tolerated achieving full engraftment in both patients receiving reduced intensity, matched unrelated donor grafts, with no severe acute or chronic graft-vs-host-disease, and in remission from their diseases 2.5 and 4 years post-HCT, respectively. These results suggest that HCT is a valid and curative option in patients with IKAROS GOF disease and severe clinical manifestations.

Impact of detectable monoclonal protein at diagnosis on outcomes in marginal zone lymphoma: a multicenter cohort study

Given the paucity of data surrounding the prognostic relevance of monoclonal paraprotein (M-protein) in marginal zone lymphoma (MZL), we sought to evaluate the impact of detecting M-protein at diagnosis on outcomes in patients with MZL in a large retrospective cohort. The study included 547 patients receiving first-line therapy for MZL. M-protein was detectable at diagnosis in 173 (32%) patients. There was no significant difference in the time from diagnosis to initiation of any therapy (systemic and local) between the M-protein and no M-protein groups. Patients with M-protein at diagnosis had significantly inferior progression-free survival (PFS) compared with those without M-protein at diagnosis. After adjusting for factors associated with inferior PFS in univariate models, presence of M-protein remained significantly associated with inferior PFS (hazard ratio, 1.74; 95% confidence interval, 1.20-2.54; P = .004). We observed no significant difference in the PFS based on the type or quantity of M-protein at diagnosis. There were differential outcomes in PFS based on the first-line therapy in patients with M-protein at diagnosis, in that, those receiving immunochemotherapy had better outcomes compared with those receiving rituximab monotherapy. The cumulative incidence of relapse in stage 1 disease among the recipients of local therapy was higher in the presence of M-protein; however, this did not reach statistical significance. We found that M-protein at diagnosis was associated with a higher risk of histologic transformation. Because the PFS difference related to presence of M-protein was not observed in patients receiving bendamustine and rituximab, immunochemotherapy may be a preferred approach over rituximab monotherapy in this group and needs to be explored further.

Impact of early relapse within 24 months after first-line systemic therapy (POD24) on outcomes in patients with marginal zone lymphoma: A US multisite study

Progression of disease within 24 months (POD24) from diagnosis in marginal zone lymphoma (MZL) was shown to portend poor outcomes in prior studies. However, many patients with MZL do not require immediate therapy, and the time from diagnosis-to-treatment interval can be highly variable with no universal criteria to initiate systemic therapy. Hence, we sought to evaluate the prognostic relevance of early relapse or progression within 24 months from systemic therapy initiation in a large US cohort. The primary objective was to evaluate the overall survival (OS) in the two groups. The secondary objective included the evaluation of factors predictive of POD24 and the assessment of cumulative incidence of histologic transformation (HT) in POD24 versus non-POD24 groups. The study included 524 patients with 143 (27%) in POD24 and 381 (73%) in non-POD24 groups. Patients with POD24 had inferior OS compared to those without POD24, regardless of the type of systemic therapy received (rituximab monotherapy or immunochemotherapy) at diagnosis. After adjusting for factors associated with inferior OS in the univariate Cox model, POD24 remained associated with significantly inferior OS (HR = 2.50, 95% CI = 1.53-4.09, p = 0.0003) in multivariable analysis. The presence of monoclonal protein at diagnosis and those who received first-line rituximab monotherapy had higher odds of POD24 on logistic regression analysis. Patients with POD24 had a significantly higher risk for HT compared to those without POD24. POD24 in MZL might be associated with adverse biology and could be used as an additional information point in clinical trials and investigated as a marker for worse prognosis.

Predictive factors and outcomes for ibrutinib in relapsed/refractory marginal zone lymphoma: a multicenter cohort study

Ibrutinib is effective in the treatment of relapsed/refractory (R/R) marginal zone lymphoma (MZL) with an overall response rate (ORR) of 48%. However, factors associated with response (or lack thereof) to ibrutinib in R/R MZL in clinical practice are largely unknown. To answer this question, we performed a multicenter (25 US centers) cohort study and divided the study population into three groups: "ibrutinib responders"-patients who achieved complete or partial response (CR/PR) to ibrutinib; "stable disease (SD)"; and "primary progressors (PP)"-patients with progression of disease as their best response to ibrutinib. One hundred and nineteen patients met the eligibility criteria with 58%/17% ORR/CR, 29% with SD, and 13% with PP. The median PFS and OS were 29 and 71.4 months, respectively, with no difference in PFS or OS based on the ibrutinib line of therapy or type of therapy before ibrutinib. Patients with complex cytogenetics had an inferior PFS (HR = 3.08, 95% CI 1.23-7.67, p = 0.02), while those with both complex cytogenetics (HR = 3.00, 95% CI 1.03-8.68, p = 0.04) and PP (HR = 13.94, 95% CI 5.17-37.62, p < 0.001) had inferior OS. Only primary refractory disease to first-line therapy predicted a higher probability of PP to ibrutinib (RR = 3.77, 95% CI 1.15-12.33, p = 0.03). In this largest study to date evaluating outcomes of R/R MZL treated with ibrutinib, we show that patients with primary refractory disease and those with PP on ibrutinib are very high-risk subsets and need to be prioritized for experimental therapies.

Clinical utility of chromosomal microarray in establishing clonality and high risk features in patients with Richter transformation

Richter transformation (RT) refers to the development of an aggressive lymphoma in patients with pre-existing chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). It carries a poor prognosis secondary to poor response to therapy or rapid disease relapse. Currently there are no randomized trials to guide treatment. Therapeutic decisions are often influenced by the presence or absence of a clonal relationship between the underlying CLL/SLL and the new lymphoma given the poor prognosis of patients with clonally related RT. Chromosomal microarray analysis (CMA) can help to establish clonality while also detecting genomic complexity and clinically relevant genetic variants such as loss of CDKN2A and/or TP53. As a result, CMA has potential prognostic and therapeutic implications. For this study, CMA results from patients with Richter transformation were evaluated in paired CLL/SLL and transformed lymphoma samples. CMA revealed that 86% of patients had common aberrations in the two samples indicating evidence of common clonality. CMA was also useful in detecting aberrations associated with a poor prognosis in 71% of patients with RT. This study highlights the potential clinical utility of CMA to investigate the clonal relationship between CLL/SLL and RT, provide prognostic information, and possibly guide therapeutic decision making for patients with Richter transformation.

Response rates in acute myeloid leukemia patients treated with attenuated durations of venetoclax in combination with hypomethylating agents

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Background: The combination of the Bcl-2 inhibitor, venetoclax, with hypomethylating agents (HMA) recently emerged as an efficacious treatment for older adults with acute myeloid leukemia (AML) who are not eligible for intensive induction therapy. In a phase III randomized controlled trial of HMA +/- venetoclax, DiNardo et al demonstrated impressive composite complete response rate and complete response with incomplete recovery (CR+CRi) of 66% in the venetoclax arm as compared to 28% in the placebo arm. Despite HMA/Venetoclax being lower intensity, 83% of patients developed grade 3 hematologic adverse events, and 42% of patients experienced febrile neutropenia in the venetoclax arm, as compared to 19% in the placebo arm. In the trial, venetoclax was given continually for 28 day cycles, with some patients receiving shortened durations of venetoclax (21 days) due to toxicity. To reduce toxicity, some institutions have further limited the duration of venetoclax in cycle 1. Here, we report response rates with attenuated durations of venetoclax with HMA. Methods: We conducted a retrospective study of AML patients who received venetoclax in combination with HMA, excluding those with prior chemotherapy for AML or MDS, or previous exposure to HMA or venetoclax. Demographic, cytogenetic, pathology, and outcome data were collected including bone marrow biopsy results at diagnosis and after cycle 1 (day +28) or cycle 2 (day +56). The primary outcome was composite response rate (CR+CRi) following cycle 1 or cycle 2 defined by 2017 ELN criteria. Results: 25 patients were identified with median age of 73 (range 63-82). 9 patients received 14 or less days of venetoclax (attenuated duration): < 8 days in 1 patient and 8-14 days in 8 patients. 16 patients received 21 days or more (standard duration): 21 days in 14 patients, and 28 days in 2 patients. Of the patients who received an attenuated duration, the median age was 74 (68-82), 22% had either a TP53 mutation or deletion, 56% had complex karyotype, and 44% had received prior cytotoxic chemotherapy. Of the patients who received standard duration therapy, the median age was 71 (63-81), 44% had either a TP53 mutation or deletion, 75% had complex karyotype, and 6% had received prior cytotoxic chemotherapy. The composite response rate was 78% in the attenuated duration group and 75% in the standard duration group (p > 0.99). Conclusions: Though a limited sample size, this data suggests high response rates can be observed with attenuated courses of venetoclax. With appropriately selected patients, the feasibility of attenuated venetoclax courses could be further explored in larger prospective studies.[Table: see text]

Outcomes in AML patients receiving HMA + venetoclax combination with prior HMA exposure

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Background: Venetoclax (Ven) is a BCL-2 inhibitor approved in combination with hypomethylating agents (HMAs) in newly diagnosed AML patients who are not candidates for intensive induction based on impressive response rates (CR+CRi of 66.4%) and median overall survival (14.7 months) compared to HMA therapy alone (DiNardo CD, NEJM, 2020). Ven was also used in combination with 10 days of a HMA (Decitabine) in a phase II study. In the subgroup of patients with relapsed AML, some of which previously received HMA, the ORR, CR+CRi, and median OS were 62%, 42%, and 7.8 months respectively. (DiNardo CD, Lancet, 2020). To our knowledge there are no studies specifically looking at patients with AML receiving HMA + Ven with previous exposure to a HMA agent. Methods: We conducted a single center retrospective study of AML patients who received HMA + Ven therapy after previously receiving a HMA agent. Baseline demographic, clinical, laboratory, pathology, and outcomes data were collected by retrospective chart review. Response criteria was determined by 2017 ELN recommendations. Kaplan Meier was constructed to summarize time to event data. Results: A total of 17 patients were identified that met these criteria. 7 patients (41%) had progressed on prior HMA treatment, 11 patients (65%) received prior intensive chemotherapy, and 5 patients (29%) received previous Allogenic SCT prior to HMA+Ven therapy. 10 patients (59%) had either a TP53 mutation or 17p deletion and 11 patients (65%) had complex cytogenetics (≥ 3 cytogenetic abnormalities). Other patient characteristics are included in table below. For the entire cohort, the ORR (CR, CRi, PR) was 41% and the CR/CRi rate was 6%; The ORR in the following subgroups for previous HMA failure, TP53 mutation/17p deletion, and complex cytogenetics were 14%, 30%, and 36% respectively. The median Progression free survival and overall survival for the entire cohort was 2 months (1-4 months 95% CI) and 3 months (1-5 months, 95% CI) respectively. 15 patients (88%) were deceased and all deaths were attributed to AML (12/15) or infection (3/15). None of the patients went on to receive an Allogenic SCT. Conclusions: Although a limited sample size which includes many patients with a TP53/17p aberration, complex cytogenetics, Allogenic SCT relapse, and/or heavily pre-treated AML, this data describes poor outcomes in patients receiving HMA+Ven after previous HMA exposure. Patients with previous HMA failure in particular had a poor response rate. None of the patients received 10 day decitabine and it is unclear if this had any effect on the results. It would be beneficial to supplement this data with experience from multiple centers. Patient Characteristics (N = 17).[Table: see text]

Outcomes of CNS involvement in blastic plasmacytoid dendritic cell neoplasm (BPDCN)

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Background: BPDCN is rare cancer commonly involving the skin and marrow. Tagraxofusp (Tag), a CD123 targeted therapy, was the first FDA approved drug for BPDCN in 2018. CNS involvement occurs in 10-60% of patients and CNS staging and prophylactic (ppx) practices are variable. The pivotal trial of Tag in BPDCN did not require CNS staging and excluded those patients with known CNS involvement. Here, we describe one of the largest cohorts of BPDCN patients with known CNS involvement, including patients treated with Tag. Methods: We collected data from 4 centers on patients with CNS involvement defined by LP or imaging with high clinical suspicion. Survival was estimated via the Kaplan-Meier method with other analyses being descriptive. Results: CNS involvement was identified in 11 patients. Median age was 74 (range 51–83) and 10 were male. 5 patients had CNS staging at initial diagnosis. At time of CNS involvement, 6/11 patients had neuro symptoms. Prior to diagnosis of CNS involvement, 5 received Tag and none received CNS ppx. Of 9 patients treated for their known CNS involvement (table), one received CNS directed systemic therapy, with all others being treated with intrathecal (IT) chemotherapy. All patients treated with 3 or more doses of IT chemotherapy cleared their CSF, and survived at least 6 months from the diagnosis of CNS involvement, including two patients (#5 and 8) with large burden CNS disease and neuro symptoms. Median survival from time of diagnosis of BPDCN was 13.8 months (2.7-35.5) and from time of diagnosis of CNS involvement was 6.0 months (0.1-25.7). Conclusions: Asymptomatic CNS involvement by BPDCN is common; routine staging and ppx should be considered at diagnosis. Tagraxofusp did not appear to prevent the development of CNS disease. IT therapy effectively cleared and controlled CNS involvement in a majority of patients. IT therapy may be sufficient to control CNS disease and IT prophylaxis should be considered, including in patients on CD123 targeting therapies. Our results provide new insights into BPDCN with CNS involvement and include patients treated with recently developed novel systemic therapies.[Table: see text]

Clinical use of PI3K inhibitors in B-cell lymphoid malignancies: today and tomorrow

INTRODUCTION

PI3K inhibitors are an important new therapeutic option for the treatment of relapsed and refractory B-cell lymphoid malignancies. Idelalisib is a PI3Kδ inhibitor that has been approved for the treatment of lymphoma and chronic lymphocytic leukemia in the relapsed/refractory setting, and several other PI3K inhibitors are being developed targeting other isoforms of the PI3K enzyme, which results in distinct toxicities and variable efficacy in the clinical setting. Areas covered: We provide a general overview of PI3K inhibitors, recommended applications, and the mechanism and management of toxicities. We further review trials, ongoing and completed, leading to the approval of idelalisib as well other PI3K inhibitors currently in development. Articles were obtained from PubMed, and abstracts were searched for the past 5 years from the websites for ASCO, ASH, EHA, and ICML/Lugano. Expert commentary: PI3K inhibitors provide an important and powerful pharmacologic tool in the armamentarium against hematologic malignancies, especially for relapsed/refractory B-cell lymphoid malignancies. Unique toxicities are associated with inhibition of different isoforms of the PI3K enzyme, as demonstrated with the infectious and autoimmune toxicities associated with the PI3Kδ inhibitor, idelalisib. Due to these unique toxicities, PI3K inhibitors should only be used in formally approved combinations and settings.