Michael Conte

Pembrolizumab in patients with CLL and Richter transformation or with relapsed CLL

Chronic lymphocytic leukemia (CLL) patients progressed early on ibrutinib often develop Richter transformation (RT) with a short survival of about 4 months. Preclinical studies suggest that programmed death 1 (PD-1) pathway is critical to inhibit immune surveillance in CLL. This phase 2 study was designed to test the efficacy and safety of pembrolizumab, a humanized PD-1-blocking antibody, at a dose of 200 mg every 3 weeks in relapsed and transformed CLL. Twenty-five patients including 16 relapsed CLL and 9 RT (all proven diffuse large cell lymphoma) patients were enrolled, and 60% received prior ibrutinib. Objective responses were observed in 4 out of 9 RT patients (44%) and in 0 out of 16 CLL patients (0%). All responses were observed in RT patients who had progression after prior therapy with ibrutinib. After a median follow-up time of 11 months, the median overall survival in the RT cohort was 10.7 months, but was not reached in RT patients who progressed after prior ibrutinib. Treatment-related grade 3 or above adverse events were reported in 15 (60%) patients and were manageable. Analyses of pretreatment tumor specimens from available patients revealed increased expression of PD-ligand 1 (PD-L1) and a trend of increased expression in PD-1 in the tumor microenvironment in patients who had confirmed responses. Overall, pembrolizumab exhibited selective efficacy in CLL patients with RT. The results of this study are the first to demonstrate the benefit of PD-1 blockade in CLL patients with RT, and could change the landscape of therapy for RT patients if further validated. This trial was registered at www.clinicaltrials.gov as #NCT02332980.

Ofatumumab‐based chemoimmunotherapy is effective and well tolerated in patients with previously untreated chronic lymphocytic leukemia (CLL)

Although rituximab‐based chemoimmunotherapy (CIT) has substantially improved clinical outcomes in chronic lymphocytic leukemia (CLL), only 40% to 50% of patients achieve a complete remission (CR). There remains interest in identifying new approaches to improve the effectiveness of CIT. Ofatumumab is a fully human anti‐CD20 monoclonal antibody with greater apparent single‐agent activity than rituximab in CLL patients.

Chronic lymphocytic leukemia in young (≤ 55 years) patients: a comprehensive analysis of prognostic factors and outcomes.

The clinical characteristics and outcomes of younger (≤55 years) patients with chronic lymphocytic leukemia in the era of modern prognostic biomarkers and chemoimmunotherapy are not well understood. Baseline characteristics and outcomes of patients with chronic lymphocytic leukemia ≤55 years who were seen at the Mayo Clinic between January 1995 and April 2012 were compared with those of patients >55 years. The overall survival of patients ≤55 years was compared to that of the age- and sex-matched normal population. The characteristics of 844 newly diagnosed chronic lymphocytic leukemia patients ≤55 years old (median, 50 years) were compared to those of 2324 patients >55 years old (median, 67 years). Younger patients were more likely to have Rai stage I or II disease (P<0.0001), be IGHV unmutated (P=0.002) and express ZAP-70 (P=0.009). These differences became more pronounced when the ≤55 age group was sub-stratified into age ≤45, 46–50 and 51–55 years. After a median follow-up of 5.5 years, 426 (51%) patients ≤55 years old had received treatment, and 192 (23%) had died. The time to treatment was shorter in patients ≤55 years than in those older than 55 years (4.0 years versus 5.2 years; P=0.001) and those ≤55 years had longer survival (12.5 years versus 9.5 years; P<0.0001). However, patients ≤55 years had significantly shorter survival than the age- and sex-matched normal population (12.5 years versus not reached; P<0.0001). Our study is the first comprehensive analysis of younger patients with chronic lymphocytic leukemia in the modern era. Adverse prognostic markers appear more common among young patients. Although the survival of young chronic lymphocytic leukemia patients is longer than that of those >55 years old, their survival relative to the age- and sex-matched normal population is profoundly shortened.

Chemoimmunotherapy for relapsed/refractory and progressive 17p13‐deleted chronic lymphocytic leukemia (CLL) combining pentostatin, alemtuzumab, and low‐dose rituximab is effective and tolerable and limits loss of CD20 expression by circulating CLL cells

Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) patients with purine analog refractory disease or TP53 dysfunction still have limited treatment options and poor survival. Alemtuzumab‐containing chemoimmunotherapy regimens can be effective but frequently cause serious infections. We report a Phase II trial testing the efficacy and tolerability of a short‐duration regimen combining pentostatin, alemtuzumab, and low‐dose high‐frequency rituximab designed to decrease the risk of treatment‐associated infections and to limit the loss of CD20 expression by CLL cells. The study enrolled 39 patients with progressive CLL that was either relapsed/refractory (n = 36) or previously untreated with 17p13 deletion (17p13−) (n = 3). Thirteen (33%) patients had both 17p13− and TP53 mutations predicted to be dysfunctional, and eight patients had purine analog refractory CLL without TP53 dysfunction. Twenty‐six (67%) patients completed therapy, with only five (13%) patients having treatment‐limiting toxicity and no treatment‐related deaths. Twenty‐two (56%) patients responded to treatment, with 11 (28%) complete responses (four with incomplete bone marrow recovery). Median progression‐free survival was 7.2 months, time to next treatment was 9.1 months, and overall survival was 34.1 months. The majority of deaths (82%) were caused by progressive disease, including transformed diffuse large B‐cell lymphoma (n = 6). Correlative studies showed that low‐dose rituximab activates complement and natural killer cells without a profound and sustained decrease in expression of CD20 by circulating CLL cells. We conclude that pentostatin, alemtuzumab, and low‐dose high‐frequency rituximab is a tolerable and effective therapy for CLL and that low‐dose rituximab therapy can activate innate immune cytotoxic mechanisms without substantially decreasing CD20 expression. Am. J. Hematol. 89:757–765, 2014.

The efficacy of ibrutinib in the treatment of Richter syndrome

To the editor: Richter syndrome (RS) is defined as the transformation of chronic lymphocytic leukemia (CLL) to a more aggressive lymphoma, most commonly diffuse large B-cell lymphoma (DLBCL).[1][1] Traditional anthracycline- or platinum-based chemotherapy is associated with complete response (CR)

Hypogammaglobulinemia in newly diagnosed chronic lymphocytic leukemia: Natural history, clinical correlates, and outcomes

Although hypogammaglobulinemia is a well recognized complication in patients with chronic lymphocytic leukemia (CLL), its prevalence at the time of CLL diagnosis, and association with novel prognostic markers and clinical outcome is not well understood.

Use of positron emission tomography-computed tomography in the management of patients with chronic lymphocytic leukemia/small lymphocytic lymphoma

Abstract Chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL) cells typically have low 2-deoxy-2-[18F]fluoro-d-glucose (FDG) avidity, and patients with CLL have an increased risk of developing FDG-avid aggressive lymphomas, second malignancies and infections. We hypothesized that FDG positron emission tomography-computed tomography (PET-CT) of the trunk is a sensitive method of detecting these complications in patients with CLL. Of the of 2299 patients with CLL seen in the Division of Hematology at Mayo Clinic Rochester between 1 January 2006 and 31 December 2011, 272 (11.8%) had 526 PET-CT scans and 472 (89.7%) of these were reported as abnormal. Among the 293 (55.7%) PET-CT scans used for routine evaluation of CLL, the PET component was of clinical value in only one instance. In contrast, in 83 (30.5%) patients, PET-CT scans used to evaluate new clinical complications localized high FDG-avidity lesions for biopsies. This resulted in clinically relevant new diagnoses in 32 patients, including those with more aggressive lymphoma (n = 16), non-hematological malignancies (n = 8) and opportunistic infections (n = 3). Twenty-seven patients had high FDG-avidity CLL, which was associated with prominent lymph node proliferation centers, an increased frequency of poor prognostic factors (17p13 deletion, unmutated immunoglobulin heavy chain variable gene [IGHV], expression of ZAP-70 and CD38) and a shorter overall survival. We conclude that FDG PET scans should not be used for routine surveillance of patients with CLL. However PET-CT scans are sensitive, but not specific, for detection of aggressive lymphomas, other cancers and systemic infections in patients with CLL.

Pharmacovigilance during ibrutinib therapy for chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL) in routine clinical practice.

Abstract Due to Cytochrome P450 3A (CYP3A) metabolism, clinical trials of ibrutinib-treated chronic lymphocytic leukemia (CLL) patients prohibited concurrent medications metabolized by CYP3A. We evaluated concomitant medication use in 118 ibrutinib-treated CLL patients outside the context of clinical trials. Seventy-five (64%) patients were on medications that could increase ibrutinib toxicity and 4 (3%) were on drugs that could decrease ibrutinib efficacy. Nineteen (16%) patients were on concomitant CYP3A inhibitors (11 moderate, 8 strong), and 4 (3%) were on CYP3A inducers (two patients were on both CYP3A inhibitors and inducers). Although the ibrutinib starting dose was changed in 18 patients on CYP3A interacting medications, no difference in 18-month progression-free survival or rate of ibrutinib discontinuation was observed in patients who were not. In routine clinical practice, 2 of 3 CLL patients commencing ibrutinib are on a concomitant medication with potential to influence ibrutinib metabolism. Formal medication review by a pharmacist should be considered in all patients initiating ibrutinib.

Hypogammaglobulinemia in newly diagnosed chronic lymphocytic leukemia

Although hypogammaglobulinemia is a well recognized complication in patients with chronic lymphocytic leukemia (CLL), its prevalence at the time of CLL diagnosis, and association with novel prognostic markers and clinical outcome is not well understood.

Akt Inhibitor MK2206 Selectively Targets CLL B-cell Receptor Induced Cytokines, Mobilizes Lymphocytes and Synergizes with Bendamustine to Induce CLL Apoptosis

Accumulating evidence supports the critical role of B-cell receptor (BCR) activation in chronic lymphocytic leukaemia (CLL) pathogenesis (Herishanu, et al 2011). Recent preclinical and clinical studies indicate BCR signal inhibitors, specifically the Bruton tyrosine kinase (BTK) inhibitor Ibrutinib and phosphatidylinositide 3-kinase (PI3K) δ inhibitor CAL101, have impressive preclinical and clinical efficacy in CLL (Byrd, et al 2013, Herman, et al 2010). Akt is downstream of the signalling cascade following BCR ligation. Preclinical studies performed using co-culture of CLL B-cells with marrow stromal cells highlight the importance of PI3K/Akt signalling in the activation of both cell types during their interactions that support survival of CLL B-cells (Ding, et al 2010, Edelmann, et al 2008). MK2206 is a highly selective oral allosteric Akt inhibitor found to have minimal side effects in a phase 1 trial of patients with refractory solid tumours (Yap, et al 2011). The present study determined the maximum tolerated dose (MTD) of MK2206 as a single-agent and its ability to target Akt in tumour cells. Here we explore the in vitro efficacy of MK2206 on CLL B-cell survival, its potential synergy with bendamustine, and its impact on BCR ligation events including cytokine release both in vitro and in vivo. Materials and methods are detailed in Appendix S1. We initially tested the effect of the Akt inhibitor, MK2206, on CLL B-cell survival. Dose and time- dependent apoptosis was induced by Akt inhibition with MK2206 (Figure 1A, n = 37, appendix S1). Unlike CLL cells, normal peripheral blood mononuclear cells did not undergo apoptosis after exposure to MK2206. Basal phosphorylation of AktS473 was detected at variable levels amongst tested CLL samples (n = 7) but was completely abolished by MK2206 treatment at the 1 μM dose (Figure 1B). MK2206 also resulted in cleavage of the poly (ADP-ribose) polymerase (PARP) protein and significantly decreased the activation of Akt target p70S6K. However, expression of the p85 subunit of PI3K, which is upstream of Akt, was not affected. Next we tested whether established prognostic factors would be associated with differential CLL apoptosis levels induced by MK2206. No significant differences in MK2206-induced cell death were found based on the presence or absence of IGHV mutation, del (17p13), positivity of ZAP70 and CD38 (Figure 1C-F). These results indicated that MK2206 is able to induce apoptosis in CLL B-cells independent of adverse prognostic factors. Figure 1 Effect of MK2206 treatment on CLL apoptosis. (A) The mean and standard error of apoptosis levels of peripheral blood mononuclear cells (PBMC) isolated from 37 CLL patients and 5 normal subjects. (B) Western blot analysis showed treatment with MK2206 decreased ... To assess whether MK2206 could enhance the drug sensitivity of CLL cells to the established agent (bendamustine) in relapsed disease (Fischer, et al 2011), we next explored the impact of MK2206 in combination with bendamustine on CLL apoptosis. An additive or synergistic affect was observed when MK2206 was added to bendamustine in 11 of the 12 CLL samples tested (figure 1G and 1H). Given the prognostic significance of BCR-induced cytokines (Sivina, et al 2011), we subsequently tested if Akt inhibition with MK2206 could abrogate BCR-mediated cytokine secretion and signal activation. BCR ligation with anti-IgM significantly increased production of selective immune cytokines (CCL3, CCL4, CCL2, IL-2Rα, IL-1Rα and IL-8) among the 30 cytokines tested (Figure 2A-B, n = 7). CCL3 and CCL4 upregulation are consistent with the previous report (Burger, et al 2009). The increase of CCL2, IL-2Rα, IL-1Rα and IL-8 following BCR ligation of CLL has not been previously reported. Pre-treatment with MK2206 abrogated the increase of CCL3, CCL4, CCL2 and IL-2Rα (Figure 2A), but not IL-1Rα and IL-8 (Figure 2B). Variable degrees of pAktS473, pGSK3βS9, p44/42Erk T202/Y204 and p70S6K T389 activation were also observed at 30 min after BCR stimulation (Figure 2C). MK2206 pretreatment reduced or abolished the activation of pAktS473, pGSK3βS9 and p70S6KT389 induced by anti-IgM and reduced the activation of p44/42Erk T202/Y204 to a variable degree. Collectively, these in vitro results indicate that MK2206 selectively abolishes BCR induced CCL3, CCL4, CCL2 and IL-2Rα production, probably via abrogating Akt and Erk signals. Other BCR-induced cytokines, such as IL-8 and IL-1Rα however were not affected by MK2206, suggesting these cytokines are induced by BCR-initiated signals other than those mediated by Akt or Erk phosphorylation. Figure 2 MK2206 selectively abrogates immune cytokine secretion induced by BCR ligation on CLL cells. (A, B) The secretion of CCL3, CCL4, CCL2, IL-2Rα, IL-1Rα and IL-8 increased with time following BCR ligation. MK2206 treatment significantly abrogates ... These preclinical studies support trials of MK2206 in combination with bendamustine for CLL patients. To that end, we initiated a phase 1/2 trial of MK2206 in combination with bendamustine and rituximab for patients with relapsed CLL (N1087) in 2011. N1087 is currently open for accrual with 10 patients enrolled to date. To evaluate the single agent effect of MK2206, this trial involves a 1-week run-in of MK2206 monotherapy prior to initiating bendamustine and rituximab (Appendix S1). Similar to the finding of lymphocyte mobilization from other BCR targeting therapies, all patients evaluated (n=8) had increases of their absolute lymphocyte count (ALC) after a single dose of MK2206 monotherapy (Figure 2D, mean increase of 8 patients: 56%). The increase in ALC after the first dose of MK2206 was modest in three of these patients (6.3%, 6.7% and 11.0% increase respectively), and more dramatic in the remaining 5 patients (mean increase of 84.3%; Figure 2D). To explore the clinical relevance of our in vitro results showing that MK2206 abrogates BCR-mediated CCL2/3/4 secretion, we investigated the effect of a single-dose MK2206 on the plasma levels of these cytokines in trial patients after one week. The majority of the tested 9 patients had a decrease in CCL3 (mean ± standard error of the mean [n=7]: 25% ± 6% reduction), CCL4 ([n=7], 22% ± 3% reduction) and CCL2 level ([n=6], 20% ± 7% reduction) after a single-dose MK2206 (Figure 2D). In contrast, two patients were found to have small increases of these three cytokines after the single-dose of MK2206. Notably these two patients also experienced the smallest increase in ALC. Although our sample size is too small to draw a definitive conclusion, these findings corroborate our in vitro results and suggest that the reduction of the BCR-stimulated CCL2/3/4 secretion is associated with lymphocyte mobilization. Collectively, our in vitro and in vivo findings indicate that MK2206 induces apoptosis of CLL B-cells and is able to block the signal activation and cytokine up-regulation induced by BCR ligation. Single agent MK2206 is capable of mobilizing leukaemic B-cells and decreases CCL3, CCL4 and CCL2 production in vivo. We believe that this data strongly encourages further clinical testing of MK2206 either alone or in combination with traditional chemotherapeutic drugs in CLL.