Small molecule obatoclax (GX15-070) antagonizes MCL-1 and overcomes MCL-1-mediated resistance to apoptosis

Elevated expression of members of the BCL-2 pro-survival family of proteins can confer resistance to apoptosis in cancer cells. Small molecule obatoclax (GX15-070), which is predicted to occupy a hydrophobic pocket within the BH3 binding groove of BCL-2, antagonizes these members and induces apoptosis, dependent on BAX and BAK. Reconstitution in yeast confirmed that obatoclax acts on the pathway and overcomes BCL-2-, BCL-XL-, BCL-w-, and MCL-1-mediated resistance to BAX or BAK. The compound potently interfered with the direct interaction between MCL-1 and BAK in intact mitochondrial outer membrane and inhibited the association between MCL-1 and BAK in intact cells. MCL-1 has been shown to confer resistance to the BCL-2/BCL-XL/BCL-w-selective antagonist ABT-737 and to the proteasome inhibitor bortezomib. In both cases, this resistance was overcome by obatoclax. These findings support a rational clinical development opportunity for the compound in cancer indications or treatments where MCL-1 contributes to resistance to cell killing.     

Phase 2 study of a combined immunochemotherapy using rituximab and fludarabine in patients with chronic lymphocytic leukemia

This multicenter phase 2 trial investigated safety and efficacy of a new immunochemotherapeutic regimen combining rituximab (R) and fludarabine (F) in patients with fludarabine- and anthracycline-naive chronic lymphocytic leukemia (CLL). The rationale for using R + F includes single-agent efficacy of both drugs, in vitro synergism of R and F, and no apparent overlapping toxicity. Of 31 eligible patients with B-CLL enrolled, 20 were previously untreated and 11 relapsed. Treatment consisted of fludarabine administered at standard doses (25 mg/m(2)/d; days 1-5, 29-33, 57-61, and 85-89) and rituximab (375 mg/m(2)/d) given on days 57, 85, 113, and 151. Side effects such as fever, chills, and exanthema were generally mild (National Cancer Institute Common Toxicity Criteria [NCI-CTC] grade 1/2 in 48% and grade 3 and/or 4 in 3% of patients). Fever and chills were mainly associated with the first rituximab infusion. Hematologic toxicity included neutropenia (grade 1 and/or 2 in 26%, grade 3 and/or 4 in 42%) and thrombocytopenia (grade 1 and/or 2 in 19%, grade 3 and/or 4 in 9%). One patient died of cerebral bleeding during prolonged thrombocytopenia after the second cycle of fludarabine. There were a total of 32 infections in 16 patients, none of which was fatal. The overall response rate (complete remission [CR] and partial remission [PR]) was 87% (27 of 31 evaluable patients). In 20 previously untreated patients, 17 (85%) responded. Ten of 31 patients achieved CR (5 of 20 untreated; 5 of 11 pretreated; 9 of 21 Binet stage B, 1 of 10 Binet stage C). The median duration of response was 75 weeks. We conclude that the combination of rituximab and fludarabine is feasible and effective in patients with B-CLL.     

Phase II trial of recombinant leukocyte A interferon in patients with advanced chronic lymphocytic leukemia

Recombinant leukocyte A interferon is a highly purified single molecular species of alpha-interferon prepared by recombinant DNA methods. In 1982, a phase II trial to evaluate the efficacy of recombinant leukocyte A interferon for patients with previously treated chronic lymphocytic leukemia was begun, and 19 patients were entered in this study. Patients received one of two dose schedules depending on their pretreatment platelet counts. Those with platelet counts greater than 100,000/mm3 received 50 X 10(6) units/m2 intramuscularly three times weekly, with dose reductions to 25 X 10(6) units/m2 and 5 X 10(6) units/m2 for unacceptable toxicity. Those with platelet counts less than 100,000/mm3 received 5 X 10(6) units/m2 intramuscularly three times weekly. Toxicity was dose-dependent and included fever, chills, fatigue, anorexia, myalgias, headache, leukopenia, and thrombocytopenia. Response was evaluable in all but one of the patients entered in this study. Two of the 12 patients treated with 50 X 10(6) units/m2 had a partial response, three had no response, and seven had progressive disease. Of the six patients starting at 5 X 10(6) units/m2 in whom response was evaluable, two had no response and four had progressive disease. Five patients with progressive disease (three at 50 X 10(6) units/m2 and two at 5 X 10(6) units/m2) had an acceleration of disease while receiving recombinant leukocyte A interferon. It is concluded that the dose and schedule of recombinant leukocyte A interferon therapy tested in this study are not effective in previously treated patients with advanced chronic lymphocytic leukemia.     

Phase II study of acalabrutinib in ibrutinibintolerant patients with relapsed/refractory chronic lymphocytic leukemia

B-cell receptor signaling inhibition by targeting Bruton tyrosine kinase (BTK) is effective in treating chronic lymphocytic leukemia. The BTK inhibitor ibrutinib may be intolerable for some patients. Acalabrutinib is a more selective BTK inhibitor that may be better tolerated by patients who are intolerant to ibrutinib. A phase II study of acalabrutinib was conducted in patients with relapsed/refractory chronic lymphocytic leukemia who were ibrutinib-intolerant and had continued disease activity. Intolerance was defined as having discontinued ibrutinib due to persistent grade 3/4 adverse events or persistent/recurrent grade 2 adverse events despite dose modification/interruption. Patients received oral acalabrutinib 100 mg twice daily until disease progression or intolerance. Sixty patients were treated. The overall response rate to acalabrutinib was 73% and three patients (5%) achieved complete remission. At a median follow-up of 35 months, the median progression-free and overall survival were not reached; 24-month estimates were 72% and 81%, respectively. The most frequent adverse events with acalabrutinib were diarrhea (53%), headache (42%), contusion (40%), dizziness (33%), upper respiratory tract infection (33%), and cough (30%). The most common reasons for acalabrutinib discontinuation were progressive disease (23%) and adverse events (17%). Most patients with baseline samples (49/52; 94%) and all with on-treatment samples (3/3; 100%) had no detectable BTK and/or PLCG2 mutations. Acalabrutinib is effective and tolerable in most patients with relapsed/refractory chronic lymphocytic leukemia who are intolerant of ibrutinib. Acalabrutinib may be useful for patients who may benefit from BTK inhibitor therapy but are ibrutinib intolerant. ClinicalTrials.gov identifier: {"type":"clinical-trial","attrs":{"text":"NCT02717611","term_id":"NCT02717611"}}NCT02717611.     

Phase II clinical study of SH L 573 (fludarabine phosphate) in patients with chronic lymphocytic leukemia

We conducted a multicenter phase II clinical study of fludarabine phosphate, a new purine nucleotide analogue, in patients with chronic lymphocytic leukemia (CLL). Fludarabine phosphate was administered at a dose of 20 mg/m2/day intravenously for 5 days every 4 weeks as one course. Six courses as a maximum were repeated. The response rate was 38.5% (95% confidence intervals: 20.2% to 59.4%), with 1 complete remission and 9 partial remissions out of 26 treated patients. Major drug-related adverse reactions were fever, nausea, weakness, and paresthesia of the fingers; as a grade-3 reaction, varicella was also reported. Neutropenia and thrombocytopenia were observed as manifestations of hematologic toxicity. Clinical laboratory test results revealed abnormalities in hepatic function, including increased GPT, but none of these was rated grade 3 or 4.     

Splenectomy in advanced chronic lymphocytic leukemia: a single institution experience with 50 patients.

PURPOSE: To assess the efficacy of splenectomy in the treatment of refractory cytopenias associated with advanced chronic lymphocytic leukemia (CLL). PATIENTS AND METHODS: The histories of 57 patients with CLL who underwent splenectomy at the Mayo Clinic between 1975 and 1991 were retrospectively reviewed. Of the 57 patients, 50 underwent splenectomy for reasons directly related to their disease process such as cytopenias or symptomatic splenomegaly. The histories from these 50 patients were studied to assess the response to splenectomy and the operative morbidity and mortality. RESULTS: Ninety-four percent of patients were in Rai stage III or IV with extensive marrow infiltration, massive splenomegaly, and cytopenias refractory to chemotherapy. A positive response to splenectomy was defined at 3 months of follow-up as: (1) a hemoglobin level of 11 g/dL or greater in a patient with a preoperative value less than 11 g/dL; or (2) a platelet count of 100 x 10(3)/mm3 or greater in a patient with a preoperative value less than 100 x 10(3)/mm3. A positive response was achieved in 77% of patients with anemia, 70% of patients with thrombocytopenia, and 64% of patients with both anemia and thrombocytopenia. The response was sustained at 1 year of follow-up in 86%, 84%, and 85% of the patients, respectively. Postoperative transfusion requirements decreased correspondingly. The operative morbidity was 26%, and the operative mortality was 4%. The mean duration of hospitalization was 9.8 days (median: 9 days; range: 5 to 24 days). The actuarial median survival after splenectomy was 41 months in responders and 14 months in nonresponders. We found no preoperative parameters that were clearly predictive of a poor hematologic response. In particular, outcome was not affected by preoperative spleen size or the degree of marrow infiltration by CLL. All patients with symptomatic splenomegaly had an improved sense of well-being. CONCLUSION: In this, the largest single institution study to date, we found splenectomy to be efficacious in providing durable remissions of refractory cytopenias and in relieving symptomatic splenomegaly in the majority of patients with CLL. The procedure is associated with a low perioperative mortality. Although the impact on survival is uncertain, the improved peripheral blood counts may allow the administration of adequate doses of myelosuppressive chemotherapy.     

A phase I study of escalated dose subcutaneous alemtuzumab given weekly with rituximab in relapsed chronic lymphocytic leukemia/small lymphocytic lymphoma

This study assessed the safety and preliminary efficacy of escalated dose subcutaneous alemtuzumab in combination with rituximab in chronic lymphocytic leukemia. Twenty-eight patients with relapsed refractory chronic lymphocytic leukemia were treated on four dosing cohorts of weekly rituximab at 375 mg/m² and alemtuzumab doses that started at 30 mg three times per week and escalated to weekly dosing over four weeks, culminating with 90 mg weekly. One dose limiting toxicity of a rituximab infusion reaction was seen in cohort 2, but the regimen was otherwise well tolerated without evidence of differential toxicity by cohort. The overall response rate by National Cancer Institute-Working Group criteria was 61%, and the rate of complete bone marrow response was 43%, most of whom were negative for minimal residual disease. The addition of CT scan evaluation per International Workshop on Chronic Lymphocytic Leukemia 2008 criteria reduced the overall response rate to 14%. Median overall survival was 35 months, with 12 patients able to proceed to stem cell transplantation. Pharmacokinetic studies showed that chronic lymphocytic leukemia involving more than 80% of the bone marrow at study start was associated with lower trough concentrations of alemtuzumab and rituximab, and that higher trough serum concentrations of alemtuzumab were associated with complete bone marrow clearance. We conclude that escalated subcutaneous doses of alemtuzumab given weekly are well tolerated and result in excellent bone marrow clearance of chronic lymphocytic leukemia, helping patients to proceed to stem cell transplantation. This study is registered at ClinicalTrials.gov (Identifier:00330252).     

Phase I study of evofosfamide,an investigational hypoxia‐activated prodrug,in patients with advanced leukemia

Tumor hypoxia causes resistance to radiation and chemotherapy. Evofosfamide (TH‐302) has exhibited specific hypoxia‐dependent cytotoxicity against primary acute lymphoblastic leukemia (ALL) and acute myeloid leukemia (AML) samples in vitro. Based on these findings, a Phase I study of evofosfamide was designed for patients with relapsed/refractory leukemia (NCT01149915). In this open‐label study, patients were treated with evofosfamide as a 30–60 min/day infusion on Days 1–5 of a 21–day cycle (Arm A, n = 38) or as a continuous infusion over 120 hr over Days 1–5 of a 21‐day cycle (Arm B, n = 11). Forty‐nine patients were treated including 39 (80%) with AML and 9 (18%) with ALL. Patients had received a median of five prior therapies. In Arm A, the dose‐limiting toxicities (DLTs) were grade 3 esophagitis, observed at a dose of 550 mg/m². The maximum tolerated dose (MTD) was a daily dose of 460 mg/m². In Arm B, the DLTs were grade 3 stomatitis and hyperbilirubinemia, observed at a daily dose of 460 mg/m². The continuous infusion MTD was a daily dose of 330 mg/m². Hypoxia markers HIF‐1α and CAIX were highly expressed in leukemic bone marrow and were significantly reduced after evofosfamide therapy. The combined overall response rate in Arms A and B was 6% (2 CR/CRi and 1 PR), with all responses seen in Arm A. Evofosfamide has shown limited activity in heavily pretreated leukemia patients. Further evaluation investigating evofosfamide in combination with cytotoxic or demethylating agents is warranted. Am. J. Hematol. 91:800–805, 2016. © 2016 Wiley Periodicals, Inc.     

Prednimustine and mitoxantrone (PmM) in patients with low-grade malignant non-Hodgkin's lymphoma (NHL), chronic lymphocytic leukemia (CLL), and prolymphocytic leukemia (PLL)

Summary Patients with intracoronary stent implantation are treated with aggressive anticoagulant and antiplatelet therapy consisting of high-dose heparin, phenprocoumon, acetylsalicylic acid, dipyridamole, and the infusion of dextran to prevent a subacute thrombotic occlusion of the stented segment. In an effort to optimize this treatment by reducing both imminent bleeding complications and subacute thrombotic occlusion, the concentrations of prothrombin fragment 1+2 (F1+2) were determined after intracoronary Palmaz-Schatz stent implantation in 19 consecutive patients. The F1+2 concentrations after stent implantation and before the initiation of oral anticoagulant therapy (OAT) were 0.35 nm/l and 0.25–0.53 nm/l (median and 25th–75th percentile), versus 0.74 nm/l and 0.52–0.78 nm/l, in healthy subjects and 0.61 nm/l and 0.30–1.02 nm/l in 15 patients with ongoing proximal DVT. Nine days after initiation of OAT, F1+2 concentrations in both patient groups had not yet reached levels observed in patients with OAT in the stable state (0.16 nm/l, 0.12–0.26 nm/l;n=76;P<0.0001 compared with healthy subjects; INR 2.0–4.5). Despite an INR greater than 2.0, accompanying heparinization was terminated on day 9. In two stented patients a minor bleeding complication arose after the removal of the arterial catheter. Subacute thrombotic occlusions were not observed. Since F1+2 concentrations did not exceed the upper limit of normal range (1.11 nm/l) in any of the 19 patients, the therapeutic regimen was not changed. Monitoring F1+2 may thus be helpful in introducing a more individual treatment if aggressive anticoagulation has to be performed.     

Recombinant interferon-alpha 2A as maintenance treatment for patients with advanced stage chronic lymphocytic leukemia responding to chemotherapy.

Forty-five patients suffering from advanced B-CLL were randomized to receive interferon-alpha (IFN alpha) or no treatment after achieving complete remission or partial response, following a chemotherapy protocol called MiNa. The two groups were fully comparable in terms of clinical characteristics and level of response obtained by chemotherapy. IFN alpha was given at a dose of 3 megaunits three times a week intramuscularly for 1 year. The IFN-treated patient group showed a significantly longer duration of response and a less frequent incidence of infections as compared to the no treatment group. A minority of patients who had had partial response to chemotherapy obtained complete remission while on therapy with IFN alpha. Toxicity was mild and patient compliance was excellent. We conclude that IFN alpha may have a role as maintenance therapy in CLL for patients responding to chemotherapy.     

A phase I dose‐ranging study of bendamustine and rituximab in chronic lymphocytic leukemia patients with comorbidities

The management of sickle cell nephropathy (SCN) at an early stage is an important issue to prevent renal and cardiovascular morbidity and mortality. This study aimed to evaluate in this population, whether angiotensin converting enzyme inhibitors (ACEIs) treatment could exert a cardio‐renal protection in a SCN cohort. Forty‐two SCN patients (urine albumin:creatinine ratio (ACR) > 10 mg/mmol) were treated with ACEIs for 6 months, then evaluated for ACR, measured glomerular filtration rate (mGFR) together with haematological and cardiovascular parameters. A 1‐month washout was also performed in order to differentiate short‐ and long‐term ACEIs effects. A decrease in ACR baseline value (>30%) was detected in 62% of cases (mean ACR: 46·4 ± 7·6 and 26·4 ± 3·9 mg/mmol at baseline and 6 months respectively; P = 0·002), whereas mGFR values were unchanged. ACR decrease was detected at 1 month following ACEI initiation (32·9 ± 6·9, P = 0·02) with a persistent trend after withdrawal (P = 0·08). ACEIs also decreased diastolic blood pressure (P = 0·007), pulse wave velocity (P = 0·01), tricuspid regurgitation velocity (TRV; P = 0·04), asymmetric dimethyl arginine (ADMA: P = 0·001) and haemoglobin (P = 0·01) while conventional haemolytic biomarkers were unchanged. Our data suggest that ACEIs are safe and effective at decreasing albuminuria in sickle cell patients with a beneficial effect on specific mortality risk factors, such as TRV and asymmetric dimethyl arginine.     

Phase I study of Topotecan, a new topoisomerase I inhibitor, in patients with refractory or relapsed acute leukemia

The purpose of this study was to define, in a phase I study in leukemia, the maximally tolerated dose (MTD), major toxicities, and possible antitumor activity of Topotecan, a new topoisomerase I (topo I) inhibitor. Topotecan was delivered by a 5-day continuous infusion every 3 to 4 weeks to patients with refractory or relapsed acute leukemia, at doses ranging from 3.5 mg/m2 to 18 mg/m2 per course. Twenty-seven patients were treated, including 17 patients with acute myelogenous or undifferentiated leukemia, 7 with acute lymphocytic leukemia, and 3 with chronic myelogenous leukemia in blastic phase. Severe mucositis was the dose-limiting toxicity occurring in two of five patients treated with Topotecan 11.8 mg/m2 per course; a third patient had prolonged myelosuppression. At the MTD of 10 mg/m2 per course, 1 of 12 patients had severe mucositis and 5 had mild-to- moderate mucositis. Nausea, vomiting, diarrhea, and prolonged myelosuppression were uncommon. Three patients (11%) achieved a complete response, two (7%) had a partial response, and one (4%) had a hematologic improvement. The overall complete plus partial response rate was 19%, and 24% in acute myelogenous or undifferentiated leukemia. A novel in vitro assay that quantifies Topotecan-stabilized topo I-DNA complexes in patient samples was used, which demonstrated heterogeneity in the ability of Topotecan to interact with topo I, the intracellular target of Topotecan. This phase I study defined the MTD of Topotecan to be 10 mg/m2 by continuous infusion over 5 days every 3 to 4 weeks in patients with refractory or relapsed acute leukemia. Severe mucositis was the dose-limiting toxicity. Future studies will define the precise activity of Topotecan in different leukemia subsets, its efficacy in combination with other antileukemic drugs, and correlations between Topotecan-induced topo I-DNA complex formation and individual patient response to Topotecan.     

The emergence of Ph-, trisomy -8+ cells in patients with chronic myeloid leukemia treated with imatinib mesylate

OBJECTIVE: To describe clinical and laboratory features of a cohort of patients with chronic myelogenous leukemia (CML) who developed Ph(-), trisomy 8(+) metaphases while on treatment with imatinib mesylate. PATIENTS AND METHODS: Conventional cytogenetics and triple-color interphase fluorescence in situ hybridization were used to identify 5 of 310 studied patients who, on follow-up analysis, had Ph(-), trisomy 8(+) cells while on therapy. RESULTS: None of the 5 patients had cytogenetic evidence of clonal evolution at the start of treatment with imatinib. All patients developed grade 3 or 4 neutropenia and thrombocytopenia during treatment. The emergence of Ph(-), trisomy 8(+) metaphases was seen at 3, 6, 13, 16, and 18 months from the start of treatment and was present at multiple time points. The maximum number of trisomy 8 metaphases ranged from 25 to 50%. Concomitantly, all patients had a profound suppression of Ph(+) cells (ranging from 0 to 65%) as well as the appearance of normal metaphases, ranging from 6 to 55%. None of the patients has shown clinical or hematologic signs of progression to a more advanced phase of CML. CONCLUSIONS: While on treatment with imatinib mesylate a small group (less than 5%) of patients with CML developed Ph(-) trisomy 8(+) clone associated with pancytopenia. None of the patients developed clinical or hematological signs of progression to a more advanced phase of CML. These observations suggest that identification of trisomy 8 cells may represent clonal Ph(-) cells that were uncovered by treatment with a selective and potent inhibitor of Ph(+) cells.     

MK-0457, a novel kinase inhibitor, is active in patients with chronic myeloid leukemia or acute lymphocytic leukemia with the T315I BCR-ABL mutation

MK-0457 (VX-680) is a small-molecule aurora kinase (AK) inhibitor with preclinical antileukemia activity. The T315I BCR-ABL mutation mediates resistance to imatinib, nilotinib, and dasatinib. MK-0457 has in vitro activity against cells expressing wild-type or mutated BCR-ABL, including the T315I BCR-ABL mutation. Three patients with T315I abl-mutated chronic myeloid leukemia (CML) or Philadelphia chromosome (Ph)–positive acute lymphocytic leukemia (ALL) have achieved clinical responses to doses of MK-04547 that are not associated with adverse events. Higher MK-0457 dose levels were associated with clinical responses and down-regulation of CrkL phosphorylation in leukemia cells. The possible role of AK inhibition in these clinical responses requires further investigation. The currently reported cases are the first observed clinical activity of a kinase inhibitor against the T315I phenotype. The observation of responses in 3 patients with T315I phenotype–refractory CML or Ph-positive ALL, at doses of MK-0457 associated with no significant extramedullary toxicity, is very encouraging.      

Results of a prospective phase 2 study combining imatinib mesylate and cytarabine for the treatment of Philadelphia-positive patients with chronic myelogenous leukemia in chronic phase

In chronic myelogenous leukemia (CML) imatinib mesylate has been shown to selectively inhibit the tyrosine kinase domain of the oncogenic bcr-abl fusion protein. Using this agent alone high rates of cytogenetic responses were recorded. However, several mechanisms of resistance have been described. In vitro studies examining the effects of imatinib mesylate plus cytarabine have shown synergistic antiproliferative effects of this combination. Thus, the CML French Group decided to perform a phase 2 trial testing a combination of imatinib mesylate and low-dose cytarabine in 30 previously untreated patients in chronic phase. Treatment was administered on 28-day cycles. Patients were treated continuously with imatinib mesylate orally at a dose of 400 mg daily. Cytarabine was given on days 15 to 28 of each cycle at an initial dose of 20 mg/m2/d via subcutaneous injection. Adverse events were frequently observed with grade 3 or 4 hematologic toxicities and nonhematologic toxicities in 53% (n = 16) and 23% (n = 7) of patients, respectively. The cumulative incidence of complete cytogenetic response (CCR) at 12 months was 83% and at 6 months 100% of the patients achieved complete hematologic response (CHR). We concluded that the combination was safe and promising given the rates of response.     

Safety and efficacy of ofatumumab, a fully human monoclonal anti-CD20 antibody, in patients with relapsed or refractory B-cell chronic lymphocytic leukemia: a phase 1-2 study

Safety and efficacy of the fully human anti-CD20 monoclonal antibody, ofatumumab, was analyzed in a multicenter dose-escalating study including 33 patients with relapsed or refractory chronic lymphocytic leukemia. Three cohorts of 3 (A), 3 (B), and 27 (C) patients received 4, once weekly, infusions of ofatumumab at the following doses: (A) one 100 mg and three 500 mg; (B) one 300 mg and three 1000 mg; (C) one 500 mg and three 2000 mg. Sixty-seven percent of the patients were Binet stage B, and the median number of previous treatments was 3. The maximum tolerated dose was not reached. The majority of related adverse events occurred at first infusion, and the number of adverse events decreased at each subsequent infusion. Seventeen (51%) of 33 patients experienced infections, 88% of them of grade 1-2. One event of interstitial pneumonia was fatal; all other cases resolved within one month. The response rate of cohort C was 50% (13/26), one patient having a nodular partial remission and 12 patients partial remission. In conclusion, ofatumumab was found to be well tolerated in patients with chronic lymphocytic leukemia (CLL) in doses up to 2000 mg. Preliminary data on safety and objective response are encouraging and support further studies on the role of ofatumumab in CLL patients. This trial was registered at www.clinicaltrials.gov as no. NCT00093314.