Ulocuplumab (BMS-936564 / MDX1338): a fully human anti-CXCR4 antibody induces cell death in chronic lymphocytic leukemia mediated through a reactive oxygen species-dependent pathway.

The CXCR4 receptor (Chemokine C-X-C motif receptor 4) is highly expressed in different hematological malignancies including chronic lymphocytic leukemia (CLL). The CXCR4 ligand (CXCL12) stimulates CXCR4 promoting cell survival and proliferation, and may contribute to the tropism of leukemia cells towards lymphoid tissues. Therefore, strategies targeting CXCR4 may constitute an effective therapeutic approach for CLL. To address that question, we studied the effect of Ulocuplumab (BMS-936564), a fully human IgG4 anti-CXCR4 antibody, using a stroma--CLL cells co-culture model. We found that Ulocuplumab (BMS-936564) inhibited CXCL12 mediated CXCR4 activation-migration of CLL cells at nanomolar concentrations. This effect was comparable to AMD3100 (Plerixafor--Mozobil), a small molecule CXCR4 inhibitor. However, Ulocuplumab (BMS-936564) but not AMD3100 induced apoptosis in CLL at nanomolar concentrations in the presence or absence of stromal cell support. This pro-apoptotic effect was independent of CLL high-risk prognostic markers, was associated with production of reactive oxygen species and did not require caspase activation. Overall, these findings are evidence that Ulocuplumab (BMS-936564) has biological activity in CLL, highlight the relevance of the CXCR4-CXCL12 pathway as a therapeutic target in CLL, and provide biological rationale for ongoing clinical trials in CLL and other hematological malignancies.

First-in-human multicenter phase I study of BMS-936561 (MDX-1203), an antibody-drug conjugate targeting CD70.

PURPOSE: The study evaluated the safety, tolerability, and pharmacokinetics of BMS-936561, a fully human monoclonal antibody-drug conjugate targeting CD70 cell-surface protein. METHODS: Eligible patients had ECOG performance status 0-2 and received ≤3 prior chemotherapy regimens. An initial accelerated titration design enrolling one patient per dose level was followed by 3 + 3 dose escalation with the first observation of a grade ≥2 adverse event (AE). We tested escalating doses of BMS-936561 (0.5, 1, 2, 4, 8, 15 mg/kg) administered every 21 days in a 42 day cycle for a maximum of 17 cycles. Pharmacokinetic samples were collected in cycle 1. RESULTS: A total of 26 patients enrolled; 16 and 10 for the escalation and expansion cohorts, respectively. Median age was 63 years (48-74); 18 males and 25 Caucasians. There was no defined MTD per protocol, but a DLT of grade 3 hypersensitivity was recorded in 2 of 16 (13%) subjects at the highest dose of 15 mg/kg. The most frequent AEs were: fatigue (85%), nausea (54%), and decreased appetite (39%). Delayed toxicities (facial edema and pleural/pericardial effusions) occurred in 6 of 16 (38%) subjects at the 15 mg/kg dose. PK analysis showed a dose-proportional increase in active drug levels with increasing doses. There was disease stabilization in 18 of 26 patients (69%) without correlation with received dose. CONCLUSIONS: BMS-936561 is well tolerated over a wide range of doses in patients with advanced ccRCC and B-NHL. The 8 mg/kg dose was the highest best tolerated dose and the recommended dose for future studies.

BMS-936564/MDX-1338: a fully human anti-CXCR4 antibody induces apoptosis in vitro and shows antitumor activity in vivo in hematologic malignancies.

PURPOSE: CXCR4 has been identified as a prognostic marker for acute myeloid leukemia (AML) and other malignancies. We describe the development and characterization of a fully human antibody to CXCR4 and its application for therapy of AML, non-Hodgkin lymphoma (NHL), chronic lymphoid leukemia (CLL), and multiple myeloma. EXPERIMENTAL DESIGN: Human transgenic mice were immunized with CXCR4-expressing cells, and antibodies reactive with CXCR4 were analyzed for apoptosis induction and ability to interfere with CXCL12-induced migration and calcium flux. In vivo efficacy was determined in multiple AML, NHL, and multiple myeloma xenograft tumors in severe combined immunodeficient mice. RESULTS: BMS-936564/MDX-1338 is a fully human IgG(4) monoclonal antibody that specifically recognizes human CXCR4. In vitro studies show that MDX-1338 binds to CXCR4-expressing cells with low nanomolar affinity, blocks CXCL12 binding to CXCR4-expressing cells, and inhibits CXCL12-induced migration and calcium flux with low nanomolar EC(50) values. When given as monotherapy, MDX-1338 exhibits antitumor activity in established tumors including AML, NHL, and multiple myeloma xenograft models. In addition, we show that MDX-1338 induced apoptosis on a panel of cell lines and propose that antibody-induced apoptosis is one of the mechanisms of tumor growth inhibition. CONCLUSIONS: BMS-936564/MDX-1338 is a potent CXCR4 antagonist which is efficacious as monotherapy in tumor-bearing mice and is currently in phase I for the treatment of relapsed/refractory AML, NHL, CLL, and multiple myeloma.

Pharmacodynamics and safety of intravenous pegaspargase during remission induction in adults aged 55 years or younger with newly diagnosed acute lymphoblastic leukemia.

In contrast to that in children, pharmacokinetic, pharmacodynamic, and safety information on pegaspargase in adults is very limited. We administered a single intravenous dose of pegaspargase (2000 IU/m2) as part of a standard frontline induction regimen to 25 adults with newly diagnosed acute lymphoblastic leukemia (ALL), and obtained serum samples on several time points. The population mean peak serum concentration of asparaginase enzymatic activity was 1 IU/mL, the elimination half-life was 7 days, and the volume of distribution was 2.43 L/m2. After the single dose, asparagine deamination was complete in all patients after 2 hours, and in 100%, 81%, and 44% on days 14, 21, and 28, respectively. A pharmocodynamic correlation model showed minimal enzymatic activity of 0.2 IU/mL for optimal asparagine depletion. The kinetic posthoc analyses demonstrated enzymatic activity for 3 weeks or more. One patient developed neutralizing antiasparaginase antibodies on day 22 after administration. Pegaspargase was well tolerated, with few grade 3/4 side effects. No allergic reactions or pancreatitis were observed. In adults aged 55 years or younger, pegaspargase produces a long duration of asparagine depletion and can be given intravenously, with a safety profile that is similar to equivalent multiple doses of intramuscular Escherichia coli asparaginase.

Asparaginase antibody and asparaginase activity in children with higher-risk acute lymphoblastic leukemia: Children's Cancer Group Study CCG-1961.

We investigated the anti-asparaginase antibody (Ab) and asparaginase enzymatic activity in the sera of 1,001 patients (CCG-1961) with high-risk acute lymphoblastic leukemia (HR-ALL). Patients received nine doses of native Escherichia coli asparaginase during induction. Half of rapid early responders (RER) were randomly assigned to standard intensity arms and continued to receive native asparaginase. The other RER patients and all slow early responders received 6 or 10 doses of PEG-asparaginase. Serum samples (n = 3,193) were assayed for determination of asparaginase Ab titers and enzymatic activity. Three hundred ninety of 1,001 patients (39%) had no elevation of Ab among multiple evaluations-that is, were Ab-negative (<1.1 over negative control)-and 611 patients (61%) had an elevated Ab titer (>1.1). Among these 611 patients, 447 had no measurable asparaginase activity during therapy. Patients who were Ab-positive but had no clinical allergies continued to receive E. coli asparaginase, the activity of which declined precipitately. No detectable asparaginase activity was found in 81 of 88 Ab-positive patients shortly after asparaginase injections (94% neutralizing Ab). The Ab-positive patients with clinical allergies subsequently were given Erwinase and achieved substantial activity (0.1-0.4 IU/ml). An interim analysis of 280 patients who were followed for 30 months from induction demonstrated that the Ab-positive titers during interim maintenance-1 and in delayed intensification-1 were associated with an increased rate of events. The CCG-1961 treatment schedule was very immunogenic, plausibly due to initially administrated native asparaginase. Anti-asparaginase Ab was associated with undetectable asparaginase activity and may be correlated with adverse outcomes in HR ALL.

A Phase I-II trial of polyethylene glycol-conjugated L-asparaginase in patients with multiple myeloma.

BACKGROUND: Multiple myeloma remains an incurable disease. New agents are needed to improve therapy for patients with this disease. Previous investigators evaluated in vitro sensitivity of myeloma cells to polyethylene glycol-conjugated L-asparaginase (PEG-L-asparaginase) using the human tumor clonogenic assay. Of the 19 myeloma samples evaluated, 63% were inhibited at 0.075 IU/mL, and 74% were inhibited at 0.75 IU/mL. PEG-L-asparaginase is a form of Escherichia coli-derived L-asparaginase that is bound covalently to polyethylene glycol. Compared with the native form, it has a longer half-life and is less likely to cause allergic reactions. METHODS: The authors conducted a Phase I-II trial using PEG-L-asparaginase as a single agent in patients with recurrent and/or refractory multiple myeloma. RESULTS: Twenty-two patients received a median of two doses of PEG-L-asparaginase. In the 17 patients who are evaluable for response, a complete response was observed in one patient after four doses, and stable disease was observed in eight patients. Progression of disease was the reason for termination from study in the remaining eight patients. The median survival was 31.7 months, with four patients who were alive at 72 months after the start of therapy. Grade 3-4 toxicity was noted by the PEG-L-asparaginase 2000 mg/m(2) level. Severe allergic reactions were noted only at the highest dose level. CONCLUSIONS: Current data suggest that the maximal tolerated dose for single agent PEG-L-asparaginase in relapse/refractory multiple myeloma patients is 1000 mg/m(2) every 4 weeks. We could not identify any correlation between dose, plasma level and response. In this advanced group of patients we noted stable disease and/or response in 52% of evaluable patients. PEG-L-asparaginase has lower tolerance when used in the standard dosage as a single agent in this group of patients. We therefore recommend further studying of PEG-L-asparaginase dose of 1000 mg/m(2) on alternate weeks with steroids and/or other immune modulators.

A randomized comparison of native Escherichia coli asparaginase and polyethylene glycol conjugated asparaginase for treatment of children with newly diagnosed standard-risk acute lymphoblastic leukemia: a Children's Cancer Group study.

For this study, 118 children with standard-risk acute lymphoblastic leukemia (ALL) were given randomized assignments to receive native or pegylated Escherichia coli asparaginase as part of induction and 2 delayed intensification phases. Patients treated with pegaspargase had more rapid clearance of lymphoblasts from day 7 and day 14 bone marrow aspirates and more prolonged asparaginase activity than those treated with native asparaginase. In the first delayed intensification phase, 26% of native asparaginase patients had high-titer antibodies, whereas 2% of pegaspargase patients had those levels. High-titer antibodies were associated with low asparaginase activity in the native arm, but not in the pegaspargase arm. Adverse events, infections, and hospitalization were similar between arms. Event-free survival at 3 years was 82%. A population pharmacodynamic model using the nonlinear mixed effects model (NONMEM) program was developed that closely fit the measured enzyme activity and asparagine concentrations. Half-lives of asparaginase were 5.5 days and 26 hours for pegaspargase and native asparaginase, respectively. There was correlation between asparaginase enzymatic activity and depletion of asparagine or glutamine in serum. In cerebrospinal fluid asparagine, depletion was similar with both enzyme preparations. Intensive pegaspargase for newly diagnosed ALL should be tested further in a larger population.