Phase 1b trial of isatuximab, an anti-CD38 monoclonal antibody, in combination with carfilzomib as treatment of relapsed/refractory multiple myeloma.

BACKGROUND: Isatuximab (Isa), an anti-CD38 monoclonal antibody, and carfilzomib (K), a next-generation proteasome inhibitor (PI), both have potent single-agent activity in relapsed and refractory multiple myeloma (RRMM). METHODS: This phase 1b study evaluated the combination of Isa and K in 33 patients with RRMM. Isa was administered by intravenous infusion in 3 dosing cohorts: dose level 1 (Isa at 10 mg/kg biweekly), dose level 2 (DL2; Isa at 10 mg/kg weekly for 4 doses and then biweekly), and dose level 3 (Isa at 20 mg/kg weekly for 4 doses and then biweekly) and all patients received K (20 mg/m2 intravenously for cycle 1, days 1 and 2, and then 27 mg/m2 for all subsequent doses). A standard 3+3 dose-escalation design was used, no dose-limiting toxicity was observed, and the maximum tolerated dose was not reached. An expansion cohort of 18 patients was enrolled at DL2 to further evaluate safety and efficacy. Responses were assessed with the International Myeloma Working Group response criteria, and patients continued treatment until disease progression or unacceptable toxicity. RESULTS: With a median follow-up of 26.7 months, in this heavily pretreated population with a median of 3 prior lines (refractory to PIs and immunomodulatory drugs, 76%; refractory to K, 27%), the overall response rate was 70% (stringent complete response/complete response, 4; very good partial response, 8; partial response, 11). The median progression-free survival was 10.1 months, and the 2-year survival probability was 76%. The most common treatment-related adverse events (grade 2 or higher) were anemia, leukopenia, neutropenia, thrombocytopenia, hypertension, and infection. Infusion reactions were common (55%) but did not limit dosing. CONCLUSIONS: Treatment with Isa plus K was well tolerated with no unexpected toxicity. The combination was effective despite the enrollment of heavily pretreated patients with RRMM. LAY SUMMARY: This phase 1b study was designed to assess the safety, pharmacokinetics, and preliminary efficacy of isatuximab and carfilzomib in patients with relapsed and refractory multiple myeloma. Thirty-three patients were treated: 15 in dose escalation and 18 in dose expansion. Patients received an average of 10 cycles. The treatment was safe and effective. No unexpected toxicity or drug-drug interactions were noted. Seventy percent of the subjects responded to therapy, and the progression-free survival was 10.1 months.

Phase II trial of aflibercept with FOLFIRI as a second-line treatment for Japanese patients with metastatic colorectal cancer.

Aflibercept targets vascular endothelial growth factor. The present study involved assessing the efficacy, safety and pharmacokinetics of aflibercept plus 5-fluorouracil/levofolinate/irinotecan (FOLFIRI) as a second-line treatment for metastatic colorectal cancer (mCRC) in Japanese patients. Aflibercept (4 mg/kg) plus FOLFIRI was administered every 2 weeks in 62 patients with mCRC until disease progression, unacceptable toxicity or patient withdrawal. Tumors were imaged every 6 weeks. The primary endpoint was objective response rate (ORR); secondary endpoints were progression-free survival, overall survival, safety, and pharmacokinetics of aflibercept, irinotecan and 5-fluorouracil. A total of 60 patients were evaluated for ORR; 50 had received prior bevacizumab. The ORR was 8.3% (95% confidence interval [CI]: 1.3%-15.3%), and the disease control rate (DCR) was 80.0% (69.9%-90.1%). The median progression-free survival was 5.42 months (4.14-6.70 months) and the median overall survival was 15.59 months (11.20-19.81 months). No treatment-related deaths were observed, and no significant drug-drug interactions were found. The most common treatment-emergent adverse events were neutropenia and decreased appetite. Free aflibercept had a mean maximum concentration (coefficient of variation) of 73.2 µg/mL (15%), clearance of 0.805 L/d (22%) and volume of distribution of 6.2 L (18%); aflibercept bound with vascular endothelial growth factor had a clearance of 0.162 L/d (9%) (N = 62). Aflibercept did not significantly affect the pharmacokinetics of irinotecan or 5-fluorouracil: The clearance was 11.1 L/h/m2 (28%) for irinotecan and, at steady state, 72.6 L/h/m2 (56%) for 5-fluorouracil (N = 10). Adding aflibercept to FOLFIRI was shown to be beneficial and well-tolerated in Japanese patients with mCRC. ClinicalTrials.gov Identifier: NCT01882868.

A phase I and pharmacokinetic study of afilbercept with FOLFIRI: comparison of Chinese and Caucasian populations.

Background This study assessed the preliminary safety, pharmacokinetics (PK) and anti-tumor effects of aflibercept in combination with 5-fluorouracil, leucovorin and irinotecan (FOLFIRI) in Chinese patients with previously-treated advanced solid malignancies. Patients and Methods This open-label single-arm Phase I study conducted at two centers in China included adult (≥18 years) patients with metastatic or unresectable solid malignancies who had received ≥1 prior treatment. Patients received aflibercept 4 mg/kg IV on Day 1 followed by FOLFIRI over Days 1 and 2 every 2 weeks, and were assessed for safety, tumor response, PK parameters and immunogenicity. Post-hoc analyses included calculation of progression-free survival (PFS) for patients with colorectal cancer (CRC). Results A total of 20 patients were enrolled. The most common Grade 3/4 adverse events included neutropenia (35%), hypertension (30%), stomatitis (20%) and proteinuria (20%), and no anti-aflibercept antibodies were detected. Six patients achieved a partial response, and in 15 patients with CRC median PFS was 5.95 months (95% CI: 5.29-8.77). Free aflibercept remained in excess of VEGF-bound aflibercept for the majority of the study treatment duration. The mean free aflibercept values for Cmax (64.8 µg/mL) AUC (291 µg.day/mL), CL (0.92 L/day) and Vss (5.9 L) were similar to those measured in Caucasian patients. The addition of aflibercept did not influence the PK of the chemotherapy agents. Conclusion For Chinese patients with pre-treated advanced solid malignancies, 4 mg/kg of aflibercept in combination with FOLFIRI was well-tolerated, demonstrated preliminary anti-tumor activity and had a PK profile consistent with that in Caucasian patients.

Prediction of CYP Down Regulation after Tusamitamab Ravtansine Administration (a DM4-Conjugate), Based on an In Vitro-In Vivo Extrapolation Approach.

Tusamitamab ravtansine is an antibody-drug conjugate (ADC) composed of a humanized monoclonal antibody (IgG1) and DM4 payload. Even if DM4 and its main metabolite methyl-DM4 (Me-DM4) circulate at low concentrations after ADC administration, their potential as perpetrators of cytochrome P450 mediated drug-drug interaction was assessed. In vitro studies in human hepatocytes indicated that Me-DM4 elicited a clear concentration-dependent down regulation of cytochrome P450 enzymes (CYP3A4, 1A2, and 2B6). Because DM4 was unstable under the incubation conditions studied, the in vitro constants could not be determined for this entity. Thus, to predict the clinical relevance of this observed downregulation, an in vitro-in vivo extrapolation (IVIVE) pharmacokinetic (PK) based approach was developed. To mitigate model prediction errors and because of their similar inhibitory effect on tubulin polymerization, the same downregulation constants were used for DM4 and Me-DM4. This approach describes the time course of decreasing CYP3A4, 1A2, and 2B6 enzyme amounts as a function of circulating concentrations of DM4 and Me-DM4 predicted from a population PK model. The developed IVIVE-PK model showed that the highest CYP abundance decrease was observed for CYP3A4, with a transient reduction of < 10% from baseline. The impact on midazolam exposure, as probe substrate of CYP3A, was then simulated based on a physiologically-based PK static method. The maximal CYP3A4 abundance reduction was associated with a predicted midazolam area under the curve (AUC) ratio of 1.14. To conclude, the observed in vitro downregulation of CYPs by Me-DM4 is not expected to have relevant clinical impact.

Translational Model-Based Strategy to Guide the Choice of Clinical Doses for Antibody-Drug Conjugates.

This work proposes a model-based approach to help select the phase 1 dosing regimen for the antibody-drug conjugate (ADC) SAR408701 leveraging the available data for 2 other ADCs of the same construct: SAR3419 and SAR566658. First, monkey and human pharmacokinetic (PK) data of SAR566658 and SAR3419 were used to establish the appropriate allometric approach to be applied to SAR408701 monkey PK data. Second, a population pharmacokinetics-pharmacodynamics (PK-PD) model was developed to describe tumor volume evolution following SAR408701 injection in mice. Third, allometric approaches identified for SAR566658 and SAR3419 were applied to SAR408701 monkey PK data to predict the human PK profile. Both SAR566658 and SAR3419 human and monkey PK were best described by a 2-compartment linear model. The relative difference was less than 10% between predicted and observed clearance using allometric exponents of 0.75 and 1, respectively. Tumor volume evolution following SAR408701 injection was best described by a full Simeoni model with a plasma concentration threshold of 4.6 µg/mL for eradication in mice. Both allometric exponents were used to predict SAR408701 PK in human from PK in monkey and to identify the potential effective dosing regimens. This translational strategy may be a valuable tool to design future clinical studies for ADCs, to support selection of the most appropriate dosing regimen, and to estimate the minimal dose required to assure antitumor activity, according to the schedule used.

A dose-escalation study of SAR3419, an anti-CD19 antibody maytansinoid conjugate, administered by intravenous infusion once weekly in patients with relapsed/refractory B-cell non-Hodgkin lymphoma.

PURPOSE: To determine recommended dose, dose-limiting toxicity, safety profile, pharmacokinetics, preliminary antitumor activity, and exploratory pharmacodynamics of SAR3419, an antibody-drug conjugate targeting CD19, administered alone by intravenous infusion weekly (qw), in a dose-escalation phase I study in patients with refractory/relapsed (R/R) non-Hodgkin lymphoma (NHL). EXPERIMENTAL DESIGN: Patients with R/R CD19(+) B-NHL were treated with escalating doses of SAR3419 repeated qw for eight to 12 doses. On the basis of clinical evidence of late or cumulative toxicities, the study protocol was amended to test an "optimized" administration schedule consisting of four qw doses followed by four biweekly (q2w) doses (qw/q2w) at the recommended dose with the intent of reducing drug accumulation. RESULTS: Forty-four patients were treated on seven dose levels ranging from 5 to 70 mg/m(2). SAR3419 recommended dose was determined as 55 mg/m(2) qw. Twenty-five patients received the qw/q2w schedule at 55 mg/m(2), which showed an improved safety profile compared with the qw schedule. Antilymphoma activity was observed with both schedules in around 30% of patients with either indolent or aggressive diseases. SAR3419 displayed a long terminal half-life (approximately 7 days) and a low clearance (approximately 0.6 L/d), with no dose effect. The qw/q2w schedule allowed limiting accumulation with a decrease in SAR3419 plasma trough and average concentrations by around 1.4-fold compared with the qw schedule. CONCLUSION: While administered weekly, SAR3419 is well tolerated and active. The qw/q2w schedule that shows an improved safety profile and preserves antilymphoma activity is selected for clinical phase II studies.

Phase I dose-escalation study of intravenous aflibercept in combination with docetaxel in patients with advanced solid tumors.

PURPOSE: This phase I study cohort investigated aflibercept in combination with docetaxel in patients with advanced solid tumors. MATERIALS AND METHODS: Eligible patients had metastatic or nonresectable cancer for which docetaxel was considered appropriate. Patients received intravenous aflibercept (either 2, 4, 5, 6, 7, or 9 mg/kg) with docetaxel (75 mg/m(2)) on day 1 every 3 weeks until disease progression or unacceptable toxicity. Primary objectives were to evaluate dose-limiting toxicities (DLT) during cycle 1 and to determine the aflibercept recommended phase II trial dose (RP2D) for combination with docetaxel. Pharmacokinetics, tolerability, and antitumor activity were also investigated. RESULTS: Fifty-four patients (mean age, 56 y) were enrolled. Most had prior chemotherapy (96%) and most (24.1%) had breast cancer. In the dose-escalation phase (n = 34), there were three DLTs: grade 4 neutropenic infection (2 mg/kg), grade 3 dysphonia (7 mg/kg), and grade 2 hypertension (9 mg/kg). An excess of free-over-bound aflibercept was observed at doses of 5 mg/kg or more. The pharmacokinetics of aflibercept and docetaxel were not modified by coadministration. Aflibercept (6 mg/kg) was defined as the RP2D based on DLT and pharmacokinetic data. Overall, the most frequent grade 3/4 adverse events (AE) were neutropenia (85.2%), leukopenia (74.1%), hypertension (18.5%), and stomatitis (16.7%). AEs associated with vascular endothelial growth factor blockade included epistaxis (all grades, 83.3%), proteinuria (68.5%), dysphonia (68.5%), and hypertension (53.7%). Seven patients had partial responses, and 32 patients had stable disease (>3 months in 18 patients). CONCLUSION: On the basis of findings from this study, aflibercept (6 mg/kg) was the dose recommended for further clinical development.