Exposure-response analyses for selection/confirmation of optimal isatuximab dosing regimen in combination with pomalidomide/dexamethasone treatment in patients with multiple myeloma.

Isatuximab is an approved anti-CD38 monoclonal antibody with multiple antitumor modes of action. An exposure-response (E-R) analysis using data from patients with relapsed/refractory multiple myeloma (RRMM) enrolled in a phase Ib clinical study who received isatuximab at doses from 5 to 20 mg/kg weekly for 1 cycle (4 weeks) followed by every 2 weeks thereafter (qw/q2w) in combination with pomalidomide/dexamethasone (n = 44) was first used to determine the optimal dose/schedule for the phase III ICARIA-MM study. It was complemented by an E-R analysis from a second phase Ib study of patients who received isatuximab at doses from 3 to 10 mg/kg q2w or 10 or 20 mg/kg qw/q2w in combination with lenalidomide/dexamethasone (n = 52). Plasma trough concentration at week 4 (CT4W) was the best predictor for response, and the benefit of the initial 4-weekly administration was confirmed. Although the predicted overall response rate (ORR) was higher at 20 mg/kg vs. 10 mg/kg, the 95% confidence intervals were overlapping. Considering the high probability of success to reach the targeted ORR of greater than or equal to 60%, 10 mg/kg qw/q2w was selected. Results of the E-R analysis from the lenalidomide/dexamethasone study and published disease modeling using data from both phase Ib clinical studies reinforced 10 mg/kg qw/q2w as the optimal dose/schedule for the phase III ICARIA-MM study. E-R analysis showed that higher CT4W was associated with higher ORR. Developed models supported the phase III isatuximab dosing regimen selection/confirmation of 10 mg/kg qw/q2w for use in combination with pomalidomide/dexamethasone in patients with RRMM.

PK/PD modeling analysis for dosing regimen selection of isatuximab as single agent and in combination therapy in patients with multiple myeloma.

This analysis describes the pharmacokinetic/pharmacodynamic (PK/PD) modeling framework that supported selection of the isatuximab (anti-CD38 monoclonal antibody) dosing regimen alongside its early clinical development in patients with relapsed/refractory multiple myeloma (RRMM). The PK/PD mathematical model characterized the variations of patient serum M-protein concentrations, the primary marker of tumor burden in multiple myeloma (MM). Three separate PK/PD models were built sequentially as data became available from phase I clinical trials. The primary PK/PD analysis was initiated using monotherapy phase I study data (n = 122), followed by analysis of data collected from phase Ib combination studies with lenalidomide and dexamethasone (Rd, n = 40) and then with pomalidomide and dexamethasone (Pd, n = 31). Using the PK/PD model, abnormal "myeloma" protein (M-protein) profiles under different isatuximab dosing regimens were simulated. Overall, simulations revealed that regimens which included a loading period of four weekly administrations followed by administration every 2 weeks thereafter (QW4-Q2W), reduced M-protein levels more than a Q2W regimen without a loading period. For isatuximab monotherapy, a 20 mg/kg dose induced greater reduction in serum M-protein levels compared with doses equal or lower than 10 mg/kg. For isatuximab in combination with either Rd or Pd, simulations yielded no substantial benefit in terms of M-protein reduction between isatuximab 10 mg/kg and 20 mg/kg. These PK/PD analyses supported the use of isatuximab 10 mg/kg QW4-Q2W in combination with Pd in the phase III trial.

Drug-Disease Interaction and Time-Dependent Population Pharmacokinetics of Isatuximab in Relapsed/Refractory Multiple Myeloma Patients.

Isatuximab, a monoclonal antibody (mAb) of immunoglobulin G (IgG) isotype, specifically targets the cluster of differentiation 38 antigen overexpressed in malignant plasma cells. Isatuximab is used to treat multiple myeloma (MM), characterized by the excessive production of abnormal "myeloma proteins" (M-proteins) that may interact with therapeutic IgG mAb on the neonatal Fc receptor (FcRn)-mediated recycling pathway. The clinical pharmacology profile of isatuximab was investigated by population pharmacokinetics (PKs) modeling in 476 patients with MM who received 1-20 mg/kg isatuximab either as single agent or in combination with pomalidomide-dexamethasone in 4 clinical trials. Isatuximab PKs were characterized by a two-compartment model with parallel time-varying linear clearance (CL) and nonlinear elimination. Due to a mechanism-based drug-disease interaction, patients secreting IgG M-protein exhibited a twofold lower drug exposure compared with patients with non-IgG MM. No dose adjustment was required based on MM immunoglobulin type because efficacy and safety profiles were comparable between IgG and non-IgG MM subpopulations. ß2-microglobulin, body weight, sex, drug material, and race have a limited effect on drug exposure and do not require any dose adjustment. A typical 50% decrease in linear CL from initial treatment to steady-state was predicted, and this decrease correlated with the best overall response rate and was slower for patients with IgG MM. These findings suggest that the time-dependent effect of isatuximab is likely mediated by a combined factor of both disease state evolution and the perturbation of the FcRn-mediated recycling pathway.

Preclinical Activity of SAR408701: A Novel Anti-CEACAM5-maytansinoid Antibody-drug Conjugate for the Treatment of CEACAM5-positive Epithelial Tumors.

PURPOSE: Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) is a glycoprotein that has limited expression in normal adult tissues, but is overexpressed in carcinomas of the gastrointestinal tract, the genitourinary and respiratory systems, and breast cancer. As such, CEACAM5 is an attractive target for antibody-based therapies designed to selectively deliver cytotoxic drugs to certain epithelial tumors. Here, we describe preclinical data for a novel antibody-drug conjugate (ADC), SAR408701, which consists of an anti-CEACAM5 antibody (SAR408377) coupled to a maytansinoid agent DM4 via a cleavable linker. EXPERIMENTAL DESIGN: The specificity and binding affinity of SAR408701 to human and cynomolgus monkey CEACAM5 were tested in vitro. The cytotoxic activity of SAR408701 was assessed in CEACAM5-expressing tumor cell lines and using patient-derived xenograft mouse models of CEACAM5-positive tumors. Pharmacokinetic-pharmacodynamic and pharmacokinetic-efficacy relationships were established. SAR408701 toxicity was evaluated in cynomolgus monkey. RESULTS: SAR408701 bound selectively to human and cynomolgus monkey CEACAM5 with similar apparent Kd values (0.017 nmol/L and 0.024 nmol/L, respectively). Both in vitro and in vivo evaluations showed that SAR408701 has cytotoxic activity, leading to in vivo efficacy in single and repeated dosing. Single doses of SAR408701 induced significant increases in the tumor expression of phosphorylated histone H3, confirming the tubulin-targeting mechanism of action. The overall toxicity profile of SAR408701 in cynomolgus monkey was similar to that observed after intravenous administration of DM4 alone. CONCLUSIONS: On the basis of these preclinical data, the ADC SAR408701 is a promising candidate for development as a potential treatment for patients with CEACAM5-positive tumors.

A dose-finding Phase 2 study of single agent isatuximab (anti-CD38 mAb) in relapsed/refractory multiple myeloma.

A Phase 2 dose-finding study evaluated isatuximab, an anti-CD38 monoclonal antibody, in relapsed/refractory multiple myeloma (RRMM; NCT01084252). Patients with ≥3 prior lines or refractory to both immunomodulatory drugs and proteasome inhibitors (dual refractory) were randomized to isatuximab 3 mg/kg every 2 weeks (Q2W), 10 mg/kg Q2W(2 cycles)/Q4W, or 10 mg/kg Q2W. A fourth arm evaluated 20 mg/kg QW(1 cycle)/Q2W. Patients (N = 97) had a median (range) age of 62 years (38-85), 5 (2-14) prior therapy lines, and 85% were double refractory. The overall response rate (ORR) was 4.3, 20.0, 29.2, and 24.0% with isatuximab 3 mg/kg Q2W, 10 mg/kg Q2W/Q4W, 10 mg/kg Q2W, and 20 mg/kg QW/Q2W, respectively. At doses ≥10 mg/kg, median progression-free survival and overall survival were 4.6 and 18.7 months, respectively, and the ORR was 40.9% (9/22) in patients with high-risk cytogenetics. CD38 receptor density was similar in responders and non-responders. The most common non-hematologic adverse events (typically grade ≤2) were nausea (34.0%), fatigue (32.0%), and upper respiratory tract infections (28.9%). Infusion reactions (typically with first infusion and grade ≤2) occurred in 51.5% of patients. In conclusion, isatuximab is active and generally well tolerated in heavily pretreated RRMM, with greatest efficacy at doses ≥10 mg/kg.

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.

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.