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Patricia Vrignaud,1 Dorothée Semiond,2 Veronique Benning,2 Eric Beys,2 Hervé Bouchard,3 Sunil Gupta4 1Sanofi Oncology, Vitry-sur-Seine, France; 2Sanofi DSAR, Alfortville, France; 3Sanofi LGCR, Vitry-sur-Seine, France; 4Sanofi Oncology, Cambridge, MA, USA Abstract: First-generation taxanes have changed the treatment paradigm for a wide variety of cancers, but innate or acquired resistance frequently limits their use. Cabazitaxel is a novel second-generation taxane developed to overcome such resistance. In vitro, cabazitaxel showed similar antiproliferative activity to docetaxel in taxane-sensitive cell lines and markedly greater activity in cell lines resistant to taxanes. In vivo, cabazitaxel demonstrated excellent antitumor activity in a broad spectrum of docetaxel-sensitive tumor xenografts, including a castration-resistant prostate tumor xenograft, HID28, where cabazitaxel exhibited greater efficacy than docetaxel. Importantly, cabazitaxel was also active against tumors with innate or acquired resistance to docetaxel, suggesting therapeutic potential for patients progressing following taxane treatment and those with docetaxel-refractory tumors. In patients with tumors of the central nervous system (CNS), and in patients with pediatric tumors, therapeutic success with first-generation taxanes has been limited. Cabazitaxel demonstrated greater antitumor activity than docetaxel in xenograft models of CNS disease and pediatric tumors, suggesting potential clinical utility in these special patient populations. Based on therapeutic synergism observed in an in vivo tumor model, cabazitaxel is also being investigated clinically in combination with cisplatin. Nonclinical evaluation of the safety of cabazitaxel in a range of animal species showed largely reversible changes in the bone marrow, lymphoid system, gastrointestinal tract, and male reproductive system. Preclinical safety signals of cabazitaxel were consistent with the previously reported safety profiles of paclitaxel and docetaxel. Clinical observations with cabazitaxel were consistent with preclinical results, and cabazitaxel is indicated, in combination with prednisone, for the treatment of patients with hormone-refractory metastatic prostate cancer previously treated with docetaxel. In conclusion, the demonstrated activity of cabazitaxel in tumors with innate or acquired resistance to docetaxel, CNS tumors, and pediatric tumors made this agent a candidate for further clinical evaluation in a broader range of patient populations compared with first-generation taxanes. Keywords: XRP6258, CNS tumors, mCRPC, pediatric tumor, taxane resistance, xenograft

This study aimed at leveraging data from phase I/II clinical trials to build a nonlinear joint model of serum M-protein kinetics and progression-free survival (PFS) accounting for the effects of isatuximab (Isa), pomalidomide (Pom), and dexamethasone (Dex) in patients with relapsed and/or refractory multiple myeloma. Serum M-protein levels and PFS data from 203 evaluable patients, included either in a phase I/II study (n = 173) or in a phase I study (n = 30), were used to build the model. First, we independently developed a longitudinal model and a PFS model. Then, we linked them in a nonlinear joint model by selecting the link function that best captured the association between serum M-protein kinetics and PFS. A Claret tumor growth-inhibition model accounting for the additive effects of Isa, with an E max function, Pom, and Dex on serum M-protein elimination was selected to describe serum M-protein kinetics. PFS was best described with a log-logistic model and associations with baseline beta-2 microglobulin level, age, and coadministration of Dex were identified. The instantaneous change in serum M-protein level was found to be associated with PFS in the final joint model. Using model simulations, we retrospectively supported the Isa 10 mg/kg weekly for 4 weeks, then biweekly (QW/Q2W) dosing regimen of the ICARIA-MM phase III pivotal study, and validated it using the same phase III pivotal study data., (© 2024 Sanofi and The Author(s). CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

In this multi-center, Phase-1 study (NCT03733717), we characterized the pharmacokinetics (PK) of the anti-CD38 antibody isatuximab (Isa) after IV administration (primary objective), and evaluated safety, immunogenicity, and preliminary anti-myeloma activity in Chinese patients with relapsed/refractory multiple myeloma (RRMM). Isa 20-mg/kg was administered weekly (QW) in cycle 1, then biweekly (Q2W). Twenty-one extensively pretreated RRMM patients (median 4 prior lines; 95.2% refractory to last regimen), received ≥ 1 dose of Isa. After first IV-infusion, mean maximum observed concentration was 402 μg/mL and mean area-under-the-concentration-versus-time curve (first 1-week dosing interval) 37,000 μg·h/mL. After repeated administration, exposure (C trough ) increased 3.11-folds (day 1/cycle 2) versus first administration (day 8/cycle 1). Safety findings were consistent with the known Isa safety profile, with no new safety signals. Any-causality, grade ≥ 3 treatment-emergent adverse events (TEAEs) were reported in 47.6% of patients. Serious, treatment-related AEs occurred in 2 patients. Isa treatment was generally well tolerated; only 1 patient discontinued due to TEAE. Preliminary efficacy results showed a 19.0% overall response rate (clinical benefit, 33.3%). Our results demonstrate a PK profile for Isa comparable to prior findings in Western and other East-Asian populations, as well as safety and tolerability of treatment with IV Isa 20-mg/kg QW-Q2W in Chinese RRMM patients.Trial registration: The trial was registered with ClinicalTrials.gov; NCT03733717. Date of first trial registration: 07/11/2018., Competing Interests: Competing interests MS, HJ, XQ, FD, and JQ: nothing to disclose. YL, ZF, SZ-L, DS, and LL are employed by Sanofi and may hold stock and/or stock options. LQ: consulting for AstraZeneca, Beigene, Xi'an Janssen, Pfizer; Speaker Bureau participation for AstraZeneca, Beigene, Xi'an Janssen, Pfizer, Roche, and Sanofi., (© 2024. The Author(s).)

Significance Statement: There is no standardized desensitization regimen for kidney transplant candidates. CD38, expressed by plasma cells, could be targeted for desensitization to deplete plasma cells producing alloantibodies and donor-specific antibodies. Few studies and case reports are available regarding the use of CD38 antibodies for desensitization in patients awaiting kidney transplant. This study shows that isatuximab, a CD38-targeting therapy, was well tolerated in kidney transplant candidates, with a durable decrease in anti-HLA antibodies and partial desensitization activity. The short treatment period and long follow-up of this study allowed for the understanding of the mechanism and timing for any antibody rebound. Isatuximab could be further investigated as an option for adjunct therapy to existing desensitization for patients on the kidney transplant waitlist., Background: Patients with calculated panel reactive antibody (cPRA) ≥80.00%, particularly those with cPRA ≥99.90%, are considered highly sensitized and underserved by the Kidney Allocation System. Desensitization removes circulating reactive antibodies and/or suppresses antibody production to increase the chances of a negative crossmatch. CD38 is expressed highly on plasma cells, thus is a potential target for desensitization., Methods: This was an open-label single-arm phase 1/2 study investigating the safety, pharmacokinetics, and preliminary efficacy of isatuximab in patients awaiting kidney transplantation. There were two cohorts, cohorts A and B, which enrolled cPRA ≥99.90% and 80.00% to <99.90%, respectively., Results: Twenty-three patients (12 cohort A, 11 cohort B) received isatuximab 10 mg/kg weekly for 4 weeks then every 2 weeks for 8 weeks. Isatuximab was well tolerated with pharmacokinetic and pharmacodynamic profiles that indicated similar exposure to multiple myeloma trials. It resulted in decreases in CD38 + plasmablasts, plasma cells, and NK cells and significant reductions in HLA-specific IgG-producing memory B cells. Overall response rate, on the basis of a predefined composite desensitization end point, was 83.3% and 81.8% in cohorts A and B. Most responders had decreases in anti-HLA antibodies that were maintained for 26 weeks after the last dose. Overall, cPRA values were minimally affected, however, with only 9/23 patients (39%) having cPRA decreases to target levels. By study cutoff (median follow-up of 68 weeks), six patients received transplant offers, of which four were accepted., Conclusions: In this open-label trial, isatuximab was well tolerated and resulted in a durable decrease in anti-HLA antibodies with partial desensitization activity., Clinical Trial Registration Number: NCT04294459 ., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Society of Nephrology.)

This study aimed to support dosing regimen selection for isatuximab as a single agent or in combination with dexamethasone for Japanese patients with relapsed/refractory multiple myeloma (RRMM). A joint model characterizing the dynamics of serum M-protein kinetics and its association with progression-free survival (PFS) was developed using data from 201 evaluable Japanese and non-Japanese patients with RRMM enrolled in two monotherapy phase I/II trials, where Japanese patients (n = 31) received isatuximab at 10 or 20 mg/kg once weekly (qw) for 4 weeks then every 2 weeks (q2w) in subsequent cycles (10 or 20 mg/kg qw-q2w). Among non-Japanese patients, 38 received isatuximab 20 mg/kg qw-q2w in combination with dexamethasone. Trial simulations were then performed to evaluate the effect of the isatuximab dosing regimens on both serum M-protein and PFS with and without dexamethasone. The model identified instantaneous changes in serum M-protein as the best on-treatment predictor for PFS. Trial simulations demonstrated that 20 mg/kg qw-q2w induced a greater decrease (30% vs. 22%) of serum M-protein at week 8 and prolonged median PFS by 2.4 weeks compared with 10 mg/kg qw-q2w. Although Japanese patients did not receive isatuximab plus dexamethasone in the phase I/II trial, simulations predicted that isatuximab 20 mg/kg qw-q2w plus dexamethasone would induce a greater decrease (67% vs. 43%) of serum M-protein and a prolonged median PFS by 7.2 weeks compared with isatuximab alone. Trial simulations support the approved isatuximab 20 mg/kg qw-q2w regimen when administered as a single agent and in combination with dexamethasone in Japanese patients., (© 2023 The Authors. CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

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., (© 2022 The Authors. CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

Aims: Addition of isatuximab (Isa) to pomalidomide/dexamethasone (Pd) significantly improved progression-free survival (PFS) in patients with relapsed/refractory multiple myeloma (RRMM). We aimed to characterize the relationship between serum M-protein kinetics and PFS in the phase 3 ICARIA-MM trial (NCT02990338), and to evaluate an alternative dosing regimen of Isa by simulation., Methods: Data from the ICARIA-MM trial comparing Isa 10 mg/kg weekly for 4 weeks then every 2 weeks (QW-Q2W) in combination with Pd versus Pd in 256 evaluable RRMM patients were used. A joint model of serum M-protein dynamics and PFS was developed. Trial simulations were then performed to evaluate whether efficacy is maintained after switching to a monthly dosing regimen., Results: The model identified instantaneous changes (slope) in serum M-protein as the best on-treatment predictor for PFS and baseline patient characteristics impacting serum M-protein kinetics (albumin and β2-microglobulin on baseline levels, non-IgG type on growth rate) and PFS (presence of plasmacytomas). Trial simulations demonstrated that switching to a monthly Isa regimen at 6 months would shorten median PFS by 2.3 weeks and induce 42.3% patients to progress earlier., Conclusions: Trial simulations supported selection of the approved Isa 10 mg/kg QW-Q2W regimen and showed that switching to a monthly regimen after 6 months may reduce clinical benefit in the overall population. However, patients with good prognostic characteristics and with a stable, very good partial response may switch to a monthly regimen after 6 months without compromising the risk of disease progression. This hypothesis will be tested in a prospective clinical trial., (© 2021 Sanofi R&D. British Journal of Clinical Pharmacology published by John Wiley & Sons Ltd on behalf of British Pharmacological Society.)

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., (© 2021 The Authors. CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

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. β2-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., (© 2020 The Authors. CPT: Pharmacometrics & Systems Pharmacology published by Wiley Periodicals LLC on behalf of American Society for Clinical Pharmacology and Therapeutics.)

This phase 1b dose-escalation study evaluated isatuximab plus pomalidomide/dexamethasone in patients with relapsed/refractory multiple myeloma (RRMM). Patients who had received ≥2 prior MM therapies, including lenalidomide and a proteasome inhibitor (PI), were enrolled and received isatuximab at 5, 10, or 20 mg/kg (weekly for 4 weeks, followed by every 2 weeks), pomalidomide 4 mg (days 1-21), and dexamethasone 40 mg (weekly) in 28-day cycles until progression/intolerable toxicity. The primary objective was to determine the safety and recommended dose of isatuximab with this combination. Secondary objectives included evaluation of pharmacokinetics, immunogenicity, and efficacy. Forty-five patients received isatuximab (5 [n = 8], 10 [n = 31], or 20 [n = 6] mg/kg). Patients received a median of 3 (range, 1-10) prior lines; most were refractory to their last regimen (91%), with 82% lenalidomide-refractory and 84% PI-refractory. Median treatment duration was 9.6 months; 19 patients (42%) remain on treatment. Most common adverse events included fatigue (62%), and upper respiratory tract infection (42%), infusion reactions (42%), and dyspnea (40%). The most common grade ≥3 treatment-emergent adverse event was pneumonia, which occurred in 8 patients (17.8%). Hematologic laboratory abnormalities were common (lymphopenia, leukopenia, anemia, 98% each; neutropenia, 93%; and thrombocytopenia, 84%). Overall response rate was 62%; median duration of response was 18.7 months; median progression-free survival was 17.6 months. These results demonstrate potential meaningful clinical activity and a manageable safety profile of isatuximab plus pomalidomide/dexamethasone in heavily pretreated patients with RRMM. The 10 mg/kg weekly/every 2 weeks isatuximab dose was selected for future studies. This trial was registered at www.clinicaltrials.gov as #NCT02283775., (© 2019 by The American Society of Hematology.)

The HGF/MET pathway is frequently activated in a variety of cancer types. Several selective small molecule inhibitors of the MET kinase are currently in clinical evaluation, in particular for NSCLC, liver, and gastric cancer patients. We report herein the discovery of a series of triazolopyridazines that are selective inhibitors of wild-type (WT) MET kinase and several clinically relevant mutants. We provide insight into their mode of binding and report unprecedented crystal structures of the Y1230H variant. A multiparametric chemical optimization approach allowed the identification of compound 12 (SAR125844) as a development candidate. In this chemical series, absence of CYP3A4 inhibition was obtained at the expense of satisfactory oral absorption. Compound 12, a promising parenteral agent for the treatment of MET-dependent cancers, promoted sustained target engagement at tolerated doses in a human xenograft tumor model. Preclinical pharmacokinetics conducted in several species were predictive for the observed pharmacokinetic behavior of 12 in cancer patients.

Purpose: To develop a population pharmacokinetic (PK) model for cabazitaxel in patients with advanced solid tumors and examine the influence of demographic and baseline parameters., Methods: One hundred and seventy patients who received cabazitaxel (10-30 mg/m(2), 1-h IV infusion) every 7 or 21 days in five Phase I-III studies were analyzed by non-linear mixed-effect modeling (NONMEM VI). Model evaluation comprised non-parametric bootstrap and visual predictive checks., Results: Cabazitaxel PK was best described by a linear three-compartment model with: first-order elimination; interindividual variability on clearance (CL), central volume of distribution (V1), and all intercompartmental rate constants except K21; interoccasion variability in CL and V1; proportional residual error of 27.8%. Cabazitaxel CL was related to body surface area (BSA) and tumor type (breast cancer; finding confounded by study). Typical CL for a non-breast cancer patient with a BSA of 1.84 m(2) was 48.5 L/h, with V1 26.0 L, steady-state volume of distribution 4,870 L and alpha, beta, and gamma half-lives of 4.4 min, 1.6, and 95 h, respectively. Sex, height, weight, age, Caucasian race, renal/hepatic function, and cytochrome P450 inducer use did not significantly further explain the PK of cabazitaxel. Bootstrap and posterior predictive checks confirmed the adequacy of the model., Conclusions: Cabazitaxel PK appears unaffected by most baseline patient factors, and the influence of BSA on CL is addressed in practice by BSA-dependent doses. This analysis suggests consistent cabazitaxel PK and exposure across most solid tumor types, although the potential influence of breast cancer on CL requires further confirmation.

Purpose: To assess the feasibility of administering XRP6258, a new taxane with a low affinity for the multidrug resistance 1 protein, as a 1-hour i.v. infusion every 3 weeks. The study also sought to determine the maximum tolerated dose and the recommended dose, to describe the pharmacokinetic (PK) behavior of the compound, and to seek preliminary evidence of anticancer activity., Experimental Design: Twenty-five patients with advanced solid malignancies were treated with 102 courses of XRP6258 at four dose levels ranging from 10 to 25 mg/m(2). Dose escalation was based on the occurrence of dose-limiting toxicity (DLT) at each dose level, provided that PK variables were favorable. The maximum tolerated dose was defined as the dose at which at least two patients developed a DLT at the first course., Results: Neutropenia was the principal DLT, with one patient experiencing febrile neutropenia and two others showing prolonged grade 4 neutropenia at the 25 mg/m(2) dose level. Nonhematologic toxicities, including nausea, vomiting, diarrhea, neurotoxicity, and fatigue, were generally mild to moderate in severity. XRP6258 exhibited dose-proportional PK, a triphasic elimination profile, a long terminal half-life (77.3 hours), a high clearance (mean CL, 53.5 L/h), and a large volume of distribution (mean V(ss), 2,034 L/m(2)). Objective antitumor activity included partial responses in two patients with metastatic prostate carcinoma, one unconfirmed partial response, and two minor responses., Conclusion: The recommended phase II dose of XRP6258 on this schedule is 20 mg/m(2). The general tolerability and encouraging antitumor activity in taxane-refractory patients warrant further evaluations of XRP6258.

Purpose: To assess the maximum tolerated dose, dose-limiting toxicity, pharmacokinetics, and preliminary antitumor activity of oral irinotecan given in combination with capecitabine to patients with advanced, refractory solid tumors., Patients and Methods: Patients were treated from day 1 with irinotecan capsules given once daily for 5 consecutive days (50 to 60 mg/m2/d) concomitantly with capecitabine given twice daily for 14 consecutive days (800 to 1,000 mg/m2); cycles were repeated every 21 days., Results: Twenty-eight patients were enrolled and received 155 cycles of therapy (median, five cycles; range, one to 18 cycles). With irinotecan 60 mg/m2/d and capecitabine 2 x 800 mg/m2/d, grade 3 delayed diarrhea in combination with grade 2 nausea (despite maximal antiemetic support) and grade 3 anorexia and colitis, were the first-cycle dose-limiting toxicities in two of six patients, respectively. At the recommended doses (irinotecan 50 mg/m2/d; capecitabine 2 x 1,000 mg/m2/d), side effects were mostly mild to moderate and uniformly reversible. Pharmacokinetic analysis showed that there was no interaction between oral irinotecan and capecitabine, and that body-surface area was not significantly contributing to the observed pharmacokinetic variability. Confirmed partial responses were observed in two patients with gallbladder carcinoma and in one patient with melanoma. Disease stabilization was noted in 16 patients., Conclusion: The recommended phase II doses for oral irinotecan and capecitabine are 50 mg/m2/d for 5 consecutive days, and 2 x 1,000 mg/m2/d for 14 consecutive days repeated every 3 weeks, respectively.