Macé, Sandrine

BACKGROUND Predictive biomarkers to guide chemotherapy decisions for metastatic castration–resistant prostate cancer (mCRPC) are lacking. Preclinical studies indicate that circulating tumor cell (CTC) studies of chromosomal instability (CTC-CIN) can predict taxane resistance. METHODS The CARD trial randomized individuals with mCRPC progressing within a year of treatment with an androgen receptor pathway inhibitor (ARPI; enzalutamide or abiraterone acetate plus prednisolone/prednisone) to cabazitaxel or the alternative ARPI. As a preplanned biomarker analysis, CTCs were isolated from blood samples obtained at baseline, cycle 2, and the end of treatment. Associations between baseline CTC and CTC-CIN counts with imaging-based progression-free survival (ibPFS), overall survival (OS), time to prostate-specific antigen (PSA) progression, RECIST 1.1 objective response rate (ORR), and PSA 50 response rate were assessed. RESULTS High baseline CTC-CIN counts significantly associated with worse OS after adjustment for confounding variables (median OS, 15.3 vs. 8.9 months; univariate HR, 2.16; 95% CI, 1.52–3.06; P < 0.001; multivariate HR, 1.56; 95% CI, 1.01–2.43; P = 0.047). Detectable CTC-CIN counts at baseline may predict a lack of ibPFS and OS benefit when comparing cabazitaxel with ARPI. CONCLUSION This preplanned analysis of biomarker data from the CARD trial confirms that CTC-CIN counts are a clinically useful prognostic and predictive biomarker of taxane resistance in mCRPC. Detectable CTC-CIN at baseline defines a patient subpopulation with unmet clinical needs in which alternative therapeutics should be tested. TRIAL REGISTRATION ClinicalTrials.gov number NCT02485691. FUNDING Funded by Sanofi and Epic Sciences.

Abstract Background: Chromosomal instability (CIN) is frequent in patients with metastatic castration-resistant prostate cancer (mCRPC) and determines taxane resistance. A circulating tumor cell (CTC) assay which morphologically identifies CTCs with CIN (CTC-CIN) from a single tube of whole blood could predict clinical outcomes in this population. We tested this hypothesis as a pre-planned, secondary outcome of the CARD trial, where patients with mCRPC progressing within a year of treatment with an androgen receptor pathway inhibitor (ARPI; enzalutamide or abiraterone acetate + prednisolone/prednisone) were randomized to treatment with cabazitaxel or the alternative ARPI. Methods: CTCs were isolated from blood samples obtained at baseline; cycle two, and end of treatment. The associations of baseline CTC and counts with imaging-based progression free survival (ibPFS), overall survival (OS), time to prostate-specific antigen (PSA) progression, RECIST 1.1 objective response rate (ORR), and PSA50 response rate (PRR) were assessed. Results: Of 255 patients randomized, CTC counts were acquired from 237 patients at screening, 213 patients at C2D1, and 166 patients at EOT. High baseline CTC counts were significantly associated with worse OS (median OS, 14.9 vs 9.8 months; univariate HR, 1.81; 95% CI, 1.30 - 2.51; p &lt; 0.001). High baseline CTC-CIN counts were significantly associated with worse OS after adjustment for confounding variables (median OS, 15.3 vs 8.9 months; univariate HR, 2.16; 95% CI, 1.52 - 3.06; p &lt; 0.001; multivariate HR, 1.56; 95% CI, 1.01 - 2.43; p = 0.047). Low CTC-CIN at baseline predicted ibPFS, ORR, and PRR benefit with cabazitaxel; conversely, high at baseline predicted no different ibPFS or OS outcomes with cabazitaxel or a second ARPI. Conclusions: This preplanned biomarker analysis of CARD confirmed that CTC-CIN counts are prognostic for OS and may be predictive of cabazitaxel benefit. (Funded by Sanofi and Epic Sciences; CARD ClinicalTrials.gov number, NCT02485691.) Citation Format: Ossian Longoria, Jan Rekowski, Santosh Gupta, Nick Beije, Klaus Pantel, Eleni Efstathiou, Cora Sternberg, Daniel Castellano, Karim Fizazi, Bertrand Tombal, Adam Sharp, Oliver Sartor, Sandrine Mace, Christine Geffriaud-Ricouard, Richard Wenstrup, Ronald de Wit, Johann de Bono. Morphological evaluation of chromosomal instability in circulating tumor cells and prediction of taxane resistance in metastatic prostate cancer: a prespecified sub-analysis of the CARD trial [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 1145

AbstractObjectivesCluster of differentiation 38 (CD38) is a key target on multiple myeloma (MM) cells. This multi‐centre, Phase 1, single‐agent study (NCT04000282) investigated SAR442085, a novel fragment crystallisable (Fc)‐modified anti‐CD38 monoclonal antibody (mAb), with enhanced affinity towards Fc‐gamma receptor on effector cells in patients with relapsed and/or refractory (RR) MM.MethodsThis study comprised two parts: Part‐A (dose‐escalation involving anti‐CD38 mAb pre‐treated and naïve patients) and Part‐B (dose expansion). Primary endpoints were maximum tolerated dose and recommended Phase 2 dose (RP2D).ResultsThirty‐seven heavily pre‐treated patients were treated in Part A. Part‐B (dose‐expansion) was not studied. Seven dose‐limiting toxicities were reported at DL3, DL5, DL6, and DL7. RP2D was determined to be 5–7·5 mg/kg. Most common treatment‐emergent adverse events were infusion‐related reactions in 70·3% (26/37) patients. Grade ≥3 thrombocytopenia was reported in 48·6% (18/37). Overall response rate was 70% in anti‐CD38 mAb naïve and 4% in anti‐CD38 pre‐treated patients, with a median progression‐free survival of 7·62 (95%CI: 2·858; not calculable) months and 2·79 (95%CI: 1·150; 4·172) months and, respectively.ConclusionsThe efficacy of SAR442085 was promising in anti‐CD38 mAb naïve patients but did not extend to the larger cohort of anti‐CD38 mAb pre‐treated patients. This observation, along with transient high‐grade thrombocytopenia, could potentially limit its clinical use.

8004 Background: The primary objective of this phase 3 trial was to demonstrate progression free survival (PFS) improvement of isatuximab (Isa), a novel anti-CD38 monoclonal antibody, combined with pomalidomide (P)/dexamethasone (d) versus (vs) Pd. Methods: Patients (pts) with RRMM who received ≥2 prior lines, including lenalidomide (len) and a proteasome inhibitor (PI), refractory to last therapy were enrolled. IsaPd arm received Isa 10 mg/kg IV weekly for first 4 weeks (wks), then every 2 wks. Both arms received approved schedules of pom and dex (4mg PO days 1-21; 40mg [20mg if >75 yrs] PO or IV weekly) every 28 days until progression or unacceptable toxicity. Results: 307 pts (154 IsaPd, 153 Pd) were randomized and analyzed (ITT). Patient characteristics were well balanced across arms. Median age: 67 (36-86) yrs; median prior lines of therapy: 3 (2-11); estimated GFR: <60ml/min in 33.9% pts; 92.5% refractory to len, 75.9% to PI; and 19.5% pts had high-risk cytogenetics. At median follow-up of 11.6 months (mos), median PFS was 11.5 mos IsaPd vs 6.5 mos Pd; HR 0.596 (95% CI 0.44-0.81), P=0.001. PFS benefit was consistent across all major subgroups. ORR (≥PR) was 60.4% IsaPd vs 35.3% Pd, P<0.0001. VGPR rate or better was 31.8% IsaPd vs 8.5% Pd, and MRD negativity (NGS, 10-5) was seen in 5.2% IsaPd pts vs 0% Pd. At analysis date, overall survival (OS) was immature (99 events) but a trend to OS improvement in IsaPd (vs Pd) was observed (HR 0.687; 95% CI 0.461-1.023). Median treatment duration was 41 wks IsaPd vs 24 wks Pd; median Isa infusion (inf.) duration was 3.3h at 1st inf. and 2.8h at subsequent inf. Grade ≥3 AEs were observed in 86.8% IsaPd vs 70.5% Pd; 7.2% IsaPd and 12.8% Pd pts discontinued due to AEs; 7.9% IsaPd and 9.4% Pd pts died due to AEs. Inf. reactions were reported in 38.2% (2.6% grade 3-4) IsaPd. Grade ≥3 infections were seen in 42.8% IsaPd and 30.2% Pd, grade ≥3 neutropenia in 84.9% (febrile 11.8%) IsaPd and 70.1% (febrile 2.0%) Pd. Conclusions: IsaPd significantly improved PFS and ORR vs Pd, with a manageable safety profile. IsaPd is an important new treatment option for the management of RRMM. Clinical trial information: NCT02990338.

Background:Despite recent advances, multiple myeloma (MM) remains incurable, and new treatment options are needed to continue to improve patient outcomes. This is the first randomized, phase 3 trial of an anti‐CD38 antibody in combination with pomalidomide (P) and dexamethasone (d) in RRMM.Aims:The primary objective of this phase 3 trial (NCT02990338) was to demonstrate progression free survival (PFS) improvement of isatuximab (Isa), a novel anti‐CD38 monoclonal antibody targeting a specific epitope, combined with Pd versus (vs) Pd in RRMM.Methods:Patients (pts) with RRMM who received ≥2 prior lines, including lenalidomide (len) and a proteasome inhibitor (PI), refractory to last therapy were enrolled. IsaPd arm received Isa 10 mg/kg IV weekly for first 4 weeks (wks), then every 2 wks. Both arms received approved schedules of pom and dex (4 mg PO days 1–21; 40 mg [20 mg if >75 yrs] PO or IV weekly) every 28 days until progression or unacceptable toxicity.Results:307 pts (154 IsaPd, 153 Pd) were randomized and analyzed (ITT). Patient characteristics were well balanced across arms. Median age: 67 (36–86) yrs; median prior lines of therapy: 3 (2–11); estimated GFR: <60 ml/min in 33.9% pts; 92.5% refractory to len, 75.9% to PI; and 19.5% pts had high‐risk cytogenetics. At median follow‐up of 11.6 months (mos), median PFS was 11.5 mos IsaPd vs 6.5 mos Pd; HR 0.596 (95% CI 0.44–0.81), P = 0.001. PFS benefit was consistent across all major subgroups. ORR (≥PR) was 60.4% IsaPd vs 35.3% Pd, P < 0.0001. VGPR rate or better was 31.8% IsaPd vs 8.5% Pd, and MRD negativity (NGS, 10−5) was seen in 5.2% IsaPd pts vs 0% Pd. At analysis date, overall survival (OS) was immature (99 events) but a trend to OS improvement in IsaPd (vs Pd) was observed (HR 0.687; 95% CI 0.461–1.023). Median treatment duration was 41 wks IsaPd vs 24 wks Pd; median Isa infusion (inf.) duration was 3.3 h at 1st inf. and 2.8 h at subsequent inf. Grade ≥3 AEs were observed in 86.8% IsaPd vs 70.5% Pd; 7.2% IsaPd and 12.8% Pd pts discontinued due to AEs; 7.9% IsaPd and 9.4% Pd pts died due to AEs. Inf. reactions were reported in 38.2% (2.6% grade 3–4) IsaPd. Grade ≥3 infections were seen in 42.8% IsaPd and 30.2% Pd, grade ≥3 neutropenia in 84.9% (febrile 11.8%) IsaPd and 70.1% (febrile 2.0%) Pd.Summary/Conclusion:Isatuximab in combination with pomalidomide and dexamethasone significantly improved PFS and ORR vs pomalidomide and dexamethasone, with a manageable safety profile. Isatuximab in combination with pomalidomide and dexamethasone is an important new treatment option for the management of RRMM.