Clinical and molecular characteristics of AMBITION patients who received olaparib plus cediranib or olaparib plus durvalumab for homologous recombination repair mutated, platinum-resistant ovarian cancer (KGOG 3045) (032)

Abstract

Objectives: AMBITION is a multi-center, open-label, five-arm, uncontrolled, umbrella trial in platinum-resistant ovarian cancer patients (NCT03699449). Here, we present an exploratory analysis of clinical and molecular characteristics associated with the benefit of two olaparib-based regimens in the homologous recombination repair (HRR) gene mutation cohort. Methods: Between December 2018 and October 2020, 30 patients who had mutations in HRR genes were randomized, and received either olaparib 200mg bid + cediranib 30mg QD (arm 1; n=16) or olaparib 300mg bid + durvalumab 1500mg q4w (arm 2; n=14). From the pre-treatment biopsy (n=22) and archival (n=8) tumor samples, next-generation whole-exome and whole-transcriptomic sequencing were conducted. We also evaluated tumor immunologic signatures, including the PD-L1 (SP263) assay and tumor-infiltrating lymphocytes (TILs). Clinical and molecular features were compared between responders and non-responders. Results: Arms 1 and 2 showed an acceptable objective response rate at 50.0% and 42.9%, respectively. The responders (n=14) had 12.4 months of a median duration of response. Overall, no differences in serum CA-125 levels, ECOG performance status, histologic subtype, prior lines of therapy, and last treatment-free interval were observed between the responders and non-responders. Intratumoral TILs and stromal TILs were also similar between the responders and non-responders. While all responders had BRCA1/2 mutations, 54.5% of non-responders had BRCA1/2 mutations. DNA damage repair pathways were enriched in the responders. Especially, enrichment of DNA mismatch repair and nucleotide excision repair pathways were associated with prolonged progression-free survival (PFS). In arm 1, cell cycle pathway enrichment significantly improved PFS (p=0.006), but PD-L1 expression did not. In arm 2, patients with PD-L1 ≥1% of tumor cells showed significantly better PFS than those with PD-L1 <1% (p=0.027), and the responders had a significantly higher level of myeloid-derived suppressor cell recruiting score than the non-responders (p=0.041). Objectives: AMBITION is a multi-center, open-label, five-arm, uncontrolled, umbrella trial in platinum-resistant ovarian cancer patients (NCT03699449). Here, we present an exploratory analysis of clinical and molecular characteristics associated with the benefit of two olaparib-based regimens in the homologous recombination repair (HRR) gene mutation cohort. Methods: Between December 2018 and October 2020, 30 patients who had mutations in HRR genes were randomized, and received either olaparib 200mg bid + cediranib 30mg QD (arm 1; n=16) or olaparib 300mg bid + durvalumab 1500mg q4w (arm 2; n=14). From the pre-treatment biopsy (n=22) and archival (n=8) tumor samples, next-generation whole-exome and whole-transcriptomic sequencing were conducted. We also evaluated tumor immunologic signatures, including the PD-L1 (SP263) assay and tumor-infiltrating lymphocytes (TILs). Clinical and molecular features were compared between responders and non-responders. Results: Arms 1 and 2 showed an acceptable objective response rate at 50.0% and 42.9%, respectively. The responders (n=14) had 12.4 months of a median duration of response. Overall, no differences in serum CA-125 levels, ECOG performance status, histologic subtype, prior lines of therapy, and last treatment-free interval were observed between the responders and non-responders. Intratumoral TILs and stromal TILs were also similar between the responders and non-responders. While all responders had BRCA1/2 mutations, 54.5% of non-responders had BRCA1/2 mutations. DNA damage repair pathways were enriched in the responders. Especially, enrichment of DNA mismatch repair and nucleotide excision repair pathways were associated with prolonged progression-free survival (PFS). In arm 1, cell cycle pathway enrichment significantly improved PFS (p=0.006), but PD-L1 expression did not. In arm 2, patients with PD-L1 ≥1% of tumor cells showed significantly better PFS than those with PD-L1 <1% (p=0.027), and the responders had a significantly higher level of myeloid-derived suppressor cell recruiting score than the non-responders (p=0.041).