The phase IIIb OPINION trial (NCT03402841) investigated olaparib maintenance monotherapy in patients without a deleterious or suspected deleterious germline BRCA1/BRCA2 mutation (gBRCAm) who had platinum-sensitive relapsed ovarian cancer (PSROC) and had received ≥2 previous lines of platinum-based chemotherapy. In this single-arm, open-label, international study, patients who had responded to platinum-based chemotherapy received maintenance olaparib tablets (300 mg twice daily) until disease progression or unacceptable toxicity. The primary endpoint was investigator-assessed progression-free survival (PFS) (modified RECIST version 1.1). A key secondary endpoint was PFS by homologous recombination deficiency (HRD) and somatic BRCAm (sBRCAm) status. The primary analysis of PFS was planned for 18 months after the last patient received their first dose. Two hundred and seventy-nine patients were enrolled and received olaparib. At data cutoff (October 2, 2020), 210 PFS events had occurred (75.3% maturity) and median PFS was 9.2 months (95% confidence interval [CI], 7.6-10.9) in the overall population. At 12 and 18 months, 38.5% and 24.3% of patients were progression-free, respectively. In the predefined biomarker subgroups, median PFS was 16.4, 11.1, 9.7, and 7.3 months in sBRCAm, HRD-positive including sBRCAm, HRD-positive excluding sBRCAm, and HRD-negative patients, respectively. The most common treatment-emergent adverse events (TEAEs) were nausea (48.4%) and fatigue/asthenia (44.1%). TEAEs led to dose interruption, dose reduction, and treatment discontinuation in 47.0%, 22.6%, and 7.5% of patients, respectively. Maintenance olaparib demonstrated clinical benefit in patients without a gBRCAm, and across all subgroups, compared with historical placebo controls. There were no new safety signals.

Early stages are under-represented in studies on the molecular and immune features of high-grade serous ovarian carcinoma (HGSOC), and specific studies focused on early-stage HGSOC are required for a better prognostic stratification and to personalize chemotherapy. The aim of this study was to determine the prognostic significance of CD8+ and CD4+ tumor-infiltrating lymphocytes (TILs), tumoral cell PD-L1 expression, BRCA mutational status and tumor mutation burden (TMB) in early-stage HGSOC. A retrospective study was performed on stage I and II HGSOC from the Molecular Reclassification of Early Stages of Ovarian Cancer (RECLAMO) cohort from the Spanish Group of Ovarian Cancer Research (GEICO). Centralized histological typing was performed based on morphological and immunohistochemical features. Intraepithelial (i) and stromal (s) CD8+ and CD4+ T cells and PD-L1 were evaluated on tissue microarrays by immunohistochemistry. BRCA1 and BRCA2 mutation status and TMB were analyzed in tumor DNA using next-generation sequencing. The study included 124 tumors. High iCD8+ (>20 TILs/core), low/intermediate CD4+ (35/core) were associated with favorable outcomes. Tumor cell PD-L1 expression (TPS ≥ 1) was present in only 8% of tumors. In total, 11 (16%) and 6 (9%) out of 69 HGSOC tested carried pathogenic or likely pathogenic BRCA1 or BRCA2 mutations, respectively. Median TMB of 40 tumors analyzed was 5.04 mutations/Mb and only 6 tumors had 10 or more mutations/Mb. BRCA status and TMB were not associated with TILs or prognosis. When compared with studies on advanced HGSOC, our results suggested that prognostic variables differed according to stage and that more studies focused on early stages of HGSOC are needed to better stratify these tumors.

The poly (ADP-Ribose) polymerase (PARP) inhibitor olaparib has shown antitumor activity in patients with ovarian or breast cancer with or without BRCA1/2 mutations. Lurbinectedin is an ecteinascidin that generates DNA double-strand breaks. We hypothesized that the combination of olaparib and lurbinectedin maximizes the DNA damage increasing the efficacy. A 3 + 3 dose-escalation study examined olaparib tablets with lurbinectedin every 21 days. The purpose of this phase I study is to determine the dose-limiting toxicities (DLTs) of the combination, to investigate the maximum tolerated dose (MTD), the recommended phase II dose (RP2D), efficacy, pharmacokinetics, in addition to genotyping and translational studies. In total, 20 patients with ovarian and endometrial cancers were included. The most common adverse events were asthenia, nausea, vomiting, constipation, abdominal pain, neutropenia, anemia. DLT grade 4 neutropenia was observed in two patients in dose level (DL) 5, DL4 was defined as the MTD, and the RP2D was lurbinectedin 1.5 mg/m² + olaparib 250 mg twice a day (BID). Mutational analysis revealed a median of 2 mutations/case, 53% of patients with mutations in the homologous recombination (HR) pathway. None of the patients reached a complete or partial response; however, 60% of stable disease was achieved. In conclusion, olaparib in combination with lurbinectedin was well tolerated with a disease control rate of 60%. These results deserve further evaluation of the combination in a phase II trial.

We hypothesized that the combination of olaparib and lurbinectedin maximizes DNA damage, thus increasing its efficacy. The POLA phase 1 trial established the recommended phase 2 dose of lurbinectedin as being 1.5 mg (day 1) and that of olaparib as being 250 mg/12 h (days 1–5) for a 21-day cycle. In phase 2, we explore the efficacy of the combination in terms of clinical response and its correlation with mutations in the HRR genes and the genomic instability (GI) parameters. Results: A total of 73 patients with high-grade ovarian (n = 46), endometrial (n = 26), and triple-negative breast cancer (n = 1) were treated with lurbinectedin and olaparib. Most patients (62%) received ≥3 lines of prior therapy. The overall response rate (ORR) and disease control rate (DCR) were 9.6% and 72.6%, respectively. The median progression-free survival (PFS) was 4.54 months (95% CI 3.0–5.2). Twelve (16.4%) patients were considered long-term responders (LTR), with a median PFS of 13.3 months. No clinical benefit was observed for cases with HRR gene mutation. In ovarian LTRs, although a direct association with GI and a total loss of heterozygosity (LOH) events was observed, the association did not reach statistical significance (p = 0.055). Globally, the total number of LOHs might be associated with the ORR (p =0.074). The most common grade 3–4 toxicities were anemia and thrombocytopenia, in 6 (8.2%) and 3 (4.1%) patients, respectively. Conclusion: The POLA study provides evidence that the administration of lurbinectedin and olaparib is feasible and tolerable, with a DCR of 72.6%. Different GI parameters showed associations with better responses.

The poly(ADP-ribose) polymerase inhibitor olaparib (Lynparza™) is approved for maintenance treatment of platinum-sensitive relapsed ovarian cancer. OPINION is a single-arm, open-label, multicenter,... Lay abstract The poly(ADP-ribose) polymerase inhibitor olaparib (Lynparza™) is approved for treatment of platinum-sensitive relapsed ovarian cancer following platinum chemotherapy, with the greates...