Poor Concordance Between Cancer Antigen-125 and RECIST Assessment for Progression in Patients With Platinum-Sensitive Relapsed Ovarian Cancer on Maintenance Therapy With a Poly(ADP-ribose) Polymerase Inhibitor

PURPOSE

Cancer antigen-125 (CA-125) is recommended by treatment guidelines and widely used to diagnose ovarian cancer recurrence. The value of CA-125 as a surrogate for disease progression (PD) and its concordance with radiologic progression are unclear, particularly for women with platinum-sensitive relapsed ovarian cancer (PSROC) who have responded to chemotherapy and treated with maintenance poly(ADP-ribose) polymerase inhibitor (PARPi).

METHODS

In this pooled analysis of four randomized trials of maintenance PARPi or placebo (Study 19, SOLO2, ARIEL3, and NOVA), we extracted data on CA-125 PD as defined by Gynecologic Cancer InterGroup criteria and RECIST v1.1. We evaluated the concordance between CA-125 and RECIST PD and reported on the negative predictive value (NPV) and positive predictive value (PPV).

RESULTS

Of 1,262 participants (n = 818 PARPi, n = 444 placebo), 403 (32%) had CA-125 PD, and of these, 366 had concordant RECIST PD (PPV, 91% [95% CI, 88 to 93]). However, of 859 (68%) without CA-125 PD, 382 also did not have RECIST PD (NPV, 44% [95% CI, 41 to 48]). Within the treatment arms, PPV remained high (PARPi, 91% [95% CI, 86 to 94]; placebo, 91% [95% CI, 86 to 95]) but NPV was lower on placebo (PARPi, 53% [95% CI, 49 to 57]; placebo, 25% [95% CI, 20 to 31]). Of 477 with RECIST-only PD, most (95%) had a normal CA-125 at the start of maintenance therapy and the majority (n = 304, 64%) had CA-125 that remained within normal range. Solid organ recurrence without peritoneal disease was more common in those with RECIST-only PD than in those with CA-125 and RECIST PD (36% v 24%; P < .001).

CONCLUSION

In patients with PSROC treated with maintenance PARPi, almost half with RECIST PD did not have CA-125 PD, challenging current guidelines. Periodic computed tomography imaging should be considered as part of surveillance, particularly in those with a normal CA-125 at the start of maintenance therapy and on treatment.

Patient-reported outcomes of maintenance rucaparib in patients with recurrent ovarian carcinoma in ARIEL3, a phase III, randomized, placebo-controlled trial

PURPOSE

To compare NFOSI-18 Disease Related Symptoms - Physical (DRSP), Total score, and side effect bother between maintenance rucaparib (600 mg twice daily) vs. placebo in the phase III ARIEL3 trial.

METHODS

ARIEL3 (NCT01968213) included patients with ovarian carcinoma who responded to second-line or later platinum-based chemotherapy. The NFOSI-18 DRS-P and Total scales were secondary endpoints. The NFOSI-18 contains a side effect impact item (GP5): "I am bothered by side effects of treatment." We compared treatment arms on change from baseline of DRS-P and Total scores using mixed models with repeated measures (MRMM). Time to first and confirmed deterioration of NFOSI-18 DRS-P and Total scales were analyzed using Cox regression. We also calculated the proportion of patients reporting moderate to high side effect bother on GP5.

RESULTS

In the intention-to-treat (ITT) cohort, mean change from baseline favored the placebo. Compared to placebo, rucaparib was associated with higher risk of deterioration [e.g., 4-point deteriorator definition hazard ratio (HR): 1.85; 95% CI: 1.46, 2.36; median time to first deterioration on DRSP: 1.9 vs. 7.0 months]. Confirmed deterioration results resembled those for first deterioration. Proportions of patients reporting moderate/high side effect bother on GP5 fluctuated around 20% across treatment cycles. Results in BRCA mutant and homologous recombination deficient cohorts were generally similar to those from the ITT cohort.

CONCLUSION

This placebo-controlled study in the maintenance therapy setting provides a unique view of the impact of PARP inhibition on the patient-reported outcomes that are commonly used in ovarian cancer clinical trials. Information regarding the adverse side effect impact of PARP inhibitors should be weighed against their clinical benefit.

A Randomized, Phase III Trial to Evaluate Rucaparib Monotherapy as Maintenance Treatment in Patients With Newly Diagnosed Ovarian Cancer (ATHENA-MONO/GOG-3020/ENGOT-ov45)

PURPOSE

ATHENA (ClinicalTrials.gov identifier: NCT03522246) was designed to evaluate rucaparib first-line maintenance treatment in a broad patient population, including those without BRCA1 or BRCA2 (BRCA) mutations or other evidence of homologous recombination deficiency (HRD), or high-risk clinical characteristics such as residual disease. We report the results from the ATHENA-MONO comparison of rucaparib versus placebo.

METHODS

Patients with stage III-IV high-grade ovarian cancer undergoing surgical cytoreduction (R0/complete resection permitted) and responding to first-line platinum-doublet chemotherapy were randomly assigned 4:1 to oral rucaparib 600 mg twice a day or placebo. Stratification factors were HRD test status, residual disease after chemotherapy, and timing of surgery. The primary end point of investigator-assessed progression-free survival was assessed in a step-down procedure, first in the HRD population (BRCA-mutant or BRCA wild-type/loss of heterozygosity high tumor), and then in the intent-to-treat population.

RESULTS

As of March 23, 2022 (data cutoff), 427 and 111 patients were randomly assigned to rucaparib or placebo, respectively (HRD population: 185 v 49). Median progression-free survival (95% CI) was 28.7 months (23.0 to not reached) with rucaparib versus 11.3 months (9.1 to 22.1) with placebo in the HRD population (log-rank P = .0004; hazard ratio [HR], 0.47; 95% CI, 0.31 to 0.72); 20.2 months (15.2 to 24.7) versus 9.2 months (8.3 to 12.2) in the intent-to-treat population (log-rank P < .0001; HR, 0.52; 95% CI, 0.40 to 0.68); and 12.1 months (11.1 to 17.7) versus 9.1 months (4.0 to 12.2) in the HRD-negative population (HR, 0.65; 95% CI, 0.45 to 0.95). The most common grade ≥ 3 treatment-emergent adverse events were anemia (rucaparib, 28.7% v placebo, 0%) and neutropenia (14.6% v 0.9%).

CONCLUSION

Rucaparib monotherapy is effective as first-line maintenance, conferring significant benefit versus placebo in patients with advanced ovarian cancer with and without HRD.

Clinical and molecular characteristics of ARIEL3 patients who derived exceptional benefit from rucaparib maintenance treatment for high-grade ovarian carcinoma

OBJECTIVE

ARIEL3 (NCT01968213) is a placebo-controlled randomized trial of the poly(ADP-ribose) polymerase inhibitor rucaparib as maintenance treatment in patients with recurrent high-grade ovarian carcinoma who responded to their latest line of platinum therapy. Rucaparib improved progression-free survival across all predefined subgroups. Here, we present an exploratory analysis of clinical and molecular characteristics associated with exceptional benefit from rucaparib.

METHODS

Patients were randomized 2:1 to receive rucaparib 600 mg twice daily or placebo. Molecular features (genomic alterations, BRCA1 promoter methylation) and baseline clinical characteristics were evaluated for association with exceptional benefit (progression-free survival ≥2 years) versus progression on first scan (short-term subgroup) and other efficacy outcomes.

RESULTS

Rucaparib treatment was significantly associated with exceptional benefit compared with placebo: 79/375 (21.1%) vs 4/189 (2.1%), respectively (p < 0.0001). Exceptional benefit was more frequent among patients with favorable baseline clinical characteristics and with carcinomas harboring molecular evidence of homologous recombination deficiency (HRD). A comparison between patients who derived exceptional benefit from rucaparib and those in the short-term subgroup revealed both clinical markers (no measurable disease at baseline, complete response to latest platinum, longer penultimate platinum-free interval) and molecular markers (BRCA1, BRCA2, RAD51C, and RAD51D alterations and genome-wide loss of heterozygosity) significantly associated with exceptional benefit.

CONCLUSIONS

Exceptional benefit in ARIEL3 was more common in, but not exclusive to, patients with favorable clinical characteristics or molecular features associated with HRD. Our results suggest that rucaparib can deliver exceptional benefit to a diverse set of patients with recurrent high-grade ovarian carcinoma.

Preexisting TP53-Variant Clonal Hematopoiesis and Risk of Secondary Myeloid Neoplasms in Patients With High-grade Ovarian Cancer Treated With Rucaparib

IMPORTANCE

A total of 1% to 3% of patients treated with a poly(adenosine diphosphate-ribose) polymerase inhibitor for high-grade ovarian cancer (HGOC) develop therapy-related myeloid neoplasms (t-MNs), which are rare but often fatal conditions. Although the cause of these t-MNs is unknown, clonal hematopoiesis of indeterminate potential (CHIP) variants can increase the risk of primary myeloid malignant neoplasms and are more frequent among patients with solid tumors.

OBJECTIVES

To examine whether preexisting CHIP variants are associated with the development of t-MNs after rucaparib treatment and how these CHIP variants are affected by treatment.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective genetic association study used peripheral blood cell (PBC) samples collected before rucaparib treatment from patients in the multicenter, single-arm ARIEL2 (Study of Rucaparib in Patients With Platinum-Sensitive, Relapsed, High-Grade Epithelial Ovarian, Fallopian Tube, or Primary Peritoneal Cancer) (n = 491; between October 30, 2013, and August 9, 2016) and the multicenter, placebo-controlled, double-blind ARIEL3 (Study of Rucaparib as Switch Maintenance Following Platinum-Based Chemotherapy in Patients With Platinum-Sensitive, High-Grade Serous or Endometrioid Epithelial Ovarian, Primary Peritoneal or Fallopian Tube Cancer) (n = 561; between April 7, 2014, and July 19, 2016), which tested rucaparib as HGOC therapy in the treatment and maintenance settings, respectively. The follow-up data cutoff date was September 1, 2019. Of 1052 patients in ARIEL2 and ARIEL3, PBC samples from 20 patients who developed t-MNs (cases) and 44 randomly selected patients who did not (controls) were analyzed for the presence of CHIP variants using targeted next-generation sequencing. Additional longitudinal analysis was performed on available ARIEL2 samples collected during treatment and at the end of treatment.

MAIN OUTCOMES AND MEASURES

Enrichment analysis of preexisting variants in 10 predefined CHIP-associated genes in cases relative to controls; association with clinical correlates.

RESULTS

Among 1052 patients (mean [SE] age, 61.7 [0.3] years) enrolled and dosed in ARIEL2 and ARIEL3, 22 (2.1%) developed t-MNs. The t-MNs were associated with longer overall exposure to prior platinum therapies (13.2 vs 9.0 months in ARIEL2, P = .04; 12.4 vs 9.6 months in ARIEL3, P = .003). The presence of homologous recombination repair gene variants in the tumor, either germline or somatic, was associated with increased prevalence of t-MNs (15 [4.1%] of 369 patients with HGOC associated with an HRR gene variant vs 7 [1.0%] of 683 patients with wild-type HGOC, P = .002). The prevalence of preexisting CHIP variants in TP53 but not other CHIP-associated genes at a variant allele frequency of 1% or greater was significantly higher in PBCs from cases vs controls (9 [45.0%] of 20 cases vs 6 [13.6%] of 44 controls, P = .009). TP53 CHIP was associated with longer prior exposure to platinum (mean 14.0 months of 15 TP53 CHIP cases vs 11.1 months of 49 non-TP53 CHIP cases; P = .02). Longitudinal analysis showed that preexisting TP53 CHIP variants expanded in patients who developed t-MNs.

CONCLUSIONS AND RELEVANCE

The findings of this genetic association study suggest that preexisting TP53 CHIP variants may be associated with t-MNs after rucaparib treatment.

Characterization of patients with long-term responses to rucaparib treatment in recurrent ovarian cancer

OBJECTIVE

To describe molecular and clinical characteristics of patients with high-grade recurrent ovarian carcinoma (HGOC) who had long-term responses to the poly(ADP-ribose) polymerase (PARP) inhibitor rucaparib.

METHODS

This post hoc analysis pooled patients from Study 10 (NCT01482715; Parts 2A and 2B; n = 54) and ARIEL2 (NCT01891344; Parts 1 and 2; n = 491). Patients with investigator-assessed complete or partial response per RECIST were classified based on duration of response (DOR): long (≥1 year), intermediate (6 months to <1 year), or short (<6 months). Next-generation sequencing was used to detect deleterious mutations and loss of heterozygosity (LOH) in tumors.

RESULTS

Overall, 25.3% (138/545) of enrolled patients were responders. Of these, 27.5% (38/138) had long-term responses; 28.3% (39/138) were intermediate- and 34.8% (48/138) were short-term responders. Most of the long-term responders harbored a BRCA1 or BRCA2 (BRCA) mutation (71.1%, 27/38), and BRCA structural variants were most frequent among long-term responders (14.8%; 4/27). Responders with HGOC harboring a BRCA structural variant (n = 5) had significantly longer DOR than patients with other mutation types (n = 81; median not reached vs 0.62 years; HR, 0.21; 95% CI, 0.10-0.43; unadjusted p = 0.014). Among responders with BRCA wild-type HGOC, most long- and intermediate-term responders had high genome-wide LOH: 81.8% (9/11) and 76.9% (10/13), respectively, including 7 with deleterious RAD51C, RAD51D, or CDK12 mutations.

CONCLUSION

Among patients who responded to rucaparib, a substantial proportion achieved responses lasting ≥1 year. These analyses demonstrate the relationship between DOR to PARP inhibitor treatment and molecular characteristics in HGOC, such as presence of reversion-resistant BRCA structural variants.

ATHENA (GOG-3020/ENGOT-ov45): a randomized, phase III trial to evaluate rucaparib as monotherapy (ATHENA-MONO) and rucaparib in combination with nivolumab (ATHENA-COMBO) as maintenance treatment following frontline platinum-based chemotherapy in ovarian cancer

Background

The optimal treatment strategy for women with newly diagnosed ovarian cancer has yet to be determined. Poly(ADP-ribose) polymerase (PARP) inhibitors have demonstrated substantial improvement in progression-free survival as monotherapy maintenance treatment in the frontline setting versus active surveillance. Furthermore, preclinical and early clinical studies have shown that PARP inhibitors and immune checkpoint inhibitors have synergistic antitumor activity and may provide an additional therapeutic option for patients in this population.

Primary Objectives

In women with newly diagnosed ovarian, fallopian tube, or peritoneal cancer, we wish to assess the efficacy of frontline maintenance treatment with the PARP inhibitor rucaparib versus placebo following response to platinum-based chemotherapy (ATHENA–MONO), and to assess the combination of rucaparib plus nivolumab (a programmed death receptor 1 (PD-1)–blocking monoclonal antibody) versus rucaparib alone (ATHENA–COMBO).

Study Hypothesis

(1) Maintenance therapy with rucaparib monotherapy may extend progression-free survival following standard treatment for ovarian cancer in the frontline setting. (2) The combination of nivolumab plus rucaparib may extend progression-free survival following standard treatment for ovarian cancer in the frontline setting compared with rucaparib alone.

Trial Design

ATHENA is an international, randomized, double-blind, phase III trial consisting of two independent comparisons (ATHENA–MONO and ATHENA–COMBO) in patients with newly diagnosed platinum-sensitive ovarian cancer. Patients are randomized 4:4:1:1 to the following: oral rucaparib+ intravenous nivolumab (arm A); oral rucaparib + intravenous placebo (arm B); oral placebo+ intravenous nivolumab (arm C); and oral placebo + intravenous placebo (arm D). The starting dose of rucaparib is 600 mg orally twice a day and nivolumab 480 mg intravenously every 4 weeks. ATHENA–MONO compares arm B with arm D to evaluate rucaparib monotherapy versus placebo, and ATHENA–COMBO evaluates arm A versus arm B to investigate the effects of rucaparib and nivolumab in combination versus rucaparib monotherapy. ATHENA–MONO and ATHENA–COMBO share a common treatment arm (arm B) but each comparison is independently powered.

Major Inclusion/Exclusion Criteria

Patients ≥18 years of age with newly diagnosed advanced, high-grade epithelial ovarian, primary peritoneal, or fallopian tube cancer who have achieved a response after completion of cytoreductive surgery and initial platinum-based chemotherapy are enrolled. No other prior treatment for ovarian cancer, other than the frontline platinum regimen, is permitted.

Primary Endpoint

The primary endpoint is investigator-assessed progression-free survival by Response Evaluation Criteria in Solid Tumors v1.1.

Sample Size

Approximately 1000 patients have been enrolled and randomized.

Estimated Dates for Completing Accrual and Presenting Results

The trial completed accrual in 2020. While dependent on event rates, primary results of ATHENA–MONO are anticipated in early 2022 and results of ATHENA–COMBO are anticipated to mature at a later date.

Trial Registration

This trial is registered at clinicaltrials.gov (NCT03522246).

Maintenance treatment with rucaparib for recurrent ovarian carcinoma in ARIEL3, a randomized phase 3 trial: The effects of best response to last platinum-based regimen and disease at baseline on efficacy and safety

Background

The efficacy and safety of rucaparib maintenance treatment in ARIEL3 were evaluated in subgroups based on best response to most recent platinum‐based chemotherapy and baseline disease.

Methods

Patients were randomized 2:1 to receive either oral rucaparib at a dosage of 600 mg twice daily or placebo. Investigator‐assessed PFS was assessed in prespecified, nested cohorts: BRCA‐mutated, homologous recombination deficient (HRD; BRCA mutated or wild‐type BRCA/high loss of heterozygosity), and the intent‐to‐treat (ITT) population.

Results

Median PFS for patients in the ITT population with a complete response to most recent platinum‐based chemotherapy was 11.1 months in the rucaparib arm (126 patients) versus 5.6 months in the placebo arm (64 patients) (HR, 0.33 [95% CI, 0.23–0.48]), and in patients with a partial response (249 vs. 125), it was 9.0 versus 5.3 months (HR, 0.38 [0.30–0.49]). In subgroups of the ITT population based on baseline disease, median PFS was 8.2 versus 5.3 months (HR, 0.40 [0.28–0.57]) in patients with measurable disease (141 rucaparib vs. 66 placebo), 10.4 versus 4.5 months (HR, 0.31 [0.20–0.48]) in those with nonmeasurable but evaluable disease (104 vs. 56), and 14.1 versus 7.3 months (HR, 0.35 [0.24–0.51]) in those with no residual disease (130 vs. 67). Across subgroups, significantly longer median PFS was observed with rucaparib versus placebo in the BRCA‐mutated and HRD cohorts. Objective responses were reported in patients with measurable disease and in patients with nonmeasurable but evaluable baseline disease. Safety was consistent across subgroups.

Conclusion

Rucaparib maintenance treatment provided clinically meaningful efficacy benefits across subgroups based on response to last platinum‐based chemotherapy or baseline disease.

Rucaparib maintenance treatment for recurrent ovarian carcinoma: the effects of progression-free interval and prior therapies on efficacy and safety in the randomized phase III trial ARIEL3

INTRODUCTION

In ARIEL3 (NCT01968213), the poly(adenosine diphosphate-ribose) polymerase inhibitor rucaparib significantly improved progression-free survival versus placebo regardless of biomarker status when used as maintenance treatment for recurrent ovarian cancer. The aim of the current analyses was to evaluate the efficacy and safety of rucaparib in subgroups based on progression-free interval following penultimate platinum, number of prior chemotherapies, and prior use of bevacizumab.

METHODS

Patients were randomized 2:1 to rucaparib 600 mg twice daily or placebo. Within subgroups, progression-free survival was assessed in prespecified, nested cohorts: BRCA-mutant, homologous recombination deficient (BRCA-mutant or wild-type BRCA/high genomic loss of heterozygosity), and the intent-to-treat population.

RESULTS

In the intent-to-treat population, median investigator-assessed progression-free survival was 8.2 months with rucaparib versus 4.1 months with placebo (n=151 vs n=76; HR 0.33, 95% CI 0.24 to 0.46, p<0.0001) for patients with progression-free interval 6 to ≤12 months, and 13.6 versus 5.6 months (n=224 vs n=113; HR 0.39, 95% CI 0.30 to 0.52, p<0.0001) for those with progression-free interval >12 months. Median progression-free survival was 10.4 versus 5.4 months (n=231 vs n=124; HR 0.42, 95% CI 0.32 to 0.54, p<0.0001) for patients who had received two prior chemotherapies, and 11.1 versus 5.3 months (n=144 vs n=65; HR 0.28, 95% CI 0.19 to 0.41, p<0.0001) for those who had received ≥3 prior chemotherapies. Median progression-free survival was 10.3 versus 5.4 months (n=83 vs n=43; HR 0.42, 95% CI 0.26 to 0.68, p=0.0004) for patients who had received prior bevacizumab, and 10.9 versus 5.4 months (n=292 vs n=146; HR 0.35, 95% CI 0.28 to 0.45, p<0.0001) for those who had not. Across subgroups, median progression-free survival was also significantly longer with rucaparib versus placebo in the BRCA-mutant and homologous recombination deficient cohorts. Safety was consistent across subgroups.

CONCLUSIONS

Rucaparib maintenance treatment significantly improved progression-free survival versus placebo irrespective of progression-free interval following penultimate platinum, number of lines of prior chemotherapy, and previous use of bevacizumab.

Population exposure-efficacy and exposure-safety analyses for rucaparib in patients with recurrent ovarian carcinoma from Study 10 and ARIEL2

OBJECTIVE

To evaluate correlations between rucaparib exposure and selected efficacy and safety endpoints in patients with recurrent ovarian carcinoma using pooled data from Study 10 and ARIEL2.

METHODS

Efficacy analyses were limited to patients with carcinomas harboring a deleterious BRCA1 or BRCA2 mutation who had received ≥2 prior lines of chemotherapy. Safety was evaluated in all patients who received ≥1 rucaparib dose. Steady-state daily area under the concentration-time curve (AUCss) and maximum concentration (Cmax,ss) for rucaparib were calculated for each patient and averaged by actual dose received over time (AUCavg,ss and Cmax,avg,ss) using a previously developed population pharmacokinetic model.

RESULTS

Rucaparib exposure was dose-proportional and not associated with baseline patient weight. In the exposure-efficacy analyses (n = 121), AUCavg,ss was positively associated with independent radiology review-assessed RECIST response in the subgroup of patients with platinum-sensitive recurrent disease (n = 75, p = 0.017). In the exposure-safety analyses (n = 393, 40 mg once daily to 840 mg twice daily [BID] starting doses), most patients received a 600 mg BID rucaparib starting dose, with 27% and 21% receiving 1 or ≥2 dose reductions, respectively. Cmax,ss was significantly correlated with grade ≥2 serum creatinine increase, grade ≥3 alanine transaminase/aspartate transaminase increase, platelet decrease, fatigue/asthenia, and maximal hemoglobin decrease (p < 0.05).

CONCLUSION

The exposure-response analyses provide support for the approved starting dose of rucaparib 600 mg BID for maximum clinical benefit with subsequent dose modification only following the occurrence of a treatment-emergent adverse event in patients with BRCA-mutated recurrent ovarian carcinoma.

Subgroup analysis of rucaparib versus chemotherapy as treatment for BRCA-mutated, advanced, relapsed ovarian carcinoma: Effect of platinum sensitivity in the randomized, phase 3 study ARIEL4

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Background: In ARIEL4 (NCT02855944), rucaparib significantly improved the primary endpoint of progression-free survival (PFS) vs chemotherapy (CT) in patients with advanced, relapsed ovarian carcinoma (OC) harboring a deleterious BRCA1/2 (BRCA) mutation (median PFS 7.4 [95% CI 7.3–9.1] vs 5.7 [5.5–7.3] months; hazard ratio (HR) 0.64 [95% CI 0.49–0.84]; P=0.001). This prespecified exploratory analysis investigated the effect of platinum sensitivity on the efficacy of rucaparib vs CT in ARIEL4. Methods: Patients were randomized 2:1 to oral rucaparib 600 mg twice daily or CT and stratified based on progression-free interval (≥1 to <6 months = platinum resistant; ≥6 to <12 months = partially platinum sensitive; ≥12 months = fully platinum sensitive). In the CT group, patients with platinum-resistant or partially platinum-sensitive disease received weekly paclitaxel 60–80 mg/m2; patients with fully platinum-sensitive disease received investigator’s choice of platinum-based CT (single-agent carboplatin or cisplatin, or platinum doublet). Patients could crossover from CT to rucaparib following radiologic disease progression. Efficacy endpoints were explored in patients with a confirmed BRCA mutation (patients with a reversion mutation were excluded), based on the randomization strata of platinum sensitivity. Results: The visit cutoff date was September 30, 2020. PFS and objective response rates (ORR) per RECIST v1.1 for rucaparib vs CT across subgroups are presented in the Table. The most common treatment-emergent adverse events in the rucaparib group were anemia/decreased hemoglobin (platinum-resistant patients: rucaparib 47% vs CT 40%; partially platinum-sensitive patients: 63% vs 27%; fully platinum-sensitive patients: 58% vs 20%) and nausea (52% vs 21%; 51% vs 23%; 60% vs 68%). In the intent-to-treat population, 74/116 (64%) patients in the CT group crossed over to receive rucaparib: 39/59 (66%) with platinum-resistant, 25/31 (81%) with partially platinum-sensitive, and 10/26 (38%) with fully platinum-sensitive disease. Conclusions: Results from this exploratory subgroup analysis suggest that rucaparib is a reasonable treatment option for heavily pretreated patients across all platinum sensitivity subgroups. Safety was consistent with prior rucaparib studies. Clinical trial information: NCT02855944. [Table: see text]

Clinical and molecular characteristics of ARIEL3 patients who derived exceptional benefit from rucaparib maintenance treatment for high-grade ovarian cancer (HGOC)

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Background: ARIEL3 is a placebo-controlled randomized trial of the PARP inhibitor (PARPi) rucaparib as maintenance treatment in HGOC patients (pts) who responded to the latest line of platinum therapy (NCT01968213). Rucaparib improved progression-free survival (PFS) across all predefined subgroups. Here, we present an exploratory analysis of clinical and molecular characteristics associated with exceptional benefit from rucaparib. Methods: Pts were randomized 2:1 to receive rucaparib 600 mg BID or placebo. At the data cutoff of Dec 31, 2019, 33/375 (9%) and 1/189 (0.5%) pts were still ongoing and receiving rucaparib or placebo, respectively. Molecular features (genomic alterations, BRCA1 promoter methylation) and baseline clinical characteristics were compared between pts who derived exceptional benefit (PFS ≥2 yrs), and those with disease progression on first scan (≈12 wks; the short-term [ST] subgroup) within each treatment arm. Results: Of 564 pts, 83 (15%) showed exceptional benefit: 79/375 (21%) in the rucaparib arm and 4/189 (2%) in the placebo arm. Within the rucaparib arm, exceptional benefit pts had more favorable clinical prognostic factors at baseline compared with the ST subgroup (Table). While BRCA mutations were enriched in the rucaparib exceptional benefit subgroup, 34/79 (43%) of these pts were BRCA wild type. Among other biomarkers, RAD51C/D mutations were associated with exceptional benefit; low genome-wide loss of heterozygosity was enriched within the ST subgroup; and high BRCA1 methylation was present at similar fractions. Trends were similar in the placebo arm (Table). Conclusions: Exceptional benefit in ARIEL3 was more common in, but not exclusive to, pts with favorable clinical characteristics and known mechanisms of PARPi sensitivity. Our results suggest that rucaparib can deliver exceptional benefit to a diverse set of HGOC pts. Clinical trial information: NCT01968213. [Table: see text]

Molecular and clinical determinants of response and resistance to rucaparib for recurrent ovarian cancer treatment in ARIEL2 (Parts 1 and 2)

ARIEL2 (NCT01891344) is a single-arm, open-label phase 2 study of the PARP inhibitor (PARPi) rucaparib in relapsed high-grade ovarian carcinoma. In this post hoc exploratory biomarker analysis of pre- and post-platinum ARIEL2 samples, RAD51C and RAD51D mutations and high-level BRCA1 promoter methylation predict response to rucaparib, similar to BRCA1/BRCA2 mutations. BRCA1 methylation loss may be a major cross-resistance mechanism to platinum and PARPi. Genomic scars associated with homologous recombination deficiency are irreversible, persisting even as platinum resistance develops, and therefore are predictive of rucaparib response only in platinum-sensitive disease. The RAS, AKT, and cell cycle pathways may be additional modulators of PARPi sensitivity.

Molecular and clinical predictors of improvement in progression-free survival with maintenance PARP inhibitor therapy in women with platinum-sensitive, recurrent ovarian cancer: A meta-analysis

BACKGROUND

The authors performed a meta-analysis to better quantify the benefit of maintenance poly(ADP-ribose) polymerase inhibitor (PARPi) therapy to inform practice in platinum-sensitive, recurrent, high-grade ovarian cancer for patient subsets with the following characteristics: germline BRCA mutation (gBRCAm), somatic BRCA mutation (sBRCAm), wild-type BRCA but homologous recombinant-deficient (HRD), homologous recombinant-proficient (HRP), and baseline clinical prognostic characteristics.

METHODS

Randomized trials comparing a PARPi versus placebo as maintenance treatment were identified from electronic databases. Treatment estimates of progression-free survival were pooled across trials using the inverse variance weighted method.

RESULTS

Four trials included 972 patients who received a PARPi (olaparib, 31%; niraparib, 35%; or rucaparib, 34%) and 530 patients who received placebo. For patients who had germline BRCA1 mutation (gBRCAm1) (N = 471), the hazard ratio (HR) was 0.29 (95% CI, 0.23-0.37); for those who had germline BRCA2 mutation (gBRCAm2) (N = 236), the HR was 0.26 (95% CI, 0.17-0.39); and, for those who had sBRCAm (N = 123), the HR was 0.22 (95% CI, 0.12-0.41). The treatment effect was similar between the gBRCAm and sBRCAm subsets (P = .48). In patients who had wild-type BRCA HRD tumors (excluding sBRCAm; N = 309), the HR was 0.41 (95% CI, 0.31-0.56); and, in those who had wild-type BRCA HRP tumors (N = 346), the HR was 0.64 (95% CI, 0.49-0.83). The relative treatment effect was greater for the BRCAm versus HRD (P = .03), BRCAm versus HRP (P < .00001), and HRD versus HRP (P < .00001) subsets. There was no difference in benefit based on age, response after recent chemotherapy, and prior bevacizumab.

CONCLUSIONS

In platinum-sensitive, recurrent, high-grade ovarian cancer, maintenance PARPi improves progression-free survival for all patient subsets. PARPi therapy has a similar magnitude of benefit for sBRCAm and gBRCAm. Although patients with BRCAm derive the greatest benefit, the absence of a BRCAm or HRD could not be used to exclude patients from maintenance PARPi therapy.

The effect of age on efficacy, safety and patient-centered outcomes with rucaparib: A post hoc exploratory analysis of ARIEL3, a phase 3, randomized, maintenance study in patients with recurrent ovarian carcinoma

BACKGROUND

In the phase 3 trial ARIEL3, maintenance treatment with the poly(ADP-ribose) polymerase (PARP) inhibitor rucaparib provided clinical benefit versus placebo for patients with recurrent, platinum-sensitive ovarian cancer. Here, we evaluate the impact of age on the clinical utility of rucaparib in ARIEL3.

METHODS

Patients with platinum-sensitive, recurrent ovarian carcinoma with ≥2 prior platinum-based chemotherapies who responded to their last platinum-based therapy were enrolled in ARIEL3 and randomized 2:1 to rucaparib 600 mg twice daily or placebo. Exploratory, post hoc analyses of progression-free survival (PFS), patient-centered outcomes (quality-adjusted PFS [QA-PFS] and quality-adjusted time without symptoms or toxicity [Q-TWiST]), and safety were conducted in three age subgroups (<65 years, 65-74 years, and ≥75 years).

RESULTS

Investigator-assessed PFS was significantly longer with rucaparib than placebo in patients aged <65 years (rucaparib n = 237 vs placebo n = 117; median, 11.1 vs 5.4 months; hazard ratio [HR]: 0.33 [95% confidence interval (95% CI) 0.25-0.43]; P < 0.0001) and 65-74 years (n = 113 vs n = 64; median, 8.3 vs 5.3 months; HR 0.43 [95% CI 0.29-0.63]; P < 0.0001) and numerically longer in patients aged ≥75 years (n = 25 vs n = 8; median, 9.2 vs 5.5 months; HR 0.47 [95% CI 0.16-1.35]; P = 0.1593). QA-PFS and Q-TWiST were significantly longer with rucaparib than placebo across all age subgroups. Safety of rucaparib was generally similar across the age subgroups.

CONCLUSIONS

Efficacy, patient-centered outcomes, and safety of rucaparib were similar between age subgroups, indicating that all eligible women with recurrent ovarian cancer should be offered this therapeutic option, irrespective of age. https://clinicaltrials.gov/ct2/show/NCT01968213.

Patient-Centered Outcomes in ARIEL3, a Phase III, Randomized, Placebo-Controlled Trial of Rucaparib Maintenance Treatment in Patients With Recurrent Ovarian Carcinoma

PURPOSE

To investigate quality-adjusted progression-free survival (QA-PFS) and quality-adjusted time without symptoms or toxicity (Q-TWiST) in a post hoc exploratory analysis of the phase III ARIEL3 study of rucaparib maintenance treatment versus placebo.

PATIENTS AND METHODS

Patients with platinum-sensitive, recurrent ovarian carcinoma were randomly assigned to rucaparib (600 mg twice per day) or placebo. QA-PFS was calculated as progression-free survival function × the 3-level version of the EQ-5D questionnaire (EQ-5D-3L) index score function. Q-TWiST analyses were performed defining TOX as the mean duration in which a patient experienced grade ≥ 3 treatment-emergent adverse events (TEAEs) or the mean duration in which a patient experienced grade ≥ 2 TEAEs of nausea, vomiting, fatigue, and asthenia. Q-TWiST was calculated as μTOX × TOX + TWiST, with μTOX calculated using EQ-5D-3L data.

RESULTS

The visit cutoff was Apr 15, 2017. Mean QA-PFS was significantly longer with rucaparib versus placebo in the intent-to-treat (ITT) population (375 randomly assigned to rucaparib v 189 randomly assigned to placebo; difference, 6.28 months [95% CI, 4.85 to 7.47 months]); BRCA-mutant cohort (130 rucaparib v 66 placebo; 9.37 months [95% CI, 6.65 to 11.85 months]); homologous recombination deficient (HRD) cohort (236 rucaparib v 118 placebo; 7.93 months [95% CI, 5.93 to 9.53 months]); and BRCA wild-type/loss of heterozygosity (LOH) low patient subgroup (107 rucaparib v 54 placebo; 2.71 months [95% CI, 0.31 to 4.44 months]). With TOX defined using grade ≥ 3 TEAEs, the difference in mean Q-TWiST (rucaparib v placebo) was 6.88 months (95% CI, 5.71 to 8.23 months), 9.73 months (95% CI, 7.10 to 11.94 months), 8.11 months (95% CI, 6.36 to 9.49 months), and 3.35 months (95% CI, 1.66 to 5.40 months) in the ITT population, BRCA-mutant cohort, HRD cohort, and BRCA wild-type/LOH low patient subgroup, respectively. Q-TWiST with TOX defined using select grade ≥ 2 TEAEs also consistently favored rucaparib.

CONCLUSION

The significant differences in QA-PFS and Q-TWiST confirm the benefit of rucaparib versus placebo in all predefined cohorts.

Characterization of patients (pts) with long-term responses to rucaparib in recurrent ovarian cancer (OC)

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Background: Pts who derive durable benefit from PARP inhibitor treatment may provide insights into improving outcomes. Here we describe long-term responders from Study 10 (NCT01482715) and ARIEL2 (NCT01891344), studies of the PARP inhibitor rucaparib for the treatment of high-grade recurrent OC. Methods: This analysis included pts enrolled in Study 10 (Part 2A: BRCA1 or BRCA2 [ BRCA]-mutant OC, platinum sensitive, 2–4 prior chemotherapies; Part 2B: any platinum status, 3–4 prior chemotherapies) and ARIEL2 (Part 1: BRCA-mutant or wild-type OC, platinum sensitive; Part 2: any platinum status, 3–4 prior chemotherapies). Final results from Study 10 (n = 54) and ARIEL2 (n = 491) were pooled. Long-term responders were defined as pts with duration of response (DOR) > 1 y, and short-term responders as pts with DOR ≤ 20 weeks; responses were evaluated using RECIST. Targeted next-generation sequencing was used to detect deleterious mutations and loss of heterozygosity (LOH) in tumors. BRCA1 methylation was quantified by digital droplet PCR. Results: Overall, 25% (138/545) of enrolled pts were responders. Of these, 29% (40/138) had long-term responses, including 16/138 (12%) with DOR > 2 y; 21% (29/138) were short-term responders. Both groups received a median of 3 prior anticancer therapies. Among patients with BRCA mutations, BRCA homozygous deletion or rearrangement was detected in 15% (4/27) of long-term responders vs 0% (0/15) of short-term responders. In an expanded analysis of the 95 pts with BRCA mutations and confirmed response, pts with BRCA homozygous deletion or rearrangement had significantly longer DOR than pts with other mutation types (median 3.5 vs 0.6 y; HR = 0.30; p = 0.024). There was no apparent difference in BRCA gene or mutation location for long- vs short-term responders. Ten of the 13 long-term responders with BRCA wild-type OC had high genome-wide LOH (≥16% LOH), a genomic scar indicative of homologous recombination deficiency, including OC associated with BRCA1 hypermethylation (n = 2) and RAD51C/D mutations (n = 2). Conclusions: Long-term responders to rucaparib include OC with BRCA mutation, particularly homozygous deletion or rearrangements, which would not be susceptible to somatic reversion mutations, as well as BRCA1 hypermethylation, and RAD51C/D mutations. Clinical trial information: NCT01482715; NCT01891344.

Rucaparib for patients with platinum-sensitive, recurrent ovarian carcinoma (ARIEL3): post-progression outcomes and updated safety results from a randomised, placebo-controlled, phase 3 trial

BACKGROUND

In ARIEL3, rucaparib maintenance treatment significantly improved progression-free survival versus placebo. Here, we report prespecified, investigator-assessed, exploratory post-progression endpoints and updated safety data.

METHODS

In this ongoing (enrolment complete) randomised, placebo-controlled, phase 3 trial, patients aged 18 years or older who had platinum-sensitive, high-grade serous or endometrioid ovarian, primary peritoneal, or fallopian tube carcinoma and an Eastern Cooperative Oncology Group performance status of 0 or 1 who had received at least two previous platinum-based chemotherapy regimens and responded to their last platinum-based regimen were randomly assigned (2:1) to oral rucaparib (600 mg twice daily) or placebo in 28-day cycles using a computer-generated sequence (block size of six with stratification based on homologous recombination repair gene mutation status, progression-free interval following penultimate platinum-based regimen, and best response to most recent platinum-based regimen). Patients, investigators, site staff, assessors, and the funder were masked to assignments. The primary endpoint of investigator-assessed progression-free survival has been previously reported. Prespecified, exploratory outcomes of chemotherapy-free interval (CFI), time to start of first subsequent therapy (TFST), time to disease progression on subsequent therapy or death (PFS2), and time to start of second subsequent therapy (TSST) and updated safety were analysed (visit cutoff Dec 31, 2017). Efficacy analyses were done in all patients randomised to three nested cohorts: patients with BRCA mutations, patients with homologous recombination deficiencies, and the intention-to-treat population. Safety analyses included all patients who received at least one dose of study treatment. This trial is registered with ClinicalTrials.gov, NCT01968213.

FINDINGS

Between April 7, 2014, and July 19, 2016, 564 patients were enrolled and randomly assigned to rucaparib (n=375) or placebo (n=189). Median follow-up was 28·1 months (IQR 22·0-33·6). In the intention-to-treat population, median CFI was 14·3 months (95% CI 13·0-17·4) in the rucaparib group versus 8·8 months (8·0-10·3) in the placebo group (hazard ratio [HR] 0·43 [95% CI 0·35-0·53]; p<0·0001), median TFST was 12·4 months (11·1-15·2) versus 7·2 months (6·4-8·6; HR 0·43 [0·35-0·52]; p<0·0001), median PFS2 was 21·0 months (18·9-23·6) versus 16·5 months (15·2-18·4; HR 0·66 [0·53-0·82]; p=0·0002), and median TSST was 22·4 months (19·1-24·5) versus 17·3 months (14·9-19·4; HR 0·68 [0·54-0·85]; p=0·0007). CFI, TFST, PFS2, and TSST were also significantly longer with rucaparib than placebo in the BRCA-mutant and homologous recombination-deficient cohorts. The most frequent treatment-emergent adverse event of grade 3 or higher was anaemia or decreased haemoglobin (80 [22%] patients in the rucaparib group vs one [1%] patient in the placebo group). Serious treatment-emergent adverse events were reported in 83 (22%) patients in the rucaparib group and 20 (11%) patients in the placebo group. Two treatment-related deaths have been previously reported in this trial; there were no new treatment-related deaths.

INTERPRETATION

In these exploratory analyses over a median follow-up of more than 2 years, rucaparib maintenance treatment led to a clinically meaningful delay in starting subsequent therapy and provided lasting clinical benefits versus placebo in all three analysis cohorts. Updated safety data were consistent with previous reports.

FUNDING

Clovis Oncology.

Antitumor activity of the poly(ADP-ribose) polymerase inhibitor rucaparib as monotherapy in patients with platinum-sensitive, relapsed, BRCA-mutated, high-grade ovarian cancer, and an update on safety

OBJECTIVE

To report results from an integrated efficacy and safety analysis supporting the European Commission's approval of the poly(ADP-ribose) polymerase inhibitor rucaparib as monotherapy treatment for relapsed, platinum-sensitive, BRCA-mutated ovarian cancer.

METHODS

Efficacy was analyzed in platinum-sensitive patients from Study 10 (NCT01482715) and ARIEL2 (NCT01891344) who had high-grade serous or endometrioid epithelial ovarian, fallopian tube, or primary peritoneal cancer and a deleterious BRCA1 or BRCA2 mutation and received two or more prior chemotherapies (including two or more platinum-based therapies). The primary end point was investigator-assessed, confirmed objective response rate (visit cut-off: April 10, 2017). Safety was analyzed in patients with ovarian cancer, regardless of BRCA mutation status or lines of prior chemotherapies, who received at least one dose of rucaparib 600 mg in either study (visit cut-off: December 31, 2017).

RESULTS

In the integrated platinum-sensitive efficacy population (n=79), objective response rate was 64.6% (95% CI, 53.0 to 75.0); 10.1% (8/79) of patients had a complete response and 54.4% (43/79) had a partial response. Median duration of response was 294 days (95% CI, 224 to 393). In the integrated safety population (n=565), the most common any-grade treatment-emergent adverse events were nausea (77.7%, 439/565), asthenia/fatigue (74.7%, 422/565), vomiting (45.8%, 259/565), and hemoglobin decreased (44.2%, 250/565). Treatment-emergent adverse events led to treatment interruption, dose reduction, or discontinuation in 60.2% (340/565), 46.0% (260/565), and 16.8% (95/565) of patients.

CONCLUSIONS

In patients with platinum-sensitive, BRCA-mutated ovarian cancer, rucaparib demonstrated antitumor activity and is the first and currently the only poly(ADP-ribose) polymerase inhibitor approved by the European Commission as treatment for this population. The safety analysis used a more recent visit cut-off date and larger population than previously published, was consistent with prior reports, and was the basis for the treatment-indication safety population in rucaparib's recently updated European Union label.

Exploratory analysis of the effect of maintenance rucaparib on postprogression outcomes in patients (pts) with platinum-sensitive recurrent ovarian carcinoma (OC) and updated safety data from the phase 3 study ARIEL3

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Background: In ARIEL3, rucaparib maintenance treatment significantly improved progression-free survival (PFS) vs placebo in all predefined, nested cohorts: BRCA mutation; BRCA mutation + wild-type BRCA/high loss of heterozygosity (LOH); and intent-to-treat (ITT) population. Methods: Pts were randomized 2:1 to receive oral rucaparib 600 mg BID or placebo. Exploratory endpoints of time to first subsequent therapy (TFST), time to investigator-assessed PFS on the subsequent line of treatment or death (PFS2), and time to second subsequent therapy (TSST) were assessed in the predefined cohorts. Results: Exploratory efficacy endpoint data are given in the Table. As of Dec 31, 2017, the most common treatment-emergent adverse events (TEAEs) of any grade (rucaparib vs placebo) were nausea (75.8% vs 36.5%), asthenia/fatigue (70.7% vs 44.4%), dysgeusia (39.8% vs 6.9%), and anemia/decreased hemoglobin (39.0% vs 5.3%). The most common grade ≥3 TEAEs were anemia/decreased hemoglobin (21.5% vs 0.5%) and alanine/aspartate aminotransferase increase (10.2% vs 0.0%). Conclusions: Rucaparib significantly improved the clinically meaningful endpoints TFST, PFS2, and TSST vs placebo in all predefined cohorts of pts with platinum-sensitive, recurrent OC. The updated safety profile was consistent with prior reports. Clinical trial information: NCT01968213. [Table: see text]

Abstract PR06: ARIEL3: A phase 3, randomized, double-blind study of rucaparib vs placebo following response to platinum-based chemotherapy for recurrent ovarian cancer (OC)

Background: Rucaparib, a poly(ADP-ribose) polymerase (PARP) inhibitor, is approved in the United States for treatment of women with deleterious BRCA mutation (germline and/or somatic) associated advanced OC who have been treated with two or more chemotherapies. Rucaparib has also demonstrated antitumor activity in the treatment setting in patients (pts) with BRCA wild-type associated recurrent OC whose tumor has high genomic loss of heterozygosity (LOH). ARIEL3 evaluated rucaparib vs placebo as maintenance treatment in pts with recurrent platinum-sensitive OC.

Methods: Eligible pts received ≥2 prior platinum-based therapies, had platinum-sensitive OC (disease progression ≥6 mo after penultimate platinum), and achieved a complete response (RECIST v1.1) or partial response (RECIST v1.1 or Gynecologic Cancer InterGroup CA-125 criteria) to their most recent platinum. All pts were required to have CA-125 less than the upper limit of normal. Pts were randomized 2:1 to receive oral rucaparib 600 mg BID or placebo. Investigator-assessed progression-free survival (PFS) (primary endpoint) was assessed in a step-down procedure for 3 nested cohorts: (1) BRCA mutant (deleterious germline or somatic BRCA mutation); (2) homologous recombination deficient (HRD) (BRCA mutant or BRCA wild type/LOH high); and (3) intent-to-treat (ITT) population. PFS was also assessed by blinded independent central review (BICR) (secondary endpoint) and LOH status in pts with BRCA wild type OC (exploratory endpoint). Adverse events (AEs) were summarized descriptively.

Results: ARIEL3 enrolled 564 pts (375, rucaparib; 189, placebo). Nearly 200 pts (n=196) had BRCA mutation-associated OC. Of these pts, 130 had a germline BRCA mutation (82 [21.9%], rucaparib; 48 [25.4%], placebo), 56 had a somatic BRCA mutation (40 [10.7%], rucaparib; 16 [8.5%], placebo), and 10 pts had tumors with germline and/or somatic BRCA status unknown (8 [2.1%], rucaparib; 2 [1.1%], placebo). Median investigator-assessed PFS in the BRCA-mutant cohort (130, rucaparib; 66 placebo) was 16.6 mo vs 5.4 mo (hazard ratio [HR], 0.23; 95% confidence interval [CI], 0.16-0.34; P&lt;0.0001). In the HRD cohort (236, rucaparib; 118, placebo), median PFS was 13.6 mo vs 5.4 mo (HR, 0.32; 95% CI, 0.24-0.42; P&lt;0.0001), and in the ITT population, median PFS was 10.8 mo vs 5.4 mo (HR, 0.37; 95% CI, 0.30-0.45; P&lt;0.0001). Median PFS by BICR in the BRCA-mutant cohort was 26.8 mo vs 5.4 mo (HR, 0.20; 95% CI, 0.13-0.32; p&lt;0.0001). In the HRD cohort, median PFS by BICR was 22.9 mo vs 5.5 mo (HR, 0.34; 95% CI, 0.24-0.47; p&lt;0.0001), and in the ITT population, median PFS by BICR was 13.7 mo vs 5.4 mo (HR, 0.35; 95% CI, 0.28-0.45; p&lt;0.0001). In the safety population (372, rucaparib; 189, placebo), the most common treatment-emergent AEs (≥35% of pts in either arm) included nausea (75.3% and 36.5%), asthenia/fatigue (69.4% and 43.9%), dysgeusia (39.2% and 6.9%), anemia (37.4% and 5.8%), constipation (36.6% and 23.8%), and vomiting (36.6% and 14.8%). The most common grade 3 or higher treatment-emergent AEs were anemia (18.8% and 0.5%) and alanine/aspartate aminotransferase increase (10.5% and 0%). At the visit cutoff date (15 April 2017), 13.4% and 1.6% of pts discontinued maintenance treatment due to treatment-emergent AEs (excluding disease progression), and 1.6% and 1.1% of pts died due to treatment-emergent AEs (including disease progression).

Conclusion: Rucaparib significantly improved PFS vs placebo in pts with platinum-sensitive, recurrent OC in all primary analysis groups of pts with platinum-sensitive, recurrent OC. Additionally, rucaparib significantly improved PFS vs placebo in pts with BRCA wild-type OC (LOH high and LOH low).

Clinical trial identification: NCT01968213.

This abstract is also being presented as Poster A47.

Citation Format: Robert L. Coleman, Amit M. Oza, Domenica Lorusso, Carol Aghajanian, Ana Oaknin, Andrew Dean, Nicoletta Colombo, Johanne I. Weberpals, Andrew Clamp, Giovanni Scambia, Alexandra Leary, Robert W. Holloway, David M. O’Malley, Terri Cameron, Lara Maloney, Sandra Goble, Kevin Lin, James Sun, Heidi Giordano, Jonathan A. Ledermann. ARIEL3: A phase 3, randomized, double-blind study of rucaparib vs placebo following response to platinum-based chemotherapy for recurrent ovarian cancer (OC). [abstract]. In: Proceedings of the AACR Conference: Addressing Critical Questions in Ovarian Cancer Research and Treatment; Oct 1-4, 2017; Pittsburgh, PA. Philadelphia (PA): AACR; Clin Cancer Res 2018;24(15_Suppl):Abstract nr PR06.

Pharmacokinetic Study of Rucaparib in Patients With Advanced Solid Tumors

The phase 1‐2 study CO‐338‐010 (Study 10; NCT01482715) is evaluating single‐agent rucaparib, a poly(ADP‐ribose) polymerase inhibitor, administered orally to patients with an advanced solid tumor. In the dose escalation phase (Part 1), we characterized the single‐dose and steady‐state pharmacokinetic profiles of rucaparib administered once daily (QD; dose range, 40‐500 mg; n = 16) or twice daily (BID; dose range, 240‐840 mg; n = 30). Across all dosing schedules examined, the plasma exposure of rucaparib was approximately dose proportional; half‐life was approximately 17 hours, and median time to maximum concentration (t_max) ranged from 1.5 to 6.0 hours after a single dose and 1.5 to 4.0 hours following repeated dosing. The steady‐state accumulation ratio ranged from 1.60 to 2.33 following QD dosing and 1.47 to 5.44 following BID dosing. No effect of food on rucaparib pharmacokinetics was observed with a single dose of 40 mg (n = 3) or 300 mg (n = 6). In a phase 2 portion of the study (Part 3), the pharmacokinetic profile of rucaparib was further evaluated at the recommended phase 2 dose of 600 mg BID (n = 26). The mean (coefficient of variation) steady‐state maximum concentration (C_max) and area under the concentration‐time curve from time zero to 12 hours (AUC_0‐12h) were 1940 ng/mL (54%) and 16 900 ng ⋅ h/mL (54%), respectively. A high‐fat meal moderately increased rucaparib exposure. The fed‐to‐fasted geometric mean ratios (90% confidence interval [CI]) for AUC_0‐24h and C_max were 138% (117%‐162%) and 120% (99.1%‐146%); the median (90%CI) t_max delay was 2.5 (0.5‐4.4) hours.

Rucaparib Monotherapy in Patients With Pancreatic Cancer and a Known Deleterious BRCA Mutation

Purpose

Pancreatic cancer has a poor prognosis and limited treatment options. Approximately 9% of pancreatic cancers harbor a germline or somatic BRCA1 or BRCA2 (BRCA1/2) mutation. Because poly (ADP-ribose) polymerase inhibitors have significant activity in BRCA1/2-mutant ovarian and breast cancers, RUCAPANC investigated the efficacy and safety of rucaparib in BRCA1/2-mutant pancreatic cancer.

Patients and Methods

RUCAPANC enrolled patients with measurable locally advanced/metastatic pancreatic cancer who had received one to two prior chemotherapy regimens. Patients received oral rucaparib (600 mg twice daily) until disease progression. The primary end point was objective response rate.

Results

Nineteen patients were enrolled. Sixteen of 19 BRCA1/2 mutations were germ-line; three were somatic. Patients had received a median of two prior chemotherapy regimens. Four patients achieved a response; two partial responses and one complete response (CR) were confirmed (objective response rate, 15.8%; 3 of 19), with an additional CR unconfirmed. The disease control rate (CR, partial response, or stable disease for ≥ 12 weeks) was 31.6% (6 of 19) in all patients and 44.4% (4 of 9) in those who had received one prior chemotherapy regimen. As prespecified in the protocol, enrollment was stopped because of an insufficient response rate among the first 15 patients. Treatment-emergent adverse events included nausea (63.2%) and anemia (47.4%). Grade ≥ 3 adverse events included anemia (31.6%), fatigue (15.8%), and ascites (15.8%). Secondary resistance mutations were detected in circulating free tumor DNA in two patients with a germline BRCA2 mutation. These mutations are predicted to lead to the reversion of a somatic-not germline-mutation.

Conclusion

Rucaparib provided clinical benefit to patients with advanced pancreatic cancer and a BRCA1/2 mutation, and demonstrated an acceptable safety profile. Additional trials of rucaparib in this population are warranted.

Abstract LB-A12: Results from the phase 3 study ARIEL3: mutations in non-BRCA homologous recombination repair genes confer sensitivity to maintenance treatment with the PARP inhibitor rucaparib in patients with recurrent platinum-sensitive high-grade ovarian carcinoma

Background: High-grade ovarian carcinomas (HGOC) with a mutation in BRCA1/2 or other core homologous recombination repair (HRR) genes are sensitive to treatment with the PARP inhibitor rucaparib. To study whether HRR gene mutations confer sensitivity to rucaparib in the maintenance setting, we performed next-generation sequencing (NGS) on carcinomas from a double-blind, placebo-controlled, phase 3 study of rucaparib in patients with HGOC following response to platinum-based chemotherapy (ARIEL3, NCT01968213). Materials and Methods: Archival ovarian carcinoma specimens were required for all 564 patients who were randomized in ARIEL3 and were sequenced using Foundation Medicine’s NGS-based assay to identify deleterious mutations in a prespecified list of HRR genes (BRCA1/2 and 28 non-BRCA HRR genes, including ATM, BARD1, BRIP1, CHEK2, RAD51C, RAD51D, RAD54L, and FANC family genes). Patients were randomized 2:1 to receive oral rucaparib 600 mg twice daily or placebo. The randomization was stratified by HRR gene mutation status (BRCA, non-BRCA HRR, no mutation in BRCA or HRR gene), progression-free interval of the penultimate platinum-based regimen, and best response to most recent platinum regimen. The primary endpoint for ARIEL3 was investigator-assessed progression-free survival (PFS) per RECIST v1.1. Exploratory analysis of confirmed response was conducted for the subgroup of patients with measurable disease at study entry. Results: Deleterious mutations in non-BRCA HRR genes were detected in ovarian carcinoma specimens from 7.6% (43/564) of randomized patients. In these patients, PFS was significantly longer with rucaparib than with placebo (hazard ratio [HR], 0.21; 95% confidence interval [CI], 0.09-0.50; P=0.0005), with a median PFS of 11.1 mo and 5.5 mo, respectively. This HR is similar to that found in women with carcinomas containing a BRCA1/2 mutation (0.23; 95% CI, 0.16-0.34). The most commonly found non-BRCA HRR gene mutations among the 28 patients in the rucaparib arm were RAD51C (n=6) and RAD51D (n=4) and among the 15 patients in the placebo arm were BRIP1 (n=5) and RAD51C (n=2). A diverse set of mutation types were detected, including frameshift insertions/deletions, homozygous deletions, and nonsense and splice site mutations. All 10 RAD51C/D mutations were homozygous within the carcinomas, indicating biallelic loss. Additionally, all RAD51C/D-mutant carcinomas exhibited high genomic loss of heterozygosity, which is a type of genomic scar characteristic of HRR deficiency. At the visit cutoff date (15 April 2017), only 2 of the 10 RAD51C/D cases in the rucaparib arm had disease progression; 7 had a PFS duration of at least 1 y (median PFS, 16.4 mo; range 5.4+ to 30.4+ mo). Three of the RAD51C/D cases were in the subgroup of patients who had measurable disease at baseline, and all achieved a confirmed response (1 complete response and 2 partial responses). In comparison, the 3 RAD51C/D cases in the placebo arm had a median PFS of 5.4 mo (range, 3.9 to 5.5 mo). Conclusions: Patients with recurrent platinum-sensitive HGOC harboring a deleterious mutation in non-BRCA HRR genes (including RAD51C/D) had significantly longer PFS with rucaparib maintenance treatment than with placebo.

Citation Format: David M. O'Malley, Robert L. Coleman, Amit M. Oza, Domenica Lorusso, Carol Aghajanian, Ana Oaknin, Andrew Dean, Nicoletta Colombo, Iain A. McNeish, Elizabeth M. Swisher, Clare L. Scott, Gottfried E. Konecny, Heidi Giordano, Terri Cameron, Lara Maloney, Sandra Goble, James Sun, Thomas C. Harding, Kevin K. Lin, Jonathan A. Ledermann. Results from the phase 3 study ARIEL3: mutations in non-BRCA homologous recombination repair genes confer sensitivity to maintenance treatment with the PARP inhibitor rucaparib in patients with recurrent platinum-sensitive high-grade ovarian carcinoma [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2017 Oct 26-30; Philadelphia, PA. Philadelphia (PA): AACR; Mol Cancer Ther 2018;17(1 Suppl):Abstract nr LB-A12.

Antitumor activity and safety of the PARP inhibitor rucaparib in patients with high-grade ovarian carcinoma and a germline or somatic BRCA1 or BRCA2 mutation: Integrated analysis of data from Study 10 and ARIEL2

OBJECTIVE

An integrated analysis was undertaken to characterize the antitumor activity and safety profile of the oral poly(ADP-ribose) polymerase inhibitor rucaparib in patients with relapsed high-grade ovarian carcinoma (HGOC).

METHODS

Eligible patients from Study 10 (NCT01482715) and ARIEL2 (NCT01891344) who received a starting dose of oral rucaparib 600mg twice daily (BID) with or without food were included in these analyses. The integrated efficacy population included patients with HGOC and a deleterious germline or somatic BRCA1 or BRCA2 (BRCA1/2) mutation who received at least two prior chemotherapies and were sensitive, resistant, or refractory to platinum-based chemotherapy. The primary endpoint was investigator-assessed confirmed objective response rate (ORR). Secondary endpoints included duration of response (DOR) and progression-free survival (PFS). The integrated safety population included patients with HGOC who received at least one dose of rucaparib 600mg BID, irrespective of BRCA1/2 mutation status and prior treatments.

RESULTS

In the efficacy population (n=106), ORR was 53.8% (95% confidence interval [CI], 43.8-63.5); 8.5% and 45.3% of patients achieved complete and partial responses, respectively. Median DOR was 9.2months (95% CI, 6.6-11.6). In the safety population (n=377), the most frequent treatment-emergent adverse events (AEs) were nausea, asthenia/fatigue, vomiting, and anemia/hemoglobin decreased. The most common grade ≥3 treatment-emergent AE was anemia/hemoglobin decreased. Treatment-emergent AEs led to treatment interruption, dose reduction, and treatment discontinuation in 58.6%, 45.9%, and 9.8% of patients, respectively. No treatment-related deaths occurred.

CONCLUSIONS

Rucaparib has antitumor activity in advanced BRCA1/2-mutated HGOC and a manageable safety profile.

Rucaparib maintenance treatment for recurrent ovarian carcinoma after response to platinum therapy (ARIEL3): a randomised, double-blind, placebo-controlled, phase 3 trial

BACKGROUND

Rucaparib, a poly(ADP-ribose) polymerase inhibitor, has anticancer activity in recurrent ovarian carcinoma harbouring a BRCA mutation or high percentage of genome-wide loss of heterozygosity. In this trial we assessed rucaparib versus placebo after response to second-line or later platinum-based chemotherapy in patients with high-grade, recurrent, platinum-sensitive ovarian carcinoma.

METHODS

In this randomised, double-blind, placebo-controlled, phase 3 trial, we recruited patients from 87 hospitals and cancer centres across 11 countries. Eligible patients were aged 18 years or older, had a platinum-sensitive, high-grade serous or endometrioid ovarian, primary peritoneal, or fallopian tube carcinoma, had received at least two previous platinum-based chemotherapy regimens, had achieved complete or partial response to their last platinum-based regimen, had a cancer antigen 125 concentration of less than the upper limit of normal, had a performance status of 0-1, and had adequate organ function. Patients were ineligible if they had symptomatic or untreated central nervous system metastases, had received anticancer therapy 14 days or fewer before starting the study, or had received previous treatment with a poly(ADP-ribose) polymerase inhibitor. We randomly allocated patients 2:1 to receive oral rucaparib 600 mg twice daily or placebo in 28 day cycles using a computer-generated sequence (block size of six, stratified by homologous recombination repair gene mutation status, progression-free interval after the penultimate platinum-based regimen, and best response to the most recent platinum-based regimen). Patients, investigators, site staff, assessors, and the funder were masked to assignments. The primary outcome was investigator-assessed progression-free survival evaluated with use of an ordered step-down procedure for three nested cohorts: patients with BRCA mutations (carcinoma associated with deleterious germline or somatic BRCA mutations), patients with homologous recombination deficiencies (BRCA mutant or BRCA wild-type and high loss of heterozygosity), and the intention-to-treat population, assessed at screening and every 12 weeks thereafter. This trial is registered with ClinicalTrials.gov, number NCT01968213; enrolment is complete.

FINDINGS

Between April 7, 2014, and July 19, 2016, we randomly allocated 564 patients: 375 (66%) to rucaparib and 189 (34%) to placebo. Median progression-free survival in patients with a BRCA-mutant carcinoma was 16·6 months (95% CI 13·4-22·9; 130 [35%] patients) in the rucaparib group versus 5·4 months (3·4-6·7; 66 [35%] patients) in the placebo group (hazard ratio 0·23 [95% CI 0·16-0·34]; p<0·0001). In patients with a homologous recombination deficient carcinoma (236 [63%] vs 118 [62%]), it was 13·6 months (10·9-16·2) versus 5·4 months (5·1-5·6; 0·32 [0·24-0·42]; p<0·0001). In the intention-to-treat population, it was 10·8 months (8·3-11·4) versus 5·4 months (5·3-5·5; 0·36 [0·30-0·45]; p<0·0001). Treatment-emergent adverse events of grade 3 or higher in the safety population (372 [99%] patients in the rucaparib group vs 189 [100%] in the placebo group) were reported in 209 (56%) patients in the rucaparib group versus 28 (15%) in the placebo group, the most common of which were anaemia or decreased haemoglobin concentration (70 [19%] vs one [1%]) and increased alanine or aspartate aminotransferase concentration (39 [10%] vs none).

INTERPRETATION

Across all primary analysis groups, rucaparib significantly improved progression-free survival in patients with platinum-sensitive ovarian cancer who had achieved a response to platinum-based chemotherapy. ARIEL3 provides further evidence that use of a poly(ADP-ribose) polymerase inhibitor in the maintenance treatment setting versus placebo could be considered a new standard of care for women with platinum-sensitive ovarian cancer following a complete or partial response to second-line or later platinum-based chemotherapy.

FUNDING

Clovis Oncology.

Abstract AP28: BRCA1 and RAD51C Promoter Hypermethylation Confer Sensitivity to PARP Inhibitors in Patients with Platinum Sensitive Ovarian Carcinoma

Germline and somatic mutations in BRCA1 and BRCA2 (BRCA) confer PARP inhibitor sensitivity. Promoter hypermethylation is an alternate mechanism of gene down-regulation, and BRCA1 promoter methylation is relatively common in sporadic ovarian cancer. The clinical significance of BRCA1 methylation is less clear than for mutations, as the Cancer Genome Atlas (TCGA) and others have failed to show improved survival in ovarian carcinomas with BRCA1 methylation. No one has previously tested whether BRCA1 methylation confers in vivo sensitivity to PARP inhibitors in patients with ovarian cancer. ARIEL2 is a phase 2 study of the PARP inhibitor rucaparib in patients with recurrent platinum sensitive high-grade ovarian, peritoneal or fallopian tube carcinoma. At enrollment, ARIEL2 required pre-treatment tumor biopsies with the goal of developing tissue predictors of PARP inhibitor sensitivity other than BRCA mutations. The number of women with known germline mutations was capped at 15 patients in order to predominantly enroll BRCA wildtype cases. As presented at ASCO 2016, in cases with no BRCA mutations, a high fraction of genomic loss of heterozygosity (LOH) significantly predicted a better progression-free survival (the primary endpoint), longer duration of response, and a higher fraction of responders compared to cases with low LOH. We assessed BRCA1 and RAD51C promoter hypermethylation using methylation-sensitive polymerase chain reaction in paired archival and pre-treatment biopsies from patients on ARIEL2. Of 165 cases for which methylation analyses were completed, 21 (12.7%) were methylated at the BRCA1 promoter and four (2.4%) at the RAD51C promoter. Methylation of BRCA1 and RAD51C was mutually exclusive with mutation in BRCA or other homologous recombination genes. All four cases with RAD51C methylation and 15/19 (78.9%) with BRCA1 methylation were associated with high LOH. In 90 paired samples archival and pre-treatment tissues, RAD51C methylation was 100% concordant and BRCA1 methylation was highly concordant (p&lt;0·001). For 13 cases with BRCA1 methylation in the archival specimen, 4 (30·8%) were unmethylated in the paired pretreatment tumor, but for 77 unmethylated archival specimens, gain of methylation in the pretreatment biopsy was observed just once. Confirmed RECIST responses were seen in 52.4% (11/21) BRCA1 methylated and 75.0% (3/4) RAD51C methylated cases. In conclusion, BRCA1 and RAD51C methylation in ovarian carcinomas correlates with a high response rate to PARP inhibitors. If methylation was to be used as a predictor of PARP inhibitor sensitivity, it would need to be assessed in a pre-treatment (not archival) specimen. The loss of BRCA1 methylation in recurrent ovarian carcinoma, which was common even in these platinum sensitive cases, could explain why BRCA1 methylation is associated with similar survival to methylated cases, despite initial improved therapeutic sensitivity.

Citation Format: Elizabeth Swisher, Maria Harrell, Kevin K. Lin, Clare Scott, Sandra Goble, Amit Oza, Robert L. Coleman, Gottfried Konecny, Anna V. Tinker, David M. O'Malley, Rebecca Kristeleit, Ling Ma, James Brenton, Katherine Bell-McGuinn, Ana Oaknin, Alexandra Leary, Elaina Mann, Heidi Giordano, Mitch Rapon, Iain McNeish, Scott H. Kaufmann. BRCA1 and RAD51C Promoter Hypermethylation Confer Sensitivity to PARP Inhibitors in Patients with Platinum Sensitive Ovarian Carcinoma [abstract]. In: Proceedings of the 11th Biennial Ovarian Cancer Research Symposium; Sep 12-13, 2016; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(11 Suppl):Abstract nr AP28.

ARIEL4: An international, multicenter randomized phase 3 study of the PARP inhibitor rucaparib vs chemotherapy in germline or somatic BRCA1- or BRCA2-mutated, relapsed, high-grade ovarian carcinoma

TPS5603

Background: In high-grade epithelial ovarian carcinoma (OC), ≈18% of patients (pts) have tumors with a germline BRCA1 or BRCA2 mutation; ≈7% have tumors with a somatic BRCA1 or BRCA2 mutation (Pennington et al. Clin Cancer Res. 2014;20:764-75). The poly(ADP-ribose) polymerase (PARP) inhibitor rucaparib is approved in the United States for treatment of pts with OC associated with a deleterious BRCA1 or BRCA2 mutation (germline and/or somatic) who have received ≥2 chemotherapies. Although PARP inhibitors have demonstrated clinical activity in OC in both treatment and maintenance settings, comparison to standard of care (SOC) has only been evaluated in the maintenance setting. Randomized studies are needed to assess the benefit-risk profile of PARP inhibitors vs current SOC as treatment for BRCA1- or BRCA2-mutated, relapsed, high-grade OC. Methods: ARIEL4 (NCT02855944) is evaluating rucaparib vs chemotherapy as treatment for pts with germline or somatic BRCA1- or BRCA2-mutated, relapsed, high-grade OC (regardless of histology) who have received ≥2 prior chemotherapy regimens. Approximately 345 pts will be randomized 2:1 to receive rucaparib (600 mg BID) (n = 230) or chemotherapy (n = 115) and stratified by progression-free interval after their most recent platinum regimen. Pts with platinum-resistant (progressive disease [PD] 1– < 6 mo after last platinum) or partially platinum-sensitive disease (PD 6– < 12 mo after last platinum) will be randomized to rucaparib or weekly paclitaxel; pts with platinum-sensitive disease (PD ≥12 mo after last platinum) will be randomized to rucaparib or platinum-based therapy (single-agent or doublet at the discretion of the investigator). Pts receiving chemotherapy have the option to cross over to rucaparib upon radiographic disease progression. The primary endpoint is progression-free survival. Secondary endpoints include investigator-assessed objective response rate (ORR) (RECIST version 1.1), ORR/CA-125 response, duration of response, overall survival, and pt-reported outcomes. Safety will be summarized descriptively using standard adverse event reporting. Clinical trial information: NCT02855944.

A phase I study of intravenous and oral rucaparib in combination with chemotherapy in patients with advanced solid tumours

BACKGROUND

This study evaluated safety, pharmacokinetics, and clinical activity of intravenous and oral rucaparib, a poly(ADP-ribose) polymerase inhibitor, combined with chemotherapy in patients with advanced solid tumours.

METHODS

Initially, patients received escalating doses of intravenous rucaparib combined with carboplatin, carboplatin/paclitaxel, cisplatin/pemetrexed, or epirubicin/cyclophosphamide. Subsequently, the study was amended to focus on oral rucaparib (once daily, days 1-14) combined with carboplatin (day 1) in 21-day cycles. Dose-limiting toxicities (DLTs) were assessed in cycle 1 and safety in all cycles.

RESULTS

Eighty-five patients were enrolled (22 breast, 15 ovarian/peritoneal, and 48 other primary cancers), with a median of three prior therapies (range, 1-7). Neutropenia (27.1%) and thrombocytopenia (18.8%) were the most common grade ⩾3 toxicities across combinations and were DLTs with the oral rucaparib/carboplatin combination. Maximum tolerated dose for the combination was 240 mg per day oral rucaparib and carboplatin area under the curve 5 mg ml-1 min-1. Oral rucaparib demonstrated dose-proportional kinetics, a long half-life (≈17 h), and good bioavailability (36%). Pharmacokinetics were unchanged by carboplatin coadministration. The rucaparib/carboplatin combination had radiologic antitumour activity, primarily in BRCA1- or BRCA2-mutated breast and ovarian/peritoneal cancers.

CONCLUSIONS

Oral rucaparib can be safely combined with a clinically relevant dose of carboplatin in patients with advanced solid tumours (Trial registration ID: NCT01009190).

Rucaparib in relapsed, platinum-sensitive high-grade ovarian carcinoma (ARIEL2 Part 1): an international, multicentre, open-label, phase 2 trial

BACKGROUND

Poly(ADP-ribose) polymerase (PARP) inhibitors have activity in ovarian carcinomas with homologous recombination deficiency. Along with BRCA1 and BRCA2 (BRCA) mutations genomic loss of heterozygosity (LOH) might also represent homologous recombination deficiency. In ARIEL2, we assessed the ability of tumour genomic LOH, quantified with a next-generation sequencing assay, to predict response to rucaparib, an oral PARP inhibitor.

METHODS

ARIEL2 is an international, multicentre, two-part, phase 2, open-label study done at 49 hospitals and cancer centres in Australia, Canada, France, Spain, the UK, and the USA. In ARIEL2 Part 1, patients with recurrent, platinum-sensitive, high-grade ovarian carcinoma were classified into one of three predefined homologous recombination deficiency subgroups on the basis of tumour mutational analysis: BRCA mutant (deleterious germline or somatic), BRCA wild-type and LOH high (LOH high group), or BRCA wild-type and LOH low (LOH low group). We prespecified a cutoff of 14% or more genomic LOH for LOH high. Patients began treatment with oral rucaparib at 600 mg twice per day for continuous 28 day cycles until disease progression or any other reason for discontinuation. The primary endpoint was progression-free survival. All patients treated with at least one dose of rucaparib were included in the safety analyses and all treated patients who were classified were included in the primary endpoint analysis. This trial is registered with ClinicalTrials.gov, number NCT01891344. Enrolment into ARIEL2 Part 1 is complete, although an extension (Part 2) is ongoing.

FINDINGS

256 patients were screened and 206 were enrolled between Oct 30, 2013, and Dec 19, 2014. At the data cutoff date (Jan 18, 2016), 204 patients had received rucaparib, with 28 patients remaining in the study. 192 patients could be classified into one of the three predefined homologous recombination deficiency subgroups: BRCA mutant (n=40), LOH high (n=82), or LOH low (n=70). Tumours from 12 patients were established as BRCA wild-type, but could not be classified for LOH, because of insufficient neoplastic nuclei in the sample. The median duration of treatment for the 204 patients was 5·7 months (IQR 2·8-10·1). 24 patients in the BRCA mutant subgroup, 56 patients in the LOH high subgroup, and 59 patients in the LOH low subgroup had disease progression or died. Median progression-free survival after rucaparib treatment was 12·8 months (95% CI 9·0-14·7) in the BRCA mutant subgroup, 5·7 months (5·3-7·6) in the LOH high subgroup, and 5·2 months (3·6-5·5) in the LOH low subgroup. Progression-free survival was significantly longer in the BRCA mutant (hazard ratio 0·27, 95% CI 0·16-0·44, p<0·0001) and LOH high (0·62, 0·42-0·90, p=0·011) subgroups compared with the LOH low subgroup. The most common grade 3 or worse treatment-emergent adverse events were anaemia or decreased haemoglobin (45 [22%] patients), and elevations in alanine aminotransferase or aspartate aminotransferase (25 [12%]). Common serious adverse events included small intestinal obstruction (10 [5%] of 204 patients), malignant neoplasm progression (10 [5%]), and anaemia (nine [4%]). Three patients died during the study (two because of disease progression and one because of sepsis and disease progression). No treatment-related deaths occurred.

INTERPRETATION

In patients with BRCA mutant or BRCA wild-type and LOH high platinum-sensitive ovarian carcinomas treated with rucaparib, progression-free survival was longer than in patients with BRCA wild-type LOH low carcinomas. Our results suggest that assessment of tumour LOH can be used to identify patients with BRCA wild-type platinum-sensitive ovarian cancers who might benefit from rucaparib. These results extend the potential usefulness of PARP inhibitors in the treatment setting beyond BRCA mutant tumours.

FUNDING

Clovis Oncology, US Department of Defense Ovarian Cancer Research Program, Stand Up To Cancer-Ovarian Cancer Research Fund Alliance-National Ovarian Cancer Coalition Dream Team Translational Research Grant, and V Foundation Translational Award.

Abstract A11: NGS-based tumor genomic profiling to identify ovarian cancer patients who benefit from the PARP inhibitor rucaparib

Background: PARP inhibitors (PARPi) are synthetically lethal to tumor cells with homologous recombination deficiency (HRD). HRD can result from deleterious BRCA1/2 mutations (BRCAmut) or other mechanisms that have not been fully elucidated. Regardless of mechanism, HRD leads to a common phenotype of genome-wide loss of heterozygosity (LOH). It has been hypothesized that this genomic phenotype can be used to identify BRCA wild-type (BRCAwt) HRD tumors likely sensitive to PARPi. Using comprehensive next generation sequencing (NGS)-based tumor genomic profiling, we developed an HRD assay for potential use as a companion diagnostic for rucaparib in high-grade ovarian cancer (HGOC) by combining tumor BRCA1/2 status and quantification of genomic LOH.

Methods: In the phase 2 study ARIEL2 Part 1 (NCT01891344), pre-treatment screening biopsies and archival formalin-fixed paraffin embedded tumor specimens were profiled using Foundation Medicine's NGS-based HRD assay, which detects all classes of genomic alterations, including base substitutions, insertions/deletions, and homozygous deletions in BRCA1/2. Genomic LOH was assessed by sequencing &gt;3,500 evenly-distributed single nucleotide polymorphisms across the genome and quantifying the extent of genomic LOH. A pre-specified genomic LOH cutoff was determined using publicly available SNP array data of ovarian tumors to predict platinum sensitivity as a surrogate marker for PARPi sensitivity. Response was assessed by RECIST v1.1 and GCIG CA-125 response criteria.

Results: As of July 1 2015, 195 archival tumor and 152 screening biopsy samples (142 matched pairs) from 206 HGOC patients enrolled (204 patients treated) in ARIEL2 Part 1 were successfully profiled using the NGS-based HRD assay. Some screening biopsies were not suitable for successful NGS-based HRD assessment primarily because of insufficient tumor nuclei or inadequate tumor volume. Most matched pairs of archival and pre-trial screening samples exhibited similar genomic LOH profiles (r=0.86); however, 14% of screening samples had higher genomic LOH compared with archival samples collected more than one year earlier. All BRCA1/2 germline and somatic mutated tumors had high genomic LOH in the screening samples. Receiver operating characteristic analysis of genomic LOH showed utility in identifying RECIST/CA-125 responders to rucaparib (AUC=0.72, p&lt;1e-4), with slightly better predictive utility using screening samples compared to archival samples (AUC=0.72 vs 0.69). Using the pre-specified genomic LOH cutoff, high genomic LOH tumors were detected in 54% of evaluable BRCAwt patients; significantly different overall response rates were found in patients with high vs low genomic LOH tumors (48% vs 26%; chi-square p=0.0074).

Conclusions: We developed an NGS-based HRD assay that assesses tumor BRCA1/2 and genomic LOH to prospectively identify HGOC patients who may benefit from rucaparib treatment. The optimized NGS-based HRD assay will be prospectively tested in the ongoing portion of the phase 2 study (ARIEL2 Part 2, NCT01891344) and a phase 3 maintenance study (ARIEL3, NCT01968213) that will investigate rucaparib in HGOC.

Citation Format: Iain A. McNeish, Kevin K. Lin, James X. Sun, Sandra Goble, Amit Oza, Robert L. Coleman, Clare L. Scott, Gottfried Konecny, Anna V. Tinker, David M. O'Malley, Rebecca Kristeleit, Ling Ma, James D. Brenton, Katherine Bell-McGuinn, Ana Oaknin, Alexandra Leary, Elaina Mann, Heidi Giordano, Roman Yelensky, Mitch Raponi, Elizabeth Swisher. NGS-based tumor genomic profiling to identify ovarian cancer patients who benefit from the PARP inhibitor rucaparib. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research: Exploiting Vulnerabilities; Oct 17-20, 2015; Orlando, FL. Philadelphia (PA): AACR; Clin Cancer Res 2016;22(2 Suppl):Abstract nr A11.