Project description:BackgroundIn a phase 2 study, rucaparib, an inhibitor of poly(ADP-ribose) polymerase (PARP), showed a high level of activity in patients who had metastatic, castration-resistant prostate cancer associated with a deleterious BRCA alteration. Data are needed to confirm and expand on the findings of the phase 2 study.MethodsIn this randomized, controlled, phase 3 trial, we enrolled patients who had metastatic, castration-resistant prostate cancer with a BRCA1, BRCA2, or ATM alteration and who had disease progression after treatment with a second-generation androgen-receptor pathway inhibitor (ARPI). We randomly assigned the patients in a 2:1 ratio to receive oral rucaparib (600 mg twice daily) or a physician's choice control (docetaxel or a second-generation ARPI [abiraterone acetate or enzalutamide]). The primary outcome was the median duration of imaging-based progression-free survival according to independent review.ResultsOf the 4855 patients who had undergone prescreening or screening, 270 were assigned to receive rucaparib and 135 to receive a control medication (intention-to-treat population); in the two groups, 201 patients and 101 patients, respectively, had a BRCA alteration. At 62 months, the duration of imaging-based progression-free survival was significantly longer in the rucaparib group than in the control group, both in the BRCA subgroup (median, 11.2 months and 6.4 months, respectively; hazard ratio, 0.50; 95% confidence interval [CI], 0.36 to 0.69) and in the intention-to-treat group (median, 10.2 months and 6.4 months, respectively; hazard ratio, 0.61; 95% CI, 0.47 to 0.80; P<0.001 for both comparisons). In an exploratory analysis in the ATM subgroup, the median duration of imaging-based progression-free survival was 8.1 months in the rucaparib group and 6.8 months in the control group (hazard ratio, 0.95; 95% CI, 0.59 to 1.52). The most frequent adverse events with rucaparib were fatigue and nausea.ConclusionsThe duration of imaging-based progression-free survival was significantly longer with rucaparib than with a control medication among patients who had metastatic, castration-resistant prostate cancer with a BRCA alteration. (Funded by Clovis Oncology; TRITON3 ClinicalTrials.gov number, NCT02975934.).
Project description:PurposeProstate cancer (PCa) is the most common malignancy in men and the cause for the second most common cancer-related death in the western world. Despite ongoing development of novel approaches such as second generation androgen receptor targeted therapies, metastatic disease is still fatal. In PCa, immunotherapy (IT) has not reached a therapeutic breakthrough as compared to several other solid tumors yet. We aimed at highlighting the underlying cellular mechanisms crucial for IT in PCa and giving an update of the most essential past and ongoing clinical trials in the field.MethodsWe searched for relevant publications on molecular and cellular mechanisms involved in the PCa tumor microenvironment and response to IT as well as completed and ongoing IT studies and screened appropriate abstracts of international congresses.ResultsTumor progression and patient outcomes depend on complex cellular and molecular interactions of the tumor with the host immune system, driven rather dormant in case of PCa. Sipuleucel-T and pembrolizumab are the only registered immune-oncology drugs to treat this malignancy. A plethora of studies assess combination of immunotherapy with other agents or treatment modalities like radiation therapy which might increase its antineoplastic activity. No robust and clinically relevant prognostic or predictive biomarkers have been established yet.ConclusionDespite immunosuppressive functional status of PCa microenvironment, current evidence, based on cellular and molecular conditions, encourages further research in this field.
Project description:The introduction of PARP inhibitors (PARPi) in prostate cancer is a milestone and provides a pathway to hope in fighting this disease. It is the first time that drugs, based on the concept of synthetic lethality, have been approved for prostate cancer. In addition, it is also the first time that genetic mutation tests have been included in the therapeutic algorithm of this disease, representing a significant step forward for precision and personalized treatment of prostate cancer. The objectives of this review are: (1) understanding the mechanism of action of PARPi in monotherapy and combinations; (2) gaining insights on patient selection for PARPi; (3) exposing the pivotal studies that have allowed its approval, and; (4) offering an overview of the ongoing trials. Nevertheless, many unsolved questions remain, such as the number of patients who could potentially benefit from PARPi, whether to use PARPi in monotherapy or in combination, and when is the best time to use them in advanced or localized disease. To answer these and other questions, many clinical trials are underway. Some of them have recently demonstrated promising results that may favor the introduction of new combinations in metastatic castration-resistant prostate cancer.
Project description:IntroductionMetastatic prostate cancer is a heterogeneous disease characterized by clinical and genomic heterogeneity. Many prostate cancers harbor mutations causing DNA repair deficiency, specifically homologous recombination deficiency, sensitizing to drugs that inhibit poly ADP-ribose polymerase (PARP). PARP is an enzyme that is involved in single-stranded DNA repair and is the target of newly approved treatments for metastatic prostate cancer.Areas coveredHere, the authors' review the clinical trials leading to the recent approvals of two PARP inhibitors (PARPi), olaparib and rucaparib, specifically TOPARP-A, TOPARP-B, PROfound and TRITON-2. They also compare the different FDA approvals for both of these medications and outline the safety of this class of drugs in prostate cancer.Expert opinionBecause PARPi are particularly effective in men with somatic or germline alterations in BRCA1 and BRCA2, we recommend that all men be tested for DNA alterations with next-generation sequencing in tumor cells obtained from either tissue or blood. We also recommend that olaparib or rucaparib be considered relatively early in the treatment sequence in metastatic castration-resistant prostate cancer patients with BRCA1 or BRCA2 mutations. Other DNA alterations might also sensitize to PARPi though the response rates are lower, so other standard therapies should be prioritized first.
Project description:BackgroundCheckMate 9KD (NCT03338790) is a non-randomized, multicohort, phase 2 trial of nivolumab plus other anticancer treatments for metastatic castration-resistant prostate cancer (mCRPC). We report results from cohorts A1 and A2 of CheckMate 9KD, specifically evaluating nivolumab plus rucaparib.MethodsCheckMate 9KD enrolled adult patients with histologically confirmed mCRPC, ongoing androgen deprivation therapy, and an Eastern Cooperative Oncology Group performance status of 0-1. Cohort A1 included patients with postchemotherapy mCRPC (1-2 prior taxane-based regimens) and ≤2 prior novel hormonal therapies (eg, abiraterone, enzalutamide, apalutamide); cohort A2 included patients with chemotherapy-naïve mCRPC and prior novel hormonal therapy. Patients received nivolumab 480 mg every 4 weeks plus rucaparib 600 mg two times per day (nivolumab dosing ≤2 years). Coprimary endpoints were objective response rate (ORR) per Prostate Cancer Clinical Trials Working Group 3 and prostate-specific antigen response rate (PSA50-RR; ≥50% PSA reduction) in all-treated patients and patients with homologous recombination deficiency (HRD)-positive tumors, determined before enrollment. Secondary endpoints included radiographic progression-free survival (rPFS), overall survival (OS), and safety.ResultsOutcomes (95% CI) among all-treated, HRD-positive, and BRCA1/2-positive populations for cohort A1 were confirmed ORR: 10.3% (3.9-21.2) (n=58), 17.2% (5.8-35.8) (n=29), and 33.3% (7.5-70.1) (n=9); confirmed PSA50-RR: 11.9% (5.9-20.8) (n=84), 18.2% (8.2-32.7) (n=44), and 41.7% (15.2-72.3) (n=12); median rPFS: 4.9 (3.7-5.7) (n=88), 5.8 (3.7-8.4) (n=45), and 5.6 (2.8-15.7) (n=12) months; and median OS: 13.9 (10.4-15.8) (n=88), 15.4 (11.4-18.2) (n=45), and 15.2 (3.0-not estimable) (n=12) months. For cohort A2 they were confirmed ORR: 15.4% (5.9-30.5) (n=39), 25.0% (8.7-49.1) (n=20), and 33.3% (7.5-70.1) (n=9); confirmed PSA50-RR: 27.3% (17.0-39.6) (n=66), 41.9 (24.5-60.9) (n=31), and 84.6% (54.6-98.1) (n=13); median rPFS: 8.1 (5.6-10.9) (n=71), 10.9 (6.7-12.0) (n=34), and 10.9 (5.6-12.0) (n=15) months; and median OS: 20.2 (14.1-22.8) (n=71), 22.7 (14.1-not estimable) (n=34), and 20.2 (11.1-not estimable) (n=15) months. In cohorts A1 and A2, respectively, the most common any-grade and grade 3-4 treatment-related adverse events (TRAEs) were nausea (40.9% and 40.8%) and anemia (20.5% and 14.1%). Discontinuation rates due to TRAEs were 27.3% and 23.9%, respectively.ConclusionsNivolumab plus rucaparib is active in patients with HRD-positive postchemotherapy or chemotherapy-naïve mCRPC, particularly those harboring BRCA1/2 mutations. Safety was as expected, with no new signals identified. Whether the addition of nivolumab incrementally improves outcomes versus rucaparib alone cannot be determined from this trial.Trial registration numberNCT03338790.
Project description:BackgroundPoly(adenosine diphosphate-ribose) polymerase (PARP) inhibitors are approved in the USA for the treatment of patients with BRCA1 or BRCA2 (BRCA) mutated (BRCA+) metastatic castration-resistant prostate cancer (mCRPC). BRCA reversion mutations are a known mechanism of acquired resistance to PARP inhibitors in multiple cancer types, although their impact and prevalence in mCRPC remain unknown.ObjectiveTo examine the prevalence of BRCA reversion mutations in the plasma of patients with BRCA+ mCRPC after progression on rucaparib.Design, setting, and participantsMen with BRCA+ mCRPC enrolled in Trial of Rucaparib in Prostate Indications 2 (TRITON2) were treated with rucaparib after progressing on one to two lines of androgen receptor-directed and one taxane-based therapy. Cell-free DNA from the plasma of 100 patients, collected at the end of treatment after confirmed progression before May 5, 2020, was queried for BRCA reversion mutations using next-generation sequencing (NGS).Outcome measurements and statistical analysisThe association of clinical efficacy and postprogression genomics was measured in 100 patients with BRCA+ mCRPC treated with rucaparib.Results and limitationsNo baseline BRCA reversion mutations were observed in 100 BRCA+ patients. NGS identified somatic BRCA reversion mutations in 39% (39/100) of patients after progression. Reversion rates were similar for BRCA2 and BRCA1, irrespective of germline or somatic status, but higher in samples with a high tumor DNA fraction. Most patients with reversions (74%, 29/39) had two or more reversion mutations occurring subclonally at lower allele frequencies than the original BRCA mutations. The incidence of BRCA reversion mutations increased with the duration of rucaparib treatment. The frequency of reversion mutations was higher in patients with an objective (58%) or a prostate-specific antigen (69%) response compared with those without either (39% and 29%, respectively).ConclusionsThese findings suggest that BRCA reversion mutations are a significant mechanism of acquired resistance to rucaparib in patients with BRCA+ mCRPC, with evidence of subclonal convergence promoting systemic resistance.Patient summaryMen with BRCA mutated metastatic castration-resistant prostate cancer enrolled in TRITON2 were treated with rucaparib after progressing on one to two lines of androgen receptor-directed and one taxane-based therapy. Cell-free DNA from the plasma of 100 patients, collected after radiographic or prostate-specific antigen progression before May 5, 2020, was analyzed by next-generation sequencing and queried for BRCA reversion mutations.
Project description:The U.S. Food and Drug Administration (FDA) granted accelerated approval to rucaparib in May 2020 for the treatment of adult patients with deleterious BRCA mutation (germline and/or somatic)-associated metastatic castrate-resistant prostate cancer (mCRPC) who have been treated with androgen receptor-directed therapy and a taxane. This approval was based on data from the ongoing multicenter, open-label single-arm trial TRITON2. The primary endpoint, confirmed objective response rate, in the 62 patients who met the above criteria, was 44% (95% confidence interval [CI]: 31%-57%). The median duration of response was not estimable (95% CI: 6.4 to not estimable). Fifty-six percent of patients had a response duration of >6 months and 15% >12 months. The safety profile of rucaparib was generally consistent with that of the class of poly-(ADP-ribose) polymerase enzyme inhibitors and other trials of rucaparib in the treatment of ovarian cancer. Deaths due to adverse events (AEs) occurred in 1.7% of patients, and 8% discontinued rucaparib because of an AE. Grade 3-4 AEs occurred in 59% of patients. No patients with prostate cancer developed myelodysplastic syndrome or acute myeloid leukemia. The trial TRITON3 in patients with mCRPC is ongoing and is planned to verify the clinical benefit of rucaparib in mCRPC. This article summarizes the FDA thought process and data supporting this accelerated approval. IMPLICATIONS FOR PRACTICE: The accelerated approval of rucaparib for the treatment of adult patients with deleterious BRCA mutation (germline and/or somatic)-associated metastatic castrate-resistant prostate cancer who have been treated with androgen receptor-directed therapy and a taxane represents the first approved therapy for this selected patient population. This approval was based on a single-arm trial demonstrating a confirmed objective response rate greater than that of available therapy with a favorable duration of response and an acceptable toxicity profile. The ongoing trial TRITON3 is verifying the clinical benefit of this drug.
Project description:PurposeThe PARP inhibitor rucaparib is approved in the United States for patients with metastatic castration-resistant prostate cancer (mCRPC) and a deleterious germline and/or somatic BRCA1 or BRCA2 (BRCA) alteration. While sequencing of tumor tissue is considered the standard for identifying patients with BRCA alterations (BRCA+), plasma profiling may provide a minimally invasive option to select patients for rucaparib treatment. Here, we report clinical efficacy in patients with BRCA+ mCRPC identified through central plasma, central tissue, or local genomic testing and enrolled in TRITON2.Patients and methodsPatients had progressed after next-generation androgen receptor-directed and taxane-based therapies for mCRPC and had BRCA alterations identified by central sequencing of plasma and/or tissue samples or local genomic testing. Concordance of plasma/tissue BRCA status and objective response rate and prostate-specific antigen (PSA) response rates were summarized.ResultsTRITON2 enrolled 115 patients with BRCA+ identified by central plasma (n = 34), central tissue (n = 37), or local (n = 44) testing. Plasma/tissue concordance was determined in 38 patients with paired samples and was 47% in 19 patients with a somatic BRCA alteration. No statistically significant differences were observed between objective and PSA response rates to rucaparib across the 3 assay groups. Patients unable to provide tissue samples and tested solely by plasma assay responded at rates no different from patients identified as BRCA+ by tissue testing.ConclusionsPlasma, tissue, and local testing of mCRPC patients can be used to identify men with BRCA+ mCRPC who can benefit from treatment with the PARP inhibitor rucaparib.
Project description:PurposeBRCA1 or BRCA2 (BRCA) alterations are common in men with metastatic castration-resistant prostate cancer (mCRPC) and may confer sensitivity to poly(ADP-ribose) polymerase inhibitors. We present results from patients with mCRPC associated with a BRCA alteration treated with rucaparib 600 mg twice daily in the phase II TRITON2 study.MethodsWe enrolled patients who progressed after one to two lines of next-generation androgen receptor-directed therapy and one taxane-based chemotherapy for mCRPC. Efficacy and safety populations included patients with a deleterious BRCA alteration who received ≥ 1 dose of rucaparib. Key efficacy end points were objective response rate (ORR; per RECIST/Prostate Cancer Clinical Trials Working Group 3 in patients with measurable disease as assessed by blinded, independent radiology review and by investigators) and locally assessed prostate-specific antigen (PSA) response (≥ 50% decrease from baseline) rate.ResultsEfficacy and safety populations included 115 patients with a BRCA alteration with or without measurable disease. Confirmed ORRs per independent radiology review and investigator assessment were 43.5% (95% CI, 31.0% to 56.7%; 27 of 62 patients) and 50.8% (95% CI, 38.1% to 63.4%; 33 of 65 patients), respectively. The confirmed PSA response rate was 54.8% (95% CI, 45.2% to 64.1%; 63 of 115 patients). ORRs were similar for patients with a germline or somatic BRCA alteration and for patients with a BRCA1 or BRCA2 alteration, while a higher PSA response rate was observed in patients with a BRCA2 alteration. The most frequent grade ≥ 3 treatment-emergent adverse event was anemia (25.2%; 29 of 115 patients).ConclusionRucaparib has antitumor activity in patients with mCRPC and a deleterious BRCA alteration, but with a manageable safety profile consistent with that reported in other solid tumor types.