Rubraca Drug Information
Generic name: RUCAPARIB
Uses of Rubraca
Maintenance Treatment of
BRCA -mutated Recurrent Ovarian Cancer RUBRACA is indicated for the maintenance treatment of adult patients with a deleterious BRCA mutation (germline and/or somatic)-associated recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to platinum-based chemotherapy.
BRCA -mutated Metastatic Castration-Resistant Prostate Cancer
RUBRACA is indicated for the treatment of adult patients with a deleterious BRCA mutation (germline and/or somatic)-associated metastatic castration-resistant prostate cancer (mCRPC) who have been treated with androgen receptor-directed therapy. Select patients for therapy based on an FDA-approved companion diagnostic for RUBRACA.
Dosage & Administration of Rubraca
| Starting Dose | 600 mg twice daily (two 300 mg tablets) |
|---|---|
| First Dose Reduction | 500 mg twice daily (two 250 mg tablets) |
| Second Dose Reduction | 400 mg twice daily (two 200 mg tablets) |
| Third Dose Reduction | 300 mg twice daily (one 300 mg tablet) |
Side Effects of Rubraca
Clinical Trials Experience
Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. The pooled safety population for patients with ovarian and prostate cancer in the WARNINGS AND PRECAUTIONS section reflect exposure to RUBRACA at 600 mg orally twice daily in 2141 patients treated on clinical trials including ARIEL3, TRITON2, and TRITON3. In ARIEL3 among the patients who received RUBRACA, 57% of patients were exposed for 6 months or longer and 33% were exposed for greater than one year. In TRITON3 among the patients with BRCA-mutated mCRPC who received RUBRACA, 66% were exposed for 6 months or longer and 34% were exposed for greater than one year.
In the pooled safety population for patients with ovarian cancer, the most common adverse reactions in ≥ 10% of patients were nausea (68%), asthenia/fatigue (65%), anemia/hemoglobin decreased (45%), AST/ALT increased (39%), vomiting (36%), diarrhea (29%), decreased appetite (27%), thrombocytopenia/platelet count decreased (25%), dysgeusia (24%), neutropenia/neutrophil count decreased (21%), blood creatinine increased (17%), dyspnea (16%), dizziness (14%), dyspepsia (11%), photosensitivity reaction (10%), and leukopenia/white blood cell count decreased (10%). In the pooled safety population for patients with BRCA -mutated mCRPC (N=373) from TRITON2 and TRITON3, the most common adverse reactions in ≥ 10% of patients were fatigue/asthenia (61%), musculoskeletal pain (52%), nausea (52%), anemia/decreased hemoglobin (49%), decreased appetite (35%), increased ALT/AST (31%), constipation (30%), diarrhea (27%), vomiting (26%), thrombocytopenia/decreased platelet count (21%), dyspnea (20%), increased blood creatinine (19%), edema (19%), dizziness (19%), weight decreased (16%), abdominal pain (15%), dysgeusia (15%), rash (13%), neuropathy peripheral (13%), urinary tract infection (13%), cough (12%), headache (12%), hemorrhage (12%), neutropenia/decreased neutrophil count (12%), and photosensitivity reaction (10%). Maintenance Treatment of BRCA -mutated Recurrent Ovarian Cancer The safety of RUBRACA for the maintenance treatment of patients with BRCA -mutated recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer was investigated in ARIEL3, a randomized (2:1), double-blind, placebo-controlled study in which 195 patients with a deleterious BRC A mutation received either RUBRACA 600 mg orally twice daily (n=129) or placebo (n=66) until disease progression or unacceptable toxicity. The median duration of study treatment was 13.6 months (range: < 1 month to 39 months) for patients who received RUBRACA and 5.5 months for patients who received placebo. Dose interruptions due to an adverse reaction of any grade occurred in 67% of patients receiving RUBRACA and 14% of those receiving placebo; dose reductions due to an adverse reaction occurred in 57% of RUBRACA patients and 6% of placebo patients.
The most frequent adverse reactions leading to dose interruption or dose reduction of RUBRACA were thrombocytopenia (25%), anemia (19%), ALT/AST increased (16%), fatigue/asthenia (14%), and nausea (10%). Discontinuation due to adverse reactions occurred in 15% of RUBRACA patients and 5% of placebo patients. Specific adverse reactions that most frequently led to discontinuation in patients treated with RUBRACA were thrombocytopenia (4%), nausea (3%), and anemia (2%). Table 2 describes the adverse reactions occurring in ≥20% of patients; while Table 3 describes the laboratory abnormalities occurring in ≥25% of patients occurring in ARIEL3. Table 2. Adverse Reactions in ≥ 20% of Patients with BRCA-mutated Ovarian Cancer in ARIEL3 a National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE version 4.03) b Consists of grouped related terms that reflect the medical concept of the adverse reaction Adverse reactions RUBRACA N=129 Placebo N=66 Grades 1-4 a % Grades 3-4 % Grades 1-4 a % Grades 3-4 % Gastrointestinal Disorders Nausea 79 2 29 0 Abdominal pain/distention b 48 3 49 2 Constipation 39 4 36 2 Vomiting 37 4 14 0 Diarrhea 34 2 18 0 Stomatitis b 28 0.8 12 0 General Disorders and Administration Site Conditions Fatigue/asthenia 74 9 52 5 Skin and Subcutaneous Tissue Disorders Rash b 45 0 23 0 Nervous System Disorders Dysgeusia 33 0 6 0 Headache 22 0 15 2 Investigations ALT/AST elevation 33 16 3 0 Blood and Lymphatic System Disorders Anemia 41 26 6 0 Thrombocytopenia 35 6 3 0 Neutropenia 22 8 6 0 Respiratory, Thoracic, and Mediastinal Disorders Nasopharyngitis/Upper respiratory tract infection b 29 0 20 2 Metabolism and Nutrition Disorders Decreased appetite 23 2 14 0 Adverse reactions occurring < 20% of patients treated with RUBRACA include insomnia (19%), dyspnea (17%), dizziness (15%), pyrexia (15%), dyspepsia (12%), peripheral edema (12%), and depression (11%). Table 3. Laboratory Abnormalities in ≥ 25% of Patients with BRCA-mutated Ovarian Cancer in ARIEL3 a Patients were allowed to enter clinical studies with laboratory values of CTCAE Grade 1. b NCI CTCAE version 4.03. Laboratory Parameter a RUBRACA N=129 Placebo N=66 Grades 1-4 b % Grades 3-4 % Grades 1-4 b % Grades 3-4 % Chemistry Increase in creatinine 96 0 89 0 Increase in ALT 67 11 6 0 Increase in AST 59 1 6 0 Increase in cholesterol 39 3 20 0 Increase in Alkaline Phosphatase 39 0 3 0 Hematology Decrease in hemoglobin 61 18 14 2 Decrease in platelets 47 2 8 0 Decrease in leukocytes 39 3 23 0 Decrease in neutrophils 38 6 18 2 Decrease in lymphocytes 33 7 14 2 Treatment of BRCA-mutated mCRPC after Androgen Receptor-directed Therapy TRITON3 The safety of RUBRACA monotherapy was evaluated in patients with BRCA-mutated mCRPC who had progressed following prior treatment with androgen receptor-directed therapy and who had not received treatment with taxane-based chemotherapy in the castration-resistant setting.. TRITON3 was a randomized, open-label, multi-center study, in which 298 patients with a deleterious BRCA mutation received either RUBRACA 600 mg twice daily (n=201) or physicians choice (n=97) of abiraterone acetate or enzalutamide, or docetaxel until disease progression, unacceptable toxicity, or up to 10 cycles for docetaxel. Among the patients who received RUBRACA, 66% were exposed for 6 months or longer and 34% were exposed for greater than one year.
Serious adverse reactions occurred in 27% of patients receiving RUBRACA. Serious adverse reactions in ≥2% of patients included anemia (4%), pneumonia (4%), urinary tract infection (3%), acute kidney injury (3%), myocardial ischemia/infarction (2%), and pulmonary embolism (2%). Fatal adverse reactions occurred in 1.5% of patients treated with RUBRACA, including cardiac failure, myocardial ischemia, and sepsis (1 patient each). Permanent discontinuation due to adverse reactions occurred in 14% of patients treated with RUBRACA. Adverse reactions which resulted in permanent discontinuation of RUBRACA in ≥2% of patients included anemia (6%), fatigue/asthenia (3%), thrombocytopenia/platelet count decreased (3%), and nausea (2%). Dosage interruptions of RUBRACA due to adverse reactions occurred in 53% of patients. Adverse reactions which required dosage interruption in ≥5% of patients included anemia (24%), fatigue/asthenia (10%), nausea (8%), and increase in ALT (5%). Dose reductions of RUBRACA due to an adverse reaction occurred in 36% of patients. Adverse reactions which required dose reduction in ≥5% of patients included anemia (16%) and fatigue/asthenia (8%). The most common adverse reactions (≥10%) in patients who received RUBRACA were fatigue/asthenia, musculoskeletal pain, nausea, decreased appetite, diarrhea, constipation, vomiting, dyspnea, dysgeusia, edema, abdominal pain, dizziness, weight decreased, rash, headache, peripheral neuropathy, photosensitivity reaction, and urinary tract infection.
The most common select laboratory abnormalities (≥25%) that worsened from baseline in patients who received RUBRACA were increased ALT, decreased neutrophils, decreased phosphate, decreased hemoglobin, increased AST, increased creatinine, increased glucose, decreased lymphocytes, decreased sodium, decreased platelets, increased calcium. Tables 4 and 5 summarize the adverse reactions and laboratory abnormalities, respectively, in patients with BRCA- mutated mCRPC in TRITON3. Table 4. Adverse Reactions in ≥ 10% of Patients with BRCA-mutated mCRPC in TRITON3 a National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE version 5.0) b Includes multiple related terms Adverse Reaction RUBRACA N=201 ARPI or Docetaxel N=97 Grades 1-4 a (%) Grades 3-4 (%) Grades 1-4 a (%) Grades 3-4 (%) General disorders and administration site conditions Fatigue/Asthenia 61 7 65 10 Edema b 18 0 20 0 Musculoskeletal and connective tissue disorders Musculoskeletal pain b 53 7 57 8 Gastrointestinal disorders Nausea 51 2 22 1 Diarrhea 31 2 29 1 Constipation 31 2 17 1 Vomiting 25 1 10 1 Abdominal pain b 17 1 10 1 Metabolism and nutrition disorders Decreased appetite 34 1 20 2 Respiratory, thoracic and mediastinal disorders Dyspnea b 19 1 13 1 Nervous system disorders Dysgeusia b 18 0 12 0 Dizziness b 16 1 9 0 Headache b 12 0 9 0 Peripheral neuropathy b 12 1 26 1 Investigations Weight decreased 16 1 13 0 Skin and subcutaneous tissue disorders Rash b 13 1 6 0 Photosensitivity reaction b 12 1 0 0 Infections and infestations Urinary tract infection b 10 3 4 1 Clinically relevant adverse reactions occurring in <10% of patients treated with RUBRACA include cough, hemorrhage, fall, hypertension, dyspepsia, pruritus, pyrexia, stomatitis, venous thromboembolism, arrhythmia, hypersensitivity, and febrile neutropenia. Table 5. Laboratory Abnormalities in ≥ 25% of Patients with BRCA-mutated mCRPC in TRITON3 a Denominator for each laboratory parameter is based on the number of patients with a baseline and post-treatment laboratory value available for 192 to 201 patients in the RUBRACA Arm and 94 to 97 patients in the ARPI or Docetaxel Arm. b NCI CTCAE version 5.0; decrease in phosphate is graded using NCI CTACE Version 4.03 Laboratory Parameter Rubraca N=201 a ARPI or Docetaxel N=97 a Grades 1-4 b (%) Grades 3-4 (%) Grades 1-4 b (%) Grades 3-4 (%) Chemistry Increase in ALT 68 4 8 0 Decrease in phosphate 64 8 45 5 Increase in AST 59 2 7 0 Increase in creatinine 56 1 16 0 Increase in glucose 45 6 38 3 Decrease in sodium 35 5 21 4 Increase in calcium 29 3 19 2 Hematology Decrease in neutrophils 67 9 24 10 Decrease in hemoglobin 60 23 31 2 Decrease in lymphocytes 43 14 45 17 Decrease in platelets 34 6 4 0 TRITON2 The safety of RUBRACA 600 mg twice daily was evaluated in a single arm trial (TRITON2). TRITON2 enrolled 209 patients with HRR-mutated mCRPC, including 115 with BRCA-mutated mCRPC. Among the patients with BRCA -mutated mCRPC, the median duration of RUBRACA treatment was 6.5 months (range 0.5 to 26.7). Fatal adverse reactions occurred in 1.7% of patients who received RUBRACA, including acute respiratory distress syndrome and pneumonia (1 patient each). Permanent discontinuation of RUBRACA due to an adverse reaction occurred in 8% of patients.
Dosage interruption of RUBRACA due to an adverse reaction occurred in 57% of patients. Dose reductions of RUBRACA occurred in 41% of patients. Tables 6 and 7 summarize the adverse reactions and laboratory abnormalities, respectively, in patients with BRCA -mutated mCRPC in TRITON2. Table 6. Adverse Reactions in ≥ 20% of Patients with BRCA-mutated mCRPC in TRITON2 a NCI CTCAE version 4.03. b Includes platelet count decreased c Includes blister, blood blister, dermatitis, dermatitis contact, eczema, genital rash, palmar-plantar erythrodysaesthesia syndrome, photosensitivity reaction, psoriasis, rash, rash maculo-papular, rash pruritic, skin exfoliation, skin lesion, urticaria Adverse Reaction Rubraca N = 115 Grades 1-4 a (%) Grades 3-4 (%) General disorders and administration site conditions Asthenia/Fatigue 62 9 Gastrointestinal disorders Nausea 52 3 Constipation 27 1 Vomiting 22 1 Diarrhea 20 0 Blood and lymphatic system disorders Anemia 43 25 Thrombocytopenia b 25 10 Metabolism and nutrition disorders Decreased appetite 28 2 Skin and subcutaneous tissue disorders Rash c 27 2 Other clinically relevant adverse reactions that occurred in less than 20% of patients included dyspnea, dizziness, bleeding, urinary tract infection, dysgeusia, dyspepsia, hypersensitivity (including flushing, asthma, choking sensation, periorbital swelling, swelling face, and wheezing), pneumonia, sepsis, ischemic cardiovascular events, renal failure, venous thromboembolism, and stomatitis.
Table 7. Laboratory Abnormalities in ≥ 35% (Grades 1-4) and ≥ 2% (Grades 3-4) Worsening from Baseline in Patients with BRCA-mutated mCRPC in TRITON2 a Denominator for each laboratory parameter is based on the number of patients with a baseline and post-treatment laboratory value available for 111 to 115 patients. b NCI CTCAE version 5.0; decrease in phosphate is graded using NCI CTACE Version 4.03 c Grade 3-4 ALT or AST elevation led to drug interruption in 4 patients, of which 1 had dose reduction upon rechallenge. Laboratory Parameter Rubraca N = 115 a Grades 1-4 b (%) Grades 3-4 (%) Clinical Chemistry Increase in ALT c 69 5 Decrease in phosphate 68 15 Increase in alkaline phosphatase 44 2 Increase in creatinine 43 2 Increase in triglycerides 42 5 Decrease in sodium 38 3 Hematologic Decrease in leukocytes 69 5 Decrease in absolute neutrophil count 62 5
Warnings & Cautions for Rubraca
Myelodysplastic Syndrome/Acute Myeloid Leukemia Myelodysplastic Syndrome (MDS)/Acute Myeloid Leukemia (AML) occur in
patients treated with RUBRACA, and are potentially fatal adverse reactions. In 2141 treated patients with ovarian and prostate cancer, MDS/AML occurred in 34 patients (1.6%), including those in long term follow-up. Of these, 14 occurred during treatment or during the 28-day safety follow-up (0.7%). The duration of RUBRACA treatment prior to the diagnosis of MDS/AML ranged from < 2 months to approximately 72 months.
The cases were typical of secondary MDS/cancer therapy-related AML; in all cases, patients had received previous platinum-containing chemotherapy regimens and/or other DNA damaging agents. In ARIEL3, of patients with a germline and/or somatic BRCA mutation treated with RUBRACA, MDS/AML occurred in 9 out of 129 (7%) patients treated with RUBRACA and 4 out of 66 (6%) patients treated with placebo. The duration of therapy with RUBRACA in patients who developed secondary MDS/cancer therapy-related AML varied from 1.2 to 4.7 years.
In TRITON3, MDS/AML occurred in 2 out of 201 patients (1%) with a BRCA mutation treated with RUBRACA. The duration of therapy with RUBRACA in patients who developed secondary MDS/cancer therapy-related AML varied from 1.4 to 2.3 years. Do not start Rubraca until patients have recovered from hematological toxicity caused by previous chemotherapy (≤ Grade 1). Monitor complete blood counts for cytopenia at baseline and monthly thereafter for clinically significant changes during treatment. For prolonged hematological toxicities (> 4 weeks), interrupt Rubraca or reduce dose according to Table 1 and monitor blood counts weekly until recovery.
If the levels have not recovered to Grade 1 or less after 4 weeks or if MDS/AML is suspected, refer the patient to a hematologist for further investigations, including bone marrow analysis and blood sample for cytogenetics. If MDS/AML is confirmed, discontinue Rubraca.
Embryo-Fetal Toxicity Rubraca can cause fetal harm when administered to a pregnant
woman based on its mechanism of action and findings from animal studies. In an animal reproduction study, administration of rucaparib to pregnant rats during the period of organogenesis resulted in embryo-fetal death at exposures that were 0.04 times the AUC 0-24h in patients receiving the recommended human dose of 600 mg twice daily. Apprise pregnant women of the potential risk to a fetus.
Advise females of reproductive potential to use effective contraception during treatment and for 6 months following the last dose of Rubraca. Based on findings from genetic toxicity and animal reproduction studies, advise male patients with female partners of reproductive potential or who are pregnant to use effective contraception during treatment and for 3 months following the last dose of Rubraca.
Drug Interactions with Rubraca
Effect of Rubraca on Other Drugs Certain
CYP1A2, CYP3A, CYP2C9, or CYP2C19 Substrates Concomitant administration of Rubraca with CYP1A2, CYP3A, CYP2C9, or CYP2C19 substrates can increase the systemic exposure of these substrates , which may increase the frequency or severity of adverse reactions of these substrates. If concomitant administration is unavoidable between Rubraca and substrates of these enzymes where minimal concentration changes may lead to serious adverse reactions, decrease the substrate dosage in accordance with the approved prescribing information. If concomitant administration with warfarin (a CYP2C9 substrate) cannot be avoided, consider increasing the frequency of international normalized ratio (INR) monitoring.
Pregnancy Safety for Rubraca
Pregnancy Risk Summary Based on findings from animal studies and its mechanism of action, Rubraca can cause fetal harm when administered to pregnant women. There are no available data in pregnant women to inform the drug-associated risk. In an animal reproduction study, administration of rucaparib to pregnant rats during organogenesis resulted in embryo-fetal death at maternal exposures that were 0.04 times the AUC 0-24h in patients receiving the recommended dose of 600 mg twice daily . Apprise pregnant women of the potential risk to a fetus.
The background risk of major birth defects and miscarriage for the indicated population is unknown. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal Data In a dose range-finding embryo-fetal development study, pregnant rats received oral doses of 50, 150, 500, or 1000 mg/kg/day of rucaparib during the period of organogenesis.
Post-implantation loss (100% early resorptions) was observed in all animals at doses greater than or equal to 50 mg/kg/day (with maternal systemic exposures approximately 0.04 times the human exposure at the recommended dose based on AUC 0-24h ).
Pediatric Use of Rubraca
Pediatric Use The safety and effectiveness of Rubraca in pediatric patients have not been established.
Clinical Studies of Rubraca
Maintenance Treatment of
BRCA -mutated Recurrent Ovarian Cancer The efficacy of Rubraca was investigated in ARIEL3 ( NCT01968213 ), a double-blind, multicenter clinical trial in which 564 patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who were in response to platinum-based chemotherapy were randomized (2:1) to receive Rubraca tablets 600 mg orally twice daily (n=375) or placebo (n=189). Treatment was continued until disease progression or unacceptable toxicity. All patients had achieved a response (complete or partial) to their most recent platinum-based chemotherapy. Randomization was stratified by best response to last platinum (complete or partial), time to progression following the penultimate platinum therapy (6 to ≤12 months and >12 months), and tumor biomarker status.
Tumor tissue samples were tested using a clinical trial assay (CTA) (N=564) and an investigational Foundation Medicine tissue test (n=518). Of the samples evaluated with both tests, tumor BRCA (t BRCA ) mutant status was confirmed for 99% (177/178) of t BRCA -positive patients determined by the CTA. Blood samples for 94% (186/196) of the t BRCA patients were evaluated using a central blood germline BRCA test. Based on these results, 70% (130/186) of the t BRCA patients had a germline BRCA mutation and 30% (56/186) had a somatic BRCA mutation. The efficacy results are based on the t BRCA (germline or somatic) subgroup.
The major efficacy outcome was investigator-assessed progression-free survival (PFS) evaluated according to Response Evaluation Criteria in Solid Tumors (RECIST), version 1.1 (v1.1). Overall survival (OS) was an additional outcome measure. Of the 564 enrolled patients, 196 patients (35%) had a t BRCA mutation. Among the patients who had a tBRCA mutation, the median age was 58 years (range: 42 to 81) for patients receiving Rubraca and 59 years (range: 36 to 84) for those on placebo; the majority were White (84%); and 100% had an ECOG performance status of 0 or 1. All patients had received at least two prior platinum-based chemotherapies (range: 2 to 5). A total of 33% of patients were in complete response (CR) to their most recent therapy.
The progression-free interval to penultimate platinum was 6-12 months in 41% of patients and >12 months in 59%. Prior bevacizumab therapy was reported for 22% of patients who received Rubraca and 17% of patients who received placebo. Measurable disease was present at baseline in 32% of patients. ARIEL3 demonstrated a statistically significant improvement in PFS for patients randomized to Rubraca as compared with placebo in patients who had a t BRCA mutation.
Results from a blinded independent radiology review were consistent. Efficacy results for patients with a t BRCA mutation are summarized in Table 8 and Figure 1. Table 8. Efficacy Results in Patients with tBRCA-mutated Ovarian Cancer – ARIEL3 (Investigator Assessment) a a t BRCA includes all patients with a deleterious germline or somatic BRCA mutation, as determined by the CTA. Rubraca N=130 Placebo N=66 Progression Free Survival Number of events, n (%) 67 (52%) 56 (85%) Median in months (95% CI) 16.6 (13.4-22.9) 5.4 (3.4-6.7) HR (95% CI) 0.23 p-value < 0.0001 Figure 1 Kaplan-Meier Curves of Progression-Free Survival in ARIEL3 as Assessed by Investigator: t BRCA Group A final OS analysis was conducted after 130 events were observed. Exploratory OS results showed a HR of 0.83 (95% CI: 0.58, 1.19) in the t BRCA subgroup with a median OS of 45.9 months (95% CI: 37.7, 59.6) for patients treated with Rubraca and 47.8 months (95% CI: 43.2, 55.8) for patients on placebo. 2
BRCA -mutated Metastatic Castration-Resistant Prostate Cancer
TRITON3 The efficacy of RUBRACA was evaluated in TRITON3 ( NCT02975934 ), a randomized, open-label, multi-center trial that evaluated RUBRACA compared to an androgen receptor pathway inhibitor (ARPI; enzalutamide or abiraterone acetate) or docetaxel in patients with progressive BRCA or ATM mutated metastatic castrate-resistant prostate cancer (mCRPC). The trial enrolled 405 patients with mCRPC, of whom 302 had BRCA mutations. Patients were required to have progressed on treatment with one ARPI and could not have received prior chemotherapy in the castrate-resistant setting. Prior taxane chemotherapy for castration-sensitive disease was permitted.
Patients were required to be surgically or medically castrated with a castrate level of serum testosterone at study entry. BRCA gene mutation status was determined prospectively testing tumor tissue or plasma using Foundation Medicine, Inc. assays or through local testing. Patients were randomized (2:1) to receive RUBRACA 600 mg twice daily (n=270) or ARPI (enzalutamide or abiraterone acetate; n=60) or docetaxel (n=75). Randomization was stratified by ECOG performance status (0 or 1), hepatic metastases (present or not), and type of mutation ( BRCA 1, BRCA 2, or ATM ). If patients were being treated with androgen deprivation therapy (ADT), therapy was continued throughout the study.
Bone-targeted agents were allowed. Of the 302 patients with BRCA m disease, the median age was 69 years (range: 45 to 92 years); 75% were White, 5% Black, 1.3% Asian, 0.3% American Indian or Alaska Native, 1% multiple races, and 18% unknown; 1.7% were Hispanic/Latino; and baseline ECOG performance status (PS) was 0 (49%) or 1 (51%). Forty percent of patients had bone-only disease; 32% had visceral disease. In the mCSPC setting, 23% of patients had received docetaxel.
Among those with BRCA m disease, 40 patients had BRCA 1 mutations, and 262 patients had BRCA 2 mutations. The major efficacy outcome measure was radiographic progression-free survival (rPFS) as determined by independent radiology review (IRR) using RECIST version 1.1 and Prostate Cancer Clinical Trials Working Group 3 (PCWG3) (bone) criteria. Additional efficacy outcome measures included overall survival (OS) and IRR-assessed objective response rate (ORR). TRITON3 demonstrated a statistically significant improvement in IRR-assessed rPFS for RUBRACA compared to ARPI or docetaxel in patients with BRCA m and in the overall population.
In an exploratory analysis in the subgroup of 103 (25%) patients with ATM mutations, the rPFS hazard ratio was 0.95 (95% CI: 0.59, 1.52) and the OS hazard ratio was 1.21 (95% CI: 0.77, 1.90), indicating that the improvement in the overall population was primarily attributed to the results seen in the subgroup of patients with BRCA m. Of patients with BRCA m who were randomized to receive ARPI or docetaxel (n=101), 52% crossed over to receive RUBRACA after disease progression. Efficacy results of the BRCA m population in TRITON3 are provided in Table 9, Figure 2 and Figure 3. Table 9. Efficacy Results from the BRCAm Subgroup of the TRITON3 Study Endpoint Rubraca N=201 f ARPI or Docetaxel N=101 f Radiographic Progression Free Survival a Number of events, n (%) 115 (57%) 67 (66%) Median in months (95% CI) 11.2 (9.2-13.8) 6.4 (5.4-8.3) Hazard ratiob (95% CI) 0.50 p-value c < 0.0001 Overall Survival d Number of events, n (%) 152 (76%) 74 (73%) Median in months (95% CI) 23.2
Hazard ratio b (95% CI) 0.91 p-value c NS Confirmed Overall Response
Rate a,e N=82 N=41 Overall response rate (95% CI) 45.1
Number of complete responses, n (%) 10 2 Number of partial responses
n (%) 27 5 NS=Not significant a Based on IRR assessment. b Cox proportional hazards model stratified by ECOG Status (0 or 1) and type of mutation ( BRCA 1 or BRCA 2). c P-value based on the stratified log-rank test d Based on pre-specified final analysis. e Based on patients with measurable disease at baseline per IRR assessment. Responses are based on soft tissue and bone lesion assessment. f Based on the BRCA mutation status used at the randomization. This excludes one patient with a reported ATM mutation at randomization but found to have a BRCA2 mutation based on the verified source.
Figure 2 Kaplan-Meier Curves of rPFS from the BRCAm Subgroup of the TRITON3 Study (IRR-assessed) Figure 3 Kaplan-Meier Curves of Final OS from the BRCAm Subgroup of the TRITON3 Study Exploratory subgroup analysis of rPFS and OS for patients with BRCA1m and BRCA2m (including one patient with a BRCA2 mutation mischaracterized as having an ATM mutation at randomization) were performed. The rPFS and OS hazard ratios were 1.01 (95% CI: 0.48, 2.13) and 0.96 (95% CI: 0.46, 2.00) respectively in the subgroup with BRCA1 mutations (n=40) and 0.46 (95% CI: 0.33, 0.65) and 0.92 (95% CI: 0.68, 1.24) respectively in the subgroup with BRCA2 mutations (n=263). TRITON2 The efficacy of Rubraca was investigated in TRITON2 ( NCT02952534 ), an ongoing multi-center, single arm clinical trial in patients with BRCA -mutated mCRPC who had been treated with androgen receptor-directed therapy and taxane-based chemotherapy. There were 115 patients with either germline or somatic BRCA mutations enrolled in TRITON2, of whom 62 patients had measurable disease at baseline by independent radiology review (IRR). Patients received Rubraca 600 mg orally twice daily until disease progression or unacceptable toxicity.
Patients also received concomitant GnRH analog or had prior bilateral orchiectomy. Objective response rate (ORR) and duration of response (DOR) were assessed in patients with measurable disease by blinded IRR and by the investigator according to modified RECIST v1.1/ Prostate Cancer Working Group 3 (PCWG3) criteria. For the 62 patients with measurable disease at baseline, the median age was 73 years (range 52 to 88); the majority were White (73%) and 10% were Black; and 98% of patients had an ECOG performance status of 0 or 1. All patients had received at least one prior androgen receptor-directed therapy, 34% had received 2 prior androgen receptor-directed therapies and 2% had received 3 prior androgen receptor-directed therapies, and all patients also received prior taxane chemotherapy.
Eighteen percent of patients had lung and 21% had liver metastases at baseline. Twenty-four percent had metastases to lymph nodes alone. Forty percent had 10 or more bone lesions at baseline.
All 62 patients had a deleterious somatic or germline BRCA mutation detected from either central plasma (26%), central tissue (32%), or local (42%) testing. Of the 62 patients, 66% had a somatic BRCA mutation, 34% had a germline BRCA mutation, 85% had a BRCA2 mutation, and 15% had a BRCA1 mutation. The major efficacy outcomes of the study were confirmed ORR by IRR using modified RECIST v1.1/PCWG3 criteria and DOR. Efficacy results of TRITON2 are provided in Table 10. The ORR by IRR was similar in patients with germline versus somatic BRCA mutation.
Table 10. Efficacy Results in Patients with BRCA-mutated mCRPC - TRITON2 (IRR-assessed) NE = not evaluable a Defined per modified RECIST v1.1 criteria and with no confirmed bone progression per PCWG3. b The range for the DOR was 1.7-24+ months. Fifteen of the 27 (56%) patients with a confirmed objective response had a DOR of ≥6 months. Rubraca (N = 62) Confirmed Objective Response Rate (95% CI) a 44% Median DOR in months (95% CI) b NE (6.4, NE) 5 4
Drug information sourced from the FDA. This content is for informational purposes only and does not constitute medical advice. Consult a healthcare professional before making any medication decisions.
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