Abstract
Purpose: Rucaparib is a potent, oral, small-molecule PARP inhibitor. This phase I–II study was the first to evaluate single-agent oral rucaparib at multiple doses.
Experimental Design: Part 1 (phase I) sought to determine the MTD, recommended phase II dose (RP2D), and pharmacokinetics of oral rucaparib administered in 21-day continuous cycles in patients with advanced solid tumors. Part 2A (phase II) enrolled patients with platinum-sensitive, high-grade ovarian carcinoma (HGOC) associated with a germline BRCA1/2 mutation who received two to four prior regimens and had a progression-free interval of 6 months or more following their most recent platinum therapy. The primary endpoint was investigator-assessed objective response rate (ORR) by RECIST version 1.1.
Results: In part 1, 56 patients received oral rucaparib (40 to 500 mg once daily and 240 to 840 mg twice daily). No MTD was identified per protocol-defined criteria; 600 mg twice daily was selected as the RP2D based on manageable toxicity and clinical activity. Pharmacokinetics were approximately dose-proportional across all dose levels. In part 2A, 42 patients with germline BRCA1/2–mutated HGOC received rucaparib 600 mg twice daily. Investigator-assessed ORR was 59.5%. The most common treatment-emergent adverse events (all grades) were asthenia/fatigue (85.7%; 36/42), nausea (83.3%; 35/42), anemia (71.4%; 30/42), alanine transaminase and/or aspartate transaminase elevations (57.1%; 24/42), and vomiting (54.8%; 23/42). Among 98 patients, 5 (5.1%) discontinued because of an adverse event (excluding disease progression).
Conclusions: Rucaparib was tolerable and had activity in patients with platinum-sensitive germline BRCA1/2–mutated HGOC. Clin Cancer Res; 23(15); 4095–106. ©2017 AACR.
This article is featured in Highlights of This Issue, p. 3975
PARP-1, PARP-2, and PARP-3 enzymes are key mediators of DNA repair in response to single-strand breaks. Inhibition of these enzymes results in accumulation of double-strand DNA breaks that are repaired through BRCA1- and BRCA2-mediated homologous recombination (HR). Defects in HR repair (e.g., BRCA1 and BRCA2 mutations) can sensitize tumors to PARP inhibition through synthetic lethality. This phase I–II study was the first to fully evaluate single-agent oral rucaparib, a PARP inhibitor, in heavily pretreated patients with advanced solid tumors. In part 1, pharmacokinetics were dose proportional, safety was manageable, and rucaparib 600 mg twice daily was the recommended phase II dose. In part 2A, rucaparib 600 mg twice-daily treatment had robust antitumor activity in patients with platinum-sensitive ovarian cancer and a germline BRCA1/2 mutation. These results support further clinical and translational investigation of rucaparib in tumors with HR repair deficiency, potentially extending applicability beyond BRCA-mutated cancers.
Introduction
PARP enzymes make up a 17-member superfamily of nuclear enzymes; PARP-1, -2, and -3 are activated by and promote the repair of DNA damage (1). PARP-1 and -2 are the most abundant enzymes and have a major role in the repair of DNA single-strand breaks through the base excision repair/single-strand break repair pathway (1). PARP inhibition results in accumulation of unrepaired single-strand breaks, which result in collapsed replication forks and an accumulation of DNA double-strand breaks (2, 3). These double-strand breaks are repaired by the homologous recombination (HR) repair pathway, in which BRCA1 and BRCA2 are key proteins (4–6). It is widely accepted that tumors with a BRCA1/2 mutation or other HR deficiency (HRD) are selectively sensitive to PARP inhibition by a mechanism of synthetic lethality (7–9). Several recent reports have proposed additional models by which PARP inhibition may result in synthetic lethality (10, 11). For example, PARP inhibition may affect the role these enzymes play in the alternative nonhomologous end-joining DNA repair pathway, which is upregulated in HR-deficient cells (12, 13). In addition, PARP inhibitors have been shown to trap PARP-1 and -2 at the site of the DNA break (14). These trapped PARP–DNA complexes may directly damage the cell by obstructing replication forks, requiring HR repair for resolution (10, 14).
Several PARP inhibitors are currently in development for the treatment of patients with tumors harboring HRD, including those with a BRCA1/2 mutation (15–26). Single-agent olaparib is approved in the United States for the treatment of patients with advanced germline BRCA1/2–mutated ovarian cancer who have received three or more lines of chemotherapy (27, 28). Rucaparib (CO-338; formerly known as AG-014447 and PF-01367338) is a potent small-molecule inhibitor of PARP-1, -2, and -3 (29, 30), and was approved in the United States in December 2016 for the treatment of patients with advanced ovarian cancer associated with deleterious germline or somatic BRCA mutations who have received two or more chemotherapies (31). Consistent with the concept of synthetic lethality, rucaparib is preferentially cytotoxic to cells with a BRCA1 or BRCA2 mutation or epigenetically silenced BRCA1 (7, 32).
An open-label, phase II study investigated intermittent dosing of intravenous rucaparib (5 days of a 21-day cycle), as well as intermittent and continuous dosing of oral rucaparib (7, 14, or 21 days of a 21-day cycle) in small cohorts of patients with advanced ovarian or breast cancer associated with a germline BRCA1/2 mutation (33). This study provided evidence that continuous dosing of oral rucaparib led to a higher rate of response than intermittent intravenous dosing (response rate, 18% vs. 2%). The intravenous formulation was discontinued. However, the maximum oral dose of rucaparib 600 mg twice daily for 21 continuous days was evaluated in only 1 patient, and the study did not establish a recommended phase II dose (RP2D) for the oral formulation, which was a secondary endpoint.
The phase I–II study reported here was the first to fully evaluate single-agent oral rucaparib administered for multiple cycles in patients with an advanced solid tumor, including a cohort of patients with BRCA1/2–mutated ovarian cancer who had received multiple prior treatments. The objectives of this study included characterization of the safety and pharmacokinetic profiles, assessment of preliminary clinical activity, and establishment of the RP2D of rucaparib. Here, we present results from Study 10 part 1 (phase I dose escalation), as well as part 2A (phase II expansion) that evaluated the RP2D of rucaparib as single-agent treatment in patients with platinum-sensitive, high-grade ovarian cancer (HGOC) associated with a germline BRCA1/2 mutation.
Materials and Methods
Study design and patients
This is an ongoing, three-part, open-label, phase I–II study of single-agent oral rucaparib (ClinicalTrials.gov identifier, NCT01482715). It was approved by the institutional review board at each study site and is being conducted in accordance with the Declaration of Helsinki and the Good Clinical Practice Guidelines of the International Conference on Harmonisation. Patients provided written consent before participating in the study. Part 1 (phase I dose escalation) enrolled patients who were at least 18 years of age with an advanced solid tumor that had progressed on standard treatment. Eligible patients had an Eastern Cooperative Oncology Group (ECOG) Performance Status (PS) of 0 to 1 and adequate hematologic, hepatic, and renal function. Measurable disease and a known BRCA1/2 mutation were not required. The primary objectives of part 1 were to characterize the safety and pharmacokinetic profile of oral rucaparib administered as a continuous daily dose and establish the MTD and RP2D in patients with an advanced solid tumor. Antitumor activity was evaluated as a secondary objective.
Part 2A (phase II expansion) evaluated the RP2D of oral rucaparib in patients with platinum-sensitive, relapsed, high-grade serous or endometrioid epithelial ovarian, fallopian tube, or primary peritoneal cancer associated with a germline BRCA1/2 mutation. Eligible patients received between two and four prior treatment regimens, had an ECOG PS of 0 to 1, had a progression-free interval (PFI) of 6 months or longer after their most recent platinum-based regimen, and had measurable disease (of any size; with or without visceral metastasis) per RECIST version 1.1. Part 2A utilized a Simon two-stage design requiring two or more responses in the first 21 patients to continue to stage 2; total planned enrollment was 41 patients. The primary endpoint was investigator-assessed objective response rate (ORR) per RECIST. Secondary objectives included evaluation of duration of response and safety. An independent radiology review of ORR for patients in part 2A was performed retrospectively.
Study treatment
Using a standard 3 + 3 design for dose escalation (part 1), patients received oral rucaparib once daily or twice daily in 21-day continuous treatment cycles, starting at 40 mg once daily with escalations to 80, 160, 300, and 500 mg once daily, then further escalation to 240, 360, 480, 600, and 840 mg twice daily. The protocol was amended approximately 10 months after enrollment began to allow intrapatient dose escalation. Patients in part 2A received the RP2D of oral rucaparib established in part 1. Treatment continued until disease progression or unacceptable toxicity. A new cycle of treatment could begin if a patient's absolute neutrophil count was 1.0 × 109/L or greater, platelet count was 75.0 × 109/L or greater, and nonhematologic toxicities had returned to baseline or were grade 1 or less.
Definition of dose-limiting toxicity and MTD
In part 1, dose-limiting toxicities (DLT) were defined as any of the following events that occurred during cycle 1 and were assessed by the investigator as related to rucaparib: absolute neutrophil count less than 0.5 × 109/L lasting for more than 5 days or febrile neutropenia; platelets less than 25 × 109/L or platelets less than 50 × 109/L with bleeding requiring a platelet transfusion; grade 4 anemia; or any nonhematologic adverse event (AE) grade 3 or greater (except nausea, vomiting, and diarrhea, if well controlled by systemic medication, and alopecia). Dose escalation continued until 33% or more of patients treated at a dose level experienced a DLT. The next lower dose was then considered the MTD.
Pharmacokinetics, safety, and efficacy assessments
Pharmacokinetic assessments in part 1 included single-dose and steady-state (day 15) profiles in cycle 1 and trough levels in selected cycles. Blood was collected prior to rucaparib dosing and from 15 minutes to 24 hours after dosing on days 1 and 15. Samples for pharmacokinetic analysis were collected before and/or after the morning dose for all patients on a twice-daily dosing schedule. Safety assessments included evaluation of AEs, hematology, clinical chemistry, vital signs, body weight, concomitant medications and/or procedures, ECOG PS, electrocardiograms, and rucaparib dose modifications. Adverse events were classified according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 4 (34).
Tumor assessments consisted of clinical examination and computed tomography scans of the chest, abdomen, and pelvis (with appropriate slice thickness per RECIST; ref. 35). Other assessments (e.g., MRI) were performed only if clinically required. Tumor assessments were performed at screening, prior to cycles 3, 5, and 7, and every three cycles of treatment thereafter from cycle 10. Tumor responses (per RECIST) were assessed in all patients; however, for those without measurable disease at baseline (permitted in part 1), only a best response of stable or progressive disease could be achieved. Response in patients with ovarian cancer was also assessed using Gynecologic Cancer InterGroup (GCIG) cancer antigen 125 (CA-125) criteria (36). Confirmatory scans were required 4 to 6 weeks after an initial complete response (CR) or partial response (PR) was noted.
Dose reductions
Up to three dose reduction steps were permitted to manage treatment-related toxicity. In the event of grade 3 or 4 toxicity, treatment was held until resolution to grade 2 or less before readministration of rucaparib. If dosing was interrupted for more than 14 consecutive days because of toxicity, treatment was discontinued unless the patient was deriving clinical benefit and the sponsor approved continuation of treatment. In part 1, rucaparib was reduced to the next lower dose level. In part 2A, rucaparib dose was reduced by increments of 120 mg.
Statistical analysis
For part 1, it was estimated that 6 to 12 dose-escalation cohorts, with a minimum of 3 patients each, would be needed to evaluate the RP2D of oral rucaparib. In part 2A, it was estimated that at least 41 patients evaluable for response would be needed to evaluate the efficacy of rucaparib.
The single-dose and steady-state rucaparib pharmacokinetic data following oral administration were analyzed using noncompartmental methods. The pharmacokinetic parameters included area under the concentration time curve (AUC) from time 0 to last measurable concentration, maximum concentration (Cmax), time to Cmax (Tmax), half-life (t1/2), apparent steady-state clearance (CLss/F), and accumulation ratio. Time to reach steady state was estimated on the basis of the plasma trough concentration–time profile. Dose proportionality was assessed for once-daily and twice-daily dosing using log-transformed pharmacokinetic parameters and dose by linear regression. The effect of food on single-dose rucaparib exposure, as measured by Cmax and AUC time 0 to 24 hours (AUC0–24), was assessed at the 40 and 300 mg once-daily dose levels.
Safety analyses were performed by study part and by dose level in all patients who received at least one dose of rucaparib. The ORR was summarized for all patients enrolled in part 2A who received at least one dose of rucaparib, and presented as percentage with 95% confidence interval (CI) using Clopper–Pearson methodology. Duration of confirmed response (CR or PR) was measured from the date of first response until the date that progressive disease was objectively documented, or censored at the last tumor evaluation. Kaplan–Meier methodology was used to analyze duration of response and presented with the median and 95% CI values.
Results
Part 1 (phase I dose escalation)
Patients and treatments.
Between December 2011 and October 2013, 56 patients were enrolled into part 1 of the study. Results from part 1 are based on a visit cut-off date of November 30, 2015.
Baseline characteristics are presented in Table 1. Most patients had either breast (48.2%; 27/56) or ovarian (35.7%; 20/56) cancer. The majority of patients (64.3%; 36/56) had a germline BRCA1 or BRCA2 mutation identified by local testing; for 7 of 56 patients (12.5%), germline status was not confirmed as local BRCA testing was conducted using DNA extracted from tissues other than blood or buccal samples (e.g., tumor tissue only). For 20 of 56 patients (35.7%), a BRCA mutation was not detected or no test was performed.
Baseline patient and disease characteristics
Parameter . | Part 1 phase I (n = 56) . | Part 2A phase II (n = 42) . |
---|---|---|
Age, median (range), y | 51 (21–71) | 57 (42–84) |
Gender, n (%) | ||
Female | 51 (91.1) | 42 (100.0) |
Male | 5 (8.9) | 0 (0) |
ECOG PS, n (%) | ||
0 | 29 (51.8) | 26 (61.9) |
1 | 27 (48.2) | 16 (38.1) |
Germline BRCA1/2 mutation, n (%) | ||
Yes | 36 (64.3) | 42 (100.0) |
No mutation detected | 9 (16.1) | 0 (0) |
No test performeda | 11 (19.6) | 0 (0) |
BRCA gene mutation, n (%) | ||
BRCA1 | 22 (39.3) | 30 (71.4) |
BRCA2 | 14 (25.0) | 12 (28.6) |
Type of cancer, n (%) | ||
Breast | 27 (48.2) | 0 (0) |
Ovarian | 20 (35.7) | 42 (100.0) |
Pancreatic (exocrine) | 2 (3.6) | 0 (0) |
Otherb | 7 (12.5) | 0 (0) |
Histologic classification, n (%) | ||
Serous | NA | 37 (88.1) |
Mixed | NA | 3 (7.1) |
Endometrioid | NA | 1 (2.4) |
Clear cell | NA | 1 (2.4) |
Platinum status of patients with ovarian cancer, n (%)c | ||
Refractory | 1 (1.8) | 0 (0) |
Resistant | 11 (19.6) | 0 (0) |
Sensitive | 8 (14.3) | 42 (100.0) |
Progression-free interval from last platinum therapy, n (%) | ||
≥6–12 mo | NA | 32 (76.2) |
>12 mo | NA | 10 (23.8) |
Previous anticancer therapies, median (range) | 4 (1–15) | 2 (2–4) |
≥3 previous anticancer therapies, n (%) | 41 (73.2) | 15 (35.7) |
Previous chemotherapies, median (range) | 3 (1–13) | 2 (2–4) |
≥3 previous chemotherapies, n (%) | 37 (66.1) | 15 (35.7) |
Previous platinum-based chemotherapies, median (range) | 1 (0–5) | 2 (2–4) |
≥3 previous platinum-based chemotherapies, n (%) | 9 (16.1) | 13 (31.0) |
Parameter . | Part 1 phase I (n = 56) . | Part 2A phase II (n = 42) . |
---|---|---|
Age, median (range), y | 51 (21–71) | 57 (42–84) |
Gender, n (%) | ||
Female | 51 (91.1) | 42 (100.0) |
Male | 5 (8.9) | 0 (0) |
ECOG PS, n (%) | ||
0 | 29 (51.8) | 26 (61.9) |
1 | 27 (48.2) | 16 (38.1) |
Germline BRCA1/2 mutation, n (%) | ||
Yes | 36 (64.3) | 42 (100.0) |
No mutation detected | 9 (16.1) | 0 (0) |
No test performeda | 11 (19.6) | 0 (0) |
BRCA gene mutation, n (%) | ||
BRCA1 | 22 (39.3) | 30 (71.4) |
BRCA2 | 14 (25.0) | 12 (28.6) |
Type of cancer, n (%) | ||
Breast | 27 (48.2) | 0 (0) |
Ovarian | 20 (35.7) | 42 (100.0) |
Pancreatic (exocrine) | 2 (3.6) | 0 (0) |
Otherb | 7 (12.5) | 0 (0) |
Histologic classification, n (%) | ||
Serous | NA | 37 (88.1) |
Mixed | NA | 3 (7.1) |
Endometrioid | NA | 1 (2.4) |
Clear cell | NA | 1 (2.4) |
Platinum status of patients with ovarian cancer, n (%)c | ||
Refractory | 1 (1.8) | 0 (0) |
Resistant | 11 (19.6) | 0 (0) |
Sensitive | 8 (14.3) | 42 (100.0) |
Progression-free interval from last platinum therapy, n (%) | ||
≥6–12 mo | NA | 32 (76.2) |
>12 mo | NA | 10 (23.8) |
Previous anticancer therapies, median (range) | 4 (1–15) | 2 (2–4) |
≥3 previous anticancer therapies, n (%) | 41 (73.2) | 15 (35.7) |
Previous chemotherapies, median (range) | 3 (1–13) | 2 (2–4) |
≥3 previous chemotherapies, n (%) | 37 (66.1) | 15 (35.7) |
Previous platinum-based chemotherapies, median (range) | 1 (0–5) | 2 (2–4) |
≥3 previous platinum-based chemotherapies, n (%) | 9 (16.1) | 13 (31.0) |
Abbreviation: NA, not applicable.
aPatients did not have local or central BRCA testing performed.
bOne each of the following: small-cell lung cancer, gastric cancer, colon cancer, desmoplastic round cell tumor, mesenchymal chondrosarcoma of the skull, astrocytoma, and angiosarcoma.
cPlatinum status was not applicable for 36 patients (64.3%) in part 1.
Twenty-six patients received rucaparib once daily, at dose levels of 40 mg (n = 6), 80 mg (n = 3), 160 mg (n = 4), 300 mg (n = 9), and 500 mg once daily (n = 4); 30 patients received rucaparib twice daily, at dose levels of 240 mg (n = 3), 360 mg (n = 8), 480 mg (n = 9), 600 mg (n = 7), and 840 mg twice daily (n = 3). Median treatment exposure across all dose levels was 3.2 months (range, 0.0–37.9); 20 of 56 patients (35.7%) received treatment for 6 months or more. One of 8 patients treated with rucaparib 360 mg twice daily experienced a DLT of grade 3 nausea not well controlled by systemic medication; no DLTs were observed at any other dose level. No MTD was identified as per the protocol-specified criteria.
Safety.
Across dose levels, treatment-emergent AEs were mostly grade 1 or 2 in severity. No grade 4 events were reported (Table 2). The most common (≥20% of patients) treatment-emergent AEs were asthenia/fatigue, gastrointestinal disorders (nausea, vomiting, and diarrhea), myelosuppression (anemia, thrombocytopenia, and neutropenia), decreased appetite, and elevated alanine transaminase (ALT) and/or aspartate transaminase (AST) levels. Treatment-emergent AEs of elevations in blood creatinine and ALT/AST levels were reported in 8.9% (5/56) and 25.0% (14/56) of patients and were mostly grade 1 or 2. Anemia was the most common grade 3 treatment-emergent AE, reported in 5 of 56 patients (8.9%) across all doses, with the highest incidence reported with the rucaparib 600 mg twice-daily dose (28.6%; 2/7). Across all cohorts, 11 of 56 patients (19.6%) had a dose reduction because of a treatment-emergent AE. At the visit cut-off date (November 30, 2015), 2 of 56 patients (3.6%) continued to receive treatment, 50 of 56 patients (89.3%) had discontinued because of disease progression (71.4%) or clinical deterioration (17.9%), and 1 patient each (1.8%) discontinued for the following reasons: vaginal fistula (considered related to disease progression), increase in CA-125 level, physician's decision, or eligibility violation (QTc higher than the allowed maximum of 450 ms). No treatment-related deaths were reported; 3 deaths resulting from disease progression were reported during the study.
Treatment-emergent AEs (occurring in ≥20% of patients in part 1 or part 2A) by rucaparib dose
. | Part 1 (phase I dose escalation), n (%) . | Part 2A (phase II expansion), n (%) . | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
. | 40–500 mg QD (n = 26)a . | 240 mg BID (n = 3) . | 360 mg BID (n = 8) . | 480 mg BID (n = 9) . | 600mg BID (n = 7) . | 840 mg BID (n = 3) . | All doses (n = 56) . | 600 mg BID (n = 42) . | ||||
Adverse event . | All grade . | All grade . | All grade . | All grade . | All grade . | All grade . | All grade . | Grade 1 . | Grade 2 . | Grade 3 . | Grade 4 . | All grade . |
Any adverse event | 26 (100.0) | 3 (100.0) | 8 (100.0) | 8 (88.9) | 7 (100.0) | 3 (100.0) | 55 (98.2) | 0 (0) | 7 (16.7) | 26 (61.9) | 6 (14.3) | 42 (100.0) |
Asthenia/fatigue | 10 (38.5) | 2 (66.7) | 5 (62.5) | 5 (55.6) | 5 (71.4) | 1 (33.3) | 28 (50.0) | 8 (19.0) | 17 (40.5) | 11 (26.2) | 0 (0) | 36 (85.7) |
Nausea | 12 (46.2) | 0 (0) | 6 (75.0) | 4 (44.4) | 4 (57.1) | 3 (100.0) | 29 (51.8) | 17 (40.5) | 15 (35.7) | 3 (7.1) | 0 (0) | 35 (83.3) |
Anemiab | 5 (19.2) | 0 (0) | 4 (50.0) | 3 (33.3) | 4 (57.1) | 1 (33.3) | 17 (30.4) | 7 (16.7) | 7 (16.7) | 13 (31.0) | 3 (7.1) | 30 (71.4) |
AST/ALT increased | 2 (7.7) | 0 (0) | 2 (25.0) | 3 (33.3) | 6 (85.7) | 1 (33.3) | 14 (25.0) | 11 (26.2) | 7 (16.7) | 6 (14.3) | 0 (0) | 24 (57.1) |
Vomiting | 10 (38.5) | 0 (0) | 3 (37.5) | 5 (55.6) | 4 (57.1) | 2 (66.7) | 24 (42.9) | 12 (28.6) | 8 (19.0) | 3 (7.1) | 0 (0) | 23 (54.8) |
Constipation | 8 (30.8) | 0 (0) | 2 (25.0) | 2 (22.2) | 1 (14.3) | 0 (0) | 13 (23.2) | 15 (35.7) | 7 (16.7) | 0 (0) | 0 (0) | 22 (52.4) |
Headache | 5 (19.2) | 0 (0) | 2 (25.0) | 1 (11.1) | 2 (28.6) | 1 (33.3) | 11 (19.6) | 13 (31.0) | 5 (11.9) | 1 (2.4) | 0 (0) | 19 (45.2) |
Abdominal pain | 7 (26.9) | 0 (0) | 2 (25.0) | 3 (33.3) | 1 (14.3) | 1 (33.3) | 14 (25.0) | 8 (19.0) | 7 (16.7) | 3 (7.1) | 0 (0) | 18 (42.9) |
Dysgeusia | 1 (3.8) | 1 (33.3) | 2 (25.0) | 1 (11.1) | 1 (14.3) | 2 (66.7) | 8 (14.3) | 11 (26.2) | 6 (14.3) | 0 (0) | 0 (0) | 17 (40.5) |
Diarrhea | 4 (15.4) | 1 (33.3) | 1 (12.5) | 2 (22.2) | 2 (28.6) | 3 (100.0) | 13 (23.2) | 8 (19.0) | 8 (19.0) | 0 (0) | 0 (0) | 16 (38.1) |
Thrombocytopeniac | 0 (0) | 0 (0) | 1 (12.5) | 2 (22.2) | 5 (71.4) | 0 (0) | 8 (14.3) | 8 (19.0) | 6 (14.3) | 1 (2.4) | 0 (0) | 15 (35.7) |
Blood creatinine increased | 2 (7.7) | 1 (33.3) | 0 (0) | 1 (11.1) | 1 (14.3) | 0 (0) | 5 (8.9) | 9 (21.4) | 5 (11.9) | 0 (0) | 0 (0) | 14 (33.3) |
Neutropeniad | 3 (11.5) | 0 (0) | 1 (12.5) | 3 (33.3) | 3 (42.9) | 0 (0) | 10 (17.9) | 4 (9.5) | 2 (4.8) | 4 (9.5) | 3 (7.1) | 13 (31.0) |
Decreased appetite | 9 (34.6) | 2 (66.7) | 3 (37.5) | 1 (11.1) | 0 (0) | 1 (33.3) | 16 (28.6) | 6 (14.3) | 5 (11.9) | 1 (2.4) | 0 (0) | 12 (28.6) |
Abdominal distension | 3 (11.5) | 0 (0) | 2 (25.0) | 2 (22.2) | 1 (14.3) | 0 (0) | 8 (14.3) | 6 (14.3) | 4 (9.5) | 0 (0) | 0 (0) | 10 (23.8) |
Blood alkaline phosphatase increased | 2 (7.7) | 0 (0) | 0 (0) | 2 (22.2) | 4 (57.1) | 0 (0) | 8 (14.3) | 10 (23.8) | 0 (0) | 0 (0) | 0 (0) | 10 (23.8) |
Dyspnea | 2 (7.7) | 0 (0) | 3 (37.5) | 3 (33.3) | 1 (14.3) | 1 (33.3) | 10 (17.9) | 8 (19.0) | 1 (2.4) | 1 (2.4) | 0 (0) | 10 (23.8) |
Upper respiratory tract infection | 1 (3.8) | 0 (0) | 1 (12.5) | 0 (0) | 0 (0) | 0 (0) | 2 (3.6) | 6 (14.3) | 4 (9.5) | 0 (0) | 0 (0) | 10 (23.8) |
Cough | 3 (11.5) | 1 (33.3) | 0 (0) | 3 (33.3) | 2 (28.6) | 2 (66.7) | 11 (19.6) | 7 (16.7) | 1 (2.4) | 1 (2.4) | 0 (0) | 9 (21.4) |
Dizziness | 2 (7.7) | 1 (33.3) | 2 (25.0) | 2 (22.2) | 2 (28.6) | 0 (0) | 9 (16.1) | 7 (16.7) | 1 (2.4) | 1 (2.4) | 0 (0) | 9 (21.4) |
. | Part 1 (phase I dose escalation), n (%) . | Part 2A (phase II expansion), n (%) . | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|
. | 40–500 mg QD (n = 26)a . | 240 mg BID (n = 3) . | 360 mg BID (n = 8) . | 480 mg BID (n = 9) . | 600mg BID (n = 7) . | 840 mg BID (n = 3) . | All doses (n = 56) . | 600 mg BID (n = 42) . | ||||
Adverse event . | All grade . | All grade . | All grade . | All grade . | All grade . | All grade . | All grade . | Grade 1 . | Grade 2 . | Grade 3 . | Grade 4 . | All grade . |
Any adverse event | 26 (100.0) | 3 (100.0) | 8 (100.0) | 8 (88.9) | 7 (100.0) | 3 (100.0) | 55 (98.2) | 0 (0) | 7 (16.7) | 26 (61.9) | 6 (14.3) | 42 (100.0) |
Asthenia/fatigue | 10 (38.5) | 2 (66.7) | 5 (62.5) | 5 (55.6) | 5 (71.4) | 1 (33.3) | 28 (50.0) | 8 (19.0) | 17 (40.5) | 11 (26.2) | 0 (0) | 36 (85.7) |
Nausea | 12 (46.2) | 0 (0) | 6 (75.0) | 4 (44.4) | 4 (57.1) | 3 (100.0) | 29 (51.8) | 17 (40.5) | 15 (35.7) | 3 (7.1) | 0 (0) | 35 (83.3) |
Anemiab | 5 (19.2) | 0 (0) | 4 (50.0) | 3 (33.3) | 4 (57.1) | 1 (33.3) | 17 (30.4) | 7 (16.7) | 7 (16.7) | 13 (31.0) | 3 (7.1) | 30 (71.4) |
AST/ALT increased | 2 (7.7) | 0 (0) | 2 (25.0) | 3 (33.3) | 6 (85.7) | 1 (33.3) | 14 (25.0) | 11 (26.2) | 7 (16.7) | 6 (14.3) | 0 (0) | 24 (57.1) |
Vomiting | 10 (38.5) | 0 (0) | 3 (37.5) | 5 (55.6) | 4 (57.1) | 2 (66.7) | 24 (42.9) | 12 (28.6) | 8 (19.0) | 3 (7.1) | 0 (0) | 23 (54.8) |
Constipation | 8 (30.8) | 0 (0) | 2 (25.0) | 2 (22.2) | 1 (14.3) | 0 (0) | 13 (23.2) | 15 (35.7) | 7 (16.7) | 0 (0) | 0 (0) | 22 (52.4) |
Headache | 5 (19.2) | 0 (0) | 2 (25.0) | 1 (11.1) | 2 (28.6) | 1 (33.3) | 11 (19.6) | 13 (31.0) | 5 (11.9) | 1 (2.4) | 0 (0) | 19 (45.2) |
Abdominal pain | 7 (26.9) | 0 (0) | 2 (25.0) | 3 (33.3) | 1 (14.3) | 1 (33.3) | 14 (25.0) | 8 (19.0) | 7 (16.7) | 3 (7.1) | 0 (0) | 18 (42.9) |
Dysgeusia | 1 (3.8) | 1 (33.3) | 2 (25.0) | 1 (11.1) | 1 (14.3) | 2 (66.7) | 8 (14.3) | 11 (26.2) | 6 (14.3) | 0 (0) | 0 (0) | 17 (40.5) |
Diarrhea | 4 (15.4) | 1 (33.3) | 1 (12.5) | 2 (22.2) | 2 (28.6) | 3 (100.0) | 13 (23.2) | 8 (19.0) | 8 (19.0) | 0 (0) | 0 (0) | 16 (38.1) |
Thrombocytopeniac | 0 (0) | 0 (0) | 1 (12.5) | 2 (22.2) | 5 (71.4) | 0 (0) | 8 (14.3) | 8 (19.0) | 6 (14.3) | 1 (2.4) | 0 (0) | 15 (35.7) |
Blood creatinine increased | 2 (7.7) | 1 (33.3) | 0 (0) | 1 (11.1) | 1 (14.3) | 0 (0) | 5 (8.9) | 9 (21.4) | 5 (11.9) | 0 (0) | 0 (0) | 14 (33.3) |
Neutropeniad | 3 (11.5) | 0 (0) | 1 (12.5) | 3 (33.3) | 3 (42.9) | 0 (0) | 10 (17.9) | 4 (9.5) | 2 (4.8) | 4 (9.5) | 3 (7.1) | 13 (31.0) |
Decreased appetite | 9 (34.6) | 2 (66.7) | 3 (37.5) | 1 (11.1) | 0 (0) | 1 (33.3) | 16 (28.6) | 6 (14.3) | 5 (11.9) | 1 (2.4) | 0 (0) | 12 (28.6) |
Abdominal distension | 3 (11.5) | 0 (0) | 2 (25.0) | 2 (22.2) | 1 (14.3) | 0 (0) | 8 (14.3) | 6 (14.3) | 4 (9.5) | 0 (0) | 0 (0) | 10 (23.8) |
Blood alkaline phosphatase increased | 2 (7.7) | 0 (0) | 0 (0) | 2 (22.2) | 4 (57.1) | 0 (0) | 8 (14.3) | 10 (23.8) | 0 (0) | 0 (0) | 0 (0) | 10 (23.8) |
Dyspnea | 2 (7.7) | 0 (0) | 3 (37.5) | 3 (33.3) | 1 (14.3) | 1 (33.3) | 10 (17.9) | 8 (19.0) | 1 (2.4) | 1 (2.4) | 0 (0) | 10 (23.8) |
Upper respiratory tract infection | 1 (3.8) | 0 (0) | 1 (12.5) | 0 (0) | 0 (0) | 0 (0) | 2 (3.6) | 6 (14.3) | 4 (9.5) | 0 (0) | 0 (0) | 10 (23.8) |
Cough | 3 (11.5) | 1 (33.3) | 0 (0) | 3 (33.3) | 2 (28.6) | 2 (66.7) | 11 (19.6) | 7 (16.7) | 1 (2.4) | 1 (2.4) | 0 (0) | 9 (21.4) |
Dizziness | 2 (7.7) | 1 (33.3) | 2 (25.0) | 2 (22.2) | 2 (28.6) | 0 (0) | 9 (16.1) | 7 (16.7) | 1 (2.4) | 1 (2.4) | 0 (0) | 9 (21.4) |
NOTE: Table is sorted by decreasing incidence in part 2A patients.
Abbreviations: BID, twice daily; QD, once daily.
a40 mg QD (n = 6), 80 mg QD (n =3), 160 mg QD (n = 4), 300 mg QD (n = 9), and 500 mg QD (n = 4).
bAnemia and/or low/decreased hemoglobin.
cThrombocytopenia and/or low or decreased platelets.
dNeutropenia and/or low or decreased absolute neutrophil count.
Efficacy.
In this portion of the study, objective responses or prolonged stable disease (SD) occurred in patients with a germline BRCA mutation. There were 2 patients who achieved a confirmed CR in part 1 (Table 3). One patient with platinum-sensitive ovarian cancer and a germline BRCA1 mutation receiving rucaparib 300 mg once daily had a PR at 6 weeks (first on-study assessment) and eventually achieved a CR at 54 weeks. At the visit cut-off date, the patient had been on study for 165 weeks, with a confirmed CR for 111 weeks. A patient with breast cancer and a germline BRCA1 mutation receiving rucaparib 360 mg twice daily had a PR at 6 weeks (first on-study assessment) and achieved a CR at 18 weeks, which lasted for 60 weeks.
Antitumor activity in patients with advanced tumors who received rucaparib in part 1 and investigator-assessed response in patients with germline BRCA1/2-mutated ovarian cancer from part 2A
Part 1 (phase I dose escalation) patients with advanced solid tumors (n = 56) . | |||||
---|---|---|---|---|---|
Dose received . | Confirmed CR or PR (RECIST) . | Duration of response (wk) . | Type of cancer . | BRCA Mutation . | Platinum status . |
300 mg QD | CR | 111 | Ovarian | Germline BRCA1 | Sensitive |
300 mg QD | PR | 15 | Breast | Germline BRCA1 | NA |
360 mg BID | CR | 60 | Breast | Germline BRCA1 | NA |
360 mg BID | PR | 28 | Pancreatic | Germline BRCA2 | NA |
480 mg BID | PR | 116 | Breast | Germline BRCA2 | NA |
480 mg BID | PR | 37 | Ovarian | Germline BRCA2 | Resistant |
480 mg BID | PR | 21 | Breast | Tumor BRCA1 | NA |
600 mg BID | PR | 13 | Ovarian | Tumor BRCA1 | Resistant |
Part 2A (phase II expansion) patients with germline BRCA1/2–mutated ovarian cancer (n = 42) | |||||
RECIST best confirmed response, n [% (95% CI)] | |||||
CR | 4 (9.5) | ||||
PR | 21 (50.0) | ||||
SD | 12 (28.6) | ||||
PD | 2 (4.8) | ||||
NE | 3 (7.1) | ||||
RECIST ORR, n [% (95% CI)] | 25 [59.5 (43.3–74.4)] | ||||
RECIST/CA-125 ORR, n [% (95% CI)] | 35 [83.3 (68.6–93.0)] | ||||
RECIST ORR by part 2A patient subsets, n/N [% (95% CI)] | |||||
BRCA gene mutation | |||||
BRCA1 | 19/30 [63.3 (43.9–80.1)] | ||||
BRCA2 | 6/12 [50.0 (21.1–78.9)] | ||||
PFI | |||||
6–12 mo | 17/32 [53.1 (34.7–70.9)] | ||||
>12 mo | 8/10 [80.0 (44.4–97.5)] | ||||
≥3 prior chemotherapy regimens | 9/15 [60.0 (32.3–83.7)] | ||||
Duration of response, median (95% CI), mo | 7.8 (5.6–10.5) |
Part 1 (phase I dose escalation) patients with advanced solid tumors (n = 56) . | |||||
---|---|---|---|---|---|
Dose received . | Confirmed CR or PR (RECIST) . | Duration of response (wk) . | Type of cancer . | BRCA Mutation . | Platinum status . |
300 mg QD | CR | 111 | Ovarian | Germline BRCA1 | Sensitive |
300 mg QD | PR | 15 | Breast | Germline BRCA1 | NA |
360 mg BID | CR | 60 | Breast | Germline BRCA1 | NA |
360 mg BID | PR | 28 | Pancreatic | Germline BRCA2 | NA |
480 mg BID | PR | 116 | Breast | Germline BRCA2 | NA |
480 mg BID | PR | 37 | Ovarian | Germline BRCA2 | Resistant |
480 mg BID | PR | 21 | Breast | Tumor BRCA1 | NA |
600 mg BID | PR | 13 | Ovarian | Tumor BRCA1 | Resistant |
Part 2A (phase II expansion) patients with germline BRCA1/2–mutated ovarian cancer (n = 42) | |||||
RECIST best confirmed response, n [% (95% CI)] | |||||
CR | 4 (9.5) | ||||
PR | 21 (50.0) | ||||
SD | 12 (28.6) | ||||
PD | 2 (4.8) | ||||
NE | 3 (7.1) | ||||
RECIST ORR, n [% (95% CI)] | 25 [59.5 (43.3–74.4)] | ||||
RECIST/CA-125 ORR, n [% (95% CI)] | 35 [83.3 (68.6–93.0)] | ||||
RECIST ORR by part 2A patient subsets, n/N [% (95% CI)] | |||||
BRCA gene mutation | |||||
BRCA1 | 19/30 [63.3 (43.9–80.1)] | ||||
BRCA2 | 6/12 [50.0 (21.1–78.9)] | ||||
PFI | |||||
6–12 mo | 17/32 [53.1 (34.7–70.9)] | ||||
>12 mo | 8/10 [80.0 (44.4–97.5)] | ||||
≥3 prior chemotherapy regimens | 9/15 [60.0 (32.3–83.7)] | ||||
Duration of response, median (95% CI), mo | 7.8 (5.6–10.5) |
Abbreviations: BID, twice daily; NA, not available; NE, not evaluable; PD, progressive disease; QD, once daily.
A confirmed PR was achieved in 6 patients (Table 3). One patient with breast cancer and a germline BRCA1 mutation receiving rucaparib 300 mg once daily had a PR for 15 weeks. One patient with pancreatic cancer and a germline BRCA2 mutation receiving rucaparib 360 mg twice daily had a PR for 28 weeks. In the rucaparib 480 mg twice-daily cohort, 1 patient with breast cancer and a germline BRCA2 mutation, 1 patient with platinum-resistant ovarian cancer and a germline BRCA2 mutation, and 1 patient with breast cancer and a tumor BRCA1 mutation achieved a PR of 116, 37, and 21 weeks' duration, respectively. One patient with platinum-resistant ovarian cancer and a tumor BRCA1 mutation who received rucaparib 600 mg twice daily had a PR for 13 weeks. Twenty-two patients (15 with ovarian, 6 with breast, and 1 with colon cancer) had a best response of SD; 14 patients had durable SD for more than 24 weeks. Of 13 patients with ovarian cancer associated with a BRCA mutation who received rucaparib twice daily (360–840 mg), 2 (15.4%; 95% CI, 1.9–45.4) achieved a confirmed PR, 10 (76.9%) had a best response of SD, and 1 (7.7%) was not evaluable. The best response in target lesions for all phase I patients with measurable disease is presented in Fig. 1A.
Waterfall plots for best overall change from baseline in target lesions in patients with advanced solid tumors (part 1, phase I dose escalation; n = 40; A) and patients with germline BRCA1/2-mutated high-grade ovarian cancer (part 2A, phase II expansion; n = 40; B) who had both baseline and postbaseline measurements. C, Duration of response for patients in part 2A. In A, patients with a BRCA1 or BRCA2 mutation detected by local testing are indicated with triangles or circles; for mutations detected in tumor tissue only (open triangles and circles), germline status was not determined.
Waterfall plots for best overall change from baseline in target lesions in patients with advanced solid tumors (part 1, phase I dose escalation; n = 40; A) and patients with germline BRCA1/2-mutated high-grade ovarian cancer (part 2A, phase II expansion; n = 40; B) who had both baseline and postbaseline measurements. C, Duration of response for patients in part 2A. In A, patients with a BRCA1 or BRCA2 mutation detected by local testing are indicated with triangles or circles; for mutations detected in tumor tissue only (open triangles and circles), germline status was not determined.
Pharmacokinetics.
Fifty-six patients entered the dose-escalation portion of the study and received oral rucaparib with or without food at doses ranging from 40 to 500 mg once daily and 240 to 840 mg twice daily (480–1,680 mg/day). Pharmacokinetic parameters are summarized in Table 4. The mean plasma rucaparib concentration–time profiles by dose level on cycle 1 days 1 and 15 following once-daily and twice-daily dosing are presented in Supplementary Figs. S1 and S2, and the relationship between dose level and exposure is presented in Supplementary Fig. S3. Plasma exposure of rucaparib was approximately dose proportional. The median values of Tmax ranged from 1.5 to 6 hours across all doses, suggesting relatively fast absorption. The estimated t1/2 for once-daily dosing was approximately 17 hours. Steady state appeared to be achieved by day 8 with once-daily or twice-daily dosing based on the predose plasma concentration of rucaparib. The estimated mean values of CLSS/F ranged from 26.7 to 47.5 L/hour for once-daily dosing and from 26.2 to 58.6 L/hour for twice-daily dosing. The accumulation ratio of rucaparib plasma exposure at steady state ranged from 1.06 to 1.8 for Cmax and 1.6 to 2.3 for AUC0–24 with once-daily dosing, and from 2.6 to 4.9 for Cmax and 1.47 to 5.44 for AUC0–12 with twice-daily dosing. The accumulation on a twice-daily schedule was approximately twice that of the once-daily schedule. The time to steady state and the observed accumulation ratios are consistent with the t1/2 values, suggesting lack of time-dependent pharmacokinetics. The effect of a high-fat meal on rucaparib pharmacokinetics was evaluated in 3 patients at 40 mg once daily and 6 patients at 300 mg once daily. A high-fat meal did not cause clinically meaningful changes of rucaparib pharmacokinetics at these dose levels (Supplementary Table S1).
Single-dose and steady-state plasma pharmacokinetic parameters of rucaparib following once- or twice-daily continuous oral administration (part 1, phase I dose escalation)
Dosage . | N . | Day . | Arithmetic mean Cmax (CV%), ng/mL . | Median Tmax (range), h . | Arithmetic mean AUC0–τ (CV%), ng·h/mL . | Arithmetic mean CLss/F (CV%), L/h . | AR (CV%) . | Arithmetic mean t1/2 (CV%), h . |
---|---|---|---|---|---|---|---|---|
40 mg QD | 3 | 1 | 129 (28) | 2.5 (1–4) | 915a | NR | NA | 13.9 (57) |
15 | 138 (36) | 4 (1–4.05) | 1,810 (44) | 26.7 (59) | 1.68a | 25.7 (23) | ||
80 mg QD | 3 | 1 | 114 (41) | 1.5 (1–2.5) | 800 (27) | NR | NA | 11.0a |
15 | 175 (37) | 2.5 (2.5–2.57) | 1,740 (20) | 47.5 (23) | 2.33 (42) | 19.5a | ||
160 mg QD | 4 | 1 | 261 (51) | 4.0 (4–6.05) | 3,050 (51) | NR | NA | 19.9 (21) |
15 | 288 (29)b | 3.75 (2.5–4)b | 4,110 (33)b | 41.6 (29)b | 1.84 (31)b | 33.6 (12)b | ||
300 mg QD | 3 | 1 | 629 (37) | 2.5 (1–4.08) | 5,740 (38) | NR | NA | 15.2 (72) |
15 | 693 (76) | 2.53 (2.5–8) | 9,610 (83) | 46.7 (63) | 1.60 (53) | 29.8a | ||
500 mg QD | 3 | 1 | 949 (52) | 4 (4–4) | 11,000 (61) | NR | NA | 15.0 (32) |
15 | 1390 (23) | 4 (4–4.17) | 19,900 (41) | 27.8 (35) | 1.94 (17) | 20.8 (38) | ||
240 mg BID | 3 | 1 | 219 (72) | 6 (4.05–6) | 2,800c | NR | NA | NRh |
15 | 971 (49) | 1.5 (1–4) | 10,700a | 27.3a | 5.44c | NRh | ||
360 mg BID | 8 | 1 | 666 (58) | 3.23 (1.5–6) | 4,860 (58)d | NR | NA | NRh |
15 | 1,300 (43)d | 3.3 (0–6.33)d | 9,430a | 40.4a | 4.08a | NRh | ||
480 mg BID | 9 | 1 | 1,150 (57) | 2.5 (1.5–4) | 8,810 (63)e | NR | NA | NRh |
15 | 3,170 (69)e | 1.51 (0–6)e | 26,300 (73)d | 26.2 (63)d | 3.97 (38)f | NRh | ||
600 mg BID | 7 | 1 | 1,030 (61) | 4 (2.42–10) | 7,200 (66)g | NR | NA | NRh |
15 | 2,420 (45) | 4 (2.53–10) | 21,400 (61)g | 58.6 (123)g | 3.23 (66)g | NRh | ||
840 mg BID | 3 | 1 | 1,380 (69) | 4 (2.5–8) | 13,200a | NR | NA | NRh |
15 | 3,030 (NR)a | 4.04 (4–4.07)a | 29,000c | 29c | 1.47c | NRh |
Dosage . | N . | Day . | Arithmetic mean Cmax (CV%), ng/mL . | Median Tmax (range), h . | Arithmetic mean AUC0–τ (CV%), ng·h/mL . | Arithmetic mean CLss/F (CV%), L/h . | AR (CV%) . | Arithmetic mean t1/2 (CV%), h . |
---|---|---|---|---|---|---|---|---|
40 mg QD | 3 | 1 | 129 (28) | 2.5 (1–4) | 915a | NR | NA | 13.9 (57) |
15 | 138 (36) | 4 (1–4.05) | 1,810 (44) | 26.7 (59) | 1.68a | 25.7 (23) | ||
80 mg QD | 3 | 1 | 114 (41) | 1.5 (1–2.5) | 800 (27) | NR | NA | 11.0a |
15 | 175 (37) | 2.5 (2.5–2.57) | 1,740 (20) | 47.5 (23) | 2.33 (42) | 19.5a | ||
160 mg QD | 4 | 1 | 261 (51) | 4.0 (4–6.05) | 3,050 (51) | NR | NA | 19.9 (21) |
15 | 288 (29)b | 3.75 (2.5–4)b | 4,110 (33)b | 41.6 (29)b | 1.84 (31)b | 33.6 (12)b | ||
300 mg QD | 3 | 1 | 629 (37) | 2.5 (1–4.08) | 5,740 (38) | NR | NA | 15.2 (72) |
15 | 693 (76) | 2.53 (2.5–8) | 9,610 (83) | 46.7 (63) | 1.60 (53) | 29.8a | ||
500 mg QD | 3 | 1 | 949 (52) | 4 (4–4) | 11,000 (61) | NR | NA | 15.0 (32) |
15 | 1390 (23) | 4 (4–4.17) | 19,900 (41) | 27.8 (35) | 1.94 (17) | 20.8 (38) | ||
240 mg BID | 3 | 1 | 219 (72) | 6 (4.05–6) | 2,800c | NR | NA | NRh |
15 | 971 (49) | 1.5 (1–4) | 10,700a | 27.3a | 5.44c | NRh | ||
360 mg BID | 8 | 1 | 666 (58) | 3.23 (1.5–6) | 4,860 (58)d | NR | NA | NRh |
15 | 1,300 (43)d | 3.3 (0–6.33)d | 9,430a | 40.4a | 4.08a | NRh | ||
480 mg BID | 9 | 1 | 1,150 (57) | 2.5 (1.5–4) | 8,810 (63)e | NR | NA | NRh |
15 | 3,170 (69)e | 1.51 (0–6)e | 26,300 (73)d | 26.2 (63)d | 3.97 (38)f | NRh | ||
600 mg BID | 7 | 1 | 1,030 (61) | 4 (2.42–10) | 7,200 (66)g | NR | NA | NRh |
15 | 2,420 (45) | 4 (2.53–10) | 21,400 (61)g | 58.6 (123)g | 3.23 (66)g | NRh | ||
840 mg BID | 3 | 1 | 1,380 (69) | 4 (2.5–8) | 13,200a | NR | NA | NRh |
15 | 3,030 (NR)a | 4.04 (4–4.07)a | 29,000c | 29c | 1.47c | NRh |
Abbreviations: AR, accumulation ratio based on AUC; AUC0–τ, area under the plasma concentration–time curve from 0 to the end of dosing interval (τ = 24 hours for QD; τ = 12 hours for BID; for BID dosing, concentration at 12 hours was calculated by extrapolation from last observed concentration in the same dosing interval); BID, twice daily; CV, coefficient of variation; NA, not available; NR, not reportable; QD, once daily.
an = 2.
bn = 3.
cn = 1.
dn = 6.
en = 8.
fn = 5.
gn = 4.
ht1/2 is too long to allow for accurate estimate in BID dosing.
RP2D.
On the basis of protocol-specified criteria, no MTD was identified for dose levels of 40 mg once daily up to 840 mg twice daily in part 1. The 600 mg twice-daily dose was selected as the RP2D upon consideration of the manageable safety and antitumor activity of rucaparib, as well as the pharmacokinetic profile observed in patients in part 1. No patients in the 600 mg twice-daily cohort discontinued because of an AE; however, myelosuppression requiring dose modification was observed in some patients after several cycles of treatment. Furthermore, antitumor activity was observed in patients in this cohort.
Part 2A (phase II expansion)
Patients and treatments.
Part 2A of the study evaluated oral rucaparib in patients with platinum-sensitive, high-grade serous, endometrioid, mixed histology, or clear cell ovarian cancer associated with a germline BRCA1/2 mutation. The majority of patients had high-grade serous cancer (Table 1). In stage 1, 3 of the first 5 patients enrolled achieved a RECIST response, satisfying the criteria to continue to stage 2. A total of 42 patients were enrolled into part 2A; the majority of patients (71.4%; 30/42) had a BRCA1 mutation, and 28.6% (12/42) had a BRCA2 mutation (Table 1). The median number of prior chemotherapy regimens was two (range, 2–4); 15 of 42 patients (35.7%) had received three or more prior chemotherapies.
At the visit cut-off date (November 30, 2015), 9 of 42 patients (21.4%) remained on treatment. Twenty-six of 42 patients (61.9%) discontinued because of disease progression (52.4%) or clinical decline (9.5%), 4 (9.5%) discontinued because of an AE, 2 (4.8%) discontinued because of increase in CA-125 level, and 1 (2.4%) discontinued upon investigator decision. Median treatment exposure was 7.4 months (range, 0.1–20.2).
Efficacy.
Of 42 patients, 25 (59.5%) achieved an investigator-assessed, confirmed RECIST response and 35 (83.3%) achieved an investigator-assessed, RECIST/GCIG CA-125 response (Table 3). Activity was observed in patients with either a BRCA1 or BRCA2 mutation, those with a PFI of 6 to 12 months or more than 12 months, as well as those who had received at least three prior chemotherapy regimens. Most patients (60.0%; 15/25) with a RECIST response achieved a response by the first disease assessment (approximately 6 weeks), and all but 2 of the responders achieved a response by the second disease assessment (approximately 12 weeks). The majority of patients (88.1%; 37/42) had a reduction in target lesion size (Fig. 1B). An example of a patient with visceral disease who had received two prior platinum-based regimens and achieved a PR to rucaparib at cycle 2 (51% decrease in sum of target lesions) is shown in Supplementary Fig. S4. Notably, the patient with clear cell ovarian cancer and the patient with endometrioid ovarian cancer each achieved a PR, as did many patients with serous ovarian cancer; thus the presence of a BRCA mutation appears to play a larger role than histology in determining response to rucaparib. The median duration of investigator-assessed confirmed response for patients in part 2A was 7.8 months (95% CI, 5.6–10.5). Nine of the 25 responders were censored at the visit cut-off date. Of these 9 patients, 5 were ongoing and 4 discontinued treatment for reasons other than disease progression (Fig. 1C). In a retrospective analysis, the confirmed ORR by independent radiology review was 52.4% (95% CI, 36.4–68.0).
Safety.
Treatment-emergent AEs (all grades) were reported in all 42 patients (100.0%; Table 2), the most common of which were asthenia/fatigue, nausea, anemia, ALT/AST elevations, vomiting, constipation, and headache. Treatment-emergent AEs of elevations in blood creatinine were reported in 33.3% of patients (14/42) and were grade 1 or 2. Grade 3 or 4 treatment-emergent AEs were reported in 32 of 42 patients (76.2%); those reported in 10% or more of patients included asthenia/fatigue [grade 3, 26.2% (11/42); grade 4, none], anemia [grade 3, 31.0% (13/42); grade 4, 7.1% (3/42)], and elevated ALT/AST [grade 3, 14.3% (6/42); grade 4, none; Table 2]. Four of 42 patients (9.5%) discontinued treatment because of an AE, including abdominal cramps, constipation, dizziness, fatigue, hypercholesterolemia, nausea, shaking, urinary tract infection, and vomiting; 26 of 42 patients (61.9%) discontinued because of disease progression or clinical deterioration. There were three deaths that resulted from disease progression; no treatment-related deaths were reported during the study.
Among 42 patients, treatment-emergent AEs led to a dose reduction in 29 patients (69.0%) and treatment interruption in 27 patients (64.3%). Thirty-eight patients (90.5%) had at least one dose reduction or treatment delay because of a treatment-emergent AE. Grade 3 or 4 AEs were managed with treatment modification and/or supportive care. In most patients, myelosuppression was a cumulative effect that manifested after cycle 1 and was successfully treated with supportive care and/or dose interruption or modification. Transient elevations in ALT and/or AST, with no other evidence of liver dysfunction, occurred relatively early after initiation of treatment (middle of cycle 1 or start of cycle 2) and resolved or stabilized over time, including during continued rucaparib exposure (Fig. 2).
Baseline and on-treatment values for alanine aminotransferase (A), aspartate aminotransferase (B), and bilirubin (C) for patients in part 2A (n = 42). Dashed gray lines indicate the upper and lower limits of the normal range.
Baseline and on-treatment values for alanine aminotransferase (A), aspartate aminotransferase (B), and bilirubin (C) for patients in part 2A (n = 42). Dashed gray lines indicate the upper and lower limits of the normal range.
Discussion
In this phase I–II study, oral rucaparib had a manageable safety profile and favorable pharmacokinetic properties. During dose escalation, rucaparib was active in patients who had a germline BRCA1/2 mutation, with responses observed in patients with ovarian (platinum-sensitive and platinum-resistant), breast, and pancreatic tumors. Part 2A data indicated that administration of rucaparib 600 mg twice daily led to robust responses in patients with platinum-sensitive, relapsed, high-grade, serous, endometrioid, and/or clear cell ovarian cancer associated with a germline or tumor BRCA1/2 mutation.
This study was the first to fully evaluate daily, single-agent oral rucaparib in patients with an advanced solid tumor and to provide a comprehensive characterization of its safety and pharmacokinetic profile. Continuous dosing of oral rucaparib was associated with approximately dose-proportional rucaparib exposure in the tested dose ranges following once-daily and twice-daily administration, with moderate interpatient variability and a t1/2 of approximately 17 hours independent of dose. In a small cohort of patients, a high-fat meal did not cause clinically meaningful changes in rucaparib pharmacokinetics, indicating that patients may take rucaparib with or without food. During the dose escalation phase of the study (part 1), no MTD was identified in patients treated with rucaparib doses up to 840 mg twice daily; however, delayed myelosuppression requiring dose modification was observed in some patients treated with rucaparib 600 mg twice daily. The 600 mg twice-daily dose was selected as the RP2D based on manageable safety and clinical activity, and was further characterized in the phase II portion.
Oral rucaparib 600 mg twice daily was tolerable, with a manageable safety profile that was consistent with its mechanism of action. Toxicities observed with rucaparib, such as myelosuppression, fatigue, and gastrointestinal disorders, are commonly observed with other PARP inhibitors (19, 23, 24, 37, 38). Myelosuppression, which generally occurs at a lower frequency with PARP inhibitors in relation to platinum-based chemotherapy, was generally observed after several cycles of rucaparib treatment and was successfully managed with supportive care and treatment modification (dose reduction and/or interruption). Other common low-grade AEs included fatigue and gastrointestinal side effects, such as nausea and vomiting. These AEs were successfully managed with supportive care and/or dose modification, as needed. Elevated serum creatinine was observed during rucaparib treatment. Elevations in creatinine have also been observed following the use of the PARP inhibitor olaparib (27). Elevations in creatinine may be attributed to the inhibition of the active tubular secretion of creatinine into the proximal tubule and subsequent apical efflux into the urine, as rucaparib has demonstrated potent inhibition of MATE1 and MATE2-K and moderate inhibition of OCT-2 in vitro. Inhibition of these transporters has also been demonstrated in vitro with the PARP inhibitor veliparib and other drugs (39, 40). Some AEs observed with rucaparib treatment, such as elevations in ALT and AST, have not been previously associated with PARP inhibitors. The mechanism responsible for the transaminase elevations has not been identified; however, such elevations were transient and resolved or stabilized during treatment. Of the 98 patients treated in Study 10 (parts 1 and 2 combined), 87 patients discontinued treatment because of disease progression (62/98; 63.3%), clinical progression (14/98; 14.3%), treatment-emergent AE (5/98; 5.1%), or other reason (6/98; 6.1%). No treatment-related deaths were reported in either part 1 or part 2A.
The benefits of PARP inhibitors for treatment of germline BRCA1/2-mutated ovarian cancer are well established, with response rates in the range of 38% to 60% reported in patients with platinum-sensitive disease (16, 18, 19, 24, 41–43). In the 42 patients with platinum-sensitive, relapsed HGOC associated with a germline BRCA1/2 mutation enrolled in part 2A of this study (600 mg twice daily), the investigator-assessed ORR was 59.5% by RECIST and 83.3% by RECIST/CA-125 criteria.
Part 2B of this study is currently assessing the efficacy of rucaparib in patients with relapsed HGOC associated with a germline or somatic BRCA1/2 mutation who had received at least three prior chemotherapy regimens. Part 3 is ongoing and currently assessing the pharmacokinetic (including the effect of food) and safety profile of a higher dose tablet of rucaparib in patients with a relapsed solid tumor associated with a germline or somatic BRCA1/2 mutation.
This study provides evidence of the antitumor activity of rucaparib in patients with germline BRCA1/2-mutated ovarian cancer. Results from this study and the ongoing phase II ARIEL2 study (NCT01891344) supported the accelerated approval of rucaparib (600 mg twice daily) by the FDA for the treatment of patients with advanced ovarian cancer associated with deleterious germline or somatic BRCA mutations who have received two or more chemotherapies. Additional preclinical data indicate that the antitumor activity of rucaparib extends beyond tumors with a BRCA1/2 mutation to a broader group of tumors with HRD (32, 44, 45). For this reason, rucaparib is being developed for the treatment of tumors with HRD, including those with a BRCA1 or BRCA2 mutation (ClinicalTrials.gov identifiers: NCT00664781, NCT01074970, NCT01482715, NCT01891344, NCT01968213, NCT02042378, and NCT02505048). In addition to the ARIEL2 study, which is investigating rucaparib in the treatment setting, rucaparib is being evaluated in the maintenance setting in patients with relapsed HGOC in the phase III ARIEL3 study (NCT01968213). The ARIEL2 and ARIEL3 studies are enrolling patients with or without a germline or somatic BRCA1/2 mutation to investigate the activity of rucaparib in a wider group of patients with HRD-associated ovarian cancer. The ARIEL clinical development program is prospectively testing a novel next-generation sequencing HRD assay and algorithm to predict which patients with ovarian cancer, including those whose tumors lack a BRCA1 or BRCA2 mutation, may benefit from rucaparib. Results from ARIEL2 part 1 indicate that some patients who have BRCA1/2 wild-type tumors and have a high percentage of tumor genomic loss of heterozygosity respond to rucaparib treatment (43). In ARIEL3, this novel HRD assay will be prospectively applied to the primary analysis of investigator-assessed progression-free survival by RECIST with the aim of validating the test to identify patients with HRD tumors who will be most likely to benefit from rucaparib.
Disclosure of Potential Conflicts of Interest
R. Kristeleit has been a consultant for Medivation, reports receiving speakers bureau honoraria from AstraZeneca, and is a consultant/advisory board member for Clovis Oncology. G.I. Shapiro reports receiving other commercial research support from Eli Lilly and Company. J. Balmaña reports receiving speakers bureau honoraria from AstraZeneca and is a consultant/advisory board member for Clovis Oncology and TESARO, Inc. Y. Drew reports receiving commercial research grants from Clovis Oncology and is a consultant/advisory board member for AstraZeneca and Clovis Oncology. L.-m. Chen reports receiving lecture fees from Clovis Oncology. H. Giordano, J. Borrow, and L. Rolfe hold ownership interest (including patents) in Clovis Oncology. J. Xiao has ownership interest in Clovis Oncology. R. Shapira-Frommer is a consultant/advisory board member for Clovis Oncology. No potential conflicts of interest were disclosed by the other authors.
Authors' Contributions
Conception and design: R. Kristeleit, G.I. Shapiro, H.A. Burris, Y. Drew, T. Safra, H. Giordano, S. Goble, L. Rolfe
Development of methodology: R. Kristeleit, H.A. Burris, H. Giordano, S. Goble, J. Isaacson, L. Rolfe
Acquisition of data (provided animals, acquired and managed patients, provided facilities, etc.): R. Kristeleit, G.I. Shapiro, H.A. Burris, A.M. Oza, P. LoRusso, M.R. Patel, S.M. Domchek, J. Balmaña, Y. Drew, L.-m. Chen, T. Safra, A. Montes, L. Maloney, J. Xiao, L. Rolfe, R. Shapira-Frommer
Analysis and interpretation of data (e.g., statistical analysis, biostatistics, computational analysis): R. Kristeleit, G.I. Shapiro, H.A. Burris, A.M. Oza, P. LoRusso, M.R. Patel, S.M. Domchek, L.-m. Chen, H. Giordano, L. Maloney, S. Goble, J. Isaacson, J. Xiao, L. Rolfe, R. Shapira-Frommer
Writing, review, and/or revision of the manuscript: R. Kristeleit, G.I. Shapiro, H.A. Burris, A.M. Oza, P. LoRusso, M.R. Patel, S.M. Domchek, J. Balmaña, Y. Drew, L.-m. Chen, T. Safra, A. Montes, H. Giordano, L. Maloney, S. Goble, J. Isaacson, J. Xiao, J. Borrow, R. Shapira-Frommer
Administrative, technical, or material support (i.e., reporting or organizing data, constructing databases): H.A. Burris, L.-m. Chen, L. Maloney, J. Borrow
Study supervision: R. Kristeleit, H.A. Burris, M.R. Patel, L.-m. Chen, H. Giordano, L. Maloney, L. Rolfe
Acknowledgments
The authors thank Mark Morgan, MD, for his thoughtful comments and discussion and Sara Jaw-Tsai for her assistance with the pharmacokinetic data. Writing and editorial assistance funded by Clovis Oncology, Inc., was provided by Tim Lohret, PhD; Nathan Yardley, PhD; and Shannon Davis of Ashfield Healthcare Communications (Middletown, Connecticut).
Grant Support
This study was funded by Clovis Oncology, Inc. R. Kristeleit and this study were supported by the UCL Experimental Cancer Medicine Centre and the NIHR UCLH Biomedical Research Centre and Clinical Research Facility.
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