Clinical Pharmacokinetics and Pharmacodynamics of Rucaparib.

Rucaparib is an oral small-molecule poly(ADP-ribose) polymerase inhibitor indicated for patients with recurrent ovarian cancer in the maintenance and treatment settings and for patients with metastatic castration-resistant prostate cancer associated with a deleterious BRCA1 or BRCA2 mutation. Rucaparib has a manageable safety profile; the most common adverse events reported were fatigue and nausea in both indications. Accumulation in plasma exposure occurred after repeated administration of the approved 600-mg twice-daily dosage. Steady state was achieved after continuous twice-daily dosing for a week. Rucaparib has moderate oral bioavailability and can be dosed with or without food. Although a high-fat meal weakly increased maximum concentration and area under the curve, the effect was not clinically significant. A mass balance analysis indicated almost a complete dose recovery of rucaparib over 12 days, with metabolism, renal, and hepatic excretion as the elimination routes. A population pharmacokinetic analysis of rucaparib revealed no effect of age, sex, race, or body weight. No starting dose adjustments were necessary for patients with mild-to-moderate hepatic or renal impairment; the effect of severe organ impairment on rucaparib exposure has not been evaluated. In patients, rucaparib moderately inhibited cytochrome P450 (CYP) 1A2 and weakly inhibited CYP3As, CYP2C9, and CYP2C19. Rucaparib weakly increased systemic exposures of oral contraceptives and oral rosuvastatin and marginally increased the exposure of oral digoxin (a P-glycoprotein substrate). In vitro studies suggested that rucaparib inhibits transporters MATE1, MATE2-K, OCT1, and OCT2. No clinically meaningful drug interactions with rucaparib as a perpetrator were observed. An exposure-response analysis revealed dose-dependent changes in selected clinical efficacy and safety endpoints. Overall, this article provides a comprehensive review of the clinical pharmacokinetics, pharmacodynamics, drug-drug interactions, effects of intrinsic and extrinsic factors, and exposure-response relationships of rucaparib.

Population pharmacokinetics of rucaparib in patients with advanced ovarian cancer or other solid tumors.

PURPOSE: To develop a population pharmacokinetics (PPK) model for rucaparib, an oral poly(ADP-ribose) polymerase inhibitor. METHODS: The PPK analysis used PK data from patients in Study 1014 (NCT01009190, n = 35), Study 10 (NCT01482715, n = 123), and ARIEL2 (NCT01891344, n = 300), including intensive intravenous data (12-40 mg), intensive and sparse oral data (12-360 mg single-dose, 40-500 mg once daily, and 240-840 mg twice daily [BID]), and intensive single-dose oral data under fasted conditions and after a high-fat meal (40, 300, and 600 mg). RESULTS: Rucaparib PK was well described by a two-compartment model with sequential zero-order release and first-order absorption and first-order elimination. A high-fat meal slightly increased bioavailability at 600 mg but not at lower doses; this is not considered clinically significant, and rucaparib can be taken with or without food. Covariate effects of baseline creatinine clearance and albumin on rucaparib clearance were identified. Despite numerical increases in exposure with renal impairment, no dose adjustment is recommended for patients with mild or moderate renal impairment. No statistically significant relationships were detected for demographics, hepatic function (normal versus mild impairment), CYP1A2 and CYP2D6 phenotypes, or strong CYP1A2 or CYP2D6 inhibitors. Concomitant proton pump inhibitors showed no clinically significant effect on absorption. External validation of the model with data from ARIEL3 (NCT01968213) and TRITON2 (NCT02952534) studies showed no clinically meaningful PK differences across indications or sex. CONCLUSION: The PPK model adequately described rucaparib PK, and none of the covariates evaluated had a clinically relevant effect. CLINICALTRIALS: GOV: Study 1014 (NCT01009190), Study 10 (NCT01482715), ARIEL2 (NCT01891344), ARIEL3 (NCT01968213), and TRITON2 (NCT02952534).

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

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

Pharmacokinetic Study of Rucaparib in Patients With Advanced Solid Tumors.

The phase 1-2 study CO-338-010 (Study 10; NCT01482715) is evaluating single-agent rucaparib, a poly(ADP-ribose) polymerase inhibitor, administered orally to patients with an advanced solid tumor. In the dose escalation phase (Part 1), we characterized the single-dose and steady-state pharmacokinetic profiles of rucaparib administered once daily (QD; dose range, 40-500 mg; n = 16) or twice daily (BID; dose range, 240-840 mg; n = 30). Across all dosing schedules examined, the plasma exposure of rucaparib was approximately dose proportional; half-life was approximately 17 hours, and median time to maximum concentration (tmax ) ranged from 1.5 to 6.0 hours after a single dose and 1.5 to 4.0 hours following repeated dosing. The steady-state accumulation ratio ranged from 1.60 to 2.33 following QD dosing and 1.47 to 5.44 following BID dosing. No effect of food on rucaparib pharmacokinetics was observed with a single dose of 40 mg (n = 3) or 300 mg (n = 6). In a phase 2 portion of the study (Part 3), the pharmacokinetic profile of rucaparib was further evaluated at the recommended phase 2 dose of 600 mg BID (n = 26). The mean (coefficient of variation) steady-state maximum concentration (Cmax ) and area under the concentration-time curve from time zero to 12 hours (AUC0-12h ) were 1940 ng/mL (54%) and 16 900 ng ⋅ h/mL (54%), respectively. A high-fat meal moderately increased rucaparib exposure. The fed-to-fasted geometric mean ratios (90% confidence interval [CI]) for AUC0-24h and Cmax were 138% (117%-162%) and 120% (99.1%-146%); the median (90%CI) tmax delay was 2.5 (0.5-4.4) hours.

BRCA Reversion Mutations in Circulating Tumor DNA Predict Primary and Acquired Resistance to the PARP Inhibitor Rucaparib in High-Grade Ovarian Carcinoma.

A key resistance mechanism to platinum-based chemotherapies and PARP inhibitors in BRCA-mutant cancers is the acquisition of BRCA reversion mutations that restore protein function. To estimate the prevalence of BRCA reversion mutations in high-grade ovarian carcinoma (HGOC), we performed targeted next-generation sequencing of circulating cell-free DNA (cfDNA) extracted from pretreatment and postprogression plasma in patients with deleterious germline or somatic BRCA mutations treated with the PARP inhibitor rucaparib. BRCA reversion mutations were identified in pretreatment cfDNA from 18% (2/11) of platinum-refractory and 13% (5/38) of platinum-resistant cancers, compared with 2% (1/48) of platinum-sensitive cancers (P = 0.049). Patients without BRCA reversion mutations detected in pretreatment cfDNA had significantly longer rucaparib progression-free survival than those with reversion mutations (median, 9.0 vs. 1.8 months; HR, 0.12; P < 0.0001). To study acquired resistance, we sequenced 78 postprogression cfDNA, identifying eight additional patients with BRCA reversion mutations not found in pretreatment cfDNA. SIGNIFICANCE: BRCA reversion mutations are detected in cfDNA from platinum-resistant or platinum-refractory HGOC and are associated with decreased clinical benefit from rucaparib treatment. Sequencing of cfDNA can detect multiple BRCA reversion mutations, highlighting the ability to capture multiclonal heterogeneity.This article is highlighted in the In This Issue feature, p. 151.

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

PURPOSE: Pancreatic cancer has a poor prognosis and limited treatment options. Approximately 9% of pancreatic cancers harbor a germline or somatic BRCA1 or BRCA2 (BRCA1/2) mutation. Because poly (ADP-ribose) polymerase inhibitors have significant activity in BRCA1/2-mutant ovarian and breast cancers, RUCAPANC investigated the efficacy and safety of rucaparib in BRCA1/2-mutant pancreatic cancer. PATIENTS AND METHODS: RUCAPANC enrolled patients with measurable locally advanced/metastatic pancreatic cancer who had received one to two prior chemotherapy regimens. Patients received oral rucaparib (600 mg twice daily) until disease progression. The primary end point was objective response rate. RESULTS: Nineteen patients were enrolled. Sixteen of 19 BRCA1/2 mutations were germ-line; three were somatic. Patients had received a median of two prior chemotherapy regimens. Four patients achieved a response; two partial responses and one complete response (CR) were confirmed (objective response rate, 15.8%; 3 of 19), with an additional CR unconfirmed. The disease control rate (CR, partial response, or stable disease for ≥ 12 weeks) was 31.6% (6 of 19) in all patients and 44.4% (4 of 9) in those who had received one prior chemotherapy regimen. As prespecified in the protocol, enrollment was stopped because of an insufficient response rate among the first 15 patients. Treatment-emergent adverse events included nausea (63.2%) and anemia (47.4%). Grade ≥ 3 adverse events included anemia (31.6%), fatigue (15.8%), and ascites (15.8%). Secondary resistance mutations were detected in circulating free tumor DNA in two patients with a germline BRCA2 mutation. These mutations are predicted to lead to the reversion of a somatic-not germline-mutation. CONCLUSION: Rucaparib provided clinical benefit to patients with advanced pancreatic cancer and a BRCA1/2 mutation, and demonstrated an acceptable safety profile. Additional trials of rucaparib in this population are warranted.

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

OBJECTIVE: An integrated analysis was undertaken to characterize the antitumor activity and safety profile of the oral poly(ADP-ribose) polymerase inhibitor rucaparib in patients with relapsed high-grade ovarian carcinoma (HGOC). METHODS: Eligible patients from Study 10 (NCT01482715) and ARIEL2 (NCT01891344) who received a starting dose of oral rucaparib 600mg twice daily (BID) with or without food were included in these analyses. The integrated efficacy population included patients with HGOC and a deleterious germline or somatic BRCA1 or BRCA2 (BRCA1/2) mutation who received at least two prior chemotherapies and were sensitive, resistant, or refractory to platinum-based chemotherapy. The primary endpoint was investigator-assessed confirmed objective response rate (ORR). Secondary endpoints included duration of response (DOR) and progression-free survival (PFS). The integrated safety population included patients with HGOC who received at least one dose of rucaparib 600mg BID, irrespective of BRCA1/2 mutation status and prior treatments. RESULTS: In the efficacy population (n=106), ORR was 53.8% (95% confidence interval [CI], 43.8-63.5); 8.5% and 45.3% of patients achieved complete and partial responses, respectively. Median DOR was 9.2months (95% CI, 6.6-11.6). In the safety population (n=377), the most frequent treatment-emergent adverse events (AEs) were nausea, asthenia/fatigue, vomiting, and anemia/hemoglobin decreased. The most common grade ≥3 treatment-emergent AE was anemia/hemoglobin decreased. Treatment-emergent AEs led to treatment interruption, dose reduction, and treatment discontinuation in 58.6%, 45.9%, and 9.8% of patients, respectively. No treatment-related deaths occurred. CONCLUSIONS: Rucaparib has antitumor activity in advanced BRCA1/2-mutated HGOC and a manageable safety profile.

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

BACKGROUND: Rucaparib, a poly(ADP-ribose) polymerase inhibitor, has anticancer activity in recurrent ovarian carcinoma harbouring a BRCA mutation or high percentage of genome-wide loss of heterozygosity. In this trial we assessed rucaparib versus placebo after response to second-line or later platinum-based chemotherapy in patients with high-grade, recurrent, platinum-sensitive ovarian carcinoma. METHODS: In this randomised, double-blind, placebo-controlled, phase 3 trial, we recruited patients from 87 hospitals and cancer centres across 11 countries. Eligible patients were aged 18 years or older, had a platinum-sensitive, high-grade serous or endometrioid ovarian, primary peritoneal, or fallopian tube carcinoma, had received at least two previous platinum-based chemotherapy regimens, had achieved complete or partial response to their last platinum-based regimen, had a cancer antigen 125 concentration of less than the upper limit of normal, had a performance status of 0-1, and had adequate organ function. Patients were ineligible if they had symptomatic or untreated central nervous system metastases, had received anticancer therapy 14 days or fewer before starting the study, or had received previous treatment with a poly(ADP-ribose) polymerase inhibitor. We randomly allocated patients 2:1 to receive oral rucaparib 600 mg twice daily or placebo in 28 day cycles using a computer-generated sequence (block size of six, stratified by homologous recombination repair gene mutation status, progression-free interval after the penultimate platinum-based regimen, and best response to the most recent platinum-based regimen). Patients, investigators, site staff, assessors, and the funder were masked to assignments. The primary outcome was investigator-assessed progression-free survival evaluated with use of an ordered step-down procedure for three nested cohorts: patients with BRCA mutations (carcinoma associated with deleterious germline or somatic BRCA mutations), patients with homologous recombination deficiencies (BRCA mutant or BRCA wild-type and high loss of heterozygosity), and the intention-to-treat population, assessed at screening and every 12 weeks thereafter. This trial is registered with ClinicalTrials.gov, number NCT01968213; enrolment is complete. FINDINGS: Between April 7, 2014, and July 19, 2016, we randomly allocated 564 patients: 375 (66%) to rucaparib and 189 (34%) to placebo. Median progression-free survival in patients with a BRCA-mutant carcinoma was 16·6 months (95% CI 13·4-22·9; 130 [35%] patients) in the rucaparib group versus 5·4 months (3·4-6·7; 66 [35%] patients) in the placebo group (hazard ratio 0·23 [95% CI 0·16-0·34]; p<0·0001). In patients with a homologous recombination deficient carcinoma (236 [63%] vs 118 [62%]), it was 13·6 months (10·9-16·2) versus 5·4 months (5·1-5·6; 0·32 [0·24-0·42]; p<0·0001). In the intention-to-treat population, it was 10·8 months (8·3-11·4) versus 5·4 months (5·3-5·5; 0·36 [0·30-0·45]; p<0·0001). Treatment-emergent adverse events of grade 3 or higher in the safety population (372 [99%] patients in the rucaparib group vs 189 [100%] in the placebo group) were reported in 209 (56%) patients in the rucaparib group versus 28 (15%) in the placebo group, the most common of which were anaemia or decreased haemoglobin concentration (70 [19%] vs one [1%]) and increased alanine or aspartate aminotransferase concentration (39 [10%] vs none). INTERPRETATION: Across all primary analysis groups, rucaparib significantly improved progression-free survival in patients with platinum-sensitive ovarian cancer who had achieved a response to platinum-based chemotherapy. ARIEL3 provides further evidence that use of a poly(ADP-ribose) polymerase inhibitor in the maintenance treatment setting versus placebo could be considered a new standard of care for women with platinum-sensitive ovarian cancer following a complete or partial response to second-line or later platinum-based chemotherapy. FUNDING: Clovis Oncology.

Secondary Somatic Mutations Restoring RAD51C and RAD51D Associated with Acquired Resistance to the PARP Inhibitor Rucaparib in High-Grade Ovarian Carcinoma.

High-grade epithelial ovarian carcinomas containing mutated BRCA1 or BRCA2 (BRCA1/2) homologous recombination (HR) genes are sensitive to platinum-based chemotherapy and PARP inhibitors (PARPi), while restoration of HR function due to secondary mutations in BRCA1/2 has been recognized as an important resistance mechanism. We sequenced core HR pathway genes in 12 pairs of pretreatment and postprogression tumor biopsy samples collected from patients in ARIEL2 Part 1, a phase II study of the PARPi rucaparib as treatment for platinum-sensitive, relapsed ovarian carcinoma. In 6 of 12 pretreatment biopsies, a truncation mutation in BRCA1, RAD51C, or RAD51D was identified. In five of six paired postprogression biopsies, one or more secondary mutations restored the open reading frame. Four distinct secondary mutations and spatial heterogeneity were observed for RAD51CIn vitro complementation assays and a patient-derived xenograft, as well as predictive molecular modeling, confirmed that resistance to rucaparib was associated with secondary mutations.Significance: Analyses of primary and secondary mutations in RAD51C and RAD51D provide evidence for these primary mutations in conferring PARPi sensitivity and secondary mutations as a mechanism of acquired PARPi resistance. PARPi resistance due to secondary mutations underpins the need for early delivery of PARPi therapy and for combination strategies. Cancer Discov; 7(9); 984-98. ©2017 AACR.See related commentary by Domchek, p. 937See related article by Quigley et al., p. 999See related article by Goodall et al., p. 1006This article is highlighted in the In This Issue feature, p. 920.

A Phase I-II Study of the Oral PARP Inhibitor Rucaparib in Patients with Germline BRCA1/2-Mutated Ovarian Carcinoma or Other Solid Tumors.

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.

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

BACKGROUND: This study evaluated safety, pharmacokinetics, and clinical activity of intravenous and oral rucaparib, a poly(ADP-ribose) polymerase inhibitor, combined with chemotherapy in patients with advanced solid tumours. METHODS: Initially, patients received escalating doses of intravenous rucaparib combined with carboplatin, carboplatin/paclitaxel, cisplatin/pemetrexed, or epirubicin/cyclophosphamide. Subsequently, the study was amended to focus on oral rucaparib (once daily, days 1-14) combined with carboplatin (day 1) in 21-day cycles. Dose-limiting toxicities (DLTs) were assessed in cycle 1 and safety in all cycles. RESULTS: Eighty-five patients were enrolled (22 breast, 15 ovarian/peritoneal, and 48 other primary cancers), with a median of three prior therapies (range, 1-7). Neutropenia (27.1%) and thrombocytopenia (18.8%) were the most common grade ⩾3 toxicities across combinations and were DLTs with the oral rucaparib/carboplatin combination. Maximum tolerated dose for the combination was 240 mg per day oral rucaparib and carboplatin area under the curve 5 mg ml-1 min-1. Oral rucaparib demonstrated dose-proportional kinetics, a long half-life (≈17 h), and good bioavailability (36%). Pharmacokinetics were unchanged by carboplatin coadministration. The rucaparib/carboplatin combination had radiologic antitumour activity, primarily in BRCA1- or BRCA2-mutated breast and ovarian/peritoneal cancers. CONCLUSIONS: Oral rucaparib can be safely combined with a clinically relevant dose of carboplatin in patients with advanced solid tumours (Trial registration ID: NCT01009190).

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

BACKGROUND: Poly(ADP-ribose) polymerase (PARP) inhibitors have activity in ovarian carcinomas with homologous recombination deficiency. Along with BRCA1 and BRCA2 (BRCA) mutations genomic loss of heterozygosity (LOH) might also represent homologous recombination deficiency. In ARIEL2, we assessed the ability of tumour genomic LOH, quantified with a next-generation sequencing assay, to predict response to rucaparib, an oral PARP inhibitor. METHODS: ARIEL2 is an international, multicentre, two-part, phase 2, open-label study done at 49 hospitals and cancer centres in Australia, Canada, France, Spain, the UK, and the USA. In ARIEL2 Part 1, patients with recurrent, platinum-sensitive, high-grade ovarian carcinoma were classified into one of three predefined homologous recombination deficiency subgroups on the basis of tumour mutational analysis: BRCA mutant (deleterious germline or somatic), BRCA wild-type and LOH high (LOH high group), or BRCA wild-type and LOH low (LOH low group). We prespecified a cutoff of 14% or more genomic LOH for LOH high. Patients began treatment with oral rucaparib at 600 mg twice per day for continuous 28 day cycles until disease progression or any other reason for discontinuation. The primary endpoint was progression-free survival. All patients treated with at least one dose of rucaparib were included in the safety analyses and all treated patients who were classified were included in the primary endpoint analysis. This trial is registered with ClinicalTrials.gov, number NCT01891344. Enrolment into ARIEL2 Part 1 is complete, although an extension (Part 2) is ongoing. FINDINGS: 256 patients were screened and 206 were enrolled between Oct 30, 2013, and Dec 19, 2014. At the data cutoff date (Jan 18, 2016), 204 patients had received rucaparib, with 28 patients remaining in the study. 192 patients could be classified into one of the three predefined homologous recombination deficiency subgroups: BRCA mutant (n=40), LOH high (n=82), or LOH low (n=70). Tumours from 12 patients were established as BRCA wild-type, but could not be classified for LOH, because of insufficient neoplastic nuclei in the sample. The median duration of treatment for the 204 patients was 5·7 months (IQR 2·8-10·1). 24 patients in the BRCA mutant subgroup, 56 patients in the LOH high subgroup, and 59 patients in the LOH low subgroup had disease progression or died. Median progression-free survival after rucaparib treatment was 12·8 months (95% CI 9·0-14·7) in the BRCA mutant subgroup, 5·7 months (5·3-7·6) in the LOH high subgroup, and 5·2 months (3·6-5·5) in the LOH low subgroup. Progression-free survival was significantly longer in the BRCA mutant (hazard ratio 0·27, 95% CI 0·16-0·44, p<0·0001) and LOH high (0·62, 0·42-0·90, p=0·011) subgroups compared with the LOH low subgroup. The most common grade 3 or worse treatment-emergent adverse events were anaemia or decreased haemoglobin (45 [22%] patients), and elevations in alanine aminotransferase or aspartate aminotransferase (25 [12%]). Common serious adverse events included small intestinal obstruction (10 [5%] of 204 patients), malignant neoplasm progression (10 [5%]), and anaemia (nine [4%]). Three patients died during the study (two because of disease progression and one because of sepsis and disease progression). No treatment-related deaths occurred. INTERPRETATION: In patients with BRCA mutant or BRCA wild-type and LOH high platinum-sensitive ovarian carcinomas treated with rucaparib, progression-free survival was longer than in patients with BRCA wild-type LOH low carcinomas. Our results suggest that assessment of tumour LOH can be used to identify patients with BRCA wild-type platinum-sensitive ovarian cancers who might benefit from rucaparib. These results extend the potential usefulness of PARP inhibitors in the treatment setting beyond BRCA mutant tumours. FUNDING: Clovis Oncology, US Department of Defense Ovarian Cancer Research Program, Stand Up To Cancer-Ovarian Cancer Research Fund Alliance-National Ovarian Cancer Coalition Dream Team Translational Research Grant, and V Foundation Translational Award.

Phase I study of oral azacitidine in myelodysplastic syndromes, chronic myelomonocytic leukemia, and acute myeloid leukemia.

PURPOSE: To determine the maximum-tolerated dose (MTD), safety, pharmacokinetic and pharmacodynamic profiles, and clinical activity of an oral formulation of azacitidine in patients with myelodysplastic syndromes (MDSs), chronic myelomonocytic leukemia (CMML), or acute myeloid leukemia (AML). PATIENTS AND METHODS: Patients received 1 cycle of subcutaneous (SC) azacitidine (75 mg/m2) on the first 7 days of cycle 1, followed by oral azacitidine daily (120 to 600 mg) on the first 7 days of each additional 28-day cycle. Pharmacokinetic and pharmacodynamic profiles were evaluated during cycles 1 and 2. Adverse events and hematologic responses were recorded. Cross-over to SC azacitidine was permitted for nonresponders who received ≥ 6 cycles of oral azacitidine. RESULTS: Overall, 41 patients received SC and oral azacitidine (MDSs, n = 29; CMML, n = 4; AML, n = 8). Dose-limiting toxicity (grade 3/4 diarrhea) occurred at the 600-mg dose and MTD was 480 mg. Most common grade 3/4 adverse events were diarrhea (12.2%), nausea (7.3%), vomiting (7.3%), febrile neutropenia (19.5%), and fatigue (9.8%). Azacitidine exposure increased with escalating oral doses. Mean relative oral bioavailability ranged from 6.3% to 20%. Oral and SC azacitidine decreased DNA methylation in blood, with maximum effect at day 15 of each cycle. Hematologic responses occurred in patients with MDSs and CMML. Overall response rate (i.e., complete remission, hematologic improvement, or RBC or platelet transfusion independence) was 35% in previously treated patients and 73% in previously untreated patients. CONCLUSION: Oral azacitidine was bioavailable and demonstrated biologic and clinical activity in patients with MDSs and CMML.