Linda Sun

The poly(ADP-ribose) polymerase inhibitor niraparib (MK4827) in BRCA mutation carriers and patients with sporadic cancer: A phase 1 dose-escalation trial

BACKGROUND Poly(ADP-ribose) polymerase (PARP) is implicated in DNA repair and transcription regulation. Niraparib (MK4827) is an oral potent, selective PARP-1 and PARP-2 inhibitor that induces synthetic lethality in preclinical tumour models with loss of BRCA and PTEN function. We investigated the safety, tolerability, maximum tolerated dose, pharmacokinetic and pharmacodynamic profiles, and preliminary antitumour activity of niraparib. METHODS In a phase 1 dose-escalation study, we enrolled patients with advanced solid tumours at one site in the UK and two sites in the USA. Eligible patients were aged at least 18 years; had a life expectancy of at least 12 weeks; had an Eastern Cooperative Oncology Group performance status of 2 or less; had assessable disease; were not suitable to receive any established treatments; had adequate organ function; and had discontinued any previous anticancer treatments at least 4 weeks previously. In part A, cohorts of three to six patients, enriched for BRCA1 and BRCA2 mutation carriers, received niraparib daily at ten escalating doses from 30 mg to 400 mg in a 21-day cycle to establish the maximum tolerated dose. Dose expansion at the maximum tolerated dose was pursued in 15 patients to confirm tolerability. In part B, we further investigated the maximum tolerated dose in patients with sporadic platinum-resistant high-grade serous ovarian cancer and sporadic prostate cancer. We obtained blood, circulating tumour cells, and optional paired tumour biopsies for pharmacokinetic and pharmacodynamic assessments. Toxic effects were assessed by common toxicity criteria and tumour responses ascribed by Response Evaluation Criteria in Solid Tumors (RECIST). Circulating tumour cells and archival tumour tissue in prostate patients were analysed for exploratory putative predictive biomarkers, such as loss of PTEN expression and ETS rearrangements. This trial is registered with ClinicalTrials.gov, NCT00749502. FINDINGS Between Sept 15, 2008, and Jan 14, 2011, we enrolled 100 patients: 60 in part A and 40 in part B. 300 mg/day was established as the maximum tolerated dose. Dose-limiting toxic effects reported in the first cycle were grade 3 fatigue (one patient given 30 mg/day), grade 3 pneumonitis (one given 60 mg/day), and grade 4 thrombocytopenia (two given 400 mg/day). Common treatment-related toxic effects were anaemia (48 patients [48%]), nausea (42 [42%]), fatigue (42 [42%]), thrombocytopenia (35 [35%]), anorexia (26 [26%]), neutropenia (24 [24%]), constipation (23 [23%]), and vomiting (20 [20%]), and were predominantly grade 1 or 2. Pharmacokinetics were dose proportional and the mean terminal elimination half-life was 36·4 h (range 32·8-46·0). Pharmacodynamic analyses confirmed PARP inhibition exceeded 50% at doses greater than 80 mg/day and antitumour activity was documented beyond doses of 60 mg/day. Eight (40% [95% CI 19-64]) of 20 BRCA1 or BRCA2 mutation carriers with ovarian cancer had RECIST partial responses, as did two (50% [7-93]) of four mutation carriers with breast cancer. Antitumour activity was also reported in sporadic high-grade serous ovarian cancer, non-small-cell lung cancer, and prostate cancer. We recorded no correlation between loss of PTEN expression or ETS rearrangements and measures of antitumour activity in patients with prostate cancer. INTERPRETATION A recommended phase 2 dose of 300 mg/day niraparib is well tolerated. Niraparib should be further assessed in inherited and sporadic cancers with homologous recombination DNA repair defects and to target PARP-mediated transcription in cancer. FUNDING Merck Sharp and Dohme.

Phase I trial of oral vorinostat (suberoylanilide hydroxamic acid, SAHA) in patients with advanced multiple myeloma

A Phase I trial (NCT00109109) of oral vorinostat 200, 250 or 300 mg twice daily for 5 days/week/4-week cycle or 200, 300, or 400 mg twice daily for 14 days/3-week cycle until progressive disease or intolerable toxicity was conducted. Patients with measurable, relapsed/refractory multiple myeloma were eligible. The objectives were to determine maximum tolerated doses (MTDs) and assess activity and safety. Thirteen patients (median age, 63 years; median prior therapies, 3) were enrolled. MTDs were not determined due to early study termination by sponsor decision. One patient (250 mg twice daily 5 days/week) developed dose-limiting toxicity (DLT; grade 3 fatigue). There were no other DLTs and the maximum administered doses were 250 mg twice daily for 5 days/week/4-week cycle and 200 mg twice daily for 14 days/3-week cycle. Drug-related adverse experiences included fatigue, anorexia, dehydration, diarrhea, and nausea and were mostly grade ≤2. Of 10 evaluable patients, 1 had a minimal response and 9 had stable disease, demonstrating modest single-agent activity in relapsed/refractory multiple myeloma.

Vorinostat or placebo in combination with bortezomib in patients with multiple myeloma (VANTAGE 088): a multicentre, randomised, double-blind study

BACKGROUND We aimed to assess efficacy and tolerability of vorinostat in combination with bortezomib for treatment of patients with relapsed or refractory multiple myeloma. METHODS In our randomised, double-blind, placebo-controlled, phase 3 trial, we enrolled adults (≥18 years) at 174 university hospitals in 31 countries worldwide. Eligible patients had to have non-refractory multiple myeloma that previously responded to treatment (one to three regimens) but were currently progressing, ECOG performance statuses of 2 or less, and no continuing toxic effects from previous treatment. We excluded patients with known resistance to bortezomib. We randomly allocated patients (1:1) using an interactive voice response system to receive 21 day cycles of bortezomib (1·3 mg/m(2) intravenously on days 1, 4, 8, and 11) in combination with oral vorinostat (400 mg) or matching placebo once-daily on days 1-14. We stratified patients by baseline tumour stage (International Staging System stage 1 or stage ≥2), previous bone-marrow transplantation (yes or no), and number of previous regimens (1 or ≥2). The primary endpoint was progression-free survival (PFS) in the intention-to-treat population. We assessed adverse events in all patients who received at least one dose of study drug. This study is registered with ClinicalTrials.gov, number 00773747. FINDINGS Between Dec 24, 2008, and Sept 8, 2011, we randomly allocated 317 eligible patients to the vorinostat group (315 of whom received at least one dose) and 320 to the placebo group (all of whom received at least one dose). Median PFS was 7·63 months (95% CI 6·87-8·40) in the vorinostat group and 6·83 months (5·67-7·73) in the placebo group (hazard ratio [HR] 0·77, 95% CI 0·64-0·94; p=0·0100). 312 (99%) of 315 patients in the vorinostat group and 315 (98%) of 320 patients in the placebo group had adverse events (300 [95%] adverse events in the vorinostat group and 282 [88%] in the control group were regarded as related to treatment). The most common grade 3-4 adverse events were thrombocytopenia (143 [45%] patients in the vorinostat group vs 77 [24%] patients in the placebo group), neutropenia (89 [28%] vs 80 [25%]), and anaemia (53 [17%] vs 40 [13%]). INTERPRETATION Although the combination of vorinostat and bortezomib prolonged PFS relative to bortezomib and placebo, the clinical relevance of the difference in PFS between the two groups is not clear. Different treatment schedules of bortezomib and vorinostat might improve tolerability and enhance activity. FUNDING Merck.

A Study to Determine the Effects of Food and Multiple Dosing on the Pharmacokinetics of Vorinostat Given Orally to Patients with Advanced Cancer

Purpose: This phase I study, conducted in advanced-stage cancer patients, assessed the safety and tolerability of oral vorinostat (suberoylanilide hydroxamic acid), single-dose and multiple-dose pharmacokinetics of vorinostat, and the effect of a high-fat meal on vorinostat pharmacokinetics. Experimental Design: Patients (n = 23) received single doses of 400 mg vorinostat on day 1 (fasted) and day 5 (fed) with 48 hours of pharmacokinetic sampling on both days. Patients received 400 mg vorinostat once daily on days 7 to 28. On day 28, vorinostat was given (fed) with pharmacokinetic sampling for 24 hours after dose. Results: The apparent t1/2 of vorinostat was short (∼1.5 hours). A high-fat meal was associated with a small increase in the extent of absorption and a modest decrease in the rate of absorption. A short lag time was observed before detectable levels of vorinostat were observed in the fed state, and Tmax was delayed. Vorinostat concentrations were qualitatively similar following single-dose and multiple-dose administration; the accumulation ratio based on area under the curve was 1.21. The elimination of vorinostat occurred primarily through metabolism, with <1% of the given dose recovered intact in urine. The most common vorinostat-related adverse experiences were mild to moderate nausea, anorexia, fatigue, increased blood creatinine, and vomiting. Conclusions: Vorinostat concentrations were qualitatively similar after single and multiple doses. A high-fat meal increased the extent and modestly decreased the rate of absorption of vorinostat; this effect is not anticipated to be clinically meaningful. Continued investigation of 400 mg vorinostat given once daily in phase II and III efficacy studies is warranted.

First-in-human trial of a poly(ADP)-ribose polymerase (PARP) inhibitor MK-4827 in advanced cancer patients with antitumor activity in BRCA-deficient tumors and sporadic ovarian cancers (soc).

3102 Background: MK4827 is an orally active, PARP 1/2 inhibitor with nanomolar potency. It induces selective synthetic lethality in homologous recombination (HR) repair deficient tumors with BRCA1/2 loss and in tumor cell lines with non-BRCA-related HR defects, supporting broad clinical application. A phase I study was undertaken to determine the toxicity and tolerability, pharmacokinetic (PK) and pharmacodynamic (PD) profiles, and preliminary anti-tumor activity. METHODS Patients (p) with advanced solid tumors enriched for BRCA-mutation carriers (BRCA-MC) and non-BRCA HR defects received once daily, escalating doses of MK4827 in cohorts of 3-6 p. Dose escalation was guided by toxicity, PK and PD data. RESULTS 60 p (M13, F47; median age 56 yr; 21 BRCA-MC) were treated at 10 dose levels from 30mg to 400mg on days 1-21 of a 28 day cycle (C) in C1, followed by continuous dosing. 20 additional p with soc were enrolled at the MTD. Prior systemic treatments were ≤2 (23p), ≥3 (17p), and ≥4 (40p). Overall, DLT was observed in 4p: grade (G) 3 fatigue in 1/6p at 30mg, reversible G3 pneumonitis in 1/6p at 60mg, and reversible G4 thrombocytopenia in 2/6p treated at 400mg. The MTD was established at 300mg. Other MK4827 related G1-2 reversible adverse events included fatigue, anorexia, nausea and myelosuppression. Dose proportional PK was observed with a mean t1/2 of 40 hours (range 37-42 hr). PD studies confirmed PARP inhibition in peripheral blood mononuclear cells at doses of ≥80 mg. Antitumor activity was observed in both sporadic and BRCA-MC cancers. In total, there have been 12p with partial responses (PR) (10 ovarian [7 BRCA-MC; 3 soc], 2 breast, 10/12 BRCA-MC cancers, 4/12 with ongoing treatment), and 8p with stable disease (SD) (4 ovarian [2 BRMC-MC], 2 NSCLC, 2/4 BRCA-MC) ≥120 days. PRs have ranged from 86(+)-483 days and SD from 18(+)-354 days. CONCLUSIONS MK-4827 was well tolerated, had linear PKs, evidence of target modulation, and promising antitumor activity in both BRCA-MC and sporadic cancer. Specific cohort expansions in other nonhereditary tumors enriched for HR defects is ongoing. Updated safety and response data will be provided.