Paclitaxel/carboplatin with or without belinostat as empiric first-line treatment for patients with carcinoma of unknown primary site: A randomized, phase 2 trial.

BACKGROUND: The objective of this study was to evaluate the efficacy of belinostat, a histone deacetylase inhibitor, when added to paclitaxel/carboplatin in the empiric first-line treatment of patients with carcinoma of unknown primary site (CUP). METHODS: In this randomized phase 2 trial, previously untreated patients with CUP were randomized to receive belinostat plus paclitaxel/carboplatin (group A) or paclitaxel/carboplatin alone (group B) repeated every 21 days. Patients were re-evaluated every 2 cycles, and those without disease progression continued treatment for 6 cycles. Patients in group A then continued receiving single-agent belinostat, whereas patients in group B stopped treatment. The primary endpoint was progression-free survival (PFS): The authors postulated that the addition of belinostat would improve PFS from 5 months (expected with paclitaxel/carboplatin) to 8 months. RESULTS: In total, 89 patients were randomized (group A, n = 44; group B, n = 45), and the demographics and disease characteristics were balanced between the 2 groups. The addition of belinostat to paclitaxel/carboplatin did not improve PFS (group A, 5.4 months [95% confidence interval, 3.0-6.0 months]; group B, 5.3 months [95% confidence interval, 2.8-6.6 months]; P = .85). Overall survival was 12.4 months for group A versus 9.1 months for group B (P = .20). The response rate favored the belinostat group (45% vs 21%; P = .02). Belinostat resulted in a modest increase in treatment toxicity. CONCLUSIONS: The addition of belinostat to paclitaxel/carboplatin did not improve the PFS of patients with CUP who were receiving first-line therapy, although the patients who received belinostat had a higher investigator-assessed response rate. Future trials in CUP should focus on specific subsets, defined either by the predicted tissue of origin or by the identification of targetable molecular abnormalities.

A Phase II trial of Belinostat (PXD101) in patients with relapsed or refractory peripheral or cutaneous T-cell lymphoma.

Belinostat is a pan-histone deacetylase inhibitor with antitumour and anti-angiogenic properties. An open label, multicentre study was conducted in patients with peripheral T-cell lymphoma (PTCL) or cutaneous T-cell lymphoma (CTCL) who failed ≥1 prior systemic therapy and were treated with belinostat (1000 mg/m(2) intravenously ×5 d of a 21-d cycle). The primary endpoint was objective response rate (ORR). Patients with PTCL (n = 24) had received a median of three prior systemic therapies (range 1-9) and 40% had stage IV disease. Patients with CTCL (n = 29) had received a median of one prior skin-directed therapy (range 0-4) and four prior systemic therapies (range 1-9); 55% had stage IV disease. The ORRs were 25% (PTCL) and 14% (CTCL). Treatment-related adverse events occurred in 77% of patients; nausea (43%), vomiting (21%), infusion site pain (13%) and dizziness (11%) had the highest incidence. Treatment-related serious adverse events were Grade 5 ventricular fibrillation; Grade 4 thrombocytopenia; Grade 3 peripheral oedema, apraxia, paralytic ileus and pneumonitis; and Grade 2 jugular vein thrombosis. Belinostat monotherapy was well tolerated and efficacious in patients with recurrent/refractory PTCL and CTCL. This trial was registered at www.clinicaltrials.gov as NCT00274651.

A phase 1 pharmacokinetic and pharmacodynamic study of the histone deacetylase inhibitor belinostat in patients with advanced solid tumors.

PURPOSE: To determine the safety, dose-limiting toxicity, maximum tolerated dose, and pharmacokinetic and pharmacodynamic profiles of the novel hydroxamate histone deacetylase inhibitor belinostat (previously named PXD101) in patients with advanced refractory solid tumors. EXPERIMENTAL DESIGN: Sequential dose-escalating cohorts of three to six patients received belinostat administered as a 30-min i.v. infusion on days 1 to 5 of a 21-day cycle. Pharmacokinetic variables were evaluated at all dose levels. Pharmacodynamic measurements included acetylation of histones extracted from peripheral blood mononuclear cells, caspase-dependent cleavage of cytokeratin-18, and interleukin-6 levels. RESULTS: Forty-six patients received belinostat at one of six dose levels (150-1,200 mg/m(2)/d). Dose-limiting toxicities were grade 3 fatigue (one patient at 600 mg/m(2); one patient at 1,200 mg/m(2)), grade 3 diarrhea combined with fatigue (one patient at 1,200 mg/m(2)), grade 3 atrial fibrillation (one patient at 1,200 mg/m(2); one patient at 1,000 mg/m(2)), and grade 2 nausea/vomiting leading to inability to complete a full 5-day cycle (two patients at 1,000 mg/m(2)). The maximum tolerated dose was 1,000 mg/m(2)/d. I.v. belinostat displayed linear pharmacokinetics with respect to C(max) and AUC. The intermediate elimination half-life was 0.3 to 1.3 h and was independent of dose. Histone H4 hyperacetylation was observed after each infusion and was sustained for 4 to 24 h in a dose-dependent manner. Increases in interleukin-6 levels were detected following belinostat treatment. Stable disease was observed in a total of 18 (39%) patients, including 15 treated for > or =4 cycles, and this was associated with caspase-dependent cleavage of cytokeratin-18. Of the 24 patients treated at the maximum tolerated dose (1,000 mg/m(2)/d), 50% achieved stable disease. CONCLUSIONS: I.v. belinostat is well tolerated, exhibits dose-dependent pharmacodynamic effects, and has promising antitumor activity.

A Phase I/II Clinical Trial of Belinostat (PXD101) in Combination with Doxorubicin in Patients with Soft Tissue Sarcomas.

Background. Belinostat is a novel histone deacetylase inhibitor. Primary Objectives. Maximum tolerated dose (MTD) and dose limiting toxicities (DLTs) of belinostat (Bel) in combination with doxorubicin (Dox) in solid tumours (phase I) and response rate (RR) in soft tissue sarcomas (phase II). Methods. Bel was administered as a 30-minute IV infusion on days 1-5 and on day 5 with Dox. The dose escalation schedule was as follows: cohort 1: Bel 600 mg/m(2) and 50 mg/m(2) Dox, cohort 2: Bel 600 mg/m(2) and 75 mg/m(2) Dox, cohort 3: Bel 800 mg/m(2) and 75 mg/m(2) Dox, and cohort 4: Bel 1000 mg/m(2) and 75 mg/m(2) Dox. Results. 41 patients were included (25 in phase I, 16 in phase II). Adverse events were fatigue (95%), nausea (76%), and alopecia (63%). There was one DLT, grade 3 rash/hand and foot syndrome. MTD was Bel 1000 mg/m(2)/d and Dox 75 mg/m(2). Four responses were seen: 2 PR in phase I, RR of 8%; in phase II, 1 PR/1 CR, RR of 13%, and 9 patients (56%) with SD. Conclusion. The combination was well tolerated. Response rate was moderate but median time to progression was 6.0 months (95% CI, 1.6-9.7 months) which is superior to some reports of single-agent Dox.

Belinostat in Patients With Relapsed or Refractory Peripheral T-Cell Lymphoma: Results of the Pivotal Phase II BELIEF (CLN-19) Study.

PURPOSE: Peripheral T-cell lymphomas (PTCLs) represent a diverse group of non-Hodgkin lymphomas with a poor prognosis and no accepted standard of care for patients with relapsed or refractory disease. This study evaluated the efficacy and tolerability of belinostat, a novel histone deacetylase inhibitor, as a single agent in relapsed or refractory PTCL. PATIENTS AND METHODS: Patients with confirmed PTCL who experienced progression after ≥ one prior therapy received belinostat 1,000 mg/m(2) as daily 30-minute infusions on days 1 to 5 every 21 days. Central assessment of response used International Working Group criteria. Primary end point was overall response rate. Secondary end points included duration of response (DoR) and progression-free and overall survival. RESULTS: A total of 129 patients were enrolled, with a median of two prior systemic therapies. Overall response rate in the 120 evaluable patients was 25.8% (31 of 120), including 13 complete (10.8%) and 18 partial responses (15%). Median DoR by International Working Group criteria was 13.6 months, with the longest ongoing patient at ≥ 36 months. Median progression-free and overall survival were 1.6 and 7.9 months, respectively. Twelve of the enrolled patients underwent stem-cell transplantation after belinostat monotherapy. The most common grade 3 to 4 adverse events were anemia (10.8%), thrombocytopenia (7%), dyspnea (6.2%), and neutropenia (6.2%). CONCLUSION: Monotherapy with belinostat produced complete and durable responses with manageable toxicity in patients with relapsed or refractory PTCL across the major subtypes, irrespective of number or type of prior therapies. These results have led to US Food and Drug Administration approval of belinostat for this indication.