VANTAGE 095: An International, Multicenter, Open-Label Study of Vorinostat (MK-0683) in Combination With Bortezomib in Patients With Relapsed and Refractory Multiple Myeloma.

BACKGROUND: The present global, open-label, single-arm, multicenter, phase IIb study was designed to determine the efficacy and tolerability of oral vorinostat combined with standard doses of bortezomib in patients with multiple myeloma considered refractory to novel myeloma agents. PATIENTS AND METHODS: Eligible patients were age ≥ 18 years, had received ≥ 2 previous regimens, had disease refractory to ≥ 1 previous bortezomib-containing regimen, and had received ≥ 1 dose of an immunomodulatory drug (thalidomide or lenalidomide)-based regimen. The patients received 21-day cycles of bortezomib (1.3 mg/m(2) intravenously on days 1, 4, 8, and 11) plus oral vorinostat (400 mg/d on days 1-14). Oral dexamethasone, 20 mg, on the day of and the day after each dose of bortezomib could be added for patients with progressive disease after 2 cycles or no change after 4 cycles. The primary endpoint was the objective response rate. RESULTS: The objective response rate was 11.3% (95% confidence interval, 6.6%-17.7%), and the median duration of response was 211 days (range, 64-550 days). The median overall survival duration was 11.2 months (95% confidence interval, 8.5-14.4 months), with a 2-year survival rate of 32%. The frequently reported adverse events were thrombocytopenia (69.7%), nausea (57.0%), diarrhea (53.5%), anemia (52.1%), and fatigue (48.6%); the overall safety profile was consistent with that of bortezomib and vorinostat. CONCLUSION: The combination of vorinostat and bortezomib is active in patients with multiple myeloma refractory to novel treatment modalities and offers a new therapeutic option for this difficult-to-treat patient population (ClinicalTrials.gov identifier, NCT00773838).

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.

Identification of a novel 5-HT(4) receptor splice variant (r5-HT(4c1)) and preliminary characterisation of specific 5-HT(4a) and 5-HT(4b) receptor antibodies.

The human 5-hydroxytryptamine (5-HT(4)) receptor is encoded by a highly complex gene which gives rise to at least 10 distinct splice variants. However, the functional relevance of these variants is unknown. In rat, only three such variants have been identified, 5-HT(4a) (r5-HT(4a)), 5-HT(4b) (r5-HT(4b)) and 5-HT(4e) (r5-HT(4e)). In the current study we identify and characterise the pharmacology of a novel rat splice variant (r5-HT(4c1)) and present the first comprehensive analysis of 5-HT(4) splice variant mRNA expression levels throughout the rat gastrointestinal tract. In addition, we describe preliminary characterisation of the first 5-HT(4) splice variant specific antibodies. In transfected cells, r5-HT(4c1) receptor exhibited similar binding properties to r5-HT(4a) and r5-HT(4b). Functional studies showed that 5-HT(4) agonists prucalopride (4-amino-5-chloro-2,3-dihydro-N-[1-(3-methoxypropyl)-4-piperidinyl]-7-benzofuran carboxamide monohydrochloride and renzapride (+/-)-endo-4-amino-5-chloro-2-methoxy-N-(1-azabicyclo[3.3.1]non-4-yl)benzamide monohydrochloride) acted as partial agonists at r5-HT(4c1), but full agonists at r5-HT(4a) and r5-HT(4b). Moreover, in contrast to r5-HT(4a) and r5-HT(4b), r5-HT(4c1) was not constitutively active. TaqMan mRNA analysis showed that r5-HT(4a) expression in brain and dorsal root ganglion exceeded that in the gastrointestinal tract, whilst the reverse was true for r5-HT(4b) and r5-HT(4c1). mRNA expression of each variant also increased distally throughout the gastrointestinal tract with the highest levels in the colon. r5-HT(4a) and r5-HT(4b) specific immunoreactivity was abundant on enteric neurons in jejunum, ileum and colon as well as neurons and satellite cells of the dorsal root ganglion. Only r5-HT(4b) immunoreactivity was observed on endocrine cells in the duodenum. These data could have implications in rat models and aid understanding of 5-HT(4) splice variant function.