Results of a randomized phase 3 study of oral sapacitabine in elderly patients with newly diagnosed acute myeloid leukemia (SEAMLESS).

BACKGROUND: Acute myeloid leukemia (AML) is fatal in elderly patients who are unfit for standard induction chemotherapy. The objective of this study was to evaluate the survival benefit of administering sapacitabine, an oral nucleoside analogue, in alternating cycles with decitabine, a low-intensity therapy, to elderly patients with newly diagnosed AML. METHODS: This randomized, open-label, phase 3 study (SEAMLESS) was conducted at 87 sites in 11 countries. Patients aged ≥70 years who were not candidates for or chose not to receive standard induction chemotherapy were randomized 1:1 to arm A (decitabine in alternating cycles with sapacitabine) received 1-hour intravenous infusions of decitabine 20 mg/m2 once daily for 5 consecutive days every 8 weeks (first cycle and subsequent odd cycles) and sapacitabine 300 mg twice daily on 3 consecutive days per week for 2 weeks every 8 weeks (second cycle and subsequent even cycles) or to control arm C who received 1-hour infusions of decitabine 20 mg/m2 once daily for 5 consecutive days every 4 weeks. Prior hypomethylating agent therapy for preexisting myelodysplastic syndromes or myeloproliferative neoplasms was an exclusion criterion. Randomization was stratified by antecedent myelodysplastic syndromes or myeloproliferative neoplasms, white blood cell count (<10 × 109 /L and ≥10 × 109 /L), and bone marrow blast percentage (≥50% vs <50%). The primary end point was overall survival (OS). Secondary end points were the rates of complete remission (CR), CR with incomplete platelet count recovery, partial remission, hematologic improvement, and stable disease along with the corresponding durations, transfusion requirements, number of hospitalized days, and 1-year survival. The trial is registered at ClinicalTrials.gov (NCT01303796). RESULTS: Between October 2011 and December 2014, 482 patients were enrolled and randomized to receive decitabine administered in alternating cycles with sapacitabine (study arm, n = 241) or decitabine monotherapy (control arm, n = 241). The median OS was 5.9 months on the study arm versus 5.7 months on the control arm (P = .8902). The CR rate was 16.6% on the study arm and 10.8% on the control arm (P = .1468). In patients with white blood cell counts <10 × 109 /L (n = 321), the median OS was higher on the study arm versus the control arm (8.0 vs 5.8 months; P = .145), as was the CR rate (21.5% vs 8.6%; P = .0017). CONCLUSIONS: The regimen of decitabine administered in alternating cycles with sapacitabine was active but did not significantly improve OS compared with decitabine monotherapy. Subgroup analyses suggest that patients with baseline white blood cell counts <10 × 109 /L might benefit from decitabine alternating with sapacitabine, with an improved CR rate and the convenience of an oral drug. These findings should be prospectively confirmed.

Phase I study of an oral histone deacetylase inhibitor, suberoylanilide hydroxamic acid, in patients with advanced cancer.

PURPOSE: To determine the safety, dosing schedules, pharmacokinetic profile, and biologic effect of orally administered histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA) in patients with advanced cancer. PATIENTS AND METHODS: Patients with solid and hematologic malignancies were treated with oral SAHA administered once or twice a day on a continuous basis or twice daily for 3 consecutive days per week. Pharmacokinetic profile and bioavailibity of oral SAHA were determined. Western blots and enzyme-linked immunosorbent assays of histones isolated from peripheral-blood mononuclear cells (PBMNCs) pre and post-therapy were performed to evaluate target inhibition. RESULTS: Seventy-three patients were treated with oral SAHA and major dose-limiting toxicities were anorexia, dehydration, diarrhea, and fatigue. The maximum tolerated dose was 400 mg qd and 200 mg bid for continuous daily dosing and 300 mg bid for 3 consecutive days per week dosing. Oral SAHA had linear pharmacokinetics from 200 to 600 mg, with an apparent half-life ranging from 91 to 127 minutes and 43% oral bioavailability. Histones isolated from PBMNCs showed consistent accumulation of acetylated histones post-therapy, and enzyme-linked immunosorbent assay demonstrated a trend towards a dose-dependent accumulation of acetylated histones from 200 to 600 mg of oral SAHA. There was one complete response, three partial responses, two unconfirmed partial responses, and 22 (30%) patients remained on study for 4 to 37+ months. CONCLUSIONS: Oral SAHA has linear pharmacokinetics and good bioavailability, inhibits histone deacetylase activity in PBMNCs, can be safely administered chronically, and has a broad range of antitumor activity.

Phase I clinical trial of histone deacetylase inhibitor: suberoylanilide hydroxamic acid administered intravenously.

PURPOSE: To evaluate the safety, pharmacokinetics, and biological activity of suberoylanilide hydroxamic acid (SAHA) administered by 2-h i.v. infusion in patients with advanced cancer. EXPERIMENTAL DESIGN: SAHA was administered for 3 days every 21 days in part A and 5 days for 1-3 weeks in part B. Dose escalation proceeded independently in patients with solid tumor and hematological malignancies (part B only). Pharmacokinetic studies were performed along with assessment of acetylated histones in peripheral blood mononuclear cells and tumor tissues. RESULTS: No dose-limiting toxicities were observed in 8 patients enrolled in part A (75, 150, 300, 600, and 900 mg/m(2)/day). Among 12 hematological and 17 solid tumor patients enrolled in part B (300, 600, and 900 mg/m(2)/day), therapy was delayed > or = 1 week for grade 3/4 leukopenia and/or thrombocytopenia in 2 of 5 hematological patients at 600 mg/m(2)/day x 5 days for 3 weeks. The maximal-tolerated dose was 300 mg/m(2)/day x 5 days for 3 weeks for hematological patients. One solid patient on 900 mg/m(2)/day x 5 days for 3 weeks developed acute respiratory distress and grade 3 hypotension. The cohort was expanded to 6 patients, and no additional dose-limiting toxicities were observed. Mean terminal half-life ranged from 21 to 58 min, and there was dose-proportional increase in area under the curve. An accumulation of acetylated histones in peripheral blood mononuclear cells up to 4 h postinfusion was observed at higher dose levels. Posttherapy tumor biopsies showed an accumulation of acetylated histones by immunohistochemistry. Four (2 lymphoma and 2 bladder) patients had objective tumor regression with clinical improvement in tumor related symptoms. CONCLUSIONS: Daily i.v. SAHA is well tolerated, inhibits the biological target in vivo, and has antitumor activity in solid and hematological tumors.

Histone deacetylase inhibitors: development as cancer therapy.

Histone deacetylase (HDAC) inhibitors represent a new class of targeted anticancer agents. A number of structural classes of HDAC inhibitors have been developed of which several are in clinical trials, including phenylbutyrate (PB) and related compounds; the hydroxamic acids, suberoylanilide hydroxamic acid (SAHA) and depsipeptide (FK-228); and the benzamides, MS-275 and C1-994. This review will focus on our studies with the hydroxamic acid HDAC inhibitors, of which SAHA is the lead agent. X-ray crystallographic studies with a HDAC homologue (HDLP) demonstrated that the hydroxamic acid group, most of the aliphatic chain and part of the phenyl amino group of SAHA inserts into the pocket-like catalytic site of the enzyme, at the base of which is a zinc molecule. SAHA inhibits the activity of class I and II HDACs and is selective in altering gene expression. SAHA is synergistic in its anticancer activity with radiation, kinase inhibitors, cytotoxic agents and differentiating agents. In phase I clinical trial with orally administered SAHA the agent caused accumulation of acetylated histones in peripheral mononuclear cells and tumour cells, has excellent bioavailability and has shown antitumour activity in patients with haematologic and solid tumours.

Phase I clinical and pharmacokinetic study of oral sapacitabine in patients with acute leukemia and myelodysplastic syndrome.

PURPOSE: Sapacitabine is an oral deoxycytidine nucleoside analog with a unique mechanism of action that is different from cytarabine. PATIENTS AND METHODS: To define the dose-limiting toxicities (DLT) and maximum-tolerated dose (MTD) of sapacitabine given orally twice daily for 7 days every 3 to 4 weeks, or twice daily for 3 days for 2 weeks (days 1 through 3 and days 8 through 10) every 3 to 4 weeks, in refractory-relapse acute leukemia and myelodysplastic syndrome (MDS). A total of 47 patients were treated in the phase I study that used a classical 3 + 3 design. Sapacitabine was escalated from 75 to 375 mg twice daily for 7 days (n = 35) and from 375 to 475 mg twice daily for 3 days on days 1 through 3 and days 8 through 10. RESULTS: The DLTs with both schedules were gastrointestinal. The MTDs were 375 mg twice daily for 7 days and 425 mg twice daily for 3 days on days 1 through 3 and days 8 through 10. The recommended phase II single-agent dose schedules were 325 mg twice daily for 7 days and 425 mg twice daily for 3 days on days 1 through 3 and days 8 through 10. Responses were observed in 13 patients (28%); four were complete responses, and nine were marrow complete responses. CONCLUSION: Sapacitabine is a new, safely administered, oral deoxycytidine analog that has encouraging activity in leukemia and MDS. Phase II studies are ongoing.

Phase II trial of the histone deacetylase inhibitor vorinostat (Zolinza, suberoylanilide hydroxamic acid, SAHA) in patients with recurrent and/or metastatic head and neck cancer.

This phase II trial was initiated to assess the efficacy and safety of oral vorinostat (Zolinza, suberoylanilide hydroxamic acid, SAHA) in patients with recurrent and/or metastatic head and neck cancer. Eligible patients must have recurrent and/or metastatic head and neck cancer unresponsive to or intolerant of conventional chemotherapy. Patients must have measurable disease, adequate hematologic, hepatic, and renal function, and be able to swallow capsules. Four or more weeks must have elapsed since prior chemotherapy, radiation therapy, major surgery or investigational anticancer therapy, and patients must have recovered from prior toxicities. Study endpoints included response rate, duration of stable disease and progression-free survival. Thirteen patients were enrolled (9 males); 1 withdrew consent prior to starting therapy. Twelve patients received oral vorinostat 400 mg once daily and were evaluable for response. The median age was 54 years (range 40-82). All patients had received prior chemotherapy (including 10 with platinum- or taxane-based combination therapy), and 9 had prior radiation therapy. No confirmed partial or complete responses were observed. One unconfirmed partial response was seen. Three patients had stable disease ranging from 9 to 26 weeks. Nine patients discontinued due to progressive disease, two withdrew consent, and one discontinued therapy for grade 3 anorexia. Grades 3-4 drug-related toxicities included thrombocytopenia (n=3), anorexia (n=2), and dehydration (n=2). Oral vorinostat 400 mg qd was generally well tolerated but did not demonstrate efficacy as defined by tumor response in this small group of heavily pre-treated patients.

Phase 2 trial of oral vorinostat (suberoylanilide hydroxamic acid, SAHA) for refractory cutaneous T-cell lymphoma (CTCL).

The activity and safety of the histone deacetylase inhibitor vorinostat (suberoylanilide hydroxamic acid, SAHA) were evaluated in patients with refractory cutaneous T-cell lymphoma (CTCL). Group 1 received vorinostat 400 mg daily, group 2 received vorinostat 300 mg twice daily for 3 days with 4 days rest, and group 3 received vorinostat 300 mg twice daily for 14 days with 7 days rest followed by 200 mg twice daily. Treatment continued until disease progression or intolerable toxicity. The primary objective was to determine the complete and partial response (PR) rate. Time to response (TTR), time to progressive disease (TTP), response duration (DOR), pruritus relief, and safety were determined. Thirty-three patients who had received a median of 5 prior therapies were enrolled. Eight patients achieved a PR, including 7 with advanced disease and 4 with Sézary syndrome. The median TTR, DOR, and TTP for responders were 11.9, 15.1, and 30.2 weeks, respectively. Fourteen of 31 evaluable patients had pruritus relief. The most common drug-related AEs were fatigue, thrombocytopenia, diarrhea, and nausea. The most common grade 3 or 4 drug-related AEs were thrombocytopenia and dehydration. Vorinostat demonstrated activity in heavily pretreated patients with CTCL. The 400 mg daily regimen had the most favorable safety profile and is being further evaluated.