| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
Regulatory Issues: FDA |
Division of Oncology Drug Products, Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Rockville, Maryland, USA
Key Words. Vorinostat • Histone deacetylase inhibitor • HDAC • Cutaneous T-cell lymphoma • CTCL
Correspondence: Bhupinder S. Mann, M.D., U.S. Food and Drug Administration, White Oak Campus, 10903 New Hampshire Avenue, Building 22, Room 2103, Silver Spring, Maryland 20993-0002, USA. Telephone: 301-796-1411; Fax: 301-796-9845; e-mail: bhupinder.mann{at}fda.hhs.gov
Received December 6, 2006; accepted for publication July 24, 2007.
Disclosure: No potential conflicts of interest were reported by the authors, planners, reviewers, or staff managers of this article.
Access and take the CME test online and receive 1 AMA PRA Category 1 CreditTM at CME.TheOncologist.com
![]()
Learning Objectives
Top
Learning Objectives
Abstract
Introduction
Patients and Methods
Results
Safety
Discussion
Acknowledgments
References
After completing this course, the reader will be able to:
| ABSTRACT |
|---|
|
|
|---|
| INTRODUCTION |
|---|
|
|
|---|
Vorinostat (suberoylanilide hydroxamic acid, Zolinza®; Merck & Co., Inc., Whitehouse Station, NJ) is an orally active, potent inhibitor of HDAC activity whose structure is shown in Figure 1. Vorinostat inhibits HDAC by binding to a zinc ion in the catalytic domain of the enzyme [4]. Vorinostat demonstrated activity in murine xenograft models and it was additive or synergistic when combined with chemotherapy drugs in induction of differentiation and apoptosis of various cancer cell lines [5].
|
Both the i.v. and oral vorinostat formulations were reasonably well tolerated. Dose-limiting toxicity included myelosuppression, gastrointestinal toxicity, and fatigue. Responses were noted in both solid tumors and hematologic malignancies, including one patient with heavily pretreated cutaneous T-cell lymphoma (CTCL), who had stable disease.
Vorinostat and other HDAC inhibitors have demonstrated activity in CTCL. Zhang and colleagues [8] investigated the effect of vorinostat in CTCL cell lines and freshly isolated peripheral blood lymphocytes (PBLs) from 11 patients with circulating malignant T cells. Vorinostat treatment (1.0–5.0 µM for 48 hours) induced dose-dependent apoptosis in all three CTCL cell lines and also induced apoptosis up to 59% in 10 of 11 CTCL PBLs.
While vorinostat evaluation was being conducted in a variety of tumors, a cyclic tetrapeptide HDAC inhibitor, depsipeptide, was being evaluated primarily in hematologic malignancies. Using a human T-cell lymphoma cell line, Piekarz et al. [9] demonstrated substantial apoptosis without significant cell cycle arrest.
A phase I depsipeptide study reported partial responses (PRs) in three of three study patients with CTCL and a complete response (CR) in one patient with peripheral T-cell lymphoma, unspecified [10]. A phase II depsipeptide study reported objective responses in five of 19 assessable CTCL patients, including two patients who achieved CRs [11].
A similar phase II trial of vorinostat (400 mg/day) enrolled 13 advanced, refractory CTCL patients who had received a mean of five prior therapies (range, 1–19). Five patients (38%) experienced a PR, with a mean duration of response of 15 weeks. More than 50% of the study patients reported clinically significant decreases in pruritus [12].
These CTCL results led the sponsor (Merck & Co. Inc., Whitehouse Station, NJ) to conduct and submit a single-arm trial evaluating vorinostat efficacy, safety, and tolerability in the treatment of CTCL patients who had failed two prior systemic therapies for consideration of regulatory approval [13].
| PATIENTS AND METHODS |
|---|
|
|
|---|
Eligible CTCL patients were
18 years old, with an Eastern Cooperative Oncology Group performance status score of 0–2, life expectancy >3 months, and stage IB or higher disease [7]. Patients had to have progressive, persistent, or recurrent disease following two systemic therapies, one of which must have contained bexarotene (unless the patient was intolerant to or not a candidate for bexarotene as described in the bexarotene package insert). Persistent disease was defined by a lack of at least a 50% improvement on therapy for at least 3 months unless the patient was intolerant to therapy because of the toxicities. Use of topical or systemic corticosteroids was not allowed on study except in Sézary syndrome patients who were on systemic steroids for at least 3 months, in patients on a stable daily dose equivalent to
10 mg of prednisone for at least 4 weeks immediately prior to receiving study therapy, or in patients who had been on topical steroids for at least 3 months on a dose that did not exceed 0.1% triamcinolone acetonide cream or equivalent for at least 4 weeks immediately prior to receiving study therapy.
The starting dose of vorinostat was 400 mg once daily, preferably taken with food. Two dose reductions were allowed for toxicity: 300 mg once daily or 300 mg once daily for 5 consecutive days per week, if necessary. Treatment was continued until progressive disease, unacceptable toxicity, lack of efficacy, or a patient's withdrawal of consent.
The primary study objective was the objective response rate. Secondary objectives were time to objective response, response duration, time to progression, pruritis relief, and safety and tolerability of vorinostat. Skin disease was assessed and scored at baseline and at scheduled follow-up visits using the Severity-Weighted Assessment Tool (SWAT). Abnormal skin not elevated from the normal skin was defined as patch, abnormal skin elevated from the normal skin by <5 mm was defined as plaque, and a plaque elevated
5 mm was considered as tumor. Percentages of the total body surface area involved with patch, plaque, and tumor were severity-weighted by multiplying by factors of 1, 2, and 4, respectively, and summed to give an overall SWAT score.
A clinical complete response (CCR) required a 100% improvement with no evidence of the disease and a PR required at least a 50% decrease in SWAT score compared with baseline, with confirmation by a second assessment after at least 4 weeks. Patients who achieved a CCR or PR by SWAT had a full computed tomography assessment of their nodal disease after the response was confirmed by a second assessment. Progressive disease (PD) required at least a 25% increase in SWAT score compared with baseline in responding patients, a 50% increase in SWAT score compared with the nadir, or at least a 50% increase in the sum of the products of the greatest diameters of pathologically positive lymph nodes (documented by biopsy) compared with baseline. PD required confirmation by a second assessment 1–4 weeks later whenever possible. Stable disease (SD) did not meet the criteria for either response or progression. Follow-up study evaluations were performed at weeks 2, 4, 6, and 8, and every 4 weeks thereafter until the patient was discontinued from the study. For each study patient, global half-body photographs and close-up photographs of distinct individual lesions were taken serially to document changes in the skin disease. These photographs were supportive only and were not used to derive SWAT scores.
The intensity of pruritus was evaluated using a patient-completed questionnaire at baseline and at each follow-up visit. A 10-point scale was used and skin itch over the past week was assessed: 0 = no itching and 10 = itching as bad as it can be. A baseline pruritus score of
3 was required for assessment. A three-point decrease in pruritis intensity, without an increase in the use of antipruritic medications and confirmed by a second assessment at least 4 weeks later, was considered clinically significant.
The safety and tolerability of vorinostat were assessed in the two submitted phase II CTCL trials and in 10 other trials that included vorinostat treatment in patients with other solid tumors and hematologic malignancies. Adverse events were graded using the National Cancer Institute Common Terminology Criteria for Adverse Events, Version 3.0.
| RESULTS |
|---|
|
|
|---|
|
|
Although pruritis relief was a secondary endpoint of the large phase II trial, the absence of both a control arm and of blinding led the U.S. Food and Drug Administration (FDA) reviewers to consider the results as unreliable. Pruritis data were not included in the label.
| SAFETY |
|---|
|
|
|---|
|
Table 3 summarizes clinical or laboratory adverse events, regardless of causality, occurring in
10% of patients. Thrombocytopenia and anemia were the most common hematologic toxicities. Other laboratory abnormalities reported included increased serum glucose in 69% of CTCL patients (59 of 86), transient increases in serum creatinine in 46.5% of patients (40 of 86), and proteinuria in 51.4% of patients (38 of 74).
Serious adverse events occurring in this patient population included pulmonary embolism, reported in four patients (4.7%); squamous cell carcinoma, three patients (3.5%); and anemia, two patients (2.3%). There were single events of cholecystitis, death (of unknown cause), deep vein thrombosis, enterococcal infection, exfoliative dermatitis, gastrointestinal hemorrhage, infection, lobar pneumonia, myocardial infarction, ischemic stroke, pelviureteric obstruction, sepsis, spinal cord injury, streptococcal bacteremia, syncope, T-cell lymphoma, thrombocytopenia, and ureteric obstruction. Whereas cardiac toxicity was expected, based on preclinical data, myocardial damage was not detected.
| DISCUSSION |
|---|
|
|
|---|
The observed response rates and response durations observed with vorinostat appear comparable with those obtained with the other FDA-approved CTCL therapies, bexarotene (Targretin®; Ligand Pharmaceuticals, San Diego, CA) and denileukin diftitox, although response assessment in the vorinostat and denileukin diftitox trials was based on the SWAT whereas assessment in the bexarotene trials was by the Composite Assessment of Index Lesion Disease Severity tool. Bexarotene, at a dose of 300 mg/m2 per day orally, produced an overall response rate of 32.3% (one complete tumor response and 19 partial tumor responses) [16, 17] and denileukin diftitox, at a dose of 9 or 18 µg/kg per day, had an overall tumor response rate of 30% (seven complete tumor responses and 14 partial tumor responses) in 71 treated patients [18].
The observed 30% objective response rate of skin disease (evaluated using SWAT, supported by patient photographs) with a median response duration of 168 days in a heavily pretreated advanced CTCL patient population was felt by the FDA reviewers to represent clinical benefit. Vorinostat was thus granted regular approval on October 6, 2006. The approved indication is that vorinostat is indicated for treatment of cutaneous manifestations of CTCL in patients with progressive, persistent, or recurrent disease on or following two systemic therapies. The recommended vorinostat dose is 400 mg orally once daily with food.
| ACKNOWLEDGMENTS |
|---|
|
|
|---|
| REFERENCES |
|---|
|
|
|---|
This article has been cited by other articles:
![]() |
K. S. Keedy, N. M. Archin, A. T. Gates, A. Espeseth, D. J. Hazuda, and D. M. Margolis A Limited Group of Class I Histone Deacetylases Acts To Repress Human Immunodeficiency Virus Type 1 Expression J. Virol., May 15, 2009; 83(10): 4749 - 4756. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Haberland, A. Johnson, M. H. Mokalled, R. L. Montgomery, and E. N. Olson Genetic dissection of histone deacetylase requirement in tumor cells PNAS, May 12, 2009; 106(19): 7751 - 7755. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. S. Cunneen, R. M. Conway, and M. C. Madigan In Vitro Effects of Histone Deacetylase Inhibitors and Mitomycin C on Tenon Capsule Fibroblasts and Conjunctival Melanoma Cells Arch Ophthalmol, April 1, 2009; 127(4): 414 - 420. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. M. Balliet, G. Chen, C. J. Gallagher, R. W. Dellinger, D. Sun, and P. Lazarus Characterization of UGTs Active against SAHA and Association between SAHA Glucuronidation Activity Phenotype with UGT Genotype Cancer Res., April 1, 2009; 69(7): 2981 - 2989. [Abstract] [Full Text] [PDF] |
||||
![]() |
W. W. Ma and A. A. Adjei Novel Agents on the Horizon for Cancer Therapy CA Cancer J Clin, March 1, 2009; 59(2): 111 - 137. [Abstract] [Full Text] [PDF] |
||||
![]() |
M Seppala, H Koistinen, R Koistinen, L Hautala, P C Chiu, and W S Yeung Glycodelin in reproductive endocrinology and hormone-related cancer Eur. J. Endocrinol., February 1, 2009; 160(2): 121 - 133. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y. Haddad, W. Choi, and D. J. McConkey Delta-Crystallin Enhancer Binding Factor 1 Controls the Epithelial to Mesenchymal Transition Phenotype and Resistance to the Epidermal Growth Factor Receptor Inhibitor Erlotinib in Human Head and Neck Squamous Cell Carcinoma Lines Clin. Cancer Res., January 15, 2009; 15(2): 532 - 542. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. L.-A. Nguyen, H. Abdelbary, M. Arguello, C. Breitbach, S. Leveille, J.-S. Diallo, A. Yasmeen, T. A. Bismar, D. Kirn, T. Falls, et al. Chemical targeting of the innate antiviral response by histone deacetylase inhibitors renders refractory cancers sensitive to viral oncolysis PNAS, September 30, 2008; 105(39): 14981 - 14986. [Abstract] [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| THE ONCOLOGIST | STEM CELLS | CME | ALPHAMED PRESS JOURNALS |