TY - JOUR
T1 - The Safety Profile of Dalfampridine Extended Release in Multiple Sclerosis Clinical Trials
AU - Cornblath, David R.
AU - Bienen, Jay E.
AU - Blight, Andrew R.
N1 - Funding Information:
The initial draft and the tables were prepared by Dr. Bienen and edited by Drs. Cornblath and Blight, all of whom take full responsibility for the content. Final approval was given by all the authors. Editorial assistance was provided by Linnéa C. Elliott of The Curry Rockefeller Group LLC, Tarrytown, New York; development of this manuscript was funded by Acorda Therapeutics Inc, Hawthorne, New York.
PY - 2012/5
Y1 - 2012/5
N2 - Background: Dalfampridine (fampridine outside the United States) is a broad-spectrum potassium channel blocker. Dalfampridine extended-release tablets have been approved by the US Food and Drug Administration to improve walking in patients with multiple sclerosis (MS). Objective: The objective of this article is to review the safety profile of dalfampridine extended-release tablets with respect to its expected use in patients with MS. Methods: We reviewed published data relevant to patient safety profiles based on searches of articles in PubMed published up to December 31, 2010, using the search terms . fampridine OR . dalfampridine OR . 4-aminopyridine AND . (multiple sclerosis) in combination with . toxicity, . safety, . clinical trial, . pharmacokinetics, and . seizures. These searches were supplemented with data derived from the approved package insert and relevant sections of the New Drug Application (22-250) as submitted to the US Food and Drug Administration. Results: The literature searches returned 58 unique citations, of which 26 were considered relevant for characterizing the safety profile of dalfampridine; excluded citations were as follows: reviews (19), evaluation of 3,4-diaminopyridine (4), intravenous dosing (2), inadequate information on patient doses (2), preclinical models (2), and "other" (3). Dalfampridine is nearly completely (approximately 96%) eliminated unchanged in urine, with limited transformation to 2 inactive metabolites and low risk for interaction with drugs metabolized by hepatic P450 cytochromes. However, in patients with renal impairment (creatinine clearance [CrCl], ≤80 mL/min), mean peak plasma concentrations were 68%-101% higher and apparent clearance was 43%-73% lower relative to those without impairment, precluding dalfampridine use in patients with moderate (CrCl, 30-50 mL/min) or severe renal impairment (CrCl, <30 mL/min). Dalfampridine has a narrow therapeutic range. At the therapeutic dose of 10 mg twice daily, adverse events were generally mild to moderate and, consistent with the mechanism of action of dalfampridine, were primarily related to stimulatory effects on the nervous system. A thorough QT study suggested a low risk of induction of QT prolongation and associated cardiac arrhythmias in healthy individuals at therapeutic (10 mg, twice daily) or supratherapeutic (30 mg, twice daily) doses. Although the incidence of seizures was dose related, data from the clinical trials of dalfampridine extended-release tablets suggest that the risk of seizure at the therapeutic dose, in patients with no history of seizure, is not likely to be higher than background rates in MS. Conclusion: In patients with MS, dalfampridine has a narrow therapeutic range but an acceptable safety profile when used at the therapeutic dose of 10 mg twice daily.
AB - Background: Dalfampridine (fampridine outside the United States) is a broad-spectrum potassium channel blocker. Dalfampridine extended-release tablets have been approved by the US Food and Drug Administration to improve walking in patients with multiple sclerosis (MS). Objective: The objective of this article is to review the safety profile of dalfampridine extended-release tablets with respect to its expected use in patients with MS. Methods: We reviewed published data relevant to patient safety profiles based on searches of articles in PubMed published up to December 31, 2010, using the search terms . fampridine OR . dalfampridine OR . 4-aminopyridine AND . (multiple sclerosis) in combination with . toxicity, . safety, . clinical trial, . pharmacokinetics, and . seizures. These searches were supplemented with data derived from the approved package insert and relevant sections of the New Drug Application (22-250) as submitted to the US Food and Drug Administration. Results: The literature searches returned 58 unique citations, of which 26 were considered relevant for characterizing the safety profile of dalfampridine; excluded citations were as follows: reviews (19), evaluation of 3,4-diaminopyridine (4), intravenous dosing (2), inadequate information on patient doses (2), preclinical models (2), and "other" (3). Dalfampridine is nearly completely (approximately 96%) eliminated unchanged in urine, with limited transformation to 2 inactive metabolites and low risk for interaction with drugs metabolized by hepatic P450 cytochromes. However, in patients with renal impairment (creatinine clearance [CrCl], ≤80 mL/min), mean peak plasma concentrations were 68%-101% higher and apparent clearance was 43%-73% lower relative to those without impairment, precluding dalfampridine use in patients with moderate (CrCl, 30-50 mL/min) or severe renal impairment (CrCl, <30 mL/min). Dalfampridine has a narrow therapeutic range. At the therapeutic dose of 10 mg twice daily, adverse events were generally mild to moderate and, consistent with the mechanism of action of dalfampridine, were primarily related to stimulatory effects on the nervous system. A thorough QT study suggested a low risk of induction of QT prolongation and associated cardiac arrhythmias in healthy individuals at therapeutic (10 mg, twice daily) or supratherapeutic (30 mg, twice daily) doses. Although the incidence of seizures was dose related, data from the clinical trials of dalfampridine extended-release tablets suggest that the risk of seizure at the therapeutic dose, in patients with no history of seizure, is not likely to be higher than background rates in MS. Conclusion: In patients with MS, dalfampridine has a narrow therapeutic range but an acceptable safety profile when used at the therapeutic dose of 10 mg twice daily.
KW - 4-aminopyridine
KW - Dalfampridine
KW - Fampridine
KW - Multiple sclerosis
KW - Safety
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U2 - 10.1016/j.clinthera.2012.03.007
DO - 10.1016/j.clinthera.2012.03.007
M3 - Review article
C2 - 22497693
AN - SCOPUS:84860755679
SN - 0149-2918
VL - 34
SP - 1056
EP - 1069
JO - Clinical therapeutics
JF - Clinical therapeutics
IS - 5
ER -