Tuesday, 7 October 2014

Pegylated Interferon

Hu X, Cui Y, White J, Zhu Y, Deykin A, Nestorov I, Hung S.
Title: Pharmacokinetics and Pharmacodynamics of Peginterferon Beta-1a in Patients with Relapsing-Remitting Multiple Sclerosis in the Randomised ADVANCE Study.Br J Clin Pharmacol. 2014 Sep. doi: 10.1111/bcp.12521. [Epub ahead of print]

AIMS:To evaluate the pharmacokinetics and pharmacodynamics of subcutaneous peginterferon beta-1a in patients with relapsing-remitting multiple sclerosis (RRMS) in the Phase 3 ADVANCE study (n=1512).
METHODS: During Year 1, patients were randomised (1:1:1) to placebo or peginterferon beta-1a 125 μg every 2 or 4 weeks. After Year 1, patients randomised to placebo were re-randomised to 125 μg peginterferon beta-1a administered every 2 weeks or every 4 weeks for Year 2. Patients randomised to peginterferon beta-1a in Year 1 remained on the same dosing regimen in Year 2. Intensive blood samples for pharmacokinetic and pharmacodynamic (neopterin elevation; a biomarker of pharmacological activity induced by interferon beta-1a) measurements were collected from 44 patients pre-dosing and at intervals over 240 hours post-dosing at Weeks 4 and 24. Sparse samples were collected from all patients after each dosing at Weeks 4, 12, 24, 56, and 84.
RESULTS: The pharmacokinetic profile of peginterferon beta-1a did not change over time or between dosing regimens. No accumulation was observed. Peak serum concentrations were reached 1-1.5 days post-dosing, with a mono-phasic decline, and a median half-life of approximately 2-3 days. Dosing every 2 weeks provided approximately 2-fold greater monthly cumulative area-under-the-curve than every 4 weeks. Neopterin elevation was sustained for 10-14 days following each dose, indicating doubled cumulative duration of pharmacological activity for dosing every 2 weeks versus every 4 weeks.
CONCLUSIONS: These pharmacokinetic/pharmacodynamic profiles potentially explain the enhanced efficacy of dosing every 2 weeks in patients with RRMS.

As the patent life of straight beta interferon dwindles into nothingness, Pharma begin to "repurpose" their own drugs so that they can re-invigorate their patent portfolio. 

So in this study they have taken interferon beta and stuck it onto polyethyleneglycol (a chemical in anti-freeze). This makes the drug hang around in the body for longer and so rather than injection a few times a week with beta interferon this can be reduced to a few times a month. This study looks at just that. After injection the compound could be found in the blood. This study shows that that dosing every two weeks was better than dosing every month to get the desired concentration of drug.  A half-life means the time taken for half the drug to disappear so after two half lives you have a quarter of the drug  left.

1 comment:

  1. I hated injections several times a week, but I am not sure "antifreeze" and injection every other week would help that much :-). Thank God for the tablets...

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