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Psychopharmacologic Drugs Advisory Committee June 16, 2003. Tarek A. Hammad, MD, PhD, MSc, MS Medical Reviewer Division of Neuropharmacological Drug Products Center for Drug Evaluation and Research, FDA. 1. Outline. Generic Drugs Registry Data Are We Seeing the Full Picture?
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Psychopharmacologic Drugs Advisory CommitteeJune 16, 2003 Tarek A. Hammad, MD, PhD, MSc, MS Medical Reviewer Division of Neuropharmacological Drug Products Center for Drug Evaluation and Research, FDA 1
Outline • Generic Drugs Registry Data • Are We Seeing the Full Picture? • Agranulocytosis Rates Stratified by Monitoring Frequency after 6 Months in the US and 1 Year in the UK 2
Generic Drugs Registry Data • Generic clozapine became available in 1997 • Data from two manufacturers- Ivax and Mylan • Only first time users of clozapine were included • First time users accounted for only about 10-20% of all users in the generic databases • Small number of patient-years • 1007 py before & 2937 py after 6 ms, across the two databases • Demographics are reasonably similar to the innovator data in the US CNR 3
Outline • Generic Drugs Registry Data • Are We Seeing the Full Picture? • Agranulocytosis Rates Stratified by Monitoring Frequency after 6 Months in the US and 1 Year in the UK 6
US Rates During First 6 months (weekly monitoring under both systems) US Rates After First 6 Months (weekly monitoring in old system and every two weeks in new system) 7
Detection of Moderate Leukopenia • UK system uses WBC and ANC • Two parallel tests increase sensitivity • Help detect more potentially vulnerable patients • Premise: Pts with low ANC preceding low WBC are detected later in a system that follows only WBC • Might explain apparent higher rates in UK 8
Mortality Rate Due to Agran by Monitoring Period: US Vs. UK 10
Outline • Generic Drugs Registry Data • Are We Seeing the Full Picture? • Agranulocytosis Rates Stratified by Monitoring Frequency after 6 Months in the US and 1 Year in the UK 11
Moderate Leukopenia and Agran Rates in the US in the current system after 6 months
Moderate Leukopenia and Agran Rates in the UK in the current system after 1 year
Progression from moderate leukopenia to agran in the UK across monitoring frequencies after 1 year
Progression from moderate leukopenia to agran in the US across monitoring frequencies after 6 months
The number of new users of clozapine for the four months prior to the repeated suicidality indication approval in December 2002 and the subsequent months to April 2003 17