Qualitative methods in early-phase drug trials: broadening the scope of data and methods from an RCT of N-acetylcysteine in schizophrenia.
OBJECTIVE
The pharmacokinetic profile of a drug often gives little indication of its potential therapeutic application, with many therapeutic uses of drugs being discovered serendipitously while being studied for different indications. As hypothesis-driven, quantitative research methodology is exclusively used in early-phase trials, unexpected but important phenomena may escape detection. In this context, this study aimed to examine the potential for integrating qualitative research methods with quantitative methods in early-phase drug trials. To our knowledge, this mixed methodology has not previously been applied to blinded psychopharmacologic trials.


METHODS
We undertook qualitative data analysis of clinical observations on the dataset of a randomized, double-blind, placebo-controlled trial of N-acetylcysteine (NAC) in patients with DSM-IV-TR-diagnosed schizophrenia (N = 140). Textual data on all participants, deliberately collected for this purpose, were coded using NVivo 2, and emergent themes were analyzed in a blinded manner in the NAC and placebo groups. The trial was conducted from November 2002 to July 2005.


RESULTS
The principal findings of the published trial could be replicated using a qualitative methodology. In addition, significant differences between NAC- and placebo-treated participants emerged for positive and affective symptoms, which had not been captured by the rating scales utilized in the quantitative trial. Qualitative data in this study subsequently led to a positive trial of NAC in bipolar disorder.


CONCLUSIONS
The use of qualitative methods may yield broader data and has the potential to complement traditional quantitative methods and detect unexpected efficacy and safety signals, thereby maximizing the findings of early-phase clinical trial research.


BACKGROUND
www.anzctr.org.au Identifier: ACTRN12605000363684.
Berk
Michael
M
Department of Clinical and Biomedical Sciences: Barwon Health, University of Melbourne, PO Box 281, Geelong 3220, Victoria, Australia. mikebe@barwonhealth.org.au
Munib
Ahmed
A
Dean
Olivia
O
Malhi
Gin S
GS
Kohlmann
Kristy
K
Schapkaitz
Ian
I
Jeavons
Sue
S
Katz
Fiona
F
Anderson-Hunt
Murray
M
Conus
Philippe
P
Hanna
Barbara
B
Otmar
Renée
R
Ng
Felicity
F
Copolov
David L
DL
Bush
Ashley I
AI
D000111:Acetylcysteine / Q000627:therapeutic use*; D000328:Adult; D003625:Data Collection / Q000379:methods* / Q000706:statistics & numerical data*; D004311:Double-Blind Method; D005260:Female; D016166:Free Radical Scavengers / Q000627:therapeutic use*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011569:Psychiatric Status Rating Scales; D012559:Schizophrenia / Q000175:diagnosis / Q000188:drug therapy*; D012565:Schizophrenic Psychology
D016166:Free Radical Scavengers; D000111:Acetylcysteine