Safety and efficacy of quinacrine in human prion disease (PRION-1 study): a patient-preference trial.
BACKGROUND
The propagation of prions, the causative agents of Creutzfeldt-Jakob disease and other human prion diseases, requires post-translational conversion of normal cellular prion protein to disease-associated forms. The antimalarial drug quinacrine (mepacrine) prevents this conversion in vitro, and was given to patients with various prion diseases to assess its safety and efficacy in changing the course of these invariably fatal and untreatable diseases.


METHODS
Patients with prion disease were recruited via the UK national referral system and were offered a choice between quinacrine (300 mg daily), no quinacrine, or randomisation to immediate quinacrine or deferred quinacrine in an open-label, patient-preference trial. The primary endpoints were death and serious adverse events possibly or probably related to the study drug. This study is registered, ISRCTN 06722585.


RESULTS
107 patients with prion disease (45 sporadic, two iatrogenic, 18 variant, and 42 inherited) were enrolled, 23 in a pilot study and 84 in the main study. Only two patients chose randomisation; 40 took quinacrine during follow-up (37 who chose it at enrollment). Choice of treatment was associated with disease severity, with those least and most severely affected more likely to choose not to receive quinacrine. 78 (73%) patients died: one randomly assigned to deferred treatment, 26 of 38 who chose immediate quinacrine, and 51 of 68 who chose no quinacrine. Although adjusted mortality was lower in those who chose to take quinacrine than in those who did not, this was due to confounding with disease severity, and there was no difference in mortality between groups after adjustment. Four of 40 patients who took quinacrine had a transient response on neurological rating scales. Only two of 14 reported serious adverse events were judged quinacrine-related.


CONCLUSIONS
Quinacrine at a dose of 300 mg per day was reasonably tolerated but did not significantly affect the clinical course of prion diseases in this observational study.
Collinge
John
J
National Prion Clinic, National Hospital for Neurology and Neurosurgery, University College London Hospital National Health Service Foundation Trust, Queen Square, London WC1N 3BG, UK. j.collinge@prion.ucl.ac.uk
Gorham
Michele
M
Hudson
Fleur
F
Kennedy
Angus
A
Keogh
Geraldine
G
Pal
Suvankar
S
Rossor
Martin
M
Rudge
Peter
P
Siddique
Durre
D
Spyer
Moira
M
Thomas
Dafydd
D
Walker
Sarah
S
Webb
Tom
T
Wroe
Steve
S
Darbyshire
Janet
J
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D017096:Prion Diseases / Q000188:drug therapy* / Q000401:mortality; D011796:Quinacrine / Q000008:administration & dosage / Q000627:therapeutic use*; D012307:Risk Factors; D012720:Severity of Illness Index; D012737:Sex Factors; D055815:Young Adult
D011796:Quinacrine