Validation of a single-patient drug trial methodology for personalized management of gastroesophageal reflux disease.
BACKGROUND
Single-patient trials (SPTs) are randomized, often multiple-crossover trials where patients serve as their own control to determine their appropriate treatment. Historically, SPTs have been individually customized, requiring significant time and cost for execution. The patient.s progress is tracked and evaluated in a blinded, multiple-crossover design comparing different therapies. Standardized, cost-efficient SPTs could help avoid (a) inappropriate extrapolation of the average-group outcomes from parallel, clinical trials to community-practice patients and (b) wasteful prescribing of high-cost drugs. Aggregate SPT results can also provide new data on appropriate drug prescribing in subpopulations.


OBJECTIVE
To validate a standardized, commercially useful SPT method for comparing drugs/doses in patients with gastroesophageal reflux disease (GERD) requiring maintenance therapy.


METHODS
A double-blind, single-dummy, randomized, 3 paired-period (28 days per period, 14 days per leg), multiple-crossover, SPT comparing omeprazole 20 mg daily and ranitidine hydrochloride (ranitidine) 150 mg twice daily was employed for 32 patients with GERD taking acid-suppressing medications chronically. Endpoints to determine effectiveness were selected from a recently approved new-drug application. Heartburn, regurgitation, difficulty swallowing, epigastric pain, and nausea were evaluated daily. Use of rescue medications was also measured. Quality of life was measured weekly by the patient.s global evaluation. Observations for days 1 to 4 were excluded by using aggregate database sensitivity analyses to define appropriate surrogate washout periods. Frequently reported adverse events found in labeling for acid-suppressing drugs were directly solicited and compared between treatments. Unsolicited events were recorded. Patients completed a test-kit-acceptability questionnaire.


RESULTS
Fourteen of 27 evaluable SPTs (52%) showed significant superiority for omeprazole over ranitidine and 7 of 27 (26%) for ranitidine over omeprazole. Four of 27 (15%) showed parity performance. Neither agent could be recommended in 2 of 27 (7%) of SPTs due to significant adverse events experienced with both drugs. For those patients taking proton pump inhibitors (PPIs) prior to enrollment, the estimated step-down substitution rate from omeprazole to ranitidine, combined with the drug therapy discontinuation rate, was 40% (90% confidence interval: 22% to 68%). The majority of patients rated the test kits as appropriate and desirable.


CONCLUSIONS
Omeprazole was the appropriate treatment in only 52% of these chronic users of acid-suppressing drugs. Eleven of 27 trials (41%) indicated that ranitidine was the preferred treatment. The SPT method proved acceptable to patients, feasible to administer, and reproducible. It can statistically discriminate effectiveness and adverse events and serve as a useful, prognostic tool in community practice by determining the least costly, evidence-based, appropriate treatment.
Wolfe
Barbara
B
University of Florida College of Pharmacy, Gainesville, USA.
Del Rio
Eve
E
Weiss
Sidney L
SL
Mendelson
Avishai
A
Elbaga
Tamer A
TA
Huser
Frederic J
FJ
Reitberg
Donald P
DP