A review of clinical trial designs used to detect a disease-modifying effect of drug therapy in Alzheimer’s disease and Parkinson’s disease

Table 1 Trial designs used in included randomised controlled trials to try to demonstrate disease-modification

	Type of trials	Wash-in analysis		Wash-out analysis		Delayed-start trial design		Long-term follow-up		Biomarkers (primary or secondary outcome measures)								Time-to-event outcomes
		Wash-in analysis		Wash-out analysis		Delayed-start trial design		Long-term follow-up		Imaging		CSF		Blood		Other		Time-to-event outcomes
		n	%	n	%	n	%	n	%	n	%	n	%	n	%	n	%	n	%
AD	Published (n = 59)	3	5	11	19	7	12	45	76	27	46	17	29	6	10	2	3	3	5
	Planned, ongoing & unpublished (n = 25)	0	0	0	0	2	8	22	88	12	48	10	40	4	16	0	0	1	4
	All (n = 84)	3	4	11	13	9	11	67	80	39	46	27	32	10	12	2	3	4	5
PD	Published (n = 36)	11	31	17	47	7	19	25	69	12	33	0	0	1	3	0	0	18	50
	Planned, ongoing & unpublished (n = 8)	0	0	3	38	0	0	4	50	4	50	1	13	0	0	0	0	3	38
	All (n = 44)	11	25	20	45	7	16	29	66	16	36	1	2	1	2	0	0	21	48

(CSF Cerebrospinal fluid. ‘Other’ biomarkers include a urine biomarker and electroencephalography used in published AD trials)

ISSN: 1471-2377