Fig. 1From: Critical appraisal of arguments for the delayed-start design proposed as alternative to the parallel-group randomized clinical trial design in the field of rare diseaseAnnual rate of lung density change from baseline to 24 and 48 months in the RAPID trial [11]. At baseline (0 months), patients are randomly assigned to receive either A1Pl or placebo (placebo-controlled phase) and they are followed for 24 months. Then, patients in the placebo group switch to the investigational treatment for another 24 months (active treatment phase)Back to article page