Toxicity-related discontinuation of therapy. (A) Reasons for discontinuation of therapy due to toxicity during induction. (B) Reasons for discontinuation of therapy due to toxicity during maintenance. y-axis absolute number of patients, reflecting the number of patients discontinuing therapy due to toxicity only. In MPT-T, there were 7 patients who went off protocol before maintenance due to other reasons: 1 for pulmonary hypertension, 1 for allergic reaction, 2 for toxicity, and 3 because of decision of physician. In the MPR-R arm, there were 5 patients who went off protocol before maintenance due to other reasons: 2 because of decision of physician and 3 for toxicity. In the thalidomide maintenance arm, 5 patients went off protocol due to other reasons: 2 for SPM, 1 died, and 2 because of refusal of patient and hematologic toxicity. In the lenalidomide maintenance arm, 18 patients went off protocol due to other reasons: 11 because of physician’s decision, mainly symptoms or side effects, 2 for dementia, 1 for renal failure, and 4 for SPM.