EFS of subsequent intensive treatment. (A) EFS of patients who had an unfavorable response to RUX and received intensive treatment. EFS was estimated from the date of additional treatment initiation to the first occurrence of disease progression, relapse, or death, or the date of the last follow-up. (B) EFS of intensive treatment by RUX response status (responders vs nonresponders) before entering intensive treatment. (C) EFS of intensive treatment by underlying etiology.