Study of Lurbinectedin Monotherapy in Pediatric and Young Adult Participants With Relapsed/Refractory Ewing Sarcoma

corrected QT interval (QTc) prolongation defined as a QTc ≥ 460 ms using the Bazett formula in age < 18 years and QTc ≥ 470 ms using the Bazett formula in age ≥ 18 years.

Known symptomatic Central nervous system (CNS) metastases requiring steroids. Participants with previously diagnosed CNS metastases are eligible if they have completed their treatment and have recovered from the acute effects of radiation therapy or surgery prior to enrollment, have discontinued high dose steroid treatment for these metastases for at least 2 weeks, and are neurologically stable (physiologic doses of steroids and short courses of steroids for other indications are acceptable).

Persisting toxicity related to prior therapy; however, alopecia, sensory neuropathy, hypothyroidism, and rash Grade ≤ 2 are acceptable, and other Grade ≤ 2 adverse events (AEs) not constituting a safety risk based on the investigator's judgement are acceptable.

An uncontrolled intercurrent illness including but not limited to ongoing or active infection requiring antibiotic, antifungal, or antiviral therapy, symptomatic heart failure, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements.