Principaux critères d’inclusion : 1. Une altération génétique ALK, ROS1 ou NTRK1-3 (mutation ponctuelle, fusion, amplification) documentée, telle qu’identifiée par des tests locaux dans un laboratoire certifié aux Etats-Unis ou dans un laboratoire de diagnostic accrédité de manière équivalente en dehors des États-Unis (É.-U.) est requise. 2. Phase 1 : Âge <12 years; Phase 2: Age 12- 25 years 3. Prior cytotoxic chemotherapy is allowed. 4. Prior immunotherapy is allowed. 5. Resolution of all acute toxic effects (excluding alopecia) of any prior anti-cancer therapy to National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) Version 4.03 Grade less than or equal to 1. 6. All subjects must have measurable disease by RECIST v1.1 or Response Assessment in Neuro-Oncology Criteria (RANO) criteria at time of enrollment. 7. Subjects with a primary CNS tumor or CNS metastases must be neurologically stable on a stable or decreasing dose of steroids for at least 14 days prior to enrollment. 8. Subjects must have a Lansky (< 16 years) or Karnofsky (≥ 16 years) score of at least 50. 9. Life expectancy greater than or equal to 12 weeks. 10. Adequate hematologic, renal and hepatic function. Phase 2 Inclusion Criteria: 1. Cohort Specific Inclusion Criteria: - Cohort 1: Subjects with NTRK fusion gene positive (NTRK+) advanced solid tumors (including primary CNS tumors), that are tropomyosin receptor kinase (TRK) TKI naïve; - Cohort 2: subjects with NTRK+ advanced solid tumors (including primary CNS tumors), that are TRK TKI pre-treated; - Cohort 3: subjects with tumors or ALCL characterized by other ALK/ROS1/NTRK alterations or NTRK fusions without centrally confirmed measurable disease or not otherwise eligible for Cohort 1 or 2. 2. Subjects in Cohorts 1 and 2 must have prospectively confirmed measurable disease by BICR prior to enrollment. Key Exclusion Criteria (Phase 1 and Phase 2): 1. Subjects with neuroblastoma with only bone marrow disease evaluable by bone marrow aspiration only. 2. Major surgery within 14 days (2 weeks) of start of repotrectinib treatment. Central venous access (Broviac, Mediport, etc.) placement does not meet criteria for major surgery. 3. Known active infections (bacterial, fungal, viral including HIV positivity). 4. Gastrointestinal disease (e.g., Crohn's disease, ulcerative colitis, or short gut syndrome) or other malabsorption syndromes that would impact drug absorption. 5. Any of the following cardiac criteria: - Mean resting corrected QT interval (ECG interval measured from the onset of the QRS complex to the end of the T wave) for heart rate (QTc)> 480 ms obtenu à partir de trois ECG, à l’aide de la valeur QTc dérivée de l’appareil d’ECG clinique de sélection - Toute anomalie cliniquement importante du rythme, de la conduction ou de la morphologie de l’ECG au repos (par ex., bloc de branche gauche complet, bloc cardiaque du troisième degré, bloc cardiaque du deuxième degré, intervalle PR > 250 ms) - Tout facteur augmentant le risque d’allongement de l’intervalle QTc ou le risque d’événements arythmiques tels qu’une insuffisance cardiaque, une hypokaliémie, un syndrome congénital du QT long, des antécédents familiaux de syndrome du QT long, ou tout médicament concomitant connu pour allonger l’intervalle QT. 6. Neuropathie périphérique de grade ≥ 2 selon les critères CTCAE. 7. Patients traités par ou anticipant la nécessité d’un traitement par des inhibiteurs ou inducteurs puissants du CYP3A4 .