A Study of Selinexor in People With Wilms Tumors and Other Solid Tumors

Inclusion criteria

• . Age ≥ 6 at the time of informed consent
• . Age ≥ 2 years to \< 6 years at time of informed consent (Refer to Section 4.3): If PK cohort 1 is open, patients in this age range may enroll onto this cohort. If PK cohort 1 has been completed and deemed sufficient to proceed, then such patients may enroll onto the phase 2.
• . Age ≥ 12 months to \< 2 years at time of informed consent (Refer to Section 4.3):
• . Cohort A: Any type of Wilms tumor or nephroblastoma is eligible for this study provided they meet at least one of these criteria: (1) in their second or greater relapse, (2) refractory or in their first relapse with high risk histology (i.e., any anaplastic or blastemal-type after neoadjuvant chemotherapy), or (3) refractory or in first relapse without high risk histology but after having received chemotherapies other than the initial 4 agents used as current standard of care in the up-front setting for non-high risk cases - specifically vincristine, dactinomycin, doxorubicin, and irinotecan (i.e., any patient who relapses following an initial regimen more intense than EE4A, DD4A, VAD, AVD, or VIVA; for example, those including cyclophosphamide/etoposide - such as Regimen I, M, or MVI - or those additionally including carboplatin - such as Regimens UH-1, UH-2, or UH-3).