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).
• ✓. Cohort B: Any Rhabdoid tumor is eligible for this cohort. This includes, but is not limited to, related subtypes of rhabdoid tumors such as atypical teratoid rhabdoid tumors (ATRT), malignant rhabdoid tumors of the kidney (MRTK), malignant rhabdoid tumors of the soft tissue and liver, small cell undifferentiated hepatoblastomas (SCUH), and small-cell carcinoma of the ovary of hypercalcemic type (SCCOHT). Patients must have failed to respond to at least 1 line of systemic therapy prior to enrollment.
• ✓. Cohort C: Patients with progressive, relapsed, unresectable or metastatic MPNST, are eligible for this cohort. Patients must have failed to respond to at least 1 line of systemic therapy prior to enrollment.
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