JSI-1187-01 Monotherapy and in Combination With Dabrafenib for Advanced Solid Tumors With MAPK Pathway Mutations

Inclusion Criteria: * Males and females ≥ 18 years of age * Have locally advanced or metastatic solid tumor malignancy with measurable disease and be an appropriate candidate for experimental therapy * Part A (JSI-1187 Monotherapy Dose Escalation): Histologically or cytologically confirmed MAPK pathway mutation, including hyperactivating pathway mutations or gene fusions, e.g., BRAF (Class I, II or III), RAS (H/K/N), MEK (MAP2K1), RAS-GAP (NF1 loss, RASA1), RAS-GEF, refractory to or relapsed on prior therapy, and have received all available therapy known to confer clinical benefit * (On hold, effective 05 July 2023) Part B (JSI-1187 Plus Dabrafenib Combination Dose Escalation): Histologically or cytologically confirmed BRAF V600E/K-mutated unresectable or metastatic melanoma, BRAF V600E-mutated metastatic NSCLC, BRAF V600E-mutated locally advanced or metastatic anaplastic thyroid cancer, or other BRAF V600E-mutated unresectable or metastatic solid tumors, refractory to, or relapsed on, prior therapy, and have received all available therapy known to confer clinical benefit * (On hold, effective 05 July 2023) Part C (JSI-1187 Plus Dabrafenib Expansion Cohorts): Histologically or cytologically confirmed: * Cohort 1: BRAF V600E/K-mutated unresectable or metastatic melanoma after 1-3 prior therapies for metastatic disease, including anti-PD1 therapy, with or without ipilimumab, and BRAF/MEK inhibitor treatment * Cohort 2: BRAF V600E/K-mutated unresectable or metastatic melan…