Study of Efficacy and Safety of LXH254 Combinations in Patients With Previously Treated Unresectable or Metastatic Melanoma

Inclusion Criteria: Male or female must be ≥ 12 years For adolescents only (12-17 years): body weight \> 40kg Histologically confirmed unresectable or metastatic cutaneous melanoma Previously treated for unresectable or metastatic melanoma: * Participants with NRAS mutation: * Participants must have received prior systemic therapy for unresectable or metastatic melanoma with checkpoint inhibitors (CPI), either an anti-PD-1/PD-L1 as a single agent or in combination with anti-CTLA-4, investigational agents, chemotherapy or locally directed anti-neoplastic agents. * A maximum of two prior lines of systemic CPI-containing immunotherapy for unresectable or metastatic melanoma are allowed. Additional agents administered with CPI are permitted. * To rule out pseudo-progression, participants must have documented confirmed progressive disease as per RECIST v1.1 while on/after treatment with checkpoint inhibitor therapy. Confirmation is not required for patients who remained on treatment for \>6 months. * Participants with BRAFV600 mutant disease: * Participants must have received prior systemic therapy for unresectable or metastatic melanoma with checkpoint inhibitors (CPI), either an anti-PD-1/PD-L1 as a single agent or in combination with anti-CTLA-4, investigational agents, chemotherapy or locally directed anti-neoplastic agents. Additionally, participants must have received targeted therapy with a RAFi as a single agent or in combination with a MEKi (+/- CPI allowed) as the las…