A Phase 1/2 Multiple Expansion Cohort Trial of the SOS1 Inhibitor MRTX0902 in Patients With Advanced Solid Tumors Harboring Mutations in the KRAS MAPK Pathway

This first-in-human clinical trial will begin with an exploration of MRTX0902 dose and regimen. Once safety experience and PK data are available for the monotherapy regimen, dose escalation of the combination of MRTX0902 and adagrasib will be initiated, and will include a separate preliminary food effect assessments on MRTX0902 PK in combination with adagrasib. As potentially viable regimens are identified, Phase 1b expansion cohorts may be implemented to ensure collection of sufficient safety and PK information, and early evidence of clinical activity are available to recommend Phase 2 regimens. In Phase 2, separate cohorts of patients by histological diagnosis and/or baseline characteristics will be evaluated for the clinical activity and efficacy of MRTX0902 in combination with adagrasib.

Inclusion Criteria:

• Histologically confirmed diagnosis of a solid tumor malignancy with any of the following oncogenic mutations detected in tumor tissue or ctDNA by a sponsor-approved test:
  1. MRTX0902 monotherapy: known KRAS mutations, known annotated recurrent activating SOS1, PTPN11, class III BRAF, or EGFR mutation, or known annotated recurrent inactivating NF1 mutation;
  2. MRTX0902 and adagrasib combination therapy: KRAS G12C mutation.
• Unresectable or metastatic disease
• No available treatment with curative intent; standard treatment is not available or patient declines
• Presence of tumor lesions to be evaluated per RECIST 1.1:
  1. Phase 1 dose escalation, RECIST 1.1 measurable or evaluable disease
  2. Phase 1b and Phase 2 cohorts, RECIST 1.1 measurable disease
• Presence of a tumor lesion amenable to mandatory biopsy for pharmacodynamic evaluation at baseline and on-study unless Sponsor-confirmed as medically unsafe or infeasible.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• Adequate organ function

Exclusion Criteria:

• Active brain metastases or carcinomatous meningitis
• Prior treatment with a KRAS G12C inhibitor (for Phase 1b expansion for MRTX0902 and adagrasib combination, and Phase 2 cohorts only)
• History of significant hemoptysis or hemorrhage within 4 weeks of the first dose of study treatment.
• Major surgery within 4 weeks of first dose of study treatment
• History of pneumonitis or interstitial lung disease
• Ongoing need for medication with following characteristics: substrate of CYP3A; strong inducer or inhibitor or CYP3A and/or P-gp; strong inhibitors of BRCP and proton pump inhibitors
• Cardiac abnormalities
• History of intestinal disease, inflammatory bowel disease, major gastric surgery, or other gastrointestinal conditions (eg, uncontrolled nausea, vomiting, malabsorption syndrome) likely to alter absorption of study treatment or result in inability to swallow oral medications