Genentech has announced positive top-line results from the Phase III Krascendo 1 trial, demonstrating that divarasib, an investigational next-generation KRAS G12C inhibitor, achieved statistically significant and clinically meaningful improvements in both progression-free survival (PFS) and overall survival (OS) compared with the approved first-generation KRAS G12C inhibitors sotorasib or adagrasib in patients with previously treated advanced KRAS G12C-mutant non-small cell lung cancer (NSCLC). These results represent the first head-to-head Phase III superiority data for a KRAS G12C inhibitor in this setting.

Clinical Takeaway

✔ Divarasib demonstrated superior PFS and OS versus sotorasib or adagrasib in previously treated KRAS G12C-mutant NSCLC, with an interim OS analysis crossing the significance threshold — a notable achievement in this historically poor-prognosis population.

✔ No new safety signals were identified, and the most common treatment-related adverse events were described as manageable and reversible, consistent with earlier-phase data.

✔ Krascendo 1 is the only global head-to-head Phase III trial comparing a KRAS G12C inhibitor directly against currently approved agents in this indication, lending particular clinical weight to these findings.

Drug Profile & Mechanism

  • Drug name: Divarasib (investigational)
  • Class: Next-generation, oral, covalent KRAS G12C inhibitor
  • Mechanism: Selectively binds to the mutant KRAS G12C protein, locking it in an inactive (“off”) state and thereby halting continuous, tumor-driving downstream signaling
  • Preclinical differentiation: Has demonstrated greater potency and selectivity compared with first-generation KRAS G12C inhibitors sotorasib and adagrasib in preclinical models
  • Regulatory designations:
    • Breakthrough Therapy Designation granted by the FDA in 2022
    • Orphan Drug Designation for KRAS G12C NSCLC granted in 2026

    Target Population & Disease Context

    • Lung cancer remains the leading cause of cancer-related death worldwide, claiming approximately 1.8 million lives annually — surpassing the combined mortality of breast, prostate, and stomach cancers
    • NSCLC accounts for approximately 85% of all lung cancer cases
    • KRAS is one of the most frequently mutated oncogenes in lung cancer, occurring in approximately 25% of newly diagnosed cases
    • The KRAS G12C mutation is found in approximately 14% of NSCLC cases and is associated with poor prognosis
    • The G12C substitution locks the KRAS protein in its constitutively active (“on”) state, driving unregulated cell proliferation and tumor growth
    • The Krascendo 1 population comprised adults with previously treated (second-line) KRAS G12C-mutant advanced or metastatic NSCLC — a setting of significant unmet need

    Study Design

    • Trial name: Krascendo 1 (NCT06497556)
    • Phase: III
    • Design: Randomized, open-label, multicenter, global
    • Sample size: 338 adults
    • Arms:
      • Experimental: Divarasib monotherapy (once daily, oral)
      • Comparator: Investigator’s choice of sotorasib (once daily) or adagrasib (twice daily) — the two currently approved first-generation KRAS G12C inhibitors
      • Population: Adults with previously treated KRAS G12C-mutant advanced or metastatic NSCLC
      • Distinction: This is the only global head-to-head Phase III trial comparing a KRAS G12C inhibitor against approved first-generation agents in this disease

      Endpoints

      Efficacy Outcomes

      • Primary endpoint met: Divarasib achieved a clinically meaningful and statistically significant improvement in PFS versus sotorasib or adagrasib by BICR assessment
      • Key secondary endpoint met: Statistical significance for OS was achieved at the interim analysis — a particularly notable finding given the historically poor prognosis of this patient population in the second-line setting
      • Genentech characterizes these results as supporting best-in-class potential for divarasib within the KRAS G12C inhibitor class
      • Full quantitative efficacy data (hazard ratios, median PFS/OS values, ORR) have not yet been disclosed and will be presented at an upcoming medical meeting

      Safety

      • The safety profile of divarasib was consistent with data from previous clinical studies
      • No new safety signals were identified
      • The most common treatment-related adverse events were described as manageable and reversible
      • Detailed safety data, including event rates and grades, will be disclosed at the forthcoming medical meeting presentation

      Broader Divarasib Development Program

      Genentech is pursuing a comprehensive Phase III program for divarasib across multiple NSCLC settings, anchored by three pivotal studies:

      • Krascendo 1 (NCT06497556): Divarasib monotherapy vs. sotorasib or adagrasib in previously treated (second-line) KRAS G12C-mutant advanced/metastatic NSCLC — results reported July 2026
      • Krascendo 2 (NCT06793215): Divarasib plus pembrolizumab (chemotherapy-free combination) vs. chemotherapy plus pembrolizumab in previously untreated (first-line) KRAS G12C-mutant advanced NSCLC
      • Krascendo 3 (NCT07541170): Adjuvant divarasib monotherapy vs. immunotherapy or observation in resected stage II–IIIB KRAS G12C-mutant NSCLC following standard-of-care chemoimmunotherapy — addressing the early-stage, curative-intent setting

      Key Clinical Implications

      ✔ Divarasib is the first KRAS G12C inhibitor to demonstrate Phase III superiority in both PFS and OS over currently approved agents in previously treated NSCLC, signaling a potential shift in the second-line treatment paradigm for this genetically defined subtype.

      ✔ An OS benefit achieved at interim analysis is a high bar in a second-line solid tumor setting; if confirmed at full data disclosure, this would substantially strengthen the case for divarasib as the preferred KRAS G12C-directed therapy.

      ✔ Oncologists managing KRAS G12C-mutant NSCLC should be aware that divarasib regulatory submissions are being prepared, and full trial data are anticipated at an upcoming major oncology conference — informing near-term treatment planning discussions with eligible patients.

      ✔ The Krascendo program’s breadth — spanning second-line, first-line, and adjuvant settings — suggests that divarasib, if approved, could ultimately be positioned across the KRAS G12C-mutant NSCLC continuum of care, with chemotherapy-free combination and early-stage data to follow.

      ✔ Molecular testing for KRAS G12C mutation at diagnosis or progression remains essential, as the rapidly evolving landscape of targeted options in this subset increasingly differentiates treatment selection within the KRAS inhibitor class itself.

      Bottom Line

      The Krascendo 1 Phase III trial has established that divarasib monotherapy is superior to sotorasib or adagrasib in previously treated KRAS G12C-mutant NSCLC, with statistically significant gains in both PFS and OS and a manageable, consistent safety profile. Genentech plans to submit these data to regulatory authorities and present full results at an upcoming medical meeting. Pending approval, divarasib has the potential to become the new standard of care for this genetically defined patient population in the second-line setting — with an ambitious broader development program targeting additional lines of therapy and disease stages already underway.

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