2026-03-24
KRASG12C: finally a target in colorectal cancer?
Oncology
By Ana Espino | Published on March 24, 2026 | 3 min read
Metastatic colorectal cancer (mCRC) remains associated with a poor prognosis, with a 5-year survival rate below 20%. Despite advances in combination chemotherapy and anti-VEGF or anti-EGFR antibodies, therapeutic options remain limited after failure of standard treatment lines.
KRAS mutations occur in approximately 40% of mCRC cases. Among these, the KRASG12C mutation—present in 3–4% of patients—is associated with aggressive tumor biology and resistance to anti-EGFR therapies. Historically, KRAS was considered “undruggable” due to its high affinity for GTP.
The identification of a specific pocket in the G12C mutant has enabled the development of selective covalent inhibitors. This review, published in Future Oncology (2025), analyzes the pharmacological, clinical, and regulatory data on adagrasib, as well as its strategic positioning in mCRC.
The article first details the pharmacological properties of adagrasib. It is a selective covalent inhibitor of KRASG12C, administered orally at 600 mg twice daily, the recommended dose established in the phase I/Ib KRYSTAL-1 study. Its prolonged half-life of approximately 23 hours allows sustained target inhibition. The drug is primarily metabolized by CYP3A4 and mainly eliminated via the fecal route.
In the phase II KRYSTAL-1 cohort evaluating adagrasib monotherapy in heavily pretreated patients, the objective response rate (ORR) was 19%, with a median progression-free survival (PFS) of 5.6 months and an overall survival (OS) of 12.2 months. No complete responses were observed. Tolerability was acceptable, with 31% grade ≥3 adverse events, mainly gastrointestinal.
Identified resistance mechanisms include compensatory reactivation of the EGFR/RTK pathway, as well as the emergence of secondary KRAS mutations or alterations in other MAPK pathway genes. These findings have supported the development of combination strategies.
The combination of adagrasib with cetuximab showed significantly improved outcomes. In an updated analysis including 94 patients, ORR reached 34%, with a median PFS of 6.9 months and a median OS of 15.9 months. The disease control rate was 85.1%. Severe adverse events occurred in 27.7% of patients, with no unexpected safety signals.
Exploratory analyses suggested a potential role for early clearance of circulating tumor DNA (ctDNA) as a predictive biomarker of response.
These data led to accelerated FDA approval in June 2024 of the adagrasib–cetuximab combination for KRASG12C-mutated mCRC after prior standard chemotherapy. Approval has not yet been granted in Europe.
KRASG12C-mutated mCRC represents a poor-prognosis subgroup with unmet therapeutic needs. Major challenges include adaptive resistance via the EGFR axis and tumor molecular heterogeneity.
This review aimed to assess the role of adagrasib in this setting. The data show moderate clinical activity as monotherapy, but significantly improved efficacy when combined with an anti-EGFR agent, with a survival benefit.
Limitations include the absence of direct comparative trials with other KRASG12C inhibitors and still limited real-world data. Sample sizes remain modest, and resistance mechanisms are multiple.
Future directions rely on phase III trials, particularly KRYSTAL-10, and on combination strategies involving SHP2 inhibitors, immunotherapy, or pan-KRAS approaches. Ultimately, optimizing combinations and identifying dynamic biomarkers could substantially improve the management of patients with KRASG12C-mutated mCRC.
About the author – Ana Espino
PhD in Immunology, specialized in Virology
As a scientific writer, Ana is passionate about bridging the gap between research and real-world impact. With expertise in immunology, virology, oncology, and clinical studies, she makes complex science clear and accessible. Her mission: to accelerate knowledge sharing and empower evidence-based decisions through impactful communication.
Metastatic colorectal cancer (mCRC) remains associated with a poor prognosis, with a 5-year survival rate below 20%. Despite advances in combination chemotherapy and anti-VEGF or anti-EGFR antibodies, therapeutic options remain limited after failure of standard treatment lines.
KRAS mutations occur in approximately 40% of mCRC cases. Among these, the KRASG12C mutation—present in 3–4% of patients—is associated with aggressive tumor biology and resistance to anti-EGFR therapies. Historically, KRAS was considered “undruggable” due to its high affinity for GTP.
The identification of a specific pocket in the G12C mutant has enabled the development of selective covalent inhibitors. This review, published in Future Oncology (2025), analyzes the pharmacological, clinical, and regulatory data on adagrasib, as well as its strategic positioning in mCRC.
Monotherapy or combination: which is more effective?
The article first details the pharmacological properties of adagrasib. It is a selective covalent inhibitor of KRASG12C, administered orally at 600 mg twice daily, the recommended dose established in the phase I/Ib KRYSTAL-1 study. Its prolonged half-life of approximately 23 hours allows sustained target inhibition. The drug is primarily metabolized by CYP3A4 and mainly eliminated via the fecal route.
In the phase II KRYSTAL-1 cohort evaluating adagrasib monotherapy in heavily pretreated patients, the objective response rate (ORR) was 19%, with a median progression-free survival (PFS) of 5.6 months and an overall survival (OS) of 12.2 months. No complete responses were observed. Tolerability was acceptable, with 31% grade ≥3 adverse events, mainly gastrointestinal.
Identified resistance mechanisms include compensatory reactivation of the EGFR/RTK pathway, as well as the emergence of secondary KRAS mutations or alterations in other MAPK pathway genes. These findings have supported the development of combination strategies.
The combination of adagrasib with cetuximab showed significantly improved outcomes. In an updated analysis including 94 patients, ORR reached 34%, with a median PFS of 6.9 months and a median OS of 15.9 months. The disease control rate was 85.1%. Severe adverse events occurred in 27.7% of patients, with no unexpected safety signals.
Exploratory analyses suggested a potential role for early clearance of circulating tumor DNA (ctDNA) as a predictive biomarker of response.
These data led to accelerated FDA approval in June 2024 of the adagrasib–cetuximab combination for KRASG12C-mutated mCRC after prior standard chemotherapy. Approval has not yet been granted in Europe.
A validated target, but an ongoing challenge
KRASG12C-mutated mCRC represents a poor-prognosis subgroup with unmet therapeutic needs. Major challenges include adaptive resistance via the EGFR axis and tumor molecular heterogeneity.
This review aimed to assess the role of adagrasib in this setting. The data show moderate clinical activity as monotherapy, but significantly improved efficacy when combined with an anti-EGFR agent, with a survival benefit.
Limitations include the absence of direct comparative trials with other KRASG12C inhibitors and still limited real-world data. Sample sizes remain modest, and resistance mechanisms are multiple.
Future directions rely on phase III trials, particularly KRYSTAL-10, and on combination strategies involving SHP2 inhibitors, immunotherapy, or pan-KRAS approaches. Ultimately, optimizing combinations and identifying dynamic biomarkers could substantially improve the management of patients with KRASG12C-mutated mCRC.
About the author – Ana Espino
PhD in Immunology, specialized in Virology
As a scientific writer, Ana is passionate about bridging the gap between research and real-world impact. With expertise in immunology, virology, oncology, and clinical studies, she makes complex science clear and accessible. Her mission: to accelerate knowledge sharing and empower evidence-based decisions through impactful communication.
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