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.
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 EspinoPhD 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.
