Amivantamab Plus Chemo Shows Promise in Metastatic Colorectal Cancer: A New Era in Treatment?
New data presented at the American Society of Clinical Oncology (ASCO) Gastrointestinal (GI) Cancers Symposium are generating excitement in the fight against metastatic colorectal cancer (mCRC).Results from the OrigAMI-1 study (NCT05379595) demonstrate that the combination of amivantamab, a bispecific EGFR-MET antibody, wiht standard chemotherapy yields a compelling 51% overall response rate (ORR) in patients with advanced disease. This combination is not onyl showing durable responses but also, remarkably, is enabling some patients to become eligible for potentially curative surgery, signaling a potential paradigm shift in how this challenging cancer is treated.
Understanding the OrigAMI-1 Study and Amivantamab
The OrigAMI-1 study is a phase 1/2 trial designed to evaluate amivantamab in patients with wild-type colorectal cancer – meaning their tumors don’t have certain common mutations. This study was initially designed as a “signal-seeking” trial, aiming to determine if amivantamab, a next-generation EGFR inhibitor, showed promise. unlike traditional EGFR inhibitors, amivantamab employs a trimodal mechanism of action, blocking the EGFR receptor, promoting its internalization and degradation, and directly targeting cancer cells. The study included several cohorts, but the recent ASCO GI presentation focused on the two cohorts receiving amivantamab in combination with either FOLFIRI (leucovorin, fluorouracil, and irinotecan) or FOLFOX (folinic acid, fluorouracil, and oxaliplatin) chemotherapy.
What Makes Amivantamab Different?
Traditional EGFR inhibitors have shown limited success in colorectal cancer, notably in tumors without specific mutations. Amivantamab’s unique bispecific nature – targeting both EGFR and MET – is believed to overcome some of these limitations. MET,another receptor tyrosine kinase,frequently enough becomes activated when EGFR is blocked,leading to resistance. By simultaneously blocking both, amivantamab aims to provide a more sustained and effective anti-cancer effect. This dual-targeting approach is a key differentiator and a driving force behind the encouraging results seen in the OrigAMI-1 study.
Key Findings and clinical Impact
The updated results presented at ASCO GI 2026, with a median follow-up of 16 months, showed an improved response rate compared to initial findings. A 51% ORR in patients, many of whom had already received prior treatment, is a significant enhancement over past data with first-generation EGFR inhibitors combined with standard chemotherapy. Furthermore, the progression-free survival (PFS) of 9.2 months is also noteworthy and warrants further investigation. These positive outcomes have spurred three ongoing phase 3 studies – OrigAMI-2 and OrigAMI-3 – designed to confirm these results in larger, randomized trials.
the Potential for Curative Surgery
Perhaps the most striking finding from the OrigAMI-1 study is the number of patients who became eligible for surgery with curative intent. Six patients,initially diagnosed with metastatic disease,experienced such a significant response to the amivantamab-chemotherapy combination that they were able to undergo resection of their metastases.This suggests that, in a subset of patients, this treatment regimen can not only control the disease but potentially lead to long-term remission.
Dr. Filippo Pietrantonio, the lead investigator, noted that the depth of response is crucial, and speculated that the dual blockade of EGFR and MET may be particularly effective in patients with liver metastases, a common and often challenging site for colorectal cancer to spread. Interestingly, patients who underwent liver resection were censored from the PFS analysis, as per the study protocol, meaning the potential benefit of surgery wasn’t fully captured in the reported PFS data. However, this underscores the possibility of converting unresectable disease into resectable disease, offering a chance for a cure.
First-Line Potential and future Directions
While the origami-1 study included patients who had received prior treatment, a subgroup analysis revealed even higher response rates in those treated with amivantamab in the first-line setting. This suggests that amivantamab could potentially replace existing EGFR inhibitors, such as cetuximab or panitumumab, as the standard of care for first-line treatment of left-sided RAS/BRAF wild-type mCRC. The hope is that amivantamab’s broader mechanism of action will prove effective in a wider range of patients, including those with right-sided tumors or those who are resistant to first-generation EGFR inhibitors.
Safety and Tolerability
The combination of amivantamab and chemotherapy was found to be manageable, with a safety profile consistent with the known side effects of both amivantamab and standard chemotherapy regimens. The most common treatment-related adverse events were skin rash (associated with amivantamab) and those typically seen with chemotherapy.The advancement of a subcutaneous formulation of amivantamab, currently being investigated in phase 3 trials, is expected to further improve tolerability and patient convenience.
Looking Ahead
The data from the OrigAMI-1 study represent a significant step forward in the treatment of metastatic colorectal cancer. The combination of amivantamab and chemotherapy offers a promising new option for patients, with the potential to improve response rates, prolong survival, and even enable curative surgery in select cases. The ongoing phase 3 trials will be critical in confirming these findings and establishing amivantamab as a new standard of care. The future looks brighter for patients battling this challenging disease,thanks to innovative therapies like amivantamab.
