Patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic colorectal cancer may benefit from a targeted therapy regimen used to treat HER2-positive breast cancer with no need for added chemotherapy, according to results from a small clinical trial.
In this patient population, investigators, led by Andrea Sartore-Bianchi, MD, Niguarda Cancer Center, Grande Ospedale, Milano Italy, evaluated the efficacy of the combination treatment of trastuzumab and oral lapatinib. Between August 2012 and May 2015, investigators screened over 900 patients with metastatic colorectal cancer and identified 48 patients with HER2-positive disease. Of these 27 were fully eligible to participate in the trial.
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About 75% of the participants involved in the study had received at least 4 prior treatment regimens and had spent a median total of 20 months on previous treatments, with some also being treated with epithelial growth factor receptor-targeted agents.
The primary endpoint of the trial was the proportion of patients achieving an objective response, which was assessed by independent central review in the intention-to-treat population. The study results were published in The Lancet Oncology.
After a median follow-up time of 94 months, 8 patients (~30%) achieved an objective response, with 1 patient (~4%) achieving a complete response and 7 patients (~26%) achieving a partial response. The disease also stabilized in another 12 patients (44%).
However, 6 patients (22%) experienced grade 3 adverse events, which presented as fatigue (4 patients), skin rash (1 patient), or increased bilirubin concentration (1 patient). No grade 4 or 5 adverse events were observed in the trial.
Therefore, investigators concluded that the combination of trastuzumab and lapatinib might be active and well tolerated in treatment-refractory patients with HER2-positive metastatic colorectal cancer.
"In this heavily pretreated population, these outcome data are extraordinary, and they show the relevance of HER2 as a target in the treatment of colorectal cancer," Hans-Joachim Schmoll, MD, PhD, Martin Luther University of Halle-Wittenberg, Germany, wrote in an editorial accompanying the study.
He added that, although the results of the study are only relevant to a small subgroup of patients, they still represent a significant breakthrough in colorectal cancer research.
