This study evaluated the safety and efficacy of adding nimotuzumab (TheraCIM, Theraloc) to radiotherapy plus capecitabine (Xeloda; chemotherapy) for locally advanced rectal cancer.

Locally advanced rectal cancer indicates that the tumor has spread to the outer layers of the rectum or has invaded the lymph nodes. Patients with locally advanced rectal cancer are often treated with a combination of radiotherapy, chemotherapy and surgery. This combination of treatments is successful at preventing the tumor from relapsing close to the original site (local recurrence), but roughly 35-40% of patients will go on to develop cancer at a distant site.

The epidermal growth factor receptor (EGFR) protein plays a role in the creation, spread and survival of cancer cells. Nimotuzumab is a drug the blocks EGFR and slows the growth and spread of cancer cells. It is not yet known whether adding nimotuzumab to radiotherapy, chemotherapy and surgery is safe and effective for treating locally advanced rectal cancer.

This study included 21 patients with locally advance rectal cancer. All patients received 400 mg nimotuzumab on days -6, 1, 8, 15, 22, and 29 of the study. They also received 825 mg/m² of capecitabine twice a day for the duration of the radiotherapy. Radiotherapy was given 5 days per week for roughly 6 weeks. 6 to 10 weeks after radiotherapy ended patients underwent rectal surgery. Tumor samples were removed from each patient before starting the treatment and during rectal surgery to see how much the tumor had shrunk. Patient survival, adverse events and cancer relapse were also recorded.

The treatment regimen led to complete disappearance of all tumor cells in 4 patients (19.0%). For 6 patients (28.6%) the tumor shrank by more than 50%. For 9 patients (42.8%) the tumor shrank by 25-50%. For 2 patients (9.5%) the tumor shrank by less than 25%.

After 3 years 63.9% of patients were still living cancer free. The cancer had spread to the liver in 3 patients (14.3%), to the lungs in 3 patients (14.3%), and to the bones in 1 patient (4.8%). After 3 years 70.0% of patients were still alive.

The most common mild to moderate adverse events included inflammation of the skin (57.1%), nausea or vomiting (52.4%), low white blood cell counts (cells needed to fight infections, 47.6%), diarrhea (47.6%), and inflammation of the lining of the rectum (38.1%). 9.5% of patients had severe diarrhea and 4.8% of patients had severely low white blood cell counts.

The authors concluded that nimotuzumab can safely and effectively be combined with radiotherapy plus capecitabine for patients with locally advanced rectal cancer. 

This was a relatively small trial, further investigation of this treatment regimen is needed. Nimotuzumab is not yet approved for the treatment of rectal cancer.