A phase I/II study of neoadjuvant chemotherapy with Pemetrexed (Alimta) in rectal cancer

The aim was to assess the feasibility of preoperative chemotherapy and possible tumour response using Pemetrexed (Alimta) in rectal cancer.

The study was a prospective, non-randomized, single-centre phase I/II feasibility trial. 37 patients with resectable rectal cancer were recruited and given three 3-week cycles of preoperative Pemetrexed therapy. Tumour size and stage were assessed by MRI scans before and after chemotherapy. Treatment tolerability and response such as changes in tumour size and symptoms were assessed.

All patients completed the chemotherapy. Whilst mild side effects were frequent (grade 1, 34/37), the risk of severe effects was limited (grade 3 or 4, 4/37). Overall, there was a significant reduction in tumour size (p < 0.001). By RECIST criteria, one patient had tumour progression, 23/36 had stable disease and 12 patients had a response of up to 65%. There was also a significant decrease in the number of pre-treatment symptoms (p < 0.018) including reduction of bleeding and diarrhoea/constipation.

Preoperative (Neoadjuvant) treatment with Pemetrexed was feasible in studied patients. Serious side effects were limited and a radiological tumour response or stable disease was seen in a majority of patients.