Acute phase proteins and recombinant IL‐2 therapy: prediction of response and survival in patients with colorectal cancer

SUMMARY Twenty‐four patients with metastatic colorectal cancer were treated with recombinant IL‐2 (rIL‐2) by continuous intravenous infusion for 5 days (18 · 106 U/m2 per 24 h), followed by three injections of 5‐fluorouracil (600 mg/m2) and folinic acid (25mg/m2) at weekly intervals. The response to treatment was assessed using standard UICC criteria (partial or complete response, stasis or progression of disease). The serum concentrations of the acute phase proteins; C‐reactive protein (CRP), retinol binding protein (RBP), α1‐antitrypsin (α1‐AT), transferrin (TF) and albumin were measured. A response to therapy occurred in the tumours of seven (29%) of the 24 patients (two complete and five partial responses). All patients who demonstrated a response to treatment had a serum albumin level of > 37 g/l and a CRP level of · 10 mg/l. In contrast, of the 17 patients who did not respond to therapy, 12 (71%) had a serum albumin of less than 37 g/dl and a CRP of greater than 10 mg/l. Examination of the survival times of the 12 patients who had a pretreatment serum albumin level of less than 37 g/l revealed that all had died within 12 months of cessation of therapy. However, 58% of patients with pretreatment serum albumin levels of greater than 37 g/l survived for longer than 12 months. These results have shown that (i) patients who respond to rIL‐2‐based therapy and (ii) those patients who have prolonged survival times, can be identified by pretreatment measurement of serum levels of acute phase proteins.