Phase III randomized, double-blind study of maintenance CAI or placebo in patients with advanced non-small cell lung cancer (NSCLC) after completion of initial therapy (NCCTG 97-24-51).

Purpose: This study assessed whether maintenance therapy with carboxyaminoimidazole (CAI), compared to placebo, prolonged overall survival in stage IIIB/IV NSCLC patients who had tumour regression or stable disease after treatment with one chemotherapy regimen.
Methods: After completion of chemotherapy, patients were randomized to receive daily oral CAI at 250mg or placebo. Treatment continued until patient refusal, disease progression or unacceptable adverse event (AE). Quality of life (QOL) was assessed by UNISCALE and Functional Assessment of Cancer Therapy for Lung Cancer (FACT-L).
Results: Registration was halted early for slow accrual (targeted 360, randomized 186: 94 CAI, 92 placebo). All patients were off active treatment at time of analyses. Non-haematologic AEs (primarily grade 1, 2) observed significantly more often in the CAI group included fatigue (54.5% versus 29.3%), anorexia (31.1% versus 13.0%), nausea (62.2% versus 30.4%), vomiting (32.2% versus 14.1%), neurosensory (60.0% versus 44.6%) and ataxia (33.3% versus 16.3%). Patients discontinued treatment for AEs, death on study or refusal more often in the CAI group (36.0% versus 8.7%, p<0.0001). No significant differences in survival or time to progression were observed (median: CAI versus placebo: 11.4 months versus 10.5 months, log rank p=0.54; 2.8 months versus 2.4 months, log rank p=0.50). More patients receiving CAI reported a clinically significant (10-point) decline in QOL particularly on the functional (58% versus 37%, p=0.05) construct of FACT-L and UNISCALE (72% versus 51%, p=0.04).
Conclusion: The addition of CAI following chemotherapy does not provide clinical benefit or improvement in QOL over placebo in advanced NSCLC.