Six trials were included in the review (2,786 patients, range 64 to 345 per comparison group). Study quality was not reported. Between 13% and 52% of patients stopped thalidomide treatment because of intolerance (reported in four trials).
Taking all studies together there was no significant improvement in overall survival with thalidomide maintenance therapy (hazard ratio 0.83, 95% CI 0.67 to 1.02; p=0.07; significant heterogeneity Ι²=50.6%). In the three trials that used concomitant therapy with steroids there was a significant benefit for overall survival (hazard ratio 0.70, 95% CI 0.52 to 0.94; p<0.05). The three trials that did not use steroid therapy demonstrated no significant benefit for overall survival (hazard ratio 1.00, 95% CI 0.83 to 1.20). When analysing the data according to differences in induction therapy, there was no clear effect.
Thalidomide maintenance therapy showed a significant benefit for progression-free survival (hazard ratio 0.65, 95% CI 0.59 to 0.73; p<0.01; six studies; no significant heterogeneity Ι²=14%) and irrespective of concomitant steroid therapy.
In the treatment groups there was a significantly increased risk of venous thrombosis (risk difference 0.024, 95% CI 0.004 to 0.045; p=0.02; five studies) and peripheral neuropathy (risk difference 0.072, 95% CI 0.049 to 0.095; p<0.01; four studies; no significant heterogeneity).