A randomized phase II trial of interferon-alpha2b versus 5-fluorouracil after trabeculectomy

The aim of the present study was to investigate the safety and potential efficacy of subconjunctival interferon-alpha2b (IFN-alpha), either alone or in combination with 5-fluorouracil (5-FU), in reducing the risk of failure of glaucoma surgery

A prospective, masked randomized phase II study was undertaken in which patients received three subconjunctival injections per week for 3-4 weeks postoperatively. Three treatments were compared: (i) IFN-alpha (1 x 10(6)IU per dose); (ii) 5-FU (5 mg per dose); and (iii) alternating IFN-alpha and 5-FU (BOTH). The primary outcome measures were: (i) rate of successful control of intra-ocular pressure without further surgery; and (ii) the incidence of side effects.

Fifty-seven patients undergoing glaucoma surgery with an increased risk of failure were evaluated, including 23 patients (40%) undergoing trabeculectomy combined with extracapsular cataract extraction as well as other conventional high-risk groups. With 53 patients (93%) completing 2 years follow up,there was no significant difference in success rates among the three groups. Intra-ocular pressure was controlled without further surgery in 79% of patients (95% confidence interval (CI): 61, 97%) receiving IFN-alpha, in 89% of patients (76, 100%) receiving 5-FU and in 89% of patients (76, 100% receiving BOTH. Side effects were similar among the three groups.

These results are consistent with a beneficial effect of IFN-alpha2b given either alone or in combination with 5-FU after glaucoma filtering surgery. However, the lack of a clear and substantial benefit over conventional anti-fibrotic therapy does not support the further clinical evaluation of these treatments.