A randomized phase II trial of interferon-α2b versus 5-fluorouracil after trabeculectomy*

Purpose: The aim of the present study was to investigate the safety and potential efficacy of subconjunctival interferon-α2b (IFN-α), either alone or in combination with 5-fluorouracil (5-FU), in reducing the risk of failure of glaucoma surgery. Methods: 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-α (1 × 10 ⁶ IU per dose); (ii) 5-FU (5 mg per dose); and (iii) alternating IFN-α 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. Results: 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-α, 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. Conclusions: These results are consistent with a beneficial effect of IFN-α2b 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.