The principles of treating ABPA include using glucocorticoids to control the immunologic activity and antifungal agents to attenuate the fungal burden in the airways.4 Glucocorticoids are the first line treatment in acute stages of ABPA, although there are no placebo-controlled trials of glucocorticoids in ABPA. However, their effectiveness in ABPA is so well established that it might be considered unethical to conduct placebo-controlled trials. In one study, 92 subjects were randomized to receive high-dose (n=44) or low-dose (n=48) prednisolone. The numbers of subjects with exacerbation after one year (high-dose: 40.9% vs. medium-dose: 50%, p=0.59) were similar in the two groups. Although the composite response rates were significantly higher in the high-dose group, the improvement in lung function and the time to first exacerbation were similar in the two groups. \[Eur Respir J. 2016;47(2):490-498\] Specific antifungal agents in ABPA can modify the immune response by removing or reducing the antigenic stimulus consequent to a decreased fungal burden. Two randomized trials have recently shown that itraconazole and voriconazole monotherapies are as effective as prednisolone in treating acute-stage ABPA. \[Chest. 2018;153(3):656-664\|Eur Respir J. 2018;52(3):1801159\] In the first randomized trial, 131 ABPA patients were randomized to receive either oral itraconazole (400 mg/day, \[n=68\]) or prednisolone (n=63) for four months. The proportion of subjects responding at six weeks was significantly higher in the prednisolone arm (100% vs. 88%; p=0.007). However, the number of subjects with exacerbations after one and two years of treatment was similar in the two groups. The time to first exacerbation was also similar in the two groups. The occurrence of adverse reactions was significantly higher in the glucocorticoid arm. Although prednisolone was more effective than itraconazole in inducing a response in acute-stage ABPA, itraconazole with fewer side effects is an acceptable alternative for treating acute-stage ABPA.\[Chest. 2018;153(3):656-664\] In the second trial, 50 ABPA patients were randomized to receive prednisolone (n=25) or voriconazole (n=25).\[Eur Respir J. 2018;52(3):1801159\] The response to treatment after six weeks and three months was similar in the two groups. The numbers of subjects with exacerbations after one year and two years were similar in the two groups. More recently, acute-stage ABPA subjects were randomized to receive either prednisolone (n=94) or prednisolone-itraconazole combination (n=97). The one-year exacerbation rate was 33% and 20.6% in the prednisolone and the prednisolone-itraconazole arms, respectively (p=0.054).\[Eur Respir J. 2022;59(4):2101787\] However, the study did not have a comparator arm of itraconazole monotherapy. Thus, it is unclear whether combination therapy is better than itraconazole or prednisolone monotherapy in reducing the occurrence of ABPA exacerbations.

The investigators hypothesize that the combination of prednisolone and itraconazole would significantly reduce the exacerbation rate at one-year than monotherapy. This study will compare the efficacy of prednisolone, itraconazole, or their combination in patients with acute stages of ABPA.