They found a striking improvement in lung function in the nine patients treated with interferon gamma-1b in addition to prednisolone, as compared with those who received only prednisolone, over the course of one year. All nine patients had improved total lung capacity and resting partial pressure of arterial oxygen, and eight of the nine had improved partial pressure of arterial oxygen on maximal exertion. By contrast, eight of the nine patients in the control group, which received prednisolone alone, had a decline in all three measurements over the same period. If this preliminary report is confirmed, it will represent a striking breakthrough in the treatment of idiopathic pulmonary fibrosis. But, as the authors acknowledge, the findings of pilot studies, however promising, cannot be used as the basis of recommendations for therapy.
Some caveats are important.
Patient selection may have been skewed, and it is possible that those studied were not representative of patients with idiopathic pulmonary fibrosis in general. It is reassuring to know that the diagnosis of idiopathic pulmonary fibrosis was based on the finding of usual interstitial pneumonia on surgical biopsy in 15 of the 18 patients, although transbronchial-biopsy specimens were the only tissue samples obtained from the other 3. Transbronchial biopsy is inadequate for the precise diagnosis of most diffuse lung diseases, especially for the differentiation between nonspecific interstitial pneumonia and usual interstitial pneumonia. Therefore, even if the findings of this preliminary study are substantiated, it will be necessary to confirm them in groups of patients more likely to be encountered in routine clinical practice. An ongoing study is testing the efficacy of interferon alfa for the treatment of idiopathic pulmonary fibrosis.