Comparison of Cytoxan and Cellcept, Therapies for Scleroderma Lung Fibrosis, Finds Both Equally Effective

A direct comparison of Cytoxan (Cyclophosphamide) and Cellcept (mycophenolate mofetil) showed that the drugs are equally effective in stabilizing, and even improving, lung function in scleroderma patients with lung fibrosis.

Since Cytoxan might be more toxic when used for extended periods, the study, “Cyclophosphamide versus mycophenolate mofetil in scleroderma interstitial lung disease (SSc-ILD) as induction therapy: a single-centre, retrospective analysis,” published in the journal Arthritis Research & Therapy, suggested that Cellcept might be a better choice for long-term treatment — an idea that, nevertheless, needs support from larger and randomized clinical trials.

Both of these immunosuppressive drugs have been used to treat lung fibrosis in scleroderma patients with positive results, but so far, no side-by-side comparisons of the drugs have been made. Researchers at the Centre For Arthritis & Rheumatism Excellence (CARE) in India recruited 57 scleroderma patients with significant lung fibrosis, who had not previously been treated with immunosuppressant drugs.

Study participants was divided into two groups, with 34 receiving Cellcept, and 23 treated with Cytoxan. Before the start of treatment, and again after three and six months, the patients’ lung function was analyzed with spirometry, looking for changes in forced vital capacity (a measure of lung function).

After six months, patients in the Cytoxan group were seen to have improved their forced vital capacity by 10.8%, and patients treated with Cellcept by, on average, 6%. While the improvement was statistically significant in both groups, researchers could not find a statistically significant difference between the treatments.

The American Thoracic Society defines improvement in lung function as an increase in forced vital capacity by 10% or more, while stabilization being defined as an increase by less than 10%. This means that although researchers could find no statistical evidence of differences between the treatments, the Cytoxan group improved, while the Cellcept group stabilized.

Looking at actual changes within the groups, the comparison showed that more patients improved and fewer worsened among those in the group receiving Cellcept — 78.26% increased, 17.39% decreased, and 4.35% experienced no change — compared to Cytoxan-treated patients, where 68.57% increased, 28.57% decreased, and 2.85% had unchanged lung function.

Nevertheless, the study was relatively small and limited by a lack of other types of measurements, such as high-resolution computed tomography lung scans. The study also lacked an untreated control group, prompting researchers to suggest that the findings need to be validated in a larger randomized trial.

While a direct comparison is crucial, other research groups have attempted to use the two drugs together. Scleroderma News recently reported that researchers attempted to treat patients with an induction therapy using Cytoxan, followed by maintenance treatment with Cellcept, which could be a way to reduce the long-term toxicity linked to Cytoxan (a chemotherapeutic drug).