The mean mRSS at baseline was comparable in 60 patients randomized to receive riociguat and 61 in the placebo group (16.8 and 16.71, respectively). These mean values at week 52 dropped to 14.63 vs. 15.73, respectively (P = .08).
“So it was close, but it didn’t reach significance,” he said.
The difference in the mRSS progression rate, however, suggested significant effects favoring riociguat (descriptive P = .02), he said.
Further, mean change from baseline to week 52 in percent predicted FVC was not different overall between the groups, but a large difference favoring riociguat was seen among patients with scleroderma interstitial lung disease at baseline (mean change of –2.7 vs. –8.9), he said.
No differences were seen between the groups in HAQ-DI or patient and physician global assessment. The proportion of patients with probability of improvement at 52 weeks as measured using ACR CRISS was also the same at 18% in both treatment arms, he noted, ”but the CRISS is designed more for assessing disease regression than for assessing prevention of progression.”
Treatment was, however, well tolerated. At week 52, fewer serious adverse events occurred with riociguat group than in the placebo group (15% vs. 25%, respectively), and no new safety signals were observed, he said.
Riociguat has previously shown antifibrotic effects in animal models and efficacy in patients with pulmonary arterial hypertension associated with connective tissue disease, so it was hypothesized that patients with dcSSc might benefit from riociguat therapy, Dr. Distler explained.
Study subjects had very early dcSSc (duration of 18 months or less; mean of 9 months), mRSS of 10-22 units, FVC of 45% predicted or greater, and diffusion capacity of the lung for carbon monoxide of at least 40% of predicted at screening.
Riociguat was given at an individually adjusted dose between 0.5 mg and 2.5 mg three times daily.
The findings demonstrate a numeric decrease in mRSS over time with riociguat versus placebo and a prevention of progression with riociguat; the failure to reach the primary endpoint may be related to the small study size and the higher than expected regression rate in the placebo group, Dr. Distler said.
Dr. Khanna is a consultant to Roche/Genentech and Bayer, which markets riociguat, and other companies. He has received research grants from Bayer, Bristol-Myers Squibb (which markets abatacept), and Pfizer. The ASSET trial he presented was sponsored by an National Institutes of Health/National Institute of Allergy and Infectious Diseases Clinical ACE grant and an investigator-initiated grant by Bristol-Myers Squibb. Dr. Distler has a consultancy relationship and/or has received research funding from Bayer, Roche/Genentech, and other companies. In addition, he has a patent on mir-29 for the treatment of systemic sclerosis.
SOURCES: Khanna D et al. Arthritis Rheumatol. 2018;70(Suppl 10): Abstract 898 and Abstract 900; Distler O et al. Arthritis Rheumatol. 2018;70(Suppl 10): Abstract 903.