Dr. Khanna also reported results of the 12-month, double-blind, randomized, placebo-controlled phase 2of abatacept, which showed no significant difference in mRSS in patients with early diffuse cutaneous SSc (dfSSc) who were treated with 125 mg of the recombinant fusion protein weekly and those who received placebo. However, certain secondary outcomes favored abatacept. No concomitant immunotherapy was allowed.
The adjusted mean decrease in the mRSS among patients who completed the 12-month treatment period was –6.24 vs. –4.49 in 34 patients in the abatacept group and 35 in the placebo group, respectively (P = .28).
The secondary outcome measures of mean change in Health Assessment Questionnaire Disability Index (HAQ-DI), patients global assessment, physician global assessment, and ACR CRISS scores were statistically significant or showed numerical results favoring abatacept over placebo: mean decrease in HAQ-DI, –0.17 vs. –0.11 (P = .05), respectively; mean change in physician global assessment scores, –1.30 vs. –0.35 (P = .03); median ACR CRISS index, 0.68 vs. 0.01 (P = .03), decline in percent predicted FVC of 4.13% and 1.34% (P = .11).
Escape therapy was allowed at 6 months for worsening SSc, but it did not change the outcomes trajectory, he said. A larger proportion of placebo vs. abatacept subjects required escape immunosuppressive therapy (36% vs. 16%; P = .03).
Patients were enrolled between 2014 and 2018 at 27 U.S., Canadian, and U.K. sites. At baseline, participants had a mean age of 49 years, 75% were women, and mean disease duration was very short at 1.59 years, with 60% having disease duration of 18 months or less. The mean baseline mRSS was 22.4, mean percent predicted FVC was 85.3%, and mean HAQ-DI was 1.0.
Compliance with both treatments was greater than 98%. Abatacept was well tolerated with comparable adverse events (AEs), serious AEs, and AEs of special interest such as infections and malignancies between treatments, Dr. Khanna said, noting that two deaths occurred in the abatacept group (caused by scleroderma renal crisis in both cases at days 11 and 46) and one occurred in a placebo group patient who experienced sudden cardiac arrest at day 310.
Of note, mRSS showed large variability, despite recruiting an early dcSSc population, Dr. Khanna said.
The finding with respect to the primary outcome is consistent with other recent trials because of improvement in mRSS that’s part of the natural history of the disease, including the tocilizumab findings that he reported at the meeting. The findings with respect to secondary endpoints and safety show promise.
“Stay tuned for robust ongoing work on the relationship between clinical changes and ongoing mechanistic work,” he said.
Similarly, in the randomized, placebo-controlled phase 2bcomparing riociguat and placebo for early dcSSc, the primary efficacy endpoint of mean change in mRSS did not reach statistical significance, but exploratory data suggested that the soluble guanylate cyclase stimulator prevented disease progression in patients with early dcSSc, reported , head of the connective tissue diseases program at University Hospital Zurich (Switzerland).