The focuSSced study of tocilizumab
For example, in the phase 3 focuSSced study comparing the interleukin-6 (IL-6) receptor–alpha antibody tocilizumab (Actemra) with placebo in patients with SSc, the primary endpoint of mean change from baseline in mRSS was not met (–6.14 vs. –4.41 points with tocilizumab vs. placebo, respectively; P = .098), Dr. Khanna said during a report of findings from the double-blind portion of the study.
Dr. Dinesh Khanna
However, when the CRISS was applied and its performance prospectively assessed as an exploratory outcome at week 48 in the focuSSced trial, the differences between the groups were statistically significant. Dr. Khanna reported those findings in a separate presentation at the meeting, noting that they marked the first prospective evaluation of the ACR CRISS in a phase 3 trial in SSc.
The CRISS was applied – using a blinded review of adverse events and serious adverse events to complete step 1 – in all patients who received study treatment, stratified by baseline IL-6 levels.
Of 104 patients in the tocilizumab arm and 106 in the placebo arm, 6 and 13 patients, respectively, had cardio-pulmonary-renal involvement and therefore received a score of 0.
Using the ACR CRISS as a continuous measure, scores favored tocilizumab over placebo at week 48 with a median increase of 0.89 vs. 0.25 points (P = .023), and using the binary form of CRISS, 51% vs. 37% of patients in the treatment and placebo arms achieved the score cutoff of 0.60 or higher at week 48 (P = .035), he said.
“The focuSSced study validates the ACR CRISS endpoint for the first time in an independent prospective clinical trial and highlights the importance of step 1 as an indicator of reduced organ progression during 48 weeks of treatment,” Dr. Khanna concluded.
The ASSET trial of abatacept
Dr. Khanna also reported results from the 12-month phase 2 ASSET trial comparing abatacept (Orencia) and placebo in early dcSSc.
Again, the change from baseline in mRSS – the primary endpoint of the study – did not differ significantly with treatment vs. placebo (–6.24 vs. –4.49; P = .28).
And again, as presented separately in a poster session at ACR, application of CRISS at 12 months – a secondary outcome measure in the trial – showed a significant difference between the groups.
The investigators prospectively performed step 1 of the CRISS using a case report form. Of 63 patients with complete data available for relevant outcomes at 12 months, 10 (5 in each group) had cardio-pulmonary-renal involvement and thus were given a score of 0.
Overall, there was evidence of significantly improved CRISS scores in the abatacept group vs. the placebo group (P = .03), he said.
Most of the individual CRISS variables, except HAQ-DI and patient global assessment, had statistically significant correlations with the CRISS, he noted, adding that “although the degree of correlation is high between the mRSS and CRISS, there is evidence that CRISS may be more sensitive to clinically meaningful treatment changes than the standard skin score endpoint.”
“This suggests further validation of CRISS as an independent primary endpoint for scleroderma clinical trials,” he concluded.