Persistent Disease:
Given the chronic nature of KHE/TA, we also tried to define disease persistence in response to therapy (Supplemental Table 3). We found that rates of persistent disease at 3 months (28.6%, p=0.024) were higher in patients receiving a combination of Siro+VCR compared to those receiving steroids alone (and a significantly higher proportion of patients in the Siro+VCR group required continuation of therapy at 3 months for persistent disease (71.4%, p<0.001). However, by 6 months, rates of persistent disease were equivalent across groups.
When looking at just the VCR and Siro groups (Table 5), a higher proportion of patients in the Siro group were reported to require continuation of therapy at 3 months for persistent disease (27.5% vs. 0%, p=0.003). However, of the VCR group, 22/25 (88%) received adjunctive therapy including 9 (36%) who had Siro added to their regimen and time to initiation of Siro ranged from 29 days to 863 days. Rationale for adding Siro included severity of disease in 5 patients, VCR toxicity in 2 patients (hoarse cry, neutropenia), and loss of central venous access in 2 patients. In the sub-analysis of sirolimus or vincristine treatment with or without steroid use (Table 6), more patients had persistent disease in the two vincristine groups, but small numbers precluded statistical comparison. It was notable that in the VCR + steroid group, 9/19 (47.4%) patients had Siro added to their treatment regimen later.