Table 1 Protocol definitions of treatment response and treatment failure

Response to treatment:

A complete or significant response to the study drug at month 6. Importantly, the absence of complete or significant response and/or flares of vasculitis occurring between enrollment (or day 1 of Stage 2) and the end of month 3 will not be considered failures; patients must continue taking the assigned study drug until at least the end of month 3, unless they have developed a severe adverse event due to the study drug that warrants its discontinuation. After month 3 (in Stages 1 and 2), the absence of complete or significant response to treatment will be considered a treatment failure

Complete response:

• No new skin lesions of vasculitis within the preceding 3 months

Significant response:

• Three or fewer skin lesions per flare with no more than 1 flare/month and minimally symptomatic, including no significant painful or necrotic lesions, within the preceding 3 months

and

• Physician global assessment reflecting minimal severity over the prior 28 days (0–2 on a 10-point scale)

and

• Patient global assessment reflecting an improvement compared to baseline by at least 1 point on a 10-point scale

Treatment failure:

A limited response or an absence of response to the study drug at month 6, or the development of a complication of vasculitis at any time after enrollment. The absence of response, a limited response, and/or flares of vasculitis occurring between enrollment (or day 1 of Stage 2) and the end of month 3 will not be considered failures unless the flares require the repeated use of prednisone for ≥ 2 courses

Limited response: a reduction in the number and/or frequency of new skin lesions of vasculitis and/or in the severity of the lesions but with physician and/or patient global assessment persistently > 2 on a 10-point scale and/or frequency of flares > 1/month

Absence of response: a complete absence of reduction or an increase in the number and/or frequency of new skin lesions of vasculitis and/or in the severity of the lesions

≥ 2 flares of skin vasculitis requiring prednisone use between enrollment (or day 1 of Stage 2) and month 3. One course of prednisone for a flare of skin vasculitis for a maximum of 3 weeks is allowed between enrollment or day 1 of Stage 2 and the end of month 3; prednisone is not allowed after month 3

Complication: appearance of an extracutaneous manifestation suggesting progression of the underlying vasculitis/condition or an incorrect initial diagnosis of skin-limited vasculitis (at any time between enrollment and month 6). Patients experiencing such complication(s) will have study drug discontinued, undergo a Treatment Stopping Visit, and be treated according to standard of care for their systemic vasculitis