Extension Study to Assess Effects of Non-interrupted Versus Interrupted and Long Term Treatment of Two Dose Regimes of Secukinumab in Subjects With Hidradenitis Suppurativa

This is a multicenter extension study to both core Phase III studies CAIN457M2301 and CAIN457M2302 (Core studies). This study contains a randomized withdrawal design, double blinded and placebo controlled up to Week 104 or loss of response. The subjects with HiSCR response after 52 weeks of treatment in the "Core studies" will be randomized at 2:1 ratio to either continue on one of the two Secukinumab dosing regimens assigned in "Core studies" for another 52 weeks or will be placed on placebo. The primary endpoint is loss of response (LOR) assessed during the 52-week treatment duration (up to Week 104). Subjects who attained LOR will be transferred to open-label treatment to continue until the end of the study. Subjects on placebo who did not reach LOR up to Week 104 will be offered to continue in the open-label treatment or discontinue the study. Thus for subjects who were HiSCR responders at Week 52 of "Core studies", the open label treatment duration will vary and start either from the time of LOR or from Week 104 dose and last until Week 260 followed by 8 weeks of a post treatment follow-up period to week 268.

Subjects who were HiSCR non-responders at the end of "Core studies" will be offered to continue in open-label treatment until Week 260.

Subjects who prematurely discontinue the study, or who complete the study will enter a post-treatment follow up period (8 weeks) The primary objective is to evaluate maintenance of HiSCR response at Week 104 in either continuous or interrupted therapy compared to placebo. Secondary objectives are to assess the long-term safety and tolerability evaluated by adverse events, abnormal laboratory values and vital signs.

Primary Outcome Measures

1. Time to Loss of Response (LOR) up to Week 104 in Hidradenitis Suppurativa Clinical Response (HiSCR) Responders
   Loss of response was defined as: * at least a 50% increase in abscess and/or nodules (AN) count compared to the average AN count from the 3 previous visits or at Week 52, whichever is lower and the increase was at least of 3 AN. * at least a 30% increase in AN compared to the average AN count from the 3 previous visits or Week 52, whichever is lower, with an increase of at least 2 AN and a further increase in the AN count of at least 2 AN at a re-assessment visit within 2-4 weeks
2. Incidence Rate of Participants Achieving Loss of Response (LOR) up to Week 104 in Hidradenitis Suppurativa Clinical Response (HiSCR) Responders
   The incidence rate of participants achieving Loss of Response (LOR) was based on the primary estimand. * Day 1 = Date of 1st dose intake in the extension study. * Subjects at risk = Subjects who did not have LOR and were not censored before or at the start of the specified time interval. * Incidence rate (%) = (number of subjects with LOR / number of subjects at risk) x 100.

Secondary Outcome Measures

1. Number of Participants With Treatment Emergent Adverse Events
   To assess the long-term safety and tolerability of Secukinumab in subjects with moderate to severe hidradenitis suppurativa (HS)