Open-label Extension to the Phase 2 Crossover Study (PRESIDIO) Evaluating KZR-616 in Patients With PM and DM.

An Open-label Extension to the Phase 2 Randomized, Double-blind, Placebo-controlled, Crossover Multicenter Study to Evaluate the Safety and Efficacy of KZR-616 in the Treatment of Patients With Active Polymyositis or Dermatomyositis

This was an open-label study to evaluate the long-term efficacy and safety of KZR-616 in patients with active polymyositis (PM) or dermatomyositis (DM) who completed the double-blind treatment period of Study KZR-616-003, up to and including the Week 32 Visit, prior to the first dose of open-label KZR-616.

This was an open-label study to evaluate the long-term efficacy and safety of KZR-616 in patients with active polymyositis or dermatomyositis who completed the double-blind treatment period of Study KZR-616-003 (NCT04033926), up to and including the Week 32 Visit, prior to the first dose of open-label KZR-616.

Patients were evaluated for eligibility according to the entry criteria at, or within 8 weeks after, the Week 32 Visit (ie, the End of Treatment [EOT] Visit [Visit 34]) of Study KZR-616-003.

All patients received a subcutaneous (SC) injection of 30 mg KZR-616 at Visit 1 (Day 1), followed by weekly SC injections of 45 mg KZR-616 up to a maximum of 96 weeks. Study drug administration ended for all patients in Study KZR-616-003E when the last patient enrolled completed 48 weeks of dosing. Patients had a final follow-up visit 12 weeks after their last dose of KZR-616 (End of Study [EOS] Visit), for a maximum potential length of participation of 108 weeks.

Inclusion Criteria:

• Must have successfully completed Study KZR-616-003 through Week 32, including the Week 32 Visit assessments
• Women of childbearing potential (WOCBP) must have a negative urine or serum pregnancy test prior to the first dose of KZR-616 in KZR-616-003E, and must agree to continue to use a highly effective method of birth control until completion of the study.
• Male patients must continue to use an effective contraception method for 1 week following their last dose of KZR-616 or be congenitally or surgically sterile.

Exclusion Criteria:

• Has participated in any clinical study other than KZR-616-003 between the Week 32 Visit of Study KZR-616-003 and the first study visit of KZR-616-003E, if they are not on the same calendar day.
• Are females who are breastfeeding or who plan to become pregnant during the study, or who are actively trying to conceive at the time of signing of the informed consent form.
• Have hypersensitivity to KZR-616 or any of its excipients.