An Open-Label Extension of XPro1595 in Patients With Alzheimer's Disease

This study is designed as a Phase 2, open label study investigating the safety, tolerability, and efficacy of XPro1595 in patients with Alzheimer's Disease (AD). The planned dose is 1.0 mg/kg of XPro1595 for all subjects that completed a previous Phase 1 or Phase 2 study with XPro1595.

Each enrolled patient will be treated with 1.0 mg/kg of XPro1595 as a subcutaneous injection once a week for 55 or 74 weeks, for a total exposure to XPro1595 of up to 78 weeks (18 months), depending on their previous study. Blood sampling for clinical lab analyses, physical exam findings, ECG and C-SSRS will be collected throughout the study to assess the safety and tolerability of XPro1595. Imaging endpoints (MRI), blood sampling for neuroinflammatory and neurodegenerative biomarkers, clinical ratings (CDR-SB, ADCS-MCI ADL, NPI-12) and cognitive performance assessed via the EMACC will be collected at screening and at Weeks 12, 24, 36, and 48. Depending on the parent study, some or all of these assessments may also be made at Weeks 55, 60 or 74.

All patients that completed 4 weeks of dosing and the week 5 PK draw in the Phase 1 PK Lead-In or completed the treatment period and End of Study (EOS) assessments in a Phase 2 study are eligible to enroll into the OLE study. All patients enrolled, including those treated with placebo in the parent study, will receive 1.0 mg/kg XPro1595. Randomized treatment will remain blinded until the parent study database is locked, the study is unblinded and results for their prior study are released.