Phase 1 randomized, double-blind, placebo-controlled trial to evaluate safety, tolerability, pharmacokinetics (PK) and immunogenicity of IDB-011 following intramuscular (IM )administration of single ascending doses to healthy adult participants.

This is a randomized, double blind, placebo-controlled, dose escalation, first-in-human, Phase I clinical trial to assess the safety, tolerability, PK and immunogenicity of IDB-011 in healthy volunteers aged 18-64. IDB-011 is comprised of IDB-774 and IDB-898, which will be administered as separate, consecutive intramuscular injections.

Volunteers will be recruited into sequential dosing cohorts. Within each cohort, eligible volunteers will be randomly allocated (6:2) to receive either IDB-011 or placebo (0.9% normal saline). A sentinel dosing scheme will be employed for the first 2 volunteers in each dosing cohort.

Volunteers will stay in a clinical research unit for up to 4 consecutive days and be followed for up to 1 year.

Inclusion Criteria:

• Healthy male or female
• Body mass index (BMI) within 18.0 kg/m2 to 30.0 kg/m^2, inclusively
• Female participants must not be pregnant, breastfeeding or intend to become pregnant through 1 year post-administration
• Male subjects must agree to not cause pregnancy or donate sperm for 1 year post-administration
• Non-smoker
• Agree to abstain from alcohol for 72 hours and caffeine for 48 hours prior to administration and during the confinement period
• Agree to not donate blood or plasma during study participation
• Agree not to travel to Rift Valley fever virus (RVFV) endemic areas during participation

Exclusion Criteria:

• Known history of RVFV infection
• Previous receipt of RVFV vaccine
• Illness with fever within 5 days prior to administration
• History of malignancy within prior 5 years
• History of significant cardiovascular, pulmonary, gastrointestinal, liver, kidney, hematologic, neurological, psychiatric, endocrine, immunologic, dermatologic disease
• History of hypersensitivity reaction
• History or clinical evidence of alcohol abuse
• Human immunodeficiency virus (HIV) positive
• Hepatitis C virus positive
• Hepatitis B virus positive
• Received immunoglobulin or antibody product within 6 months of administration
• Vaccine within 28 days of administration
• Received investigational agent within 3 months or < 5 half-lives (whichever is longer) prior to administration
• Donation of plasma, 1 unit or > 500 mL blood donation in 56 days prior to administration

Double blind