The purpose of this study is to evaluate the safety and pharmacokinetics of MEDI8852 compared to placebo when administered to healthy adult subjects.

This is a phase 1, single-dose, double-blind, placebo-controlled, dose-escalation study to evaluate the safety and pharmacokinetics of MEDI8852 compared to placebo when administered to healthy adult subjects. Approximately 40 subjects will be entered to receive treatment across 4 fixed dose cohorts at 1 site. Investigational product will be delivered intravenously (IV). A total of 4 different dose levels of investigational product will be evaluated across the cohorts. Subjects will be followed for approximately 100 days.

Inclusion Criteria:

1. Age 18 through 65 years at the time of screening
2. Weight ≥ 45 kg and ≤ 110 kg at screening
3. Healthy by medical history, physical examination, and baseline safety laboratory studies.
4. Systolic blood pressure (BP) < 140 mm Hg and diastolic BP < 90 mm Hg at screening
5. Electrocardiogram without clinically significant abnormalities at screening
6. Able to complete the follow-up period through Day 101 as required by the protocol
7. Females of childbearing potential who are sexually active with a nonsterilized male partner must use a highly effective method of contraception for at least 28 days prior to the first dose of investigational product and must agree to continue using such precautions through Day 101 of the study

Exclusion Criteria:

1. Acute illness, including fever > 99.5°F, on day prior to or day of planned dosing
2. Any drug therapy within 7 days prior to Day 1 (except contraceptives or a single use of acetaminophen, aspirin, antihistamine. and other nutritional supplements that have not been taken for at least 30 days prior to enrollment, are not exclusionary.
3. Blood drawn in excess of a total of 450 mL (1 unit) for any reason within 2 months prior to screening
4. Receipt of immunoglobulin or blood products within 6 months prior to screening
5. Receipt of any vaccine within 14 days prior to investigational product dosing or planned receipt of any influenza vaccine within 100 days after investigational product dosing
6. Either history of active infection with hepatitis B or C or positive test for hepatitis C or for hepatitis B surface antigen at screening
7. Aspartate aminotransferase (AST), alanine aminotransferase (ALT), or serum creatinine above the upper limit of normal or hemoglobin, white blood cell count, or platelet count below the lower limit of normal at screening
8. History of malignancy other than treated non-melanoma skin cancers or locally-treated cervical cancer in previous 5 years
9. Pregnant or nursing mother
10. History of alcohol or drug abuse within the past 2 years tha OR positive Class A drug screen for amphetamines, barbiturates, opiates, or cocaine at screening.