The purpose of the study is to evaluate the safety, tolerability, pharmacokinetics (PK), and pharmacodynamics (PD) of multiple intravenous (IV) doses of ALXN1007 in healthy male and female subjects.

Inclusion Criteria:

Healthy male or female (not of childbearing potential) subjects ≥25 and ≤55 years old.

2. QTcF ≤450 msec and ≤470 for females. 3. Willing and able to give written informed consent and comply with the study visit schedule.

4. Male subject and his female spouse/partner who is of childbearing potential must be using highly effective congraception1 consisting of two forms of birth control (at least one of which must be a barrier method) starting at Screening and continuing until the end of study.

1. Highly effective contraception is defined as:

   • Established use of oral, injected or implanted hormonal methods of contraception.

   • Placement of an intrauterine device or intrauterine system.

   • Barrier methods of contraception: condom or occlusive cap (diaphragm or cervical/vault caps) with spermicidal foam/gel/film/cream/suppository.

     5. Male subjects must not donate sperm starting at Screening until the end of study.

     6. Documented vaccination with meningococcal conjugate vaccine (MCV4) at least 14 days and not more than 5 years, prior to dosing.

Exclusion Criteria:

Female subjects of childbearing potential, including any female who has experienced menarche and who has not undergone successful surgical sterilization (hysterectomy, bilateral tubal ligation, or bilateral oophorectomy) or is not postmenopausal. Postmenopausal is defined as:

• Amenorrhea ≥ 12 consecutive months without another cause and a documented serum follicle stimulating hormone (FSH) level >35 mIU/mL or

• Female subjects with irregular menstrual periods and a documented serum FSH level > 35 mIU/mL.

• Women on hormone replacement therapy (HRT). Women who are using oral contraceptives, other hormonal contraceptives (i.e., vaginal products, skin patches, or implanted or injectable products), or mechanical products such as an intrauterine device or barrier methods (i.e., diaphragm, condoms, spermicides) to prevent pregnancy, or are practicing abstinence or where their partner is sterile (e.g., vasectomy) should be considered to be of childbearing potential.

  2. Positive serum pregnancy test at Screening or Day -1. 3. Serum creatinine great than the upper limit of normal (ULN) of the testing laboratory at Screening and Day -1.

  4. Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) >ULN of the testing laboratory at Screening and Day -1.