To investigate the safety, tolerability, pharmacokinetics, and pharmacodynamics of MGTA-145 in healthy volunteers as a single agent and in combination with plerixafor.

The study consists of up to four parts: Part A, to investigate the safety and tolerability of MGTA-145; Part B, to investigate the safety and tolerability of MGTA-145 when administered in combination with plerixafor; Part C, to investigate the safety and tolerability of two sequential days of dosing MGTA-145 in combination with plerixafor; and Part D, to investigate the safety, tolerability, and measure by apheresis, the total number of CD34+ cells mobilized after a dose of MGTA-145 administered in combination with plerixafor.

Inclusion Criteria:

1. Age from 18 to 60 years
2. Body weight ≥50 kg and body mass index 19 to 33 kg/m2
3. No clinically significant abnormalities on physical examination at Screening
4. Non-smoker for at least 2 years
5. No clinically significant lab abnormalities for renal, hepatic or hematologic parameters
6. No clinically significant abnormalities on ECG
7. Female subjects must be of non-childbearing potential
8. Male subjects who are sexually abstinent or surgically sterilized (vasectomy), or those who are sexually active with a female partner(s) and agree to use an acceptable method of contraception
9. No contraindications for apheresis

Exclusion Criteria:

1. Any clinically significant laboratory value outside the normal range at screening
2. Donation of more than 500 mL of blood or plasma within 12 weeks prior to dosing
3. History of alcoholism or drug abuse within the past 3 years
4. Subject has used any prescription drugs within 14 days prior to dosing or any dietary supplements or non-prescription drugs within 7 days prior to dosing
5. Acute illness, infection (requiring medical treatment [eg, antibiotics]), or surgery within 4 weeks of dosing
6. Seropositive for hepatitis B surface antigen, hepatitis C virus antibody, or human immunodeficiency virus
7. Subject has received another investigational drug or participated in an investigational drug or device study within 12 weeks prior to dosing
8. History of anaphylaxis or clinically important reaction to any drug including plerixafor
9. Any clinically significant hematologic, cardiovascular, pulmonary, central nervous system, metabolic, renal, hepatic, or gastrointestinal conditions

Double Blind