This will be the first-in-human study designed to evaluate the safety, pharmacokinetics (PK), and pharmacodynamics (PD) of single ascending doses of DS-7011a in healthy participants.

This study will assess the safety, PK, and PD properties of single ascending intravenous (IV) and subcutaneous (SC) doses of DS-7011a in healthy participants.

This study will be conducted in 3 stages:

• Stage 1 - single ascending IV dose cohorts of DS-7011a (ie, up to 6 dose levels will be assessed starting at 0.1 mg/kg);
• Stage 2 - single ascending SC cohorts of DS-7011a (ie, up to 3 dose levels centered around the estimated therapeutic dose confirmed in Stage 1 will be assessed); and
• Stage 3 - a single IV cohort of DS-7011a in healthy participants of Japanese ethnicity (ie, 1 dose level at the estimated therapeutic dose as confirmed in Stage 1 will be assessed).

Inclusion Criteria:

• Male and female participants 18 to 45 years of age (inclusive), with a body mass index (BMI) of 18 kg/m^2 to 30 kg/m^2 (inclusive) at Screening.

• Participants fully vaccinated against COVID-19 per current CDC guidelines or recovered from prior SARS-CoV-2 infection.

• All women must have a negative serum pregnancy test at Screening and a negative urine pregnancy test on Day -1.

• Women of childbearing potential must agree to use 2 different means of nonhormonal contraceptive methods.

• Women of non-childbearing potential must be either:

  • Surgically sterile (ie, bilateral tubal ligation or removal of both ovaries and/or uterus at least 6 months prior to dosing) or
  • Naturally postmenopausal for at least 24 consecutive months prior to dosing, spontaneous cessation of menses, with a follicle-stimulating hormone (FSH) level at Screening of ≥40 mIU/mL.

• Men must be surgically sterile (vasectomy 3 months before the dose of study drug) or agree to use approved contraception in addition to having their female partner (if of childbearing potential) use another acceptable form of contraception at any time during the study and for a period of 90 days after the dose of the study drug.

• Males may not donate sperm during the study for a period of 90 days

• Participants must be in overall good health, with no history of immunological and other chronic disorders, even if in remission and not requiring treatment.

• Confirmed Japanese ethnicity (Stage 3 only)

Exclusion Criteria:

• History or current chronic lung disease including asthma, COPD, or heavy smoking of >10 pack years
• Previous or current treatment with systemic corticosteroids or any immunosuppressive agents
• Participants who have received a transfusion or any blood products within the last year prior to dosing
• Participants who have made a blood donation or have had a loss of blood ≥500 mL within 56 days prior to the dose of study drug
• Participants who consume more than 28 units of alcohol per week (1 unit of alcohol equals 1/2 pint of beer, 4 ounces of wine, or 1 ounce of spirits) or those participants who have a significant history of alcoholism or drug/chemical abuse within the last 2 years
• Participants with positive results on tests for drugs of abuse, cotinine, or alcohol at Screening and/or Day -1