This will be a double masked, randomized, placebo controlled, single and multiple oral dose study conducted in 3 parts. The safety and tolerability of single and multiple ascending oral doses of QA102 in healthy young and older adult subjects will be evaluated. The study will also characterize the pharmacokinetic (PK) profile of QA102 in plasma and urine after single and multiple oral doses of QA102. Besides, the metabolite profile of QA102 will also be characterized.

Part 1 will comprise a single dose, sequential cohort design. Part 2 will comprise a multiple dose, sequential cohort study. Part 3 will comprise a multiple dose, single cohort study in older subjects.

Inclusion Criteria:

1. Body mass index between 18.0 and 32.0 kg/m2, inclusive.
2. In good health, determined by no clinically significant findings from medical history, physical examination, visual acuity testing, 12 lead ECG, vital signs measurements, and clinical laboratory evaluations at screening and check in as assessed by the investigator or designee.
3. Females of nonchildbearing potential defined as permanently sterile or postmenopausal. Males will agree to use contraception.
4. Able to comprehend and willing to sign an ICF and to abide by the study restrictions.
5. Young (between 18 and 59 years of age, for Part 1 and 2) or Older (between 60 and 75 years of age, for Part 3) males or females of nonchildbearing potential, of any race, inclusive, at screening.

Exclusion Criteria:

1. Subject is mentally or legally incapacitated or has significant emotional problems at the time of the screening visit or expected during the conduct of the study.
2. Significant history or clinical manifestation of any metabolic, allergic, dermatological, hepatic, renal, hematological, pulmonary, cardiovascular, gastrointestinal, neurological, respiratory, endocrine, or psychiatric disorder, as determined by the investigator (or designee).
3. History of significant hypersensitivity, intolerance, or allergy to any drug compound, food, or other substance, unless approved by the investigator (or designee).
4. Active or recent (within 30 days of screening) infection or history of recurrent chronic infections with underlying condition that may predispose one to infections. Viral infections with symptoms resolved will be allowed up to 14 days prior to check-in.
5. History of malignancy of any type, other than surgically excised non-melanomatous skin cancers or in situ cervical cancer within 5 years before check-in.
6. Female subjects (surgically sterile females only) with a positive pregnancy test at screening or check in or who are lactating.
7. History of alcoholism or drug/chemical abuse within 2 years prior to check in.
8. Positive urine drug or alcohol results at screening or check in.
9. Participation in a clinical study involving administration of an investigational drug (new chemical entity) in the past 30 days or 5 half-lives (whichever is longer) prior to dosing.
10. Consumption of alcohol from 48 hours prior to check-in.
11. Administration of any vaccine, including a Coronavirus Disease 2019 vaccine, within the past 30 days prior to dosing.
12. Subjects who, in the opinion of the investigator (or designee), should not participate in this study.