The study is a randomized , open-label, two-stage crossover food effect study of single doses of DDO-3055 tablets in healthy subjects. 14 healthy subjects were randomly divided into groups A and B, 7 subjects in each group. Two stage washout period is 6 days.

Inclusion Criteria:

• 1. Healthy male volunteers, aged 18~45.
• 2. Body weight ≥ 50 kg, body mass index (BMI) between 18 to 28.
• 3. Hemoglobin is in the normal range.
• 4. Signed informed consent.

Exclusion Criteria:

• 1. Vital signs, physical examination, laboratory results are abnormal and clinically significant.
• 2. Currently suffering from cardiovascular, liver, kidney, digestive, nervous, blood, thyroid or mental diseases.
• 3. Suspected allergy to the active ingredient or excipient of the experimental drug.
• 4. Have used erythropoietin within 1 month prior to screening or are currently using erythropoietin.
• 5. Had donated blood or blood transfusion within 3 months prior to screening.
• 6. Vein blood collection is difficult or physical condition can not afford blood collection.
• 7. Hepatitis b virus surface antigen (HBsAg), hepatitis c virus antibody (HCVAb), Syphilis antibody, human immunodeficiency virus antibody (HIVAb)were positive.
• 8. Average daily smoking ≥5 cigarettes within 3 months before screening; average daily intake of alcohol within one week is more than 15g (15g alcohol is equivalent to 450mL beer or 150mL wine or 50mL low-alcohol liquor);or 2 days before taking the study drug and during the trial take the tobacco and alcohol and caffeinated foods or drinks, and have special dietary requirements and cannot follow a uniform diet.
• 9. 3 months prior to screening involved in any drug or medical device clinical trials, or within 5 half-life of drugs before screening.
• 10. Any health care products, Over-the-counter drugs or prescription drugs that affects the absorption, distribution, metabolism and excretion of the experimental drug was used within 1 month before the administration.
• 11. With a history of drug abuse or screening visit/baseline visit urine drug abuse screening positive.
• 12. Subjects who are unwilling to take contraceptives or who are likely to donate sperm during the trial and within 30 days after administration; or who do not agree to physical contraception during the trial.
• 13. Other conditions in which the study physician considered the subject not suitable for the trial.