The purpose of this study is to evaluate the drug-drug-interaction (DDI), pharmacokinetics (PK) and tolerability of GLS4/RTV combined with TAF in healthy subjects.

This is a 2-part study with each part is an open-label study in healthy adult subjects.

Total 28 subjects will be enrolled into the study and divided into 2 part (Part A and Part B), 14 subjects in each part. With each part, the subject will be receive study drug per the defined treatment periods.

Inclusion Criteria:

• Males or females, of any race, between 18 and 50 years of age, inclusive, at Screening;
• Body mass index between 18.0 and 28.0 kg/m2, inclusive, at Screening;
• Females of childbearing potential and male subjects will agree to use contraception from screening to the 6 months after the last administration.

Exclusion Criteria:

• In the 12 months prior to screening, observing clinical significance of the following diseases, including but not limited to, gastrointestinal, kidney, liver, nerve, blood, endocrine, tumor, lung, immune, mental, or cardio-cerebrovascular diseases;
• Allergic constitution (multiple drug and food allergies);
• A history of alcoholism;
• Take any prescription drug, over-the-counter drug, vitamin product or herbal medicine within 14 days of screening;
• Any drug that changes the liver enzyme activity, such as barbiturates and Rifampicin, was taken within 30 days before screening;
• P-GP, BCRP, OATP1B1, OATP1B3, OAT1, OAT3 or MRP4 inhibitors or inducers, such as azithromycin, pantoprazole or St. John's herb, etc., was taken within 30 days before screening;
• Female subjects are lactating or have positive blood pregnancy results during the screening period;