This study is a Phase I, randomized, open-label, cross-over study with three single-dose treatments to compare the bioavailability of an oral tablet relative to an oral capsule of GLPG1690 after single dose intake in healthy male subjects and to evaluate the effect of food on the bioavailability of the oral tablet.

Inclusion Criteria:

1. Male between 18-50 years of age, inclusive
2. Body mass index (BMI) between 18-30 kg/m2, inclusive, with a weight of at least 50 kg.
3. Judged by the investigator to be in good health based upon the results of a medical history, physical examination, vital signs, 12-lead ECG, and laboratory findings.
4. Discontinuation of all medications except occasional paracetamol at least 2 weeks or 5 half-lives prior to the first study drug administration
5. Non-smokers and not using any nicotine-containing products.
6. Negative urine drug screen and alcohol breath test.
7. Current sexually active male agrees to use adequate contraception/preventive exposure measures from the time of first dose of study drug, during the study and until 12 weeks after the last study drug dose.
8. Subjects should be willing to consume the non-vegetarian high-fat and high-calorie breakfast.
9. Able and willing to sign the ICF

Exclusion Criteria:

1. Known hypersensitivity to study drug ingredients or a significant allergic reaction to any drug
2. Positive serology for hepatitis B virus surface antigen (HBsAg) or hepatitis C virus (HCV) or any history of hepatitis from any cause with the exception of hepatitis A.
3. History of or a current immunosuppressive condition.
4. Presence of abnormal liver function. Diagnosis of disease of Gilbert is accepted. Retesting is allowed.
5. Renal function with an estimated creatinine clearance <80 ml/min based on the Cockcroft-Gault formula. Retesting is allowed.
6. Presence of any condition known to interfere with absorption, distribution, metabolism or excretion of drugs.
7. History of malignancy within the past 5 years
8. Clinically relevant abnormalities detected on ECG regarding either rhythm or conduction (e.g., QTcF >450 ms, or a known long QT syndrome).
9. Clinically relevant abnormalities detected on vital signs.
10. Dietary requirements precluding participation in the study
11. Significant blood loss (including blood donation [≥450 mL]), or transfusion of any blood product within 8 weeks prior to the signing of ICF.
12. Active drug or alcohol abuse within 2 years prior to the initial study drug administration.
13. Consumption of large quantities of caffeinated coffee or tea (>6 cups/day), or equivalent.
14. Concurrent participation or participation in a drug or drug/device investigational research study.
15. Subjects who participated in a previous study with the same compound (GLPG1690).
16. Investigator or any sub-investigator, or other staff or relative.
17. Any condition or circumstances that in the opinion of the investigator may make a subject unlikely or unable to complete the study or comply with study procedures and requirements.