Effect of Tigulixostat on the Pharmacokinetics of Theophylline

Inclusion Criteria:

• Male or female, Ages 18 to 55, inclusive.
• BMI 18.0 - 32.0 kg/m2, inclusive, at screening.
• In good general health as determined by medical history, clinical laboratoryassessments, vital sign measurements, 12-lead ECG results, and physical examinationfindings at screening.
• Females of childbearing potential and males who agree to use contraception.Non-pregnant, non-lactating females who must have a negative pregnancy test atscreening and check-in.

Exclusion Criteria:

• Significant history or indications of ill-health, as judged by the investigator.
• Any surgical or medical condition(s) possibly affecting drug absorption, distribution,metabolism, and excretion.
• eGFRcr of <60 (mL/min)/1.73 m2 at screening.
• alanine aminotransferase, aspartate aminotransferase, or total bilirubin ≥2 times theupper limit of normal at screening and check-in.
• Used any prescription or over-the-counter medications (except acetaminophen [Tylenol]up to 2 g per day), including herbal or nutritional supplements, within 14 days beforethe first dose of study drug.
• Consumed grapefruit or grapefruit juice, Seville orange or Seville orange-containingproducts (eg, marmalade), or caffeine- or xanthine-containing products within 48 hoursbefore the first dose of study drug.
• History of hypersensitivity to theophylline or other xanthines and tigulixostat.