Immunotherapy may change how your body processes other drugs

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * ≥ 18 years old at the time of informed consent * Diagnosed with cancer AND initiating therapy with single agent or combination therapy that includes an immune checkpoint inhibitor (e.g., atezolizumab, cemiplimab, durvalumab, ipilimumab, nivolumab, pembrolizumab, relatlimab, tremelimumab) * Ability to provide written informed consent and HIPAA authorization Exclusion Criteria: * Actively pregnant or breastfeeding * Body weight less than 50 kg or a BMI \>35 * Low baseline hemoglobin, defined as \<10 g/dL * Note: if a prospective patient's hemoglobin returns to the normal range, they can be re-screened for trial inclusion) * Past medical history of chronic liver disease, signs and symptom of liver disease (e.g., jaundice, ascites), or aspartate aminotransferase \>96 U/L, alanine aminotransferase \> 80 IU/L, alkaline phosphatase \>260 U/L, or total bilirubin \> 2.6 mg/dL * Note: if a prospective patient's liver function tests return to the normal ranges, they can be re-screened for trial inclusion) * Past medical history of chronic kidney disease, signs and symptom of kidney disease (e.g., decreased urine output, swelling in feet and ankles), or estimated glomerular filtration rate \<45 mL/minute/1.73 m2 BSA * Note: if a prospective patient's kidney function returns to the normal range, they can be re-screened for trial inclusion) * Poor performance status that makes it unlikely the patient will complete 3 cycles of immune checkpoint inhibitor (at the treating oncologist's discretion) * Diagnosis or past medical history of autoimmune disorder, including systemic lupus erythematosus, Crohn's disease, Sjogren's syndrome, multiple sclerosis, type 1 diabetes mellitus, Behcet's disease, and ankylosing spondylitis * History of intolerance, allergic reaction, or hypersensitivity to any of the study drugs (tizanidine, bupropion, flurbiprofen, omeprazole, dextromethorphan, midazolam, rosuvastatin) * Current infection requiring medical treatment (note: if a prospective patient's infection resolves, they can be re-screened for trial inclusion) * Concomitant treatment with systemic immunosuppressant drugs (see Appendix 3 for list) * Note: patients may be re-screened for trial eligibility if they discontinue any exclusionary drugs for ≥7 days prior to Study Visit 1 * Concomitant treatment with a CYP/transporter probe cocktail drug or strong inhibitors, inducers, or agents that affect the pharmacokinetics of the relevant CYP enzymes or drug transporters (see Appendix 4 for list) * Note: patients may be re-screened for trial eligibility if they discontinue any exclusionary drugs for ≥7 days prior to Study Visit 1 * Are unwilling/unable to avoid drugs of abuse, tobacco products or marijuana, or consuming more than 2 alcoholic drinks per day during the study * Inability to take oral medication