This is a Phase 1, single-center, open-label, randomized, 3-period, 2-sequence crossover study of cobimetinib in healthy participants to evaluate the effect of the proton-pump inhibitor (PPI) rabeprazole on the relative bioavailability of cobimetinib in healthy participants when administered in the fed or fasted states.

Inclusion Criteria

• With a body mass index range of 18.5 to 29.9 kilograms per meter square (kg/m^2)
• In good health, determined by no clinically significant findings from medical history, 12-lead electrocardiogram (ECG), and vital signs
• Clinical laboratory evaluations within the reference range for the test laboratory
• Negative test for selected drugs of abuse at Screening (does not include alcohol) and at each Check-in
• Negative hepatitis panel (including hepatitis B virus surface antigen [HBsAg] and hepatitis C virus antibody [anti-HCV]) and negative human immunodeficiency virus (HIV) antibody screens
• Healthy males and females of nonchildbearing potential who agree to use effective contraception

Exclusion Criteria

• Significant history or clinical manifestation of any significant metabolic, allergic, dermatological, hepatic, renal, hematological, pulmonary, cardiovascular, gastrointestinal, neurological, or psychiatric disorder
• History of significant hypersensitivity, intolerance, or allergy to any drug compound, food, or other substance
• History of stomach or intestinal surgery or resection that would potentially alter absorption and/or excretion of orally administered drugs, except that appendectomy, hernia repair, and/or cholecystectomy will be allowed
• History or presence of an abnormal ECG
• History of alcoholism or drug addiction within 1 year prior to Period 1 Check-in
• Use of any tobacco- or nicotine-containing products within 6 months prior to Period 1 Check-in
• Participation in any other investigational study drug trial in which receipt of an investigational study drug occurred within 30 days or 5 half-lives, whichever is longer, prior to Period 1 Check-in
• Use of any prescription medications/products within 14 days prior to Period 1 Check-in
• Use of any over-the-counter, non-prescription preparations within 7 days prior to Period 1 Check-in
• Use of alcohol-, grapefruit-, or caffeine-containing foods or beverages within 72 hours prior to Period 1 Check-in
• Poor peripheral venous access
• Any acute or chronic condition that would limit the participant's ability to complete and/or participate in this clinical study
• Female participant is pregnant, lactating, or breastfeeding
• Use of PPIs or histamine H2 receptor antagonists within 1 month prior to Period 1 Check-in
• Known hypersensitivity to rabeprazole or any of its components or to derived products of benzimidazoles
• Predisposing factors to retinal vein occlusion (RVO)

All enrolled participants

Adverse events were recorded from start of study treatment in first period to end of last period (up to 36 days)

Three participants discontinued study in second period and did not receive Cobimetinib [Fasted] + Rabeprazole in third period. Therefore, only 17 participants were evaluable for adverse events in the Cobimetinib [Fasted] + Rabeprazole treatment arm.