The main purpose of this study is to compare two different formulations (mixtures) of pirtobrutinib (LOXO-305) in healthy participants. This study will compare how much of each formulation gets into the blood stream and how long it takes the body to remove it. Information about any side effects that may occur will be collected. The study will last up to 65 days.

Inclusion Criteria:

• Males and females of non-childbearing potential.
• Within body mass index (BMI) range 18.0 to 32.0 kilograms per square meter (kg/m²).
• Participants will be in good general health, based on medical history, physical examination findings, vital signs, 12 lead electrocardiogram (ECG), or clinical laboratory tests, as determined by the Investigator (or designee).

Exclusion Criteria:

• History or presence of any of the following, deemed clinically significant by the Investigator (or designee), and/or Sponsor:

  1. liver disease
  2. pancreatitis
  3. peptic ulcer disease
  4. intestinal malabsorption
  5. cholecystectomy
  6. gastric reduction surgery
  7. history or presence of clinically significant cardiovascular disease.

• Participants with out-of-range, at-rest vital signs.

• Abnormal laboratory values determined to be clinically significant by the Investigator (or designee).

• Clinically significant abnormality, as determined by the Investigator (or designee), from physical examination.

• Participation in any other investigational study drug trial involving administration of any investigational drug in the past 30 days or 5 half-lives, whichever was longer, prior to Day 1.

• Use or intention to use any prescription or over-the-counter medications within 14 days prior to Day 1 and through end of trial.

• History or presence, upon clinical evaluation, of any illness that, in the opinion of the Investigator, would interfere with the ability to provide informed consent or comply with study instructions, or that might confound the interpretation of the study results, or put the participant at undue risk.

• Donation of blood from 56 days prior to Screening, plasma or platelets from 4 weeks prior to Screening.

• Receipt of blood products within 2 months prior to Check-in (Day -1).

• Significant history or clinical manifestation of any metabolic, allergic, dermatological, hepatic, biliary, renal, hematological, pulmonary, cardiovascular (including any prior history of cardiomyopathy or cardiac failure), gastrointestinal (GI), neurological, or psychiatric disorder (as determined by the Investigator), or cancer within the past 5 years (except localized basal cell, squamous, or in situ cancer of the skin).

All randomized participants.

Baseline to Follow-up (Up To Day 24)

All randomized participants who received at least one dose of study drug.