This is a sequential, randomized, double-blind, placebo-controlled Phase 1 single (SAD) and multiple (MAD) ascending dose study to evaluate the safety, tolerability, and pharmacokinetics (PK) and Pharmacodynamics of orally administered LTG-305 in healthy male and female participants. The study will also include a randomized, double-blind, placebo-controlled within-participant crossover evaluation of pain tolerance during a cold pressor test in healthy male participants 18-55 years of age.

Inclusion Criteria:

• Male and female participants aged 18 to 55 years, inclusive, at the time of signing the informed consent for SAD and MAD only. For Cold Pressor male participants 18 to 55 years.
• Overtly healthy with no clinically relevant abnormalities based on the medical history, physical examinations, clinical laboratory evaluations, and 12-lead ECG that, in the opinion of the investigator, would affect participant safety.
• Body mass index (BMI) within the range of 18-32 kg/m2 (inclusive).

Exclusion Criteria:

• Clinically significant cardiovascular, hematological, renal, hepatic, pulmonary, endocrine, gastrointestinal, immunological, dermatological, neurological, or psychiatric disease which could interfere with, or the treatment for which might interfere with, the conduct of the study or which would, in the opinion of the investigator, unacceptably increase the participant's risk by participating in the study
• Past or current history or evidence of alcohol abuse and/or dependence on recreational drug use
• Donation of over 500 mL blood ≤ 3 months prior to start of participation
• Participant is under legal custodianship.