A Single- and Multiple-Ascending Dose Study to Evaluate the Safety, Tolerability, and Pharmacokinetics of LY4066708 in Healthy Participants

Launched by ELI LILLY AND COMPANY · Jun 27, 2025

Keywords

ClinConnect Summary

This clinical trial is testing a new drug called LY4066708 to see if it is safe and well-tolerated in healthy adults. The study will also look at how the drug moves through the body, including how much enters the bloodstream and the brain, and how long it stays in the body. Each person in the study may take part for up to 24 weeks, during which the researchers will carefully monitor their health and any side effects.

To join this study, participants need to be generally healthy adults between about 18 and 74 years old. The study is open to both men and women, but women must not be able to have children, and men need to agree to use birth control during the trial. Participants must be of Japanese or Chinese descent, depending on the group they are in, and have a body weight within a certain healthy range. Some procedures, like spinal fluid collection through lumbar punctures, may be part of the study, so participants should be comfortable with these tests. People with certain heart conditions, infections like hepatitis, allergies to similar drugs, or who have recently been in other drug studies might not be eligible. Overall, the goal is to ensure the drug is safe before it is tested in patients with cancer.

Gender

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Eligibility criteria

• Inclusion Criteria:
• • Are overtly healthy as determined by medical evaluation including medical history, physical examination, laboratory tests, and cardiac monitoring.
• • Japanese Participants Only: To qualify as a participant of first-generation Japanese origin, the participant, the participant's biological parents, and all the participant's biological grandparents must be of exclusive Japanese descent and born in Japan.
• • Chinese Participants Only: To qualify as Chinese for the purpose of this study, all 4 of the participants' biological grandparents must be of exclusive Chinese descent and born in China, Hong Kong, Macau, or Taiwan.
• • Have a body mass index (BMI) at the time of screening within the range 18.5 to 30 kilogram per meter squared (kg/m²) (inclusive).
• • Participants assigned female at birth (AFAB) not of childbearing potential and participants assigned male at birth (AMAB) willing to practice effective contraception throughout the study may participate.
• • Willingness to undergo study procedures which may include repeated lumbar punctures
• Exclusion Criteria:
• • Are individuals of childbearing potential (IOCBP). Notwithstanding their IOCBP status, participants AFAB are excluded if they are breastfeeding.
• • A history of additional risk factors for Torsades de Pointes (for example, heart failure, hypokalemia, family history of Long QT Syndrome).
• • The use of concomitant medications that prolong the QT/QTc interval.
• • Have known allergies to LY4066708 or any components of the formulation, or history of allergic reactions to any transferrin receptor (TfR) antibodies.
• • Have participated, within the 3 months of screening, in a clinical trial involving a study intervention (other than the study intervention used in this study). If the previous investigational product has a long half-life (t½), 3 months or 5 half-lives (whichever is longer) should have passed.
• • Are persons who have previously completed or withdrawn from this study and have previously received the study intervention. This exclusion criterion does not apply to subjects who are allowed to rescreen prior to randomization.
• • Have a 12-lead electrocardiogram (ECG) abnormality at screening that, in the opinion of the investigator, increases the risks associated with participating in the study, or may confound ECG data analysis.
• • Show evidence of hepatitis C and/or positive hepatitis C antibody.
• • Current infection with hepatitis B virus (HBV) or evidence of past infection with HBV, that is, positive for Hepatitis B surface antigen (HBsAg) or Hepatitis B core total antibody (anti-HBc).
• • A marked baseline prolongation of time from the start of the Q wave to the end of the T wave/ corrected QT interval (QT/QTc) interval (for example, repeated demonstration of a corrected time from the start of the Q wave to the end of the T wave interval - Fridericia formula (QTcF) interval greater than 450 ms).