A Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of DNL593 in Healthy Participants and Participants With Frontotemporal Dementia (FTD-GRN)

Key Inclusion Criteria:

Part A:

• Women of non-childbearing potential (surgically sterilized or post menopausal) ormen, aged ≥18 to ≤ 55 years

• BMI of ≥ 18 to ≤ 32 kg/m²

• When engaging in sex with a woman of child bearing potential, two forms of birthcontrol are required

Part B:

• Women of non-childbearing potential (surgically sterilized or post menopausal) ormen, aged ≥18 to ≤ 80 years. Women who are of childbearing potential but on highlyeffective, low user dependent contraceptive methods will be allowed.

• BMI of ≥ 18 to ≤ 32 kg/m²

• Have a Clinical Dementia Rating® plus National Alzheimer's Coordinating Centerfrontotemporal lobar degeneration global score ≥ 0.5

• Have confirmed granulin (GRN) mutation via genetic testing or historical recordsavailable for review by investigator

• When engaging in sex with a woman of child bearing potential, both the maleparticipant and his female partner must use highly effective contraception

Part C:

• All participants who completed Part B of this trial are eligible for an 18-month OLEif the participant has no unresolved clinically significant TEAEs, where continueddosing may represent a risk to participant safety.

Key Exclusion Criteria:

• Have any history of clinically significant neurologic, psychiatric, endocrine,pulmonary, cardiovascular, gastrointestinal, hepatic, pancreatic, renal, metabolic,hematologic, immunologic, or allergic disease, or other major disorders

• Have a history of malignancy, except fully resected basal cell carcinoma or othermalignancies at low risk of recurrence

• Have a clinically significant history of stroke, cognitive impairment due to causesother than FTD, seizure within 5 years of screening, or head trauma with loss ofconsciousness within 2 years of screening

• Have a positive serum pregnancy test or are currently lactating or breastfeeding