A Study of RO7830698 in Healthy Participants and Participants With Chronic Obstructive Pulmonary Disease

• RO7830698 (Drug): Participants will receive RO7830698 as per the schedule described in the protocol.
• Placebo (Drug), also known as RO7275887: Participants will receive placebo as per the schedule described in the protocol.

Primary outcomes

• Part 1: Incidence and Severity of Adverse Events (AEs) [Up to approximately 50 weeks]
• Part 2: Incidence and Severity of AEs [Up to approximately 44 weeks]
• Part 1: Incidence of Dose-limiting Adverse Events (DLAEs) [Up to approximately 50 weeks]
• Part 2: Incidence of DLAEs [Up to approximately 44 weeks]

Secondary outcomes

• Part 1 and Part 2: Plasma Concentration of RO7830698 [Part 1: Up to approximately 50; Part 2: Up to approximately 44 weeks]
• Part 1: Bioavailability (F) of RO7830698 [Up to approximately 50 weeks]
• Part 1: Area Under the Concentration-Time Curve From Time 0 To Infinity (AUC inf) of RO7830698 [Up to approximately 50 weeks]
• Part 1 and Part 2: Incidence of Anti-Drug Antibodies (ADAs) to RO7830698 [Part 1: Up to approximately 50; Part 2: Up to approximately 44 weeks]

Sex: All, ages: 18 Years to 80 Years, accepts healthy volunteers

Inclusion Criteria:

All participants:

* Body mass index (BMI) between 18 and 32 kilograms per meter square (kg/m2)
* Agreement to adhere to the contraception requirements

Part 1:

* Absence of evidence of any active or chronic disease

Part 2:

* Confirmed diagnosis of COPD for > 6 months, as defined by the Global Initiative for Chronic obstructive Lung Disease (GOLD) guidelines
* Using maintenance inhaled therapy that may include inhaled corticosteroids (ICS) and/or long-acting β-agonist (LABA) and/or long-acting muscarinic antagonist (LAMA) as separate inhaler(s) or in combination preparation(s)
* Current smoker or ex-smoker with a tobacco history of >= 10 pack years

Exclusion Criteria:

* Pregnant or breastfeeding, or planning to become pregnant during the study or within the timeframe in which contraception is required
* Current or chronic history of clinically significant liver disease or known hepatic or biliary abnormalities (with the exception of Gilbert syndrome or asymptomatic gallstones) or cirrhosis
* Known history of allergy to drugs or other substances, or clinically significant, acute, and/or uncontrolled allergic disease
* Known or suspected history of immunosuppression
* History of recurrent severe infections and underlying conditions predisposing participant to infections
* History of disseminated herpes simplex infection, or recurrent (> 1 episode) or disseminated herpes zoster
* Autoimmune disease requiring systemic immunosuppressive therapy
* History of or presence of any clinically significant unstable cardiovascular disease
* Treatment with medications targeting the same pathways as RO7830698, immunomodulatory/ immunosuppressive therapy, or licensed biologics for COPD and asthma within protocol-defined periods
* Positive results for hepatitis B infection, human immunodeficiency virus infection, or hepatitis C infection at the Screening visit
* Evidence of tuberculosis infection or disease
* Participation in any clinical study of a drug or medical device within protocol-defined periods
* Any other conditions that may affect providing informed consent or study protocol adherence, or if study participation may affect study results or participant safety

• Clinical Trials, Study director, Hoffmann-La Roche