Rademikibart IV for Acute Asthma and COPD Exacerbation

Inclusion Criteria - Asthma cohort * Body weight of ≥40 kg and BMI ≤45 kg/m2 at SV1a. * Physician-diagnosed asthma * Currently receiving treatment with low, medium, to high dose ICS in combination with at least 1 additional asthma controller medication. * Must have experienced at least 1 asthma exacerbation requiring the use of systemic corticosteroids. * Participants in a stable condition, must have a historical peripheral blood eosinophil count of ≥250 cells/μL and/or FeNO ≥ 25 ppb. * Current acute asthma exacerbation requiring an urgent healthcare visit for treatment. * Peripheral blood eosinophil count of ≥300 cells/µL as part of the assessment of an index acute asthma exacerbation. * Requires systemic corticosteroid as SoC in the urgent healthcare setting to treat the current acute asthma exacerbation. * FEV1 ≥30% predicted. Exclusion Criteria - Asthma cohort * Regular use of immunosuppressive medication. * Unstable ischemic heart disease, cardiomyopathy, heart failure, uncontrolled hypertension. * Current or former smoker, with a smoking history of ≥5 pack-years if \<30 years old or ≥10 pack-years if ≥30 years old * COPD and other clinically significant pulmonary disease other than asthma. * Known or suspected history of immunosuppression. * History of known immunodeficiency disorder or hepatitis B or C. * History of alcohol abuse and/or drug abuse. * Recent history of cancer except basal cell carcinoma or in situ carcinoma of the cervix or other malignancies treated with apparent success with curative therapy. * Female participant who is pregnant, lactating or breast-feeding. * Recent receipt of any marketed nonbiologic drug that modulates type 2 cytokines. * Recent receipt of any marketed biologic drug or any investigational biologic for asthma or other diseases. * Recent live, attenuated vaccinations or planned live, attenuated vaccinations during the trial. * Participants that have been recently treated with bronchial thermoplasty. * Recent receipt of any investigational nonbiologic drug. * A recent chest X-ray or computed tomography with findings that are inconsistent for an asthmatic population. Inclusion Criteria - COPD cohort * Body weight of ≥45 kg and BMI ≤45 kg/m2 * Physician-diagnosed COPD * Must have experienced at least 1 COPD exacerbation requiring the use of systemic corticosteroids. * Participants in a stable condition must have a historical peripheral blood eosinophil count of ≥250 cells/μL and/or FeNO ≥ 25 ppb. * Current or former smoker with a history of smoking of ≥10 pack-years. * Current acute COPD exacerbation requiring an urgent healthcare visit for treatment. * Peripheral blood eosinophil count of ≥300 cells/μL as part of the assessment of the index acute COPD exacerbation. * Requires systemic corticosteroids as standard of care treatment in the urgent healthcare setting for the current acute COPD exacerbation. Exclusion Criteria - COPD cohort * Regular use of immunosuppressive medication 12 weeks or 5 half-lives prior to approximately 12 weeks or 5 half-lives, whichever is longer. * Current diagnosis or a history of asthma, according to the Global Initiative for Asthma; or participants with a current diagnosis or history of Asthma COPD Overlap Syndrome. * Other respiratory disorders that might compromise the safety of the participant or affect the interpretation of the results. * Unstable ischemic heart disease, cardiomyopathy, heart failure, uncontrolled hypertension. Cardiac arrhythmias including paroxysmal atrial fibrillation. * Transient ischemic attack or stroke \<6 months from Screening Visit; hospitalization for any cardiovascular or cerebrovascular event \<6 months from Screening Visit. * Known or suspected history of immunosuppression. * History of known immunodeficiency disorder or hepatitis B or C. * History of alcohol abuse and/or drug abuse. * Recent history of cancer except basal cell carcinoma or in situ carcinoma of the cervix treated with apparent success. * Chronic treatment with long-term oxygen therapy or nocturnal oxygen therapy required for \>15 hours a day. * Participants on long-term macrolide. * Current acute COPD exacerbation for which SoC was started \>48 hours prior to Screening. * A recent chest X-ray or computed tomography scan reveals evidence of clinically significant abnormalities or pulmonary infection. * Female participant who is pregnant, lactating or breast-feeding. * Receipt of any marketed nonbiologic drug that modulates type 2 cytokines 30 days or 5 half-lives prior to SV1b, whichever is longer. * Receipt of any marketed or any investigational biologic for COPD or other diseases within 16 weeks or 5 half-lives, whichever is longer. * Live, attenuated vaccinations within 4 weeks prior to screening or planned live, attenuated vaccinations during the trial. The above inclusion and exclusion criteria are not intended to contain all considerations relevant to a patient's potential participation in a clinical trial.