A Single Heterologous Booster Vaccination Study of TAK-019 in Healthy Japanese Adults (COVID-19)

A Phase 3, Single Arm, Open-Label Trial to Evaluate the Immunogenicity and Safety of a Single Heterologous Booster Vaccination of TAK-019 in Healthy Japanese Male and Female Adults Aged 20 Years and Older (COVID-19)

TAK-019 is a vaccine in development to protect people against Covid-19. The main aims of the study are to learn if TAK-019 can protect people from Covid-19 and to check for side effects from TAK-019 for participants who will receive TAK-019 as heterologous booster vaccination. This study consists of two parts, main part and extension part. Firstly, participants who completed 2 doses primary vaccinations 6 to 12 months prior to the trial vaccination can take part in main study. At the first visit of main part of this study, the study doctor will check if each person can take part. Participants who can take part will receive an injection of TAK-019 as booster vaccination. Participants will be asked to record their temperature and any medical problems in an electronic diary for up to 7 days after the injection. During the main part, participants will visit the clinic for regular check-ups, blood tests, and sometimes for nose swab samples. When all participants have attended a clinic visit 28 days after the injection, the study sponsor (Takeda) will check how many participants have made enough antibodies to protect them against Covid-19. Participants who received the first single booster vaccination of TAK-019 in the main part and remained in study follow-up at least 5 months will be able to decide to take part in the extension part of this study. At the first visit of extension part of this study, the study doctor will check if each person can take part. Participants who can take part will receive an injection of TAK-019 as a second booster vaccination at the first visit of extension part. The participants will stay in the main part of this study for up to 12 months after they have had their injection or up to the start of extension part. For participants who will take part in the extension part, they will stay in the extension part for up to 12 months from the start of extension part. During this time, the doctors will continue to collect blood samples to check immune response. Also, they will check if participants have any more side effects from TAK-019.

TAK-019 0 .5 mL, intramuscular injection in the mid deltoid, preferable in the non-dominant upper arm. The participants who received the first single booster vaccination of TAK-019 in the main part and remained in study follow-up at least 5 months will receive a second single booster vaccination of TAK-019 by intramuscular injection.

Main Part: Geometric Mean Titers (GMT) Ratio of Neutralizing Antibody Titers to the Ancestral Strain (Wild-type Virus) on Day 15 Compared With That Observed on Day 36 in Participants From the TAK-019-1501 Study

GMT was the immunogenicity outcome expressed as reciprocal antibody titer with average for each group. Titer values was measured as below lower limit of quantification (LLOQ) were imputed to a value that was half of the LLOQ. LLOQ was equal to 20. GMT for each group and GMT ratio of neutralizing antibody titers to the ancestral strain (wild-type virus) on Day15 after a single booster vaccination (14 days after the booster vaccination) compared with that observed on Day 36 (14 days after the second vaccination) in participants from the TAK-019-1501 study (NCT04712110) were reported. GMT ratio was calculated with GMT of TAK-019-3001 on Day 15 divided by GMT of TAK-019-1501 study on Day 36. Here, ELISA is Enzyme-linked immunosorbent assay.

Day 15 for this study (14 days after the vaccination); Day 36 for TAK-019-1501 study (14 days after the second vaccination)

Main Part: Percentage of Participants With Reported Solicited Local Adverse Events (AEs) for 7 Days Following the First Single Booster Vaccination

AE was defined as any untoward medical occurrence in a clinical investigation participant administered an investigational medicinal product (IMP); it did not necessarily have to have a causal relationship with IMP administration. Reported solicited local AEs were defined as injection site pain, tenderness, erythema/redness, induration, and swelling.

Main Part: Percentage of Participants With Solicited Systemic AEs for 7 Days Following the First Single Booster Vaccination

Solicited systemic AEs were defined as fever, fatigue, malaise, myalgia, arthralgia, nausea/vomiting, and headache.

Main Part: Percentage of Participants With Unsolicited AEs for 28 Days Following the First Single Booster Vaccination

An SAE was defined as any untoward medical occurrence that: Results in death, Is life-threatening, Requires inpatient hospitalization or prolongation of existing hospitalization, Results in persistent or significant disability/incapacity, Leads to a congenital anomaly/birth defect in the offspring of a participant, or Is an important medical event. Solicited SAEs and Unsolicited SAEs were reported,

An AESI was defined as AEs that will be specifically highlighted to the Investigator. AESIs for the study included the Potential Immune Mediated Medical Conditions (PIMMC) and AEs specific to COVID-19. PIMMC is categorized as following; Neuroinflammatory Disorders, Musculoskeletal and Connective Tissue Disorders, Vasculitides, Gastrointestinal Disorders, Hepatic Disorders, Renal Disorders, Cardiac Disorders, Skin Disorder, Hematologic Disorders, Metabolic Disorders, and Other Disorders.

Main Part: Percentage of Participants With Any AE Leading to Participant's Withdrawal From the Trial Until Day 29

Main Part: GMT of Serum IgG Antibody Levels to SARS-CoV-2 rS Protein on Day 8, 15, 29, 91, 181, and 366

Main Part: Geometric Mean Fold Rise (GMFR) of Serum IgG Antibody Levels to SARS-CoV-2 rS Protein on Day 8, 15, 29, 91, 181, and 366

Main Part: Seroconversion Rate (SCR) of Serum IgG Antibody Levels to SARS-CoV-2 rS Protein on Day 8, 15, 29, 91, 181, and 366

Main Part: GMT of Serum Neutralizing Antibody Titters to the Ancestral Strain (Wild-type Virus) on Day 8, 15, 29, 91, 181, and 366

Main Part: GMFR of Serum Neutralizing Antibody Titters to the Ancestral Strain (Wild-type Virus) on Day 8, 15, 29, 91, 181, and 366

Main Part: SCR of Serum Neutralizing Antibody Titters to the Ancestral Strain (Wild-type Virus) on Day 8, 15, 29, 91, 181, and 366

Main Part: Percentage of Participants With Any AE Leading to Participant's Withdrawal From the Trial From the Day of the First Single Booster Vaccination Throughout the Trial

Extension Part: GMT of Serum IgG Antibody Levels to SARS-CoV-2 rS Protein on Extension Part Day 15, Day 29, Day 91, Day 181, and Day 366

Extension Part: GMFR of Serum IgG Antibody Levels to SARS-CoV-2 rS Protein on Extension Part Day 15, Day 29, Day 91, Day 181, and Day 366

Extension Part: SCR of Serum IgG Antibody Levels to SARS-CoV-2 rS Protein on Extension Part Day 15, Day 29, Day 91, Day 181, and Day 366

SCR is defined at percentage of participants with >= 4-fold rises from baseline (Extension Part Day 1).

Extension Part: GMT of Serum Neutralizing Antibody Titers to the Ancestral Strain (Wild-type Virus) on Extension Part Day 15, Day 29, Day 91, Day 181, and Day 366

Extension Part: GMFR of Serum Neutralizing Antibody Titers to the Ancestral Strain (Wild-type Virus) on Extension Part Day 15, Day 29, Day 91, Day 181, and Day 366

Extension Part: SCR of Serum Neutralizing Antibody Titers to the Ancestral Strain (Wild-type Virus) on Extension Part Day 15, Day 29, Day 91, Day 181, and Day 366

SCR is defined at percentage of participants with >= 4-fold rises from baseline (Extension Part Day 1).

Extension Part: Percentage of Participants With Reported Solicited Local AEs for 7 Days Following the Second Single Booster Vaccination

Extension Part: Percentage of Participants With Solicited Systemic AEs for 7 Days Following the Second Single Booster Vaccination

Extension Part: Percentage of Participants With Unsolicited AEs for 28 Days Following the Second Single Booster Vaccination

Extension Part: Percentage of Participants With Any AEs Leading to Participant's Withdrawal From the Trial Until Extension Part Day 29

Extension Part: Percentage of Participants With Any AEs Leading to Participant's Withdrawal From the Trial From the Day of the Second Single Booster Vaccination Throughout the Extension Part

Inclusion Criteria: MAIN PART: Healthy Japanese male and female adult participants aged >= 20 years of age at the time of signing of informed consent. Participant who completed 2 doses primary vaccinations with another specified mRNA vaccine which is available in Japan 6 to 12 months prior to the trial vaccination. EXTENSION PART: Participants who received the first trial vaccination at least 5 months earlier and are currently enrolled in the Main Part (ie, not have withdrawn or discontinued early). Exclusion Criteria: MAIN PART: Participants who received any other SARS-CoV-2 vaccine (except for the specified mRNA vaccine) or other experimental novel coronavirus vaccine prior to the trial. Participant who received a booster vaccination (i.e. 3rd dose) Participants who have close contact of anyone known to have COVID-19 within 14 days prior to the trial vaccination. Participants who were tested positive for SARS-CoV-2 prior to the trial. Participants who have traveled outside of Japan in the 30 days prior to the trial participation. Participants with a clinically significant active infection or oral temperature >= 38 degree Celsius within 3 days of the intended date of the first single booster vaccination. Participants with body mass index (BMI) greater than or equal to 30 kg/m^2 (BMI= weight in kg/ height in meters^2) EXTENSION PART: Participants with a clinically significant active infection or oral temperature >=38 degree Celsius within 3 days of the intended date of the second single booster vaccination.

Takeda provides access to the de-identified individual participant data (IPD) for eligible studies to aid qualified researchers in addressing legitimate scientific objectives (Takeda's data sharing commitment is available on https://clinicaltrials.takeda.com/takedas-commitment?commitment=5). These IPDs will be provided in a secure research environment following approval of a data sharing request, and under the terms of a data sharing agreement.

IPD from eligible studies will be shared with qualified researchers according to the criteria and process described on https://vivli.org/ourmember/takeda/ For approved requests, the researchers will be provided access to anonymized data (to respect patient privacy in line with applicable laws and regulations) and with information necessary to address the research objectives under the terms of a data sharing agreement.