key: cord-0756078-ji5zmmc2 authors: Thuluva, S.; Paradkar, V.; Turaga, K.; Gunneri, S.; Yerroju, V.; Mogulla, R. R.; Pothakamuri, V. S.; Kyasani, M.; Manoharan, S.; Adabala, S.; Javvadi, A. S.; Medigeshi, G. R.; Singh, J.; Shaman, H.; Binayke, A.; Zaheer, A.; Awasrhi, A.; Singh, C.; A, V. R.; Basu, I.; Khobragade, A. A. K.; Pandey, A. K. title: Immunogenic superiority and safety of Biological E CORBEVAX vaccine compared to COVISHIELD (ChAdOx1 nCoV-19) vaccine studied in a phase III, single blind, multicenter, randomized clinical trial date: 2022-03-22 journal: nan DOI: 10.1101/2022.03.20.22271891 sha: ed3870b768a385570c99a05bc3bf27ff1dbbf649 doc_id: 756078 cord_uid: ji5zmmc2 Background: Optimum formulation of Biological Es CORBEVAX vaccine that contains protein sub unit of Receptor Binding Domain (RBD) from the spike protein of SARS-COV-2 formulated with aluminum hydroxide (Al3+) and CpG1018 as adjuvants was selected in phase-1 and 2 studies and proven to be safe, well tolerated and immunogenic in healthy adult population. In the current study, additional data was generated to determine immunogenic superiority of CORBEVAX vaccine over COVISHIELD vaccine and safety in larger and older population. Methods: This is a phase III prospective, single blinded, randomized, active controlled study (CTRI/2021/08/036074) conducted at 18 sites across India in healthy adults aged between 18-80 years. This study has two arms; immunogenicity arm and safety arm. Participants in immunogenicity arm were randomized equally to either CORBEVAX or COVISHIELD vaccination groups to determine the immunogenic superiority. Healthy adults without a history of Covid-19 vaccination or SARS-CoV-2 infection, were enrolled. Findings: The safety profile of CORBEVAX vaccine was comparable to the comparator vaccine COVISHIELD in terms of overall AE rates, related AE rates and medically attended AEs. Majority of reported AEs were mild in nature, and overall CORBEVAX appeared to cause fewer local and systemic adverse reactions/events. Overall, two grade-3 serious AEs (Dengue fever and femur fracture) were reported and they are unrelated to study vaccine. Neutralizing Antibody titers, against both Ancestral and Delta strain, induced post two-dose vaccination regimen were higher in the CORBEVAX arm as compared to COVISHIELD and the analysis of GMT ratios demonstrated immunogenic superiority of CORBEVAX in comparison with COVISHIELD. Both CORBEVAX and COVISHIELD vaccines showed comparable seroconversion post vaccination when assessed against anti-RBD IgG response. The subjects in CORBEVAX cohort also exhibited higher Interferon-gamma secreting PBMCs post stimulation with SARS-COV-2 RBD peptides than the subjects in COVISHIELD cohort. Interpretations: Neutralizing antibody titers induced by CORBEVAX vaccine against Delta and Ancestral strains were protective, indicative of vaccine effectiveness of >90% for prevention of symptomatic infections based on the Correlates of Protection assessment performed during Moderna and Astra-Zeneca vaccine Phase III studies. Safety findings revealed that CORBEVAX vaccine has excellent safety profile when tested in larger and older population. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infections has led to a global COVID-19 pandemic (WHO Covid-19 Situation report -51) and there has been widespread impact on health, including substantial mortality among older people and those with pre-existing health conditions. 1 It also severely affected global economy. Vaccines play an important role in increasing population immunity and preventing severe form of the disease. Global efforts to develop and test vaccines against SARS-CoV2 has resulted in approval of several vaccine candidates with varied efficacy. 2 WHO has so far granted emergency use listing to ten covid-19 vaccines and five others are under assessment. Out of ten WHO recognized vaccines, only Novavax COVID-19 Vaccine (NVX-CoV2373) is a subunit vaccine and all others are either inactivated virus, nucleic acid based or viral vector-based vaccines. NVX-CoV2373 is based on of full-length, prefusion trimers of spike glycoprotein of prototype Wuhan sequence. Biological E developed a protein sub-unit vaccine (known as CORBEVAX™) that consists of Receptor Binding Domain (RBD) from the spike protein of SARS-COV-2 as the antigen that is formulated with aluminum hydroxide (Al3+) and CpG1018 as adjuvants after preclinical evaluation. 3, 4 The recombinant protein is expressed in yeast and uses a technology similar to the one for producing the recombinant hepatitis B vaccine that has been widely accepted for decades by populations in low-and middle-income countries. Therefore, CORBEVAX™ is potentially well suited as a COVID-19 vaccine for global health and to address both vaccine equity and hesitancy. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; https://doi.org/10.1101 https://doi.org/10. /2022 The optimum dose of the candidate vaccine, CORBEVAX™, was determined in Phase I/II studies conducted in adults and consists of 25 mcg of RBD protein, 750 mcg of Al3+ (in Aluminum Hydroxide) and 750 mcg of CpG1018 per 0·5 mL dose. The optimum formulation showed excellent safety profile with minimal reactogenicity and high humoral immune response in terms of anti-RBD IgG titers and neutralizing antibody titers against Ancestral, Beta and Delta strains of SARS-COV-2 as well as desired Th1 skew of the cellular immune response. 5 In the current phase III study using the optimum formulation of CORBEVAX™, we report the safety and immunogenic superiority of CORBEVAX™ vaccine over COVISHIELD™ vaccine. This is an ongoing phase III prospective, single blinded, randomized, active controlled study conducted at 18 sites across India in accordance with the principles defined in the Declaration of Helsinki, International Conference on Harmonization guidelines (Good Clinical Practices), and the local regulatory guidelines. The Investigational Review Board or Ethics Committee at each study site approved the protocol. All participants provided written informed consent before enrollment into the study. Participants were healthy adults, aged between 18 to 80 years. This study has two arms; one is to determine the immunogenic superiority of CORBEVAX™ vaccine over COVISHIELD™ vaccine. Other arm is to determine only safety of CORBEVAX™ vaccine. Subjects enrolled into immunogenicity arm were also assessed for safety. A total of 6485 subjects were screened, of which 2140 subjects randomized and 2139 subjects enrolled (639 subjects in immunogenicity arm & 1500 subjects in safety arm). Safety data until day 56 (safety) and All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; https://doi.org/10.1101 https://doi.org/10. /2022 immunogenicity data at day 42 compared to day 0 (baseline) is presented in this manuscript. Participants were seronegative to anti-SARS-CoV-2 IgG antibody prior to randomization into immunogenicity arm, whereas in safety arm subjects were randomized irrespective of their serostatus for SARS-CoV-2. Other key eligibility criteria applicable to all participants were: virologically negative to SARS-CoV-2 infection confirmed by RT-PCR test, seronegative to HIV 1 & 2, HBV and HCV infection. Health status assessed during the screening period was based on medical history and clinical laboratory findings, vital signs, and physical examination. All those who were with axillary temperature of more than 38·0°C, part of any other clinical trial, with a hhistory of vaccination with any investigational vaccine against Covid-19 disease, known allergy to vaccine components, or were on immunosuppressants, immunodeficient conditions were excluded from the study. Complete list of eligibility criteria provided as supplementary information. During the conduct of this study, there were no major protocol deviations reported at any of the study sites. Few subjects reported for their visits out of window period but these deviations were not found to be significant and all deviations were notified to ethics committees of the respective study sites. Participants enrolled into immunogenicity arm were randomized equally either to receive CORBEVAX™ TM vaccine or COVISHIELD™ vaccine. Randomization occurred after all screening-related activities were completed and prior to the first dose of study vaccine using the interactive web response system (IWRS) platform. A subject was considered All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; https://doi.org/10.1101 https://doi.org/10. /2022 randomized when he/she has met all the eligibility criteria and have received the randomization number from IWRS. A randomization scheme was generated by using a validated system. This is also a single-blind study where study participants randomized into immunogenicity arm are kept blinded of the vaccination group to which they have been assigned, but the investigator and study staff are aware of the assigned group (CORBEVAX™ or COVISHIELD™). Biological E's CORBEVAX™ vaccine is based on recombinant RBD protein, which is produced in Pichia Pastoris culture as secretory protein and purified via multiple chromatography and ultrafiltration/normal-filtration steps. The RBD subunit is coformulated along with aluminum Hydroxide and CpG1018. 5 The active comparator used in immunogenicity arm of the study is COVISHIELD™ A 0·5 mL dose of the candidate COVID-19 vaccine (CORBEVAX™) or COVISHIELD™ vaccine was administered via an intramuscular (IM) injection into the deltoid muscle of the non-dominant arm in a 2-dose schedule with 28 days' interval between doses. No prophylactic medication was prescribed either before or after vaccination. Follow-up were scheduled at day 42, day 56, day 118 (3 months post second All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; https://doi.org/10.1101 https://doi.org/10. /2022 dose) and day 208 (6 months post second dose). Study is ongoing and subjects are under follow-up period. Participants were evaluated with SARS-CoV-2 real-time RT-PCR for absence of infection using Diasorin kit and a serology test for seronegative status (Anti-SARS CoV-2 Human S1/S2 IgG ELISA COVID using Diasorin kit). 6 Participants who were negative for both Anti-SARS CoV-2 human S1/S2 IgG antibodies and SARS CoV-2 infection were enrolled to study immune responses (immunogenicity arm). The primary outcome of the study was demonstration of immunogenic superiority of BE's CORBEVAX™ vaccine against COVISHIELD™ vaccine in terms of GMTs of anti-SARS-CoV-2 virus neutralizing antibodies at day 42 (14 days after 2nd dose). Other secondary outcomes were demonstration of immune response against the Delta variant in terms virus neutralizing antibodies (VNA) at day-42. Anti-RBD antibody concentration in terms of GMC's and to descriptively assess the safety, tolerability and reactogenicity of CORBEVAX™ vaccine during the study period. The exploratory end-point included cellular immune response assessment in a subset of subjects via ELISPOT method. The safety assessments of the study include solicited and unsolicited, non-serious and serious adverse events (AEs) and medically attended AEs (MAAEs) reported in the study from the time of first dose of the vaccine. Participants were observed for 1-hour post vaccination to assess reactogenicity. Solicited local and systemic reactions were recorded for 7 consecutive days (Day 0-6), captured through subject diary after each vaccine dose. Solicited local AEs were pain, redness, swelling, itchy or warmth at injection site. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; Solicited systemic AEs were fever, headache, chills, Myalgia, arthralgia, fatigue, nausea, urticaria, rhinorrhoea, irritability, Hypotonic-hyporesponsive episodes, Somnolence, seizure and acute allergic reaction. Unsolicited local and systemic adverse events (AEs) were recorded during the postvaccination follow up period until 28 days after each dose. Serious adverse events (SAEs), medically attended adverse events (MAAEs) and adverse events of special interest (AESIs) if any, were collected during the entire study duration. Local and systemic reactions were scored by severity (mild, moderate, severe and life threatening) and the erythema and swelling or induration by the maximum diameter per day. Relatedness of study vaccine was also assessed for all reported AEs. Sera samples were collected from all the subjects in the immunogenicity cohort at Day-0 (pre-vaccination) and at Day-42 (14 days after second vaccine dose) time points. Following measurements were conducted to assess humoral immune response 1. Anti-RBD IgG concentration by ELISA, conducted at Dang's Lab, India. The antibody concentrations were reported in ELISA Units/mL for each subject and Geometric Mean Concentrations were calculated for both time-points for both cohorts. % Seroconversion was also calculated at Day-42 timepoint for both cohorts 2. Neutralizing Antibody Titers (nAb titers) conducted at THSTI, India. 7 The testing was conducted against Wild-Type SARS-COV-2 strains using Micro Neutralization Assay (MNA) in a BSL-3 facility at Translational Health Science and Technology Institute (THSTI), India. For prototype Wuhan Strain, the All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; Victoria isolate from Australia was used while the Delta strain used in the assay was isolated in India. 3. Cellular immune response was assessed by ELISPOT method conducted at THSTI, India. Whole blood samples were collected post two-dose vaccination and PBMC's were isolated and stored frozen. The PBMC's were subsequently stimulated with various stimulants; SARS-COV-2 RBD peptides for specific response, DMSO for non-specific response and PHA for assay validity criteria. Post-stimulation, the number of PBMC's that secrete cytokine Interferon-gamma were identified and quantified by ELISPOT technique and the Spot Forming Units (SFU's) per million PBMC's were calculated for each subject sample. For the purposes of analysis, recruited subjects were further identified as total vaccinated cohort (TVC) and the according to protocol (ATP) cohort. All the demographic and primary safety analyses have been based on TVC population, defined as subjects who entered into the study and have received at least one single intramuscular dose of study vaccination. ATP population is defined as population, who have blood samples available for immunogenicity analysis at all protocol specified time points from both CORBEVAX™ and COVISHIELD™ vaccinated cohorts. This has been the primary analysis population for immunogenicity assessment. The Geometric Mean Titers (nAb) were calculated postvaccination against both Wuhan and Delta strains and then the ratio of the GMT's for CORBEVAX™ to COVISHIELD™ cohort. Variances for each cohort were calculated All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; from Log 10 converted nAb titer values for each subject. Then the lower bound (LB) of the 95% confidence interval (CI) for the ratio of GMT's were calculated via standard statistical methods. Superiority was concluded, if the lower limit of the one-sided 95% confidence interval (CI) for the ratio of two GMT's) is >1.0. Non-inferiority to be inferred, if the lower limit of the one-sided 95% confidence interval (CI) for the ratio of two GMT's is ≥ 0·67. All data were summarized descriptively and data listings were based on all subjects enrolled in the study. By default, descriptive statistics for quantitative measurements included the number of subjects (n), mean, standard deviation (SD), minimum, median (IQR) and maximum. Safety data were summarised by System Organ Class and Preferred term. Serious adverse events, related adverse events, adverse events leading to death or withdrawal, solicited adverse events, medically attended adverse events and adverse events of special interest were summarised separately. In addition, adverse events were also summarized by severity. All analyses were conducted using SAS ® Version 9·4 or higher. BIRAC-a division of the Department of Biotechnology, Govt of India provided partial funding for the execution of trials. CEPI provided support for nAb titer testing in terms of reagents. Funding sources were not involved in the study conduct, data analysis/interpretation or writing the manuscript. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; https://doi.org/10.1101 https://doi.org/10. /2022 A total of 6485 subjects were screened and 2140 subjects were randomized in the study. One subject did not received vaccination randomized into immunogenicity arm (subject choice). So, in total 2139 subjects were enrolled into either immunogenicity arm (n=639) or safety arm (n=1500). Immunogenicity arm has two groups, receiving two doses of CORBEVAX™ vaccine (n=319) or COVISHIELD™ vaccine (n=320). Total vaccinated subjects with CORBEVAX™ vaccine including subjects from both immunogenicity and safety arm were n=1819. All subjects in the study were of Indian origin (100%). Demographic characteristics were comparable between subjects vaccinated with CORBEVAX™ or COVISHIELD™. Median age of CORBEVAX™ vaccinated cohort Safety data was presented for subjects enrolled into immunogenicity arm (n=639) including CORBEVAX™ vaccinated cohort (n=319) and COVISHIELD™ vaccinated cohort (n=320) and a safety cohort (n=1500) exclusively enrolled for safety assessment of CORBEVAX™ vaccine. Safety assessment of Immunogenicity group: Out of total 639 enrolled subjects, 68/319 (21·3%) subjects reported 84 events and 136/320 (42·5%) subjects reported 184 events in CORBEVAX™ and COVISHIELD™ arms respectively. CORBEVAX™ appeared to cause fewer local and systemic adverse reactions/events. The safety profile of All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; https://doi.org/10.1101 https://doi.org/10. /2022 CORBEVAX™ was comparable to the comparator vaccine COVISHIELD™ in terms of overall AE rates, related AE rates and medically attended AEs. All the reported adverse events were mild to moderate in their intensity and most of the reported adverse events were related to the study vaccine. Summary of AEs occurred in immunogenicity cohorts by system organ class (SOC) and preferred term (PT), severity grade and causality is listed in Table 2 (Table 3) . Two serious AEs were reported in the safety group, which was of grade-3 severity and were diagnosed to be Dengue fever and Femur fracture. Causality of the events Dengue fever and femur fracture with the study vaccine (CORBEVAX™) is considered as not related by Principal Investigator and sponsor. There were no adverse events reported in the first 60 minutes' post vaccination and no deaths reported in the study. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; https://doi.org/10. 1101 /2022 No marked changes overtime, were noted in the vital signs recorded. The AEs observed and physical examination results did not indicate any safety issues of concern. Majority of adverse events are mild to moderate in intensity and no AESI were reported in the study. Summary of AEs occurred in safety cohort by system organ class (SOC) and preferred term (PT), severity grade and causality is listed in Table 3 . Humoral and cellular immune responses were evaluated from immunogenicity arm (n=639) of the study aimed to test immunogenic superiority of CORBEVAX™ vaccine (n=319) compared to COVISHIELD™ vaccine (n=320). Paired anti-RBD IgG concentration data at day 0 and day 42 were available in 304 subjects of CORBEVAX™ cohort and in 307 subjects of COVISHIELD™ cohort. Anti-RBD IgG concentrations (GMCs) increased significantly in both CORBEVAX™ and COVISHIELD™ vaccinated groups after the administration of two doses of vaccine compared to baseline (CORBEVAX™: 1439 EU/ml at day 0 Vs 24478 EU/ml at day 42; COVISHIELD™ : 1503 EU/ml at day 0 Vs 16203 EU/ml at day 42). However, the total antibody response against the RBD antigen is significantly higher in CORBEVAX™ cohort as compared to COVISHIELD™ cohort (24478 EU/ml Vs 16203 EU/ml at day 42) (Figure 2 ). Percent All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. Table 4 . In this trial, immunogenicity of a novel sub-unit vaccine for Covid-19 vaccine CORBEVAX™ was studied for safety and immunogenicity against RBD domain of SARS-CoV-2. Results indicated that CORBEVAX™ is a safe and well tolerated with no vaccine related serious adverse events, MAAEs or AESI when administered to adult individuals of Indian origin. This safety profile of CORBEVAX™ is comparable with that of another sub-unit vaccine Covavax. 9 High immune responses in terms of anti-RBD IgG specific binding and protective antibodies were observed after second dose of vaccination. Here we also report, immunogenic superiority of CORBEVAX™ vaccine over COVISHIELD™, an adenoviral vector-based vaccine which is licensed in multiple countries, in terms of higher GMT's of neutralizing antibodies against both the SARS-COV-2 Ancestral strain and the Delta strain. In the present study, there were two SAEs reported which were unrelated to study vaccine: Dengue and a hip injury from a fall. In the immunogenicity arm of the study, All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; only the subjects who were seronegative to SARS-CoV-2 were recruited, while in safety arm, seropositive subjects were also recruited because of rapidly increasing daily cases of COVID-19 in India (second wave), it was difficult to enroll seronegative subjects. Irrespective of the subjects being seronegative or seropositive at baseline, CORBEVAX™ vaccine was well tolerated by both the groups. To establish relative immunogenicity of novel CORBEVAX™, we compared anti-RBD This study has several limitations like efficacy of the vaccine against Covid-19 infection was not studied and long-term safety was not established as interim results are available only until day 56. However, it is worth noting that in a small set of patients (n=360) safety was established until 12 months and significantly higher neutralizing antibody titres (nAbs) persisted at least 6 months after second dose of the vaccination when compared to human convalescent serum (HCS). 5 All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. The copyright holder for this preprint this version posted March 22, 2022. ; Overall, we conclude that CORBEVAX™ is safe, well tolerated and elicited excellent antibody and cellular immune responses that can offer significant protection against symptomatic infection from SARS-CoV-2 virus. All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. (2) Unrelated (2) Back pain 2 (0·13%) 2 Mild (1) Related (1) Moderate (1) Unrelated (1) Myalgia 156 (10·40%) 158 Mild (154) Related (154) Moderate (4) Unrelated ( (1) Unrelated (23) Nasal obstruction 3 (0·20%) 3 Mild Related (1) Unrelated (2) All rights reserved. No reuse allowed without permission. (which was not certified by peer review) is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity. Comorbidity and its Impact on Patients with COVID-19 A vaccine targeting the RBD of the S protein of SARS-CoV-2 induces protective immunity Selection of optimum formulation of RBD-based protein sub-unit covid19 vaccine (CORBEVAX) based on safety and immunogenicity in an open-label, randomized Phase-1 and 2 clinical studies medRxiv The fully automated serology test for the detection of SARS-CoV-2 IgG Antibodies Quantification of SARS-CoV-2 neutralizing antibody by wild-type plaque reduction neutralization, microneutralization and pseudotyped virus neutralization assays Neutralizing antibody levels are highly predictive of immune protection from symptomatic SARS-CoV-2 infection Note: Percentages were calculated using column header count as denominator. 95% CI was calculated by Clopper-Pearson Method. N 1 : Subject Count, N: Sample Size, n:Event Count, NE: Not Estimable. General Note: • All AE's were represented as: Subject count (Percentage of subjects) [95% CI] Event Count. • Solicited Local and Systemic AEs were recored during 7 days Unsolicited adverse event reported at any time, until 28 days after the each dose Systemic AEs by SOC and PT Treatment Group CORBEVAX™ (N=1500) N1 (%) General disorders and administration site conditions 265 (17·67%) Nervous system disorders 120 (8·00%) Note: Percentages were calculated using column header count as denominator. 95% CI was calculated by Clopper-Pearson Method. N 1 : Subject Count, N: Sample Size, n:Event Count, NE: Not Estimable. General Note: • All AE's were represented as: Subject count (Percentage of subjects) [95% CI] Event Count. • Solicited Local and Systemic AEs were recored during 7 days Unsolicited adverse event reported at any time, until 28 days after the each dose We are thankful to all the study participants, the principal