A phase 2 study of a combined diphtheria-tetanus-acellular pertussis vaccine with a Sabin-derived inactivated poliovirus vaccine in children

Safety and immunogenicity of 3 formulations of a Sabin inactivated poliovirus vaccine produced on the PER.C6® cell line: A phase 2, double-blind, randomized, controlled study in infants vaccinated at 6, 10 and 14 weeks of age

An inactivated poliovirus vaccine candidate using Sabin strains (sIPV) grown on the PER.C6® cell line was assessed in infants after demonstrated immunogenicity and safety in adults. The study recruited 300 infants who were randomized (1:1:1:1) to receive one of 3 dose levels of sIPV or a conventional IPV based on Salk strains (cIPV). Poliovirus-neutralizing antibodies were measured before the first dose and 28 days after the third dose. Reactogenicity was assessed for 7 days and unsolicited adverse events (AEs) for 28 days after each vaccination. Serious AEs (SAEs) were recorded throughout the study. Solicited AEs were mostly mild to moderate. None of the SAEs reported in the study were judged vaccine related, including one fatal SAE due to aspiration of vomitus that occurred 26 days after the third dose of low-dose sIPV. After 3 sIPV vaccinations and across all dose levels, seroconversion (SC) rates were at least 92% against Sabin poliovirus types and at least 80% against Salk types, with a dose-response in neutralizing antibody geometric mean titers (GMTs) observed across the 3 sIPV groups. Compared to cIPV, the 3 sIPV groups displayed similar or higher SC rates and GMTs against the 3 Sabin types but showed a lower response against Salk types 1 and 2; this was most visible for Salk type 1. While the PER.C6® cell line-based sIPV showed an acceptable safety profile and immunogenicity in infants, lower seroprotection against type 1 warrants optimization of dose level and additional clinical evaluation.

Immunochemical and Biophysical Characterization of Inactivated Sabin Poliovirus Products: Insights into Rapid Quality Assessment Tools

The aim of this study was to demonstrate the strength of combining immunochemical and biophysical analysis tools for assessing the quality of Sabin inactivated poliovirus vaccine (Sabin-IPV) bulk products. We assessed Sabin-IPV serotypes 1, 2 and 3 from six different manufacturers and evaluated their comparability through biosensor analysis and biophysical characterization methods, including tryptophan fluorescence and asymmetrical flow field-flow fractionation - multi-angle light scattering analysis. These methods enabled us to assess antigenic as well as conformational and structural integrity profiles, respectively. Based on Sabin-IPV samples that were subjected to accelerated storage conditions, we revealed that existing immunochemical methods exhibit remarkably similar trends to the results obtained by the biophysical characterization methods. While the results underpin that the comparability of Sabin-IPV bulk products of different manufacturers is poor, information about their quality can rapidly be obtained by using both immunochemical and biophysical methods. Furthermore, the study highlights that quality assessment of Sabin-IPV can be obtained through biophysical techniques can complement the assessments performed with monoclonal antibodies and suggests that similar techniques could be employed to characterize other enteroviruses.

Safety and immunogenicity of a new Sabin inactivated poliovirus vaccine candidate produced on the PER.C6® cell-line: a phase 1 randomized controlled trial in adults

This first-in-human study (NCT03032588), conducted in Belgium, evaluated a new inactivated poliovirus vaccines (IPV) candidate based on Sabin poliovirus strains grown on the high-yield PER.C6® cell line. Healthy adults (N = 32) were randomized (1:1) to receive a single dose of PER.C6-based Sabin-IPV (sIPV, 15:35:112.5 DU/dose) or conventional Salk-IPV (cIPV, 40:8:32 DU/dose). Reactogenicity was assessed up to 7 days after vaccination, immunogenicity 28 days after vaccination, and safety up to 6 months after vaccination.Solicited adverse events (AEs) were mild to moderate, no changes of concern in vital signs or safety laboratory values were observed, and no severe AEs (SAEs) or vaccine-related unsolicited AEs were reported after vaccination. A trend to more frequent solicited AEs after sIPV than after cIPV administration was observed. Most participants had preexisting neutralizing antibodies against poliovirus types (titer ≥8), which were strongly boosted by sIPV. Post-vaccination geometric mean titers were high (≥12,000) and similar across the two vaccination groups. Only participants with very high preexisting antibody levels did not show a vaccine-induced response, defined in seropositive participants as a 4-fold titer increase. The 10 initially seronegative (titer <8) participants (n = 5 in each study group) seroconverted and all participants had seroprotective antibody levels post-vaccination. The antibodies elicited by sIPV neutralized both Sabin and Salk poliovirus strains.In conclusion, the PER.C6®-based sIPV was well tolerated and highly immunogenic in adults with preexisting antibodies to poliovirus.

2020 White Paper on Recent Issues in Bioanalysis: BAV Guidance, CLSI H62, Biotherapeutics Stability, Parallelism Testing, CyTOF and Regulatory Feedback (Part 2A - Recommendations on Biotherapeutics Stability, PK LBA Regulated Bioanalysis, Biomarkers Assays, Cytometry Validation & Innovation Part 2B - Regulatory Agencies' Inputs on Bioanalysis, Biomarkers, Immunogenicity, Gene & Cell Therapy and Vaccine)

The 14^th edition of the Workshop on Recent Issues in Bioanalysis (14^th WRIB) was held virtually on June 15-29, 2020 with an attendance of over 1000 representatives from pharmaceutical/biopharmaceutical companies, biotechnology companies, contract research organizations, and regulatory agencies worldwide. The 14^th WRIB included three Main Workshops, seven Specialized Workshops that together spanned 11 days in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy and vaccine. Moreover, a comprehensive vaccine assays track; an enhanced cytometry track and updated Industry/Regulators consensus on BMV of biotherapeutics by LCMS were special features in 2020. As in previous years, this year's WRIB continued to gather a wide diversity of international industry opinion leaders and regulatory authority experts working on both small and large molecules to facilitate sharing and discussions focused on improving quality, increasing regulatory compliance and achieving scientific excellence on bioanalytical issues. This 2020 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop, and is aimed to provide the Global Bioanalytical Community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2020 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication covers the recommendations on (Part 2A) BAV, PK LBA, Flow Cytometry Validation and Cytometry Innovation and (Part 2B) Regulatory Input. Part 1 (Innovation in Small Molecules, Hybrid LBA/LCMS & Regulated Bioanalysis), Part 3 (Vaccine, Gene/Cell Therapy, NAb Harmonization and Immunogenicity) are published in volume 13 of Bioanalysis, issues 4, and 6 (2021), respectively.

Safety and immunogenicity of experimental stand-alone trivalent, inactivated Sabin-strain polio vaccine formulations in healthy infants: A randomized, observer-blind, controlled phase 1/2 trial

BACKGROUND

To increase the global supply of affordable IPV vaccine, preferably using Sabin viruses to comply with GAPIII requirements, Takeda has assessed three dosages of a stand-alone sIPV.

METHODS

In this phase I/II study two cohorts of 40 adults and 60 toddlers, respectively, were initially assessed for safety after receiving high-dosage sIPV compared with placebo (adults) or Salk IPV (toddlers). A cohort of 240 infants was then enrolled and randomized (1:1:1:1) to receive low-, medium- or high-dosage sIPV, or a reference Salk IPV in a three-dose primary schedule at 6, 10 and 14 weeks of age. Parents completed safety diaries for 4 weeks after each dose, and immunogenicity was measured as neutralization antibody titers at baseline and four weeks after vaccination.

RESULTS

All vaccinations were generally well-tolerated and sIPV had a comparable safety profile to the control arm in adults or the reference Salk IPV vaccine in toddlers and infants. Infants displayed dosage-dependent immune responses to sIPV when assayed using Sabin strains, which were equivalent to the reference IPV in the high-dosage sIPV group for serotypes 1 and 2, but not for Sabin and Salk serotype 3. Seroconversion rates (SCR) of the low- and medium-dosage groups were significantly lower than the Salk IPV group for both Sabin and Salk serotypes 1 and type 2 (p < 0.05), with no significant differences for Salk or Sabin serotypes 3. Responses to sIPV, particularly to Sabin types 1 and 2, were higher in initially seronegative infants, indicating possible interference by maternally-derived antibodies.

CONCLUSIONS

A novel stand-alone Sabin-based IPV vaccine was well tolerated with an acceptable safety profile, but less immunogenic than reference Salk IPV at 6, 10 and 14 weeks of age for Salk serotypes 1 and 2, with apparent interference by maternal antibodies. Additional preclinical assessments will be made before any further clinical development.

Immunogenicity of three sequential schedules with Sabin inactivated poliovirus vaccine and bivalent oral poliovirus vaccine in Zhejiang, China: an open-label, randomised, controlled trial

BACKGROUND

The globally synchronised introduction of inactivated poliovirus vaccine (IPV) and replacement of trivalent oral poliovirus vaccine (OPV) with bivalent OPV (bOPV) were successfully implemented in China's routine immunisation programme in May, 2016. In response to the global shortage of Salk-strain IPV, Sabin-strain IPV production was encouraged to develop and use in low-income and middle-income countries. We assessed the immunogenicity of the current routine poliovirus vaccination schedule in China and compared it with alternative schedules that use Sabin-strain IPV (sIPV) and bOPV.

METHODS

This open-label, randomised, controlled trial recruited healthy infants aged 60-75 days from two centres in Zhejiang, China. Eligible infants were full-term, due for their first polio vaccination, weighed more than 2·5 kg at birth, were healthy on physical examination with no obvious medical conditions, and had no contraindications to vaccination. Infants were randomly assigned (1:1:1) using permuted block randomisation (block size of 12) to one of three polio vaccination schedules, with the first, second, and third doses given at ages 2 months, 3 months, and 4 months, respectively: sIPV-bOPV-bOPV (1sIPV+2bOPV group; current regimen), sIPV-sIPV-bOPV (2sIPV+1bOPV group), or sIPV-sIPV-sIPV (3sIPV group). The primary endpoint was the proportion of infants with seroconversion to each of the three poliovirus serotypes 1 month after the third dose. Serious and medically important adverse events were monitored for up to 30 days after each vaccination. We assessed immunity in the per-protocol population (all children who completed all three vaccinations and had pre-vaccination and post-vaccination laboratory data) and safety in all children who received at least one dose of study vaccine. This trial is registered with Clinicaltrials.gov, NCT03147560.

RESULTS

Between May 1, 2016, and Dec 1, 2017, we enrolled and randomly assigned 528 eligible infants to one of the three treatment groups (176 in each group); 473 infants (158 in the 1sIPV+2bOPV group, 152 in the 2sIPV+1bOPV group, and 163 in the 3sIPV group) were included in the per-protocol population. 100% seroconversion against poliovirus types 1 and 3 was observed in all three groups. Infants who received an immunisation schedule containing bOPV had significantly higher antibody titres against poliovirus types 1 and 3 than did the sIPV-only group (2048 in all three treatment groups; p<0·0001). Seroconversion against type 2 poliovirus was observed in 98 (62%) infants in the 1sIPV+2bOPV group, 145 (95%) infants in the 2sIPV+1bOPV group, and 161 (99%) infants in the 3sIPV group. No serious adverse events occurred during the study; 14 minor, transient adverse events were observed, with no significant differences across study groups.

INTERPRETATION

All three study schedules were well tolerated and highly immunogenic against poliovirus types 1 and 3. Schedules containing two or three sIPV doses had higher seroconversion rates against poliovirus type 2 than did the schedule with a single dose of sIPV. Our findings support inclusion of two sIPV doses in the routine poliovirus vaccination schedule in China to provide better protection against poliovirus type 2 than provided by the current regimen.

FUNDING

Chinese Center for Disease Control and Prevention and China National Biotec Group Company.