Immunogenicity and lot-to-lot consistency of a ready to use liquid bovine-human reassortant pentavalent rotavirus vaccine (ROTASIIL - Liquid) in Indian infants.

BACKGROUND: A lyophilized bovine-human rotavirus reassortant pentavalent vaccine (BRV-PV, Rotasiil®) was licensed in 2016. A liquid formulation of this vaccine (LBRV-PV, Rotasiil - Liquid) was subsequently developed and was tested for non-inferiority to Rotasiil® and for lot-to-lot consistency. METHODS: This Phase II/III, open label, randomized study was conducted at seven sites across India from November 2017 to June 2018. Participants were randomized into four arms; Lots A, B, and C of LBRV-PV and Rotasiil® in 1:1:1:1 ratio. Three doses of study vaccines were given at 6, 10, and 14 weeks of age. Blood samples were collected four weeks after the third dose to assess rotavirus IgA antibody levels. Non-inferiority of LBRV-PV to Rotasiil was proven if the lower limit two-sided 95% confidence interval (CI) of geometric mean concentration (GMC) ratio was at least 0.5. Lot-to-lot consistency was proven if 95% CI of the GMC ratios of three lots were between 0.5 and 2. Solicited reactions were collected by using diary cards. RESULTS: Of the 1500 randomized infants, 1436 infants completed the study. The IgA GMC ratio of LBRV-PV to Rotasiil® was 1.19 (95% CI 0.96, 1.48). The corresponding IgA seropositivity rates were 60.41% (57.41, 63.35) and 52.75% (47.48, 57.97). The IgA GMC ratios among the three LBRV-PV lots were: Lot A versus Lot B: 1.34 (1.03, 1.75); Lot A versus Lot C: 1.22 (0.93, 1.60); and Lot B versus Lot C: 0.91 (0.69, 1.19). The 95% CIs for the GMC ratios were between 0.69 and 1.75. The incidence of solicited reactions was comparable across the four arms. Only one serious adverse event of gastroenteritis event in the Rotasiil® group was causally related. CONCLUSION: The immunological non-inferiority of LBRV-PV against Rotasiil® as well as lot-to-lot consistency of LBRV-PV was demonstrated. LBRV-PV had safety profile similar to Rotasiil®. TRIAL REGISTRATION NUMBER: Clinical Trials.Gov [NCT03474055] and Clinical Trial Registry of India [CTRI/2017/10/010104].

Lack of immune interference between inactivated polio vaccine and inactivated rotavirus vaccine co-administered by intramuscular injection in two animal species.

A parenteral inactivated rotavirus vaccine (IRV) in development could address three problems with current live oral rotavirus vaccines (ORV): their lower efficacy in low and middle-income countries (LMICs), lingering concerns about their association with intussusception, and their requirement for a separate supply chain with large volume cold storage. Adding a new parenteral IRV to the current schedule of childhood immunizations would be more acceptable if it could be combined with another injectable vaccine such as inactivated polio vaccine (IPV). Current plans for polio eradication call for phasing out oral polio vaccine (OPV) and transitioning to IPV, initially in LMICs as a single dose booster after two doses of OPV and ultimately as a two dose schedule. Today in many LMICs, IPV is administered as a standalone vaccine, which involves a separate cold chain and is relatively costly. We therefore tested in two animal models formulations of IPV with IRV to determine whether co-administration might interfere with the immune response to each product and spare antigen dose for both vaccines. Our results demonstrate that IRV when adjuvanted with alum and administered alone or in combination with IPV did not impair the immune responses to either rotavirus or poliovirus serotypes 1, 2 and 3. Similarly, IPV when formulated and administered alone or together with IRV induced comparable levels of neutralizing antibody to poliovirus type 1, 2 and 3. Furthermore, comparable antibody titers were observed in animals vaccinated with low, middle or high dose of IPV or IRV in combination. This dose sparing and the lack of interference between IPV and IRV administered together represent another step to support the further development of this novel combination vaccine for children.

A randomized Phase III clinical trial to assess the efficacy of a bovine-human reassortant pentavalent rotavirus vaccine in Indian infants.

Rotavirus is the most common cause of moderate-to-severe infant diarrhoea in developing countries, resulting in enormous morbidity, mortality, and economic burden. A bovine-human reassortant pentavalent rotavirus vaccine (BRV-PV) targeting the globally most common strains was developed in India and tested in a randomized, double-blind, placebo-controlled end-point driven Phase III efficacy clinical trial implemented at six sites across India. Infants 6 to 8weeks of age were randomized (1:1) to receive three oral doses of BRV-PV or placebo at 6, 10, and 14weeks of age along with routine vaccines. Home visit surveillance was conducted to detect severe rotavirus gastroenteritis (SRVGE) and safety outcomes until the children reached two years of age. A total of 3749 infants received BRV-PV while 3751 received placebo. At the time of the primary end-point (when the minimum number of cases needed for analysis were accrued) the vaccine efficacy against SRVGE was 36% (95% CI 11.7, 53.6, p=0.0067) in the per protocol (PP) analysis, and 41.9% (95% CI 21.1, 57.3, p=0.0005) in the intent to treat (ITT) analysis. Vaccine efficacy over the entire follow-up period (until children reached two years of age) was 39.5% (95% CI 26.7, 50, p<0.0001) in the PP analysis and 38.8% (95% CI, 26.4, 49, p<0.0001) in the ITT analysis. Vaccine efficacy against the very severe rotavirus cases (VSRVGE, Vesikari score≥16) was 60.5% (95% CI 17.7, 81, p=0.0131) at the time of the primary analysis and 54.7% (95% CI 29.7, 70.8, p=0.0004) for the complete follow-period in the PP population. The incidence of solicited, unsolicited, and serious adverse events were similar in both the vaccine and placebo groups. Likewise, the number of intussusceptions and deaths were similar between both groups. Thus, BRV-PV is an effective, well tolerated and safe vaccine in Indian infants. (Trial registration: Clinical Trials.Gov [NCT 02133690] and Clinical Trial Registry of India [CTRI/2013/05/003667]).

Stability of heat stable, live attenuated Rotavirus vaccine (ROTASIIL®).

Vaccines currently available across the globe are stored and transported in a continuous cold-chain at 2-8°C or below -20°C. A temperature excursion outside this range affects the potency of the vaccines. Such vaccines need to be discarded leading wastage. The Rotavirus disease burden is predominantly reported in developing and low-income countries and therefore, has entered or poised to enter their national immunization programs. These countries already have several limitations for effective storage, maintenance and distribution of vaccines in a cold-chain and this introduction is expected to further stress this fragile ecosystem. To help mitigate the cold chain related issues, SIIPL has developed a thermostable rotavirus vaccine ROTASIIL® which can be stored at a temperature below 25°C for 36months, completely by-passing the standard 2-8°C cold storages. In addition it has the capability to withstand temperatures of 37°C and 40°C for 18months and short term exposure to 55°C. It can also tolerate a temperature shock of being thawed from an extreme cold temperature of -20°C to a high temperature of 42°C. The vaccine contains serotypes G1, G2, G3, G4 and G9 (UK-Bovine reassortant strains procured from National Institute of Health-USA). The vaccine is recently licensed in India.

Bovine rotavirus pentavalent vaccine development in India.

A bovine rotavirus pentavalent vaccine (BRV-PV) containing rotavirus human-bovine (UK) reassortant strains of serotype G1, G2, G3, G4 and G9 has been developed by the Serum Institute of India Ltd, in collaboration with the National Institute of Allergy and Infectious Diseases (NIAID), USA. The vaccine underwent animal toxicity studies and Phase I and II studies in adults, toddlers and infants. It has been found safe and immunogenic and will undergo a large Phase III study to assess efficacy against severe rotavirus gastroenteritis.