HIPRA’s COVID-19 vaccine induces a good neutralising antibody response against the new subvariants of Omicron

Recent studies have shown that the adjuvanted bivalent recombinant protein vaccine against COVID-19 developed by the biotechnology company HIPRA also confers protection against the BA.2, BA.4 and BA.5 Omicron subvariants behind the latest surge in cases.

An increase in neutralising antibodies against BA.2, BA.4 and BA.5 was observed 14 days after administration of the HIPRA vaccine as a booster dose in participants previously vaccinated with two doses of the Pfizer/BioNTech mRNA vaccine. An increase in neutralising antibodies against BA.4/BA5 was also observed 14 days after a booster dose of the HIPRA vaccine in a subgroup of participants previously vaccinated with the Moderna mRNA vaccine.

In addition, the recently published results of the Phase IIb trial show that the HIPRA vaccine as a heterologous booster dose elicits a potent neutralising antibody response (greater than 10-fold increase) against all variants studied (Wuhan, Beta, Delta and Omicron (BA.1) at 14 and 98 days. These increases were statistically significantly higher than those induced by a booster dose of the Pfizer-BioNTech vaccine at 98 days against the Beta, Delta and Omicron (BA.1) variants, and at 14 days against the Beta and Omicron (BA.1) variants). These outcomes indicate that the HIPRA vaccine generates a more sustained neutralising antibody response over time than the Pfizer-BioNTech mRNA vaccine, suggesting more durable and effective protection against the newly circulating variants.

As HIPRA has done every time new variants of SARS-CoV-2 have appeared, the IrsiCaixa research center, with which they have collaborated since the beginning of the project, has been in charge of designing and producing the pseudoviruses that are necessary to test the efficacy of the HIPRA vaccine against these new variants. The technology that successfully analyzes the levels of neutralizing antibodies in the sera of people who have been vaccinated has been perfected by IrsiCaixa and has made it possible to carry out the analyzes in the clinical trials of the HIPRA vaccine.

The HIPRA vaccine also showed good safety and tolerability in clinical trials, with no relevant adverse effects recorded in study participants (the most common adverse effects were pain at the injection site, headache and fatigue which at no time interfered with activities of daily living and resolved within a few days). Note that recombinant protein vaccines have already been used for many years in other diseases and that the safety and efficacy of the adjuvant used (SQBA, an oil-in-water emulsion) have already been demonstrated in other vaccines.

Extension study: effectiveness of the vaccine as a 4th dose

To expand on the data collected in clinical trials and, in parallel to the rolling review of the European Medicines Agency (EMA), the company plans to conduct an extension of the Phase IIb trial (HIPRA-HH-2). The objective is to evaluate the safety and immune response of a 4th booster dose of the HIPRA vaccine. A total of 200 volunteers from 10 hospitals in Spain are expected to participate in the study. Of these participants, half will have previously received two doses of the Pfizer-BioNTech vaccine + one dose of the HIPRA vaccine. The other half will have received three doses of the Pfizer-BioNTech vaccine.

The study, which is scheduled to start at the end of the summer, will launch once it has been approved by the Ethics Committee of the Hospital Clínic de Barcelona and the Spanish Agency of Medicines and Medical Devices (AEMPS).

Final Phase of the HIPRA Vaccine

On 29 March, the European Medicines Agency (EMA) began rolling review of the HIPRA vaccine. The EMA has been evaluating the compliance of the vaccine with the usual EU standards for effectiveness, safety and quality. This rolling review precedes the marketing authorisation of the vaccine.

For the company, “the HIPRA vaccine meets the current needs of the European Region. With close to 50% of the population still without a booster dose and with the autumn vaccination campaigns in mind, it can only be a good thing that vaccines based on technologies other than mRNA are available to European citizens. The broad spectrum of protection against the variants that have emerged and its good safety profile make the HIPRA vaccine an appealing solution for people who need to be vaccinated in accordance with the recommendations of health authorities.”

The data mentioned in this press release have been shared with the regulatory authorities. Some have already been published on the MedRxiv server.