Argentina shows interest in 2 Cuban vaccines against Covid-19 in Phase III trials

RIO DE JANEIRO, BRAZIL – Cuban scientists are working on four vaccine candidates against Covid-19: Soberana 1 (in Phase II), Soberana 2 (in Phase III), Mambisa (in Phase I) and Abdala (in Phase III). A fifth candidate, Soberana +, is a reformulation of Soberana 1, intended for convalescents of the disease.

If all trial phases are successfully completed and approval is granted by Cuba’s National Regulatory Agency, any of these immunizers would become the first vaccine against the disease conceived and produced in Latin America in the coming months.

Despite the objections of international science, President Alberto Fernández confirmed that he is negotiating the purchase of Cuban vaccines. The Argentine president announced that he has started negotiations with his Cuban counterpart, Miguel Díaz Canel, to access Soberana 2 and Abdala, the scientific developments against the coronavirus that the Venezuela’s National Academy of Medicine qualified as “experimental products whose composition, safety and efficacy are not known.” “They are not true vaccines,” the entity warned.

“I have been talking with the president of Cuba, with engineer Díaz Canel. Cuba has done a job that all scientists say is wonderful, very important, developing a vaccine called Soberana, which has two versions, in Phase III. I asked him about his production capacity, he told me about the challenges he is facing and I offered to work together so that all Latin America could have access to a vaccine,” said Fernández.

Venezuela’s National Academy of Medicine warned in recent days about the lack of reliable data on the potential vaccine after dictator Nicolás Maduro announced that 2 million doses of Abdala, one of the Cuban candidates against the disease, will be produced in Venezuela every month.

But how do they work? All the Cuban prototypes are based on inoculating a protein from the spicule of the coronavirus, the part that binds to the cells it infects, to produce an immune response. Soberana 2, in which the highest expectations are placed, also adds an immune response enhancer. The latter is injectable; two doses are planned, with two-week intervals between each one, plus a possible booster. And it brings a novelty in the field: it does not require freezers for its maintenance, a further attraction for the world’s poor countries.

It is a conjugate vaccine, since it has an antigen that fuses with a carrier molecule to reinforce its stability and efficacy. In its development, a tetanus toxin was joined to the protein with which the virus adheres to the cell. Thus, when the virus tries to enter the cell using this protein, an immune reaction is produced against the toxin carried by the protein, blocking its entry into the cell. Experts affirm that the Soberana 2 technology has already been successfully used in other vaccines manufactured in Cuba.

On March 21st, the island nation announced that it would begin a new trial on the efficacy of the vaccine developed by the state-run Finlay Vaccine Institute (IFV) in an intervention study with 150,000 volunteers in Havana, as part of Phase III of its development. The trial, approved by the State Center for the Control of Medicines and Medical Devices, evaluates the direct and indirect effects of vaccination on “population cohorts” at risk of infection, disease and epidemic spread.

While Soberana uses an antigen obtained from mammalian cells in various formulations; Abdala uses an antigen taken from yeast, also in various formulations. The vaccine, produced by the Center for Genetic Engineering and Biotechnology (CIGB), inserts genetic information into a less evolved unicellular microorganism (the yeast Pichia Pastoris) and builds on the long experience and impressive track record of the CIGB, whose hepatitis B vaccines have been used in Cuba for 25 years.

Last April 3rd, the first dose of this vaccine was administered to 48,000 volunteers in the eastern provinces of Santiago de Cuba, Guantánamo and Granma, and on April 5th, the second shot began to be applied, of which three doses (0, 14 and 28 days) will be administered in two groups, an experimental and a control group. On the same day, the application of the second dose of Soberana 2 to the volunteers included in the Phase III trial in Havana also began.

“It is a moment of great pride for the country,” said CIGB Deputy Director General Marta Ayala at a press conference. The scientist highlighted the positive results of safety and immunogenicity obtained in the first two stages of testing of this formula, carried out in Santiago de Cuba between last December and February and in which almost 800 people participated (132 in Phase 1 and 660 in Phase 2).

The BioCubaFarma laboratories, an entity comprising 32 institutes, research centers and biotechnological and pharmaceutical production industries, have already produced more than 300,000 doses of Soberana 2 and Abdala, and its directors assure that they have the capacity to produce 100 million vials before the end of 2021. The stated goal is to have at least one vaccine ready in the summer and start mass vaccination in July and August. The aim is immunize half of the population by September and all Cubans before the end of the year.

“The results so far are encouraging: both vaccine candidates have proven to be safe and capable of generating specific antibodies against the virus. We are optimistic,” declared shortly before the start of Phase III Eulogio Pimentel, vice-president of the BioCubaFarma business group, which produces 8 of the 13 vaccines part of the island’s national vaccination program.

Despite its limited material resources, Cuba is responsible for developing 2 of the 23 coronavirus vaccines that have entered Phase III trials worldwide. For the country, successfully completing the development of its vaccines is of crucial importance for the scientific and political prestige it represents, but also for economic reasons at a time when the island is experiencing one of the worst crises in its history.

The Caribbean country has focused on making its own vaccine that it intends to export, since it did not acquire doses in the international market nor did it join the Covax facility, created under the auspices of the World Health Organization (WHO) to favor equitable access to immunization.

Source: Infobae