Jerusalem’s Hadassah-University Medical Center has signed a letter of intent to carry out at least part of the Phase III trial of Israel’s vaccine candidate in Brazil, a top Hadassah doctor has told The Jerusalem Post.
The letter was signed last month during a visit to Israel by top Brazilian officials, said Prof. Yossi Karko, director of Hadassah’s clinical research unit. He is leading the Phase II trial of Brilife, Israel’s vaccine candidate, for the hospital.
The Brazilian delegation was led by Foreign Minister Ernesto Araujo. It included President Jair Bolsonaro’s son Eduardo Bolsonaro, who is chairman of the Foreign Affairs and Defense Committee, and Health Minister Eduardo Pazuello.
Brilife was developed by the Israel Institute for Biological Research, which Karko said is supportive of the decision.
“Understanding that the third phase of the clinical trial of the vaccine developed at the biological institute will be carried out abroad due to the vaccination campaign in Israel and the required number of volunteers, preliminary tests are being conducted with a number of countries to examine the issue,” an IIBR spokesperson told the Post. “It has not yet been decided where the third phase of the experiment will take place.”
During the Brazilian visit, officials met with representatives of several Israeli hospitals, including Hadassah, and the letter of intent was signed, Hadassah Director-General Prof. Zeev Rotstein confirmed.
President Bolsonaro’s adviser on international affairs, Filipe G. Martins, said the delegation was in Israel “in order to deepen our partnership in the area of science, technology and innovation, including through cooperation in the development of medicines and vaccines against COVID-19,” the Post reported last week.
A Phase III trial would need to take place outside of Israel because it requires the participation of 30,000 to 40,000 volunteers and must be undertaken in an area that still has high infection. Israel’s mass vaccination campaign has left few eligible volunteers and continues to bring down morbidity.
Only around 20 to 30 people volunteer each day to take part in the Phase II trial, which has led to a slight delay, Karko said.
Some other countries have also expressed willingness to take part in a Phase III trial, including several from South America, Eastern Europe and Africa, where vaccines are harder to come by, he said. He named Argentina, Panama and Zambia as examples.
Brilife’s Phase II trial is expected to be completed by the end of April. So far, some 500 subjects have been enrolled in the study, which was designed to test safety, efficacy and dosing, Karko said. About 50% of the participants are being managed by Hadassah.
The study has already eliminated a low-dose regimen and found that a booster shot 20 days after initial inoculation would be required. It is preparing to add a fourth “top dose,” or optimal, dosing regimen to the study.
Around 800 people will have participated in Phase II by the end of the trial, Karko said, adding that the Phase III study is currently being designed.
“The Phase II trial is really concerned with safety, and up until now there are no safety concerns,” he told the Post. “There are no side effects at all that are clinically significant. This is very reassuring.”
The study has also provided preliminary data that indicates good immunological response, “but we will only know for sure sometime during the summer,” Karko said.
The Brilife vaccine is different than the Pfizer or Moderna vaccines, which are messenger RNA vaccines.
Brilife is a vector-based vaccine. The vaccine takes the vesicular stomatitis virus (VSV) and genetically engineers it so that it will express the spike protein of the novel coronavirus on its envelope.
Once injected, it does not cause a disease by itself. VSV does not infect humans. Instead, the body recognizes the spike protein that is expressed on the envelope and begins to develop an immunological response.
“It’s like getting a virus like coronavirus without getting the disease,” Karko said. “Then, if you happen to be exposed to the real coronavirus, the immunological response that was triggered by the vaccine will prevent infection.”