AstraZeneca has secured $486 million from the U.S. government to fund two phase 3 clinical trials of its anti-SARS-CoV-2 antibody cocktail AZD7442. The larger of the two studies will assess the ability of the long-acting antibodies to prevent infection with the pandemic coronavirus for up to 12 months.
Many early discussions of the role of anti-SARS-CoV-2 antibodies in the COVID-19 pandemic centered on their therapeutic potential. AstraZeneca, while interested in the therapeutic use of antibodies, has consistently talked up the role the drugs can play in preventing people from catching the virus and developing COVID-19, particularly in populations that may be poorly served by vaccines.
That focus on prophylaxis has shaped AstraZeneca’s approach to its antibodies. While Regeneron took unmodified antibodies into the clinic, AstraZeneca used half-life extension technologies. The result is a drug AstraZeneca calculates could provide protection for up to 12 months.
The anticipated durability of AZD7442 has landed AstraZeneca a deal with the U.S. government, which is investing around $486 million to support two phase 3 trials and a large-scale manufacturing demonstration project. In return, the government has secured up to 100,000 doses of AZD7442 for use in the U.S. Supply of the antibodies is set to start toward the end of the year. The government has an option to buy up to 1 million doses in 2021.
AstraZeneca plans to start the two phase 3 trials in the coming weeks. The larger of the two studies will enroll around 5,000 people and evaluate the effectiveness of AZD7442 at preventing infection for up to 12 months.
With multiple vaccines already in phase 3 trials, AZD7442 is unlikely to become the primary means of protecting people from the coronavirus. However, vaccines can fail to confer immunity to seniors and other groups, potentially leaving the people who most need protecting from SARS-CoV-2 vulnerable to the virus.
AZD7442, like anti-SARS-CoV-2 antibodies in development at companies such as Eli Lilly and Regeneron, could protect people who are unable to mount a sufficient immune response to vaccines to quickly eliminate the coronavirus upon infection. Similarly, antibodies could be given in addition to vaccines to provide additional protection to high-risk people.
The second phase 3 trial will enroll around 1,100 people to assess the effect of AZD7442 on patients who have just been infected with the coronavirus. If successful, that trial could establish AZD7442 as a means of post-exposure prophylaxis or a preemptive treatment in recently infected patients. The cost of antibody therapies suggests the use of AZD7442 in that context may be limited to high-risk patients.
AstraZeneca is also planning to enroll around 4,000 COVID-19 patients to evaluate the efficacy of its antibodies in the treatment of the disease. Lilly and Regeneron, both of which filed for emergency use authorization last week, are well ahead of AstraZeneca in the therapeutic space.
The COVID-19 antibody front-runners are also running prophylactic clinical trials. However, neither company has publicly committed to the up to 12-month durability targeted by AstraZeneca, which is a long time for even engineered antibodies.
AstraZeneca has become increasingly bullish about the durability of AZD7442. When AstraZeneca started a phase 1 trial of AZD7442 in August, it said the antibodies should provide at least six months of protection. Now, AstraZeneca is targeting up to 12 months of protection, potentially making the use of AZD7442 as a prophylactic economically viable in more people. While AstraZeneca is selling its COVID-19 vaccine at cost, it plans to provide AZD7442 “at commercial terms.”