China’s growing array of oral Covid drugs

It has been a heated race to develop Covid antiviral pills. A Chinese biopharma firm tweaked a technology patented by the US drug giant Gilead—and then handily beat Gilead to the market.

Chinese drug regulators approved two new domestically developed covid pills: Simcere Pharmaceutical Group’s new drug, Xiannuoxin, and Junshi Biosciences’ new antiviral Covid pill, VV116. The latter is based closely on an antiviral invented by Gilead.

With the addition of these two drugs, China has now approved five oral covid treatments for sale: Azvudine, from the Chinese company Genuine Biotech; Pfizer’s Paxlovid; and Merck’s Molnupiravir.

These antivirals augment China’s pandemic arsenal at a time when the government has discarded its zero-covid policies, allowing the Coronavirus to rip through its population at dramatic speed. A government scientist estimated that 80% of the population had been infected, as of January 21, 2023.

While vaccines remain the best protection against severe illness and death caused by Covid, large numbers of the most vulnerable populations in China have yet to receive their three shots. For them, effective antivirals could offer another line of defense. Accessibility is the key to getting more people vaccinated, which can save lives. 

How the US and China compete in drug innovation

The development of VV116 offers an example of how the US-China technological competition plays out at the level of an individual product. It’s also a reminder that the spoils of tech don’t necessarily accrue to the original inventor; instead, they can be reaped by others who scale and commercialize that technology.

This has played out in products like silicon solar cells and lithium-iron-phosphate batteries—both invented in the US years ago, but whose supply chains are now completely dominated by China.

Early in the pandemic, Gilead chose to push its patented Remdesivir as an intravenously administered covid treatment, instead of considering another of its antivirals: GS-441524

Scientists at Junshi Biosciences, a Shanghai-based company, and at the Chinese Academy of Sciences, spotted an opportunity. They modified GS-441524 through a process called deuteration, and filed a patent application for their new drug as early as April 2020. Three years later, they received the green light to bring VV116 to market.

In a statement to Quartz, Gilead said that it is “fully committed” to helping covid patients and that it’s continuing to investigate the use of remdesivir in vulnerable groups, as well as pushing ahead with developing its own covid antiviral pill, dubbed GS-5245.

Eric Xu, one of the scientists who worked on VV116, described to the state-run outlet The Paper, how researchers first determined the structure of a key Coronavirus enzyme, then studied how it enables viral replication. That formed a roadmap for other scientists well-versed in nucleoside analogs, a type of antiviral. They then experimented with dozens of compounds, eventually settling on VV116.  

Thus, amid the upheaval of covid, a relative newcomer piggybacked on the work of an industry giant, acquired a competitive edge, and leapfrogged it. Gilead turned only belatedly to developing its own covid tablet, GS-5245. However, its late-stage Phase 3 trial is still ongoing.

China’s homegrown trio of Covid pills

The question now is whether China’s roster of three homegrown antivirals, in addition to Pfizer’s Paxlovid and Merck’s Molnupiravir, can meaningfully minimize deaths, particularly in the face of potential infection, driven by new variants.

Of the three approved [homegrown] drugs in China, VV116 appears the most promising, given that it’s essentially a GS-441524 clone and there is a bulk of encouraging preclinical data for this drug. Some chemists have argued, since 2020, that GS-441524 is superior to Remdesivir for treating Covid. 

Currently, Pfizer’s Paxlovid is considered one of the most effective treatments for preventing severe Covid. VV116 may not be far off: research has shown that VV116 is not inferior to Paxlovid, according to results published in December 2022 from a Phase 3 trial.

But, Paxlovid’s emergency-use authorization in the US is based on a trial that included only unvaccinated and previously uninfected patients. That leaves unanswered the question of how effective Paxlovid is for people who have been vaccinated and boosted or have already had Covid.

Simcere expects the selling of Xiannuoxin in China, according to China’s state-run outlet Securities Daily. Junshi told the same newspaper that it is ready to start production immediately and can ramp up to meet nation-wide demand.

The reality is that Covid is still a global threat, thus the reason that these newly innovated drugs have been created.

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