J&J’s experimental antiviral drug shows promise against COVID-19 and emerging coronaviruses

Johnson & Johnson’s pharmaceutical arm, Janssen, has shared early preclinical findings on its new antiviral drug, JNJ-9676, which shows promise in combating COVID-19 and other serious coronaviruses.

This early-stage experimental drug has been tested in laboratory settings and has demonstrated effectiveness against a group of viruses known as beta coronaviruses — a family that includes not only the virus responsible for COVID-19, but also those behind SARS and MERS. These viruses typically originate in animals such as bats and rodents and have triggered several global outbreaks over the past two decades.

JNJ-9676 has been specifically designed to target the most dangerous forms of these viruses, potentially offering a new line of defence against future pandemics.

This development comes at a time when pharmaceutical firms are discontinuing discovery efforts in next-generation COVID-19 treatments — especially in light of the virus’s ongoing mutations, the limitations of existing therapies, and the threat posed by new pathogens emerging from animal reservoirs such as bats and pangolins.

The study, published in the Nature journal last month, explains how JNJ-9676 blocks the coronavirus’s M protein — an essential enzyme for the virus to replicate and assemble.

“Our Nature publication shows that, unlike well-known viral proteases (such as MPro, the target of Pfizer’s drug Paxlovid), JNJ-9676 uniquely targets the membrane (M) protein — the most abundant structural protein required for forming infectious virus particles. No one had discovered previously any drug targeting M Protein’ said Dr Anil Koul, the corresponding author of this study,  who is professor of Translational Disovery at London School of Hygiene and Tropical Medicine.  “JNJ-9676 locks this M protein in a non-functional state, preventing the virus from assembling and spreading in human cells," he said.

The research team engineered several versions of JNJ-9676 to target highly conserved regions of the M protein, aiming to ensure the drug remains effective across major pathogenic forms of coronavirus strains.

“This novel unexplored M protein is a valuable addition to the global antiviral target portfolio. With strong preclinical efficacy and a favourable resistance profile, we believe this chemical series to which JNJ-9676 belongs has great potential both in the treatment of COVID-19 and in preventing future pandemics caused by this viral family,” Dr Koul added.

Dr Koul has contributed to the discovery and development of Bedaquiline, a treatment for drug-resistant tuberculosis, which is included in the World Health Organization’s (WHO) list of essential medicines.

He emphasised that the discovery of the JNJ-9676 chemical class could significantly contribute to global pandemic preparedness, particularly given the estimated 30 per cent likelihood of another pandemic occurring within the next decade. This work builds previous reach in COVID-19 therapies, which include studies on protease inhibitors like Paxlovid (nirmatrelvir/ritonavir as well as new generation like ensitrelvir) and polymerase inhibitors such as remdesivir, which target different parts of the virus to stop it from multiplying.

Health authorities and regulatory bodies continue to call for more COVID-19 treatment options with better safety and efficacy profiles, particularly as concerns rise about drug resistance and the need for longer-term solutions.

Dr Koul believes M protein inhibitors could significantly expand the COVID-19 treatment toolkit, especially in areas where transmission remains high. His team has demonstrated that this new class of drugs is also effective against emerging beta-coronaviruses isolated from bats and pangolins, which are likely to be the source of future outbreaks.

“This is one of the most striking aspects of our study,” Dr Koul noted. “We have shown that this new chemical drug class works against novel coronaviruses found in bats and pangolins.”

India, a global hub for antiviral manufacturing, could play a key role in the production and licensing of any new antiviral like JNJ-9676 or new chemical matter, should they advance to later stages of development. Given its track record in producing generic COVID-19 treatments, the Indian pharmaceutical sector is closely monitoring developments in covid antiviral space.

“This study presents a new antiviral strategy beyond the typical protease and polymerase inhibitors,” Dr Koul said. “It opens the door to broad-spectrum coronavirus treatments that could be safer and more effective in the event of another pandemic. Advances like these are essential for global readiness.”

The research was carried out in collaboration with Janssen Pharmaceuticals and other institutions, including the University of Lübeck (Germany), Institut Pasteur (France), KU Leuven and the Rega Institute for Medical Research (Belgium), and the U.S. government’s Biodefence agency, BARDA.