South Korea has bought an additional 400,000 courses of Paxlovid, the COVID-19 antiviral pills developed by Pfizer, health officials said Wednesday evening. With the latest purchase, the country has secured enough oral treatments for 1 million people in total -- Pfizer’s for 762,000 people, and the rest from Merck.

“Adding pills to our treatment protocol will help stabilize and expand the at-home COVID-19 care scheme, a key pillar of our return to normal,” the Korea Disease Control and Prevention Agency said in a release Thursday. 



When are they coming?

The agency said the first shipments of Paxlovid are due to arrive in mid-January, although details like how many courses were still being negotiated. 



Who can take them?

Paxlovid is approved for use in Korea for patients ages 12 years and older weighing at least 40 kilograms. 

The pills have to be taken within the first few days’ of onset of symptoms. Patients who are already severely sick and requiring hospitalization cannot take them.

The agency said although treatment guidelines are still being developed, pills will be mostly prescribed to COVID-19 patients in home recovery who are at higher risk of severe disease.

Dr. Kim Woo-joo, an infectious disease specialist at Korea University Medical Center, worried that the scope of use of Paxlovid, or ritonavir-boosted nirmatrelvir, is probably limited by a long list of other medicines that cannot or may not be mixed with it.

“Paxlovid is contraindicated in patients with severe kidney or lung disease, according to the company,” he said.

Some of the medicines that must not be used with Paxlovid include those used to treat cancer, allergies, bacterial infections, migraines, high blood pressure, depression and anxiety. Patients taking oral contraceptive pills, hepatitis C antivirals or medicines used for smoking cessation, among other products, are also advised to inform their doctors.

“As Paxlovid is distributed across larger populations, safety monitoring will be important, as it has been with vaccines,” Kim said. 



Likely effective against omicron

The agency said later-strage trials show Paxlovid reduces hospitalizations or deaths by almost 90 percent. Although it’s probably still effective against omicron, there was no official announcement yet from Pfizer on Paxlovid’s effectiveness against omicron, it said, and the studies were still underway.

Dr. Paik Soon-young, who was formerly on the Central Pharmaceutical Affairs Council under the Ministry of Food and Drug Safety, said unlike monoclonal antibodies, the way the pills works was not likely to be affected by the viral mutations. 



Chances slim with other pill, molnupiravir

Merck applied for the emergency use approval of its molnupiravir medication, which uses the brand name Lagevrio, with Korean regulatory authorities in mid-November, but its review is still pending. Pfizer’s Paxlovid, on the other hand, was cleared for emergency use here on Dec. 27, five days after submitting its application.

The disease control agency said Thursday that with molnupiravir, the Drug Ministry has yet to determine whether to issue an emergency authorization.

Kim Jeong-ki, a pharmaceutical microbiology expert of the Pharmaceutical Society of Korea, believes molnupiravir stands a slim chance in Korea.

France has canceled its orders for Merck’s treatment following trial results indicating it was only about 30 percent effective in reducing hospitalizations and deaths in high-risk people. India has also forgone using the pill over safety concerns, like its potential to cause mutations in human DNA, which could theoretically harm sperm cells or a developing fetus.

Kim said given the safety issues, molnupiravir is unlikely to gain traction in Korea, even if it’s approved for use.

“That means Korea would only be left with 700,000-something courses of Pfizer pills. At the current rates the amount we have looks like it’s going to be enough, but it also depends on how omicron will play out,” he said.

By Kim Arin (arin@heraldcorp.com)