Pfizer’s COVID-19 pill data made a splash last week, helping the drugmaker win an efficacy showdown 89% to 50% against rival Merck’s own offering. Yet Pfizer took a backseat to Merck in another arena: Media mentions.

Although it’s roughly half as effective, according to interim results shared by the companies, Merck’s molnupiravir data must have impressed more reporters, editors and producers than Pfizer’s candidate. It garnered almost 50% more earned media mentions. 

“There’s clearly a benefit to being first, and that’s what the media data is telling you more than anything,” said Zack Jenkins, SVP, sales and account management at media intel firm Critical Mention.

Indeed, Merck was first out of the gate with news of an effective oral antiviral. Its October 1 announcement showed its nucleoside analog halved the chance of dying or being hospitalized for COVID-19 patients at high risk of serious illness. On November 5, Pfizer declared that its protease inhibitor, to be sold under the brand name Paxlovid, cut the chance of hospitalization or death for adults at risk of severe disease by a far greater 89%.

“At first blush, I would say the protease inhibitor approach, which is co-administered with ritonavir, appears to be the better drug,” said Dr. Paul Auwaerter, clinical director, division of infectious diseases, and professor of medicine at the Johns Hopkins School of Medicine. (He was not involved in either study.) 

Which made its quieter reception among journalists puzzling. Over a two-week period spanning either side of the October 1 press release, mentions of terms like “molnupiravir” in traditional media, along with either “Merck,” “antiviral” or “COVID,” generated 50% more hits than comparable mentions for Pfizer’s candidate (33,698 for Merck versus 21,922 for Pfizer), according to data from Critical Mention.

Content examined included TV, radio, podcasts and online news and print, but not Facebook or YouTube. Publicity value — the amount it would take to reach an equivalent audience in terms of paid advertising — was also about 50% higher for Merck (see charts).

Some of those differences can be attributed to nuances between the pills. Paxlovid — or ‘332, as the candidate is known in medical circles — is a so-called designer drug, developed last summer. 

The drug works by inhibiting the virus’ replication process and needs to be boosted with ritonavir, another antiviral. The Pfizer phase 2/3 trial showed side effects were far less significant in the active arm compared to placebo, which is encouraging, although ritonavir has the potential to interfere with other drugs a patient may be taking.

Molnupiravir, which works by interfering with the virus’ RNA, is a preexisting molecule that was known by scientists to have antiviral activity. While some may refer to it as an off-the-shelf drug, it has never been approved and never been in use in any country. (This changed last week, when the U.K. authorized it based on preliminary data).

Infectious disease specialists, Auwaerter explained, have been reluctant to employ molnupiravir for treating the Ebola virus or hepatitis C due to concerns its short half life could lead to resistance. Similarly, because nucleoside analogues work by causing the virus to develop mutations in its RNA, there is some concern it could potentially cause mutagenesis in human DNA.

That’s one reason the drug probably would not be recommended for use in pregnant women or anyone anticipating getting pregnant in the near future, Auwaerter cautioned. “At least in the scientific community, there has been a bit more hesitation because this drug has been around for a while.” 

Nevertheless, when it looked like Merck would be first to market with an effective oral antiviral for COVID-19 — especially compared to the litany of oral medications that have been tried, such as hydroxychloroquine, ivermectin and fluvoxamine — reporters jumped on the story.

Eric Lebowitz, VP of marketing for Critical Mention, said that outreach to journalists could well have made a difference. “It’s hard to know what the strategies of the two companies are and relationships they have with journalists, but it’s certainly possible,” he noted.

Both companies stopped trials of their drugs early thanks to positive results. Merck said it will present its phase 3 data to the FDA on November 30 and that it plans to seek emergency approval as soon as possible. Pfizer, for its part, said it plans to submit interim data to the FDA by November 25 and that its pill could secure approval by year’s end. The U.S. government has already contracted to buy millions of doses of each.

The pills could give physicians a leg up in bringing the pandemic to heel. Currently, the only therapies approved for outpatient treatment of COVID-19, at least in the U.S., are monoclonal antibody therapies. Their ability to prevent hospitalization or death is roughly 80% to 85%, said Auwaerter, adding that Paxlovid is “very equivalent to that based on this one trial.” 

Meanwhile, owing to its superior side effect profile, Paxlovid could be used without a confirmed COVID-19 diagnosis “as long as you didn’t have a concern that ritonavir may interact with other medications someone is on,” Auwaerter noted.

Not unlike prescribing Roche’s Tamiflu for influenza, this would represent “a huge advantage to put a potent antiviral on board very early, especially for patients at high risk,” he continued. “If this drug could be widely manufactured and prescribed after the vaccine and was easier to distribute, there is the potential it could help, especially in countries that may not have rapid diagnostics.”

That said, both Pfizer and Merck could wind up seeing a windfall from their pills. As with any antiviral, if a drug is used quite a bit there’s always potential for resistance, especially when using only one drug. 

Said Auwaerter, There’s already been some people wondering if the drugs [‘332 and molnupiravir] should be used together to avoid potential mutational emergence.”