- An experimental antiviral drug helped improve flu symptoms faster than placebo in elderly or other high-risk patients, helping to strengthen Swiss pharma Roche's case that the new medicine could offset sliding revenues from its aging Tamiflu brand.
- In addition to improving symptoms, baloxavir marboxil, which was developed by Shionogi and licensed to Roche, cut the time during which the influenza virus continued to be released in the body. Known as viral shedding, ongoing release of the virus is thought to be linked with transmission to other people.
- Roche currently markets Tamiflu for acute, uncomplicated influenza. But entry of generic versions in the U.S. has caused sales to slump, just as biosimilars threaten the pharma's top-earning cancer medicines.
Even before generic competition dragged sales of Tamiflu down by a third, the 20-year-old neuraminidase inhibitor didn't account for much of Roche's revenues. In 2016, for example, the drug represented only 2% of the oncology-focused pharma's overall sales.
But as Roche's top three cancer biologics — which collectively brought in 34% of the company's roughly $26 billion in pharmaceutical sales last year — face looming competition, proving future growth potential has become the order of the day.
Last month, Roche was granted Priority Review from the Food and Drug Administration for baloxavir marboxil, supported by data from its first Phase 3 CAPSTONE-1 study as well as an earlier Phase 2 trial. A decision on approval from the regulator is expected by Dec. 24.
That submission is aimed at securing a label for acute, uncomplicated influenza in people 12 years or older — a more limited indication than that of Tamiflu currently.
CAPSTONE-2, results of which Roche disclosed Tuesday, tested baloxavir marboxil in people at high risk of complications from the flu. This population includes those above 65 years of age as well as people with exacerbating conditions like asthma or diabetes.
Securing an OK in these patients would give Roche a shot at growing its market beyond Tamiflu's reach. This is important because Tamiflu generics could prove tough competition in the broader, less-at-risk patient population.
In CAPSTONE-1, baloxavir marboxil proved about equal to Tamiflu in how quickly it alleviated flu symptoms in patients aged 20 years or older. The new drug was more effective, however, in limiting viral shedding.
No detailed results were provided from CAPSTONE-2, with Roche and Shionogi withholding the full data set for an unspecified future medical meeting.
But the pharma did say baloxavir marboxil met its secondary endpoints testing the drug's effect on viral shedding and reducing viral levels versus both placebo and Tamiflu. No safety signals were identified and the drug was well-tolerated.
Reducing viral shedding is a key piece of Roche's argument for baloxavir marboxil.
"I think this is important from a seasonal impact standpoint, the public health standpoint, it's potentially important in a pandemic situation," said Roche Pharmaceuticals CEO Daniel O'Day on a first-quarter earnings call in April.
"All of these things I think make [baloxavir marboxil] an attractive product profile and we feel a meaningful difference for patients with influenza."
Per a 2016 licensing deal, Roche holds rights to baloxavir marboxil outside of Japan and Taiwan, where Shionogi retained an exclusive license. Shionogi currently sells the drug in Japan under the brand name Xofluza.
Roche said it will submit the results from CAPSTONE-2 to health authorities, but the data will not be included in the New Drug Submission which the FDA already accepted.