Moderna shares hit by COVID-19 vax trial delay report, but biotech says July start still on track


Moderna’s shares shrunk by nearly 5% before the long holiday weekend Thursday after a report by Stat said the biotech would have to delay the start of its major phase 3 pandemic vaccine trial.

Shares were off by as much as 10% Thursday before ending the day down 4.9%, bumping up slightly after-hours. An anonymous investigator spoke to healthcare publication Stat saying the heavily funded biotech had changed the trial’s protocol, pushing back its timeline. It did not say by how long nor what the original start date was set to be.

These changes are not uncommon, but the reaction shows just how closely watched these trials are. “My understanding was that they wanted to get the first vaccines given in July, and they say they’re still committed to do that,” one investigator said to Stat. “As best I can tell, they’re close to being on target for that.”

Moderna, seeing its shares wilt, put out a release on Twitter Thursday essentially confirming that, saying it was still on track to start the test this month as it had planned. The company did not directly address Stat’s allegations of a delay but did say: “We have worked closely with NIH/OWS to align the final protocol in order to begin the trial on time.”

Last month, Moderna said it had finalized the design and dosage of its phase 3 COVID-19 vaccine trial, keeping it on track to start the pivotal test next month. Work to get the 30,000-subject phase 3 trial underway is advancing in parallel to ongoing enrollment in earlier phases of development.

The messenger RNA biotech set out its expectations for the phase 3 trial when it shared a first glimpse at clinical data on its mRNA-1273 vaccine in May. At that time, Moderna expected the phase 3 trial to test a dose between 25 µg and 100 µg, reflecting the adverse events seen in the 250-µg cohort, and to get underway in July.

Moderna looks set to hew closely to those proposals. Having spoken to the FDA, Moderna plans to randomize 30,000 people in the U.S. on a one-to-one basis to receive either 100 µg of mRNA-1273 or placebo. It’s not clear what about the protocol has changed since this last update.

In its June update, Moderna said the primary objective of the trial is to assess the ability of mRNA-1273 to prevent symptomatic COVID-19 disease. Secondary endpoints will assess the ability of mRNA-1273 to prevent hospitalization and infection with SARS-CoV-2.