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Monkeypox Emergency Clearance Excludes Siga’s Tpoxx Medicine (2)

Aug. 11, 2022, 9:45 AMUpdated: Aug. 11, 2022, 7:57 PM

The Biden administration’s decision to activate FDA emergency powers for monkeypox could quintuple the US vaccine supply, but the latest action doesn’t use that authority to boost treatment options.

HHS Secretary Xavier Becerra gave the Food and Drug Administration the green light to clear a technique that involves injecting smaller doses of the monkeypox vaccine into the upper layer of the skin. The emergency use authorization is limited to vaccines and doesn’t include therapeutics or testing.

“I was surprised to see that it just covers vaccines. I’m glad to see the declaration for vaccines. But there’s an urgent need for more accessible therapeutics,” Stacy Cline Amin, former chief counsel for the FDA under the Trump administration who now leads Morrison and Foerster’s FDA regulatory & compliance practice, said.

“People are really suffering. And it’s really unacceptable that they haven’t been able to access therapeutics that can relieve their excruciating pain,” she said.

Mary Foote, medical director of the New York City Department of Health and Mental Hygiene, said she’s been encouraged by the recent emergency measures to address this outbreak, and looks forward to seeing additional actions from the federal government.

“It is unclear why antiviral treatment couldn’t also be included in this emergency determination,” Foote said Thursday during an Infectious Diseases Society of America press briefing. “Providing care for our patients should not be this hard. The US has all the tools that we need to ensure that every at-risk person can get the care they need to prevent and treat monkeypox infections. We just need to use these tools. No one should be left behind. That is not acceptable.”

The FDA can issue EUAs to bring unapproved uses of products onto the market more quickly and with less rigor than full approval during a public health emergency when there aren’t other adequate available alternatives. An EUA would broaden access to monkeypox treatment by allowing the distribution of authorized therapeutics for the duration of the emergency.

“The concept is that FDA can use EUAs to authorize off-label uses of products that are approved, but where the use wouldn’t be consistent with their approvals,” Denise Esposito, co-chair of Covington & Burling’s global food, drug, and device practice group, said.

Expanded Access

Siga Technologies Inc.’s smallpox antiviral Tpoxx (tecovirimat) is available to treat monkeypox under an expanded access protocol, which allows access to unapproved drugs outside of a clinical trial. Under expanded access, a clinician must request access to that drug from federal authorities and patients must have a serious or life-threatening condition.

The FDA and the Centers for Disease Control and Prevention have said they’ve cut down the paperwork for expanded access, but complaints linger that it’s a cumbersome process for health-care providers.

While those steps definitely made it easier for prescribers, Foote said the expanded access-investigational new drug protocol remains a labor-intensive process, requiring significant time and follow-up visits.

“We’re hearing from numerous providers, especially in smaller community clinics, who still cannot take on the burden of the IND process, and that they are forgoing it altogether and trying to refer their patients out,” Foote said.

Patients have driven more than three hours to the Massachusetts General Hospital Sexual Health Clinic to access Tpoxx because there were no closer options, Kevin Ard, the clinic’s director and medical director of the National LGBTQIA+ Health Education Center at The Fenway Institute, said during the same press briefing as Foote.

An EUA “wouldn’t leave prescribing purely up to individual physicians but would announce prescribing guidance that must be followed to comply with the EUA. For this reason, an EUA might be preferable to having CDC allow off-label prescribing,” Govind Persad, a bioethicist at the University of Denver, said.

Neither an EUA nor expanded access qualify as an approval, which is a more rigorous process to pass the FDA’s full safety and efficacy bar.

An EUA for Tpoxx has caught the attention of at least one member of Congress. House Oversight Chair Carolyn B. Maloney (D-N.Y.) sent a letter to Becerra and called on him “to take all necessary steps to make TPOXX more accessible—including steps to evaluate a potential emergency use authorization—so that we can ensure patients receive the very best care and help protect our communities during this public health emergency.”

Clinical Trials

An EUA could help reduce regulatory barriers but it still must be coupled with a fully funded clinical trial that measures tecovirimat’s efficacy against monkeypox, Persad said.

“While an EUA can be an important step to improving short-term access, an EUA should not be allowed to lead to a situation where we do not do clinical trials and so never learn whether the EUA product is actually effective against the emergency disease,” he said.

A spokesperson for the Department of Health and Human Services didn’t indicate whether the department would expand the monkeypox EUA to include therapeutics but underscored the importance of clinical trials.

“There are currently no data demonstrating the effectiveness of Tpoxx for the treatment of smallpox or monkeypox in humans. Tpoxx has only been tested in healthy human volunteers, without smallpox or monkeypox infection, to assess safety,” the spokesperson told Bloomberg Law. “Conducting randomized, controlled trials is necessary to assess Tpoxx’s safety and efficacy in humans with monkeypox infections and to inform the appropriate use of the product by health-care providers.”

Siga may run its first human trials as early as next month, the drugmaker told Bloomberg News last week.

Persad also said that despite the benefits of an EUA, it would be undesirable if off-label prescribing allowed low-risk people who do not have monkeypox—and are unlikely to have been exposed—to obtain limited supplies of Tpoxx. “I don’t know how likely this is, but I can imagine some people at low risk who are very fearful of monkeypox seeking to be prescribed prophylactic tecovirimat,” he said.

Emergency Flexibilities

Federal statutes offer health authorities several levers to pull when responding to an infectious disease outbreak, with options for how broadly those emergency flexibilities can apply.

First, the HHS secretary must issue a public health emergency determination under Section 564 of the Food Drug and Cosmetic Act. Then the secretary may issue a declaration under 564 saying that circumstances exist to justify the emergency authorization of unapproved medical products, or approved medical products for unapproved uses.

The declaration can either be categorical by applying only to drugs or diagnostics, or it can apply to all medical countermeasures for a particular outbreak. Once the declaration is in place, the FDA can issue EUAs for specific products within the scope of the declaration.

The HHS under the Trump administration rolled out product-specific EUAs for Covid-19, but it started with diagnostics before clearing treatments and vaccines. The difference between the two outbreaks is that early on there were no available countermeasures for Covid-19, whereas products were available to treat orthopoxes, Amin said.

“There’s no reason for the EUA authority to be invoked unless it’s ready to be used,” Amin said, adding that in the early days of Covid, the emergency authority was ready to be used to address testing but there weren’t vaccines or treatments online yet when the product-specific EUA came out.

Amin said she expects to see an EUA determination for diagnostics and therapeutics to follow shortly after the one for vaccines.

“I understand that measures have been taken to ease access to therapeutic products, but really, I think emergency use authorization should be considered as well because it could potentially, significantly reduce the bureaucracy involved in patients getting access to therapeutics that are desperately needed,” she said.

(Updated with Rep. Maloney's letter to Becerra in the 16th paragraph)

To contact the reporter on this story: Jeannie Baumann in Washington at jbaumann@bloombergindustry.com

To contact the editors responsible for this story: Alexis Kramer at akramer@bloomberglaw.com; Karl Hardy at khardy@bloomberglaw.com; Cheryl Saenz at csaenz@bloombergindustry.com