Approved in late January 2020, the only FDA-approved peanut immunotherapy was due to be released onto the US market, but the arrival of the pandemic effectively shut it down.
The peanut-powder Palforzia allergen treatment is designed to desensitise peanut allergies in children and adolescents, and circumvent potentially life-threatening reactions.
It is unclear to what extent peanut allergy immunotherapy (IT) and other forms of IT will be embraced by the US public. While subcutaneous IT has been practised for a long time, oral IT such as sublingual IT tablets are relatively new, with only a few products currently having regulatory approval in the US and Europe.
However, there are questions as to whether the US will ever widely accept IT, given factors such as the high treatment burden. Speaking to MedPage Today, Edwin Kim, MD, director of the University of North Carolina Food Allergy Initiative in Chapel Hill, said that it may not be clear for a while to what extent the treatment is accepted.
“COVID-19 shined a spotlight on the downsides of a treatment that requires so many physician visits,” he said. “If it was an easy treatment we might have seen more uptake, but it’s not an easy treatment.”
Thomas Casale, MD, of the University of South Florida in Tampa, acknowledged to MedPage Today that Palforzia’s uptake in the past year has been slow as “A treatment like this requires a lot of contact with the patient.”
The dosing schedule involves around a dozen physician visits, of 30-90 minutes duration each. A single-day initial dose escalation phase is needed, with up-dosing every two weeks with physician observation to attain 11 increasing dose levels. After this, there is a daily home-dosing maintenance phase.
The 300-mg peanut protein maintenance dose is equivalent to eating a single peanut. “If you are able to tolerate 300 mg of peanut you can effectively prevent about 95% of adverse reactions,” Casale said. “So 300 mg is an important indicator of some degree of safety.”
In pooled trial data on Palforzia presented by Dr Casale, only 1.2% of long-term patients had a treatment-related severe systemic allergic reaction, all of which were treated with epinephrine.
“I think that after COVID is gone, which hopefully will be sooner than later, the uptake of this type of therapy will be a lot greater than it is today,” Dr Casale said.
Viaskin Peanut, an extracutaneous peanut IT, is undergoing investigational trials, with the FDA rejecting application for its approval. The agency cited concerns about the impact of patch-site adhesion on efficacy, and demanded modifications and additional trials.
Christina Ciaccio, MD, chief of allergy/immunology and pediatric pulmonology and sleep medicine at the University of Chicago, said that there were many challenges remaining.
“We have numerous forms of immunotherapy that are currently under investigation,” she said. “The fact that only one allergen-specific IT treatment for food allergy has been approved by the FDA highlights the remaining challenges.”
“For those that do have peanut allergies, this treatment [IT] is not universally effective and it is not universally available,” Ciaccio said. “The side effects are too frequent, and as it stands right now, this is a life-long therapy. These are all things we would like to work on.”
Source: MedPage Today
