Unpacking the FDA Approval Conundrum: The Journey of Sublingual Immunotherapy to Regulatory Recognition

Allergies affect millions of people across the world. This means there is a constant need for management for those who suffer. Sublingual immunotherapy (SLIT)—more commonly known as “allergy drops“—is an emerging potential game-changer for those afflicted with a history of allergy problems. However, with this said, the lack of FDA approval begs the ever-important question: Why hasn’t sublingual immunotherapy been approved by the FDA?

Sublingual immunotherapy is a kind of allergy immunotherapy wherein a small amount of allergen extract is placed under the tongue. Companies such as Curex provide allergy drops for different types of indoor and outdoor allergies. This is a desensitizing procedure aiming to reduce probable allergic reactions from the body’s immune response. It is administered differently from allergy shots that use a needle in traditional treatment and is usually painless.

The FDA plays a pivotal role in regulating products intended to protect lives or enhance public health. Before any drug or treatment can be allowed in the USA, the FDA ensures that products are proven safe and effective, with side effects restricted by very strict conditions. The FDA’s stringent regulatory framework presents a significant hurdle in obtaining FDA approval for sublingual immunotherapy.

The other major obstacle to getting FDA approval for allergy drops is the requirement that the dosage level has to be standardized. Allergy drops, however, are tailored to an individual’s particular sensitivity, resulting in varying dosage amounts. This kind of individualized treatment is more of a therapy than a conventional product, further complicating matters for FDA approval. Although it is not approved by the FDA, researchers have indicated that in most cases, patients treated using sublingual immunotherapy have benefited from a decrease in allergic symptoms. Studies have shown that with sublingual immunotherapy, the severity of symptoms related to allergic rhinitis is greatly reduced. Furthermore, it was previously demonstrated that the beneficial effects of SLIT, such as the reduction in severity of symptoms, may even outlast a patient’s discontinuation of the therapy.

While allergy drops await FDA approval, avenues for future approval remain open. The FDA describes detailed pathways of approval for personalized medicine underpinned by biomarkers and surrogate endpoints in defining treatment effectiveness. These pathways would offer the opportunity to design more robust clinical trials with the primary goal to show the safety and effectiveness of SLIT.

Additionally, many of the constituents used in the allergy drop formulation are already FDA-approved, suggesting many of these formulations wouldn’t need de novo approval. FDA approval aside, seeking guidance from a healthcare provider is crucial for individuals considering allergy drops. A provider should be able to evaluate when the scope of sublingual immunotherapy would apply to any given type of allergy. Furthermore, a provider can ensure allergy drops are taken safely and assure that extracts are obtained from a reliable pharmacy. The path from allergy drops to FDA approval may be long and winding, but the promise of benefits in allergy treatment is one that will simply be too big to ignore. And so, with ongoing research and a focus on personalized medicine, allergy drops might one day receive the regulatory recognition they need.