Merck’s Hope Blooms for Allergen Therapy Approvals, but Challenges Rain on Potential Success

Merck has received a nod from the FDA Allergenic Products Advisory Committee (APAC) in support of a licence application for its allergic rhinitis (AR) therapy Ragwitek; however, the healthcare giant still faces a number of significant challenges even if approval is granted, says an analyst with research and consulting firm GlobalData.

The APAC’s support for Ragwitek’s Biologics License Application (BLA) is a positive step forward for the ragweed allergen therapy, which is the second offering to arise from Merck’s partnership with ALK-Abello. The company’s grass allergen tablet Grastek was unanimously endorsed by the APAC in December 2013.

Claire Gibson, PhD, GlobalData’s Healthcare Analyst covering Cardiovascular and Metabolic Disorders, says: “If either of these tablets’ BLA is successful, it will become the first sublingual immunotherapy to be approved for use in AR in the US, as patients with a severe form of the increasingly prevalent condition are currently treated with subcutaneous immunotherapy (SCIT).

“While highly inconvenient, SCIT-delivered allergen extracts are cheap and considered very safe, despite a lack of safety and efficacy testing in clinical trials. Meanwhile, allergy immunotherapy tablet (AIT) formulations are currently being evaluated in clinical trials, and even though this therapy is undoubtedly more convenient, allowing patients to self-administer the medication at home, its efficacy is often doubted.”

Although the potential approval of Merck’s AITs will represent a pioneering step forward in registered, FDA-approved AR treatments in the US, GlobalData does not expect them to revolutionise the AR immunotherapy market.

Gibson continues: “Allergen extracts in the US are currently prepared by physicians ‘in house’ according to individual patients’ needs. Without a financial incentive, physicians may be reluctant to prescribe the standardised allergen tablets over SCIT.

“Furthermore, both Ragwitek and Grastek are aimed at treating a single allergy, while Stallergenes’ AIT Oralair, which was also recommended by the APAC last year, contains grass allergens for Kentucky blue, orchard, perennial rye and sweet vernal. Additionally, Oralair is only taken for approximately six months a year, whereas Merck’s Grastek must be taken all year round.”

A BLA has been submitted to FDA for each of these tablets, and a response will be delivered to the respective companies in the first half of 2014. GlobalData is certain that both Merck and Stallergenes will be hoping for a positive response before the start of the 2014 pollen seasons.