A US Food and Drug Administration (FDA) advisory committee recommended approval of two oral immunotherapy products for common seasonal allergies from Merck & Co and Stallergenes last week.
Stallergenes’ Oralair and Merck’s Grastek both take the form of tablets that are placed under the tongue and are designed to work by a process called allergen desensitisation, exposing the body to a trigger antigen until the immune system adapts and no longer reacts to it.
Oralair includes allergen extracts from mixed pollens comprising sweet vernal, orchard, perennial rye, Timothy, and Kentucky blue grass, while Grastek contains timothy grass pollen only. Both Grastek and Oralair have been on the market in Europe and various other countries for several years.
At the moment no sublingual (under the tongue) allergen immunotherapy has been approved in the US, although subcutaneous immunotherapies are available. The Merck and Stallergenes products allow patients to be treated at home rather than in a clinic, and side step localised reactions that can occur with subcutaneous injections.
The FDA’s Allergenic Products Advisory Committee (APAC) backed approval of Oralair based on a clinical trials programme in around 2,500 adults and children aged five or older with grass pollen-induced allergic rhinitis or conjunctivitis.
The FDA panel opted not to vote on the use of Oralair in younger children as the dataset for those aged five to nine was small, and instead limited its deliberations to children aged 10 and over and adults under 65.
There were some concerns raised about the risk of serious hypersensitivity reactions to the allergens in Oralair on the back of side effects in patients with asthma, which could suggest possible anaphylactic reactions.
The committee recommended that all patients taking Oralair have an epinephrine auto-injector to hand as a precaution, and some panellists suggested follow-up studies in asthma patients – as well as pregnant women – could be of value.
Stallergenes recently signed a deal with Greer, granting the latter exclusive commercialisation rights to Oralair in the US.
Turning to Grastek, which was originally developed by Danish drugmaker Alk-Abello, the panel recommended approval in people aged five to 65, once again on the proviso that those taking it have access to epinephrine and also with a recommendation that studies in patients with asthma are also undertaken.
The lower age range was in part given the go-ahead because Grastek is formulated as a fast-dissolving tablet, which makes it more suitable for younger children.
If approved in the US, the new products are not expected to be massive sellers despite the convenience over injectable immunotherapies, with most analysts predicting peak sales in the $150m-$300m range.
Even at the top end that would correspond to a minor product for Merck, although it has other products in the pipeline for ragweed pollen and dust mite allergy which, taken collectively, could become a meaningful franchise. Meanwhile for Stallergenes – with annual sales of around €250m – the upside could be significant.