Oral/sublingual Phleum pretense grass tablet (Grazax/Grastek) to treat allergic rhinitis in the USA

Abstract

With the approval of two grass tablets and one ragweed tablet for sublingual immunotherapy (SLIT) by the US FDA in April 2014, the practice of allergy immunotherapy (AIT) in the USA has dramatically changed. Until this time, there were no approved allergen extracts for sublingual administration and physicians who prescribed SLIT for their patients did so without full knowledge of proper dosing or assurance of its safety. Now sublingual allergen tablets are available that have proven safe and effective doses. This article describes, in detail, the studies that have been conducted with a timothy grass SLIT tablet and draws some comparisons to the alternative 5-grass SLIT tablet. It also attempts to predict what will be the impact of the introduction of these tablets on the practice of AIT in the USA over the next few years.

Keywords::

• AIT
• allergy immunotherapy
• grass immunotherapy
• SCIT
• SLIT
• subcutaneous immunotherapy
• sublingual immunotherapy

Financial & competing interests disclosure

HS Nelson has been a consultant for Merck and a consultant and investigator for Circassia. The author has no other relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript apart from those disclosed.

No writing assistance was utilized in the production of this manuscript.

Key issues

• Grastek is a rapidly dissolving tablet for sublingual administration containing 2800 bioequivalent allergen units, or 75,000 standardized quality units of timothy pollen extract.

• Timothy pollen is cross-reactive with other members of the Pooideae subfamily or Northern Pasture grasses, but has limited or no cross-reactivity with southern grasses such a Bermuda, Bahia and Johnson grasses.

• Treatment with the tablets should be initiated at least 12 weeks before the onset and continued through the pollen season.

• When administered continuously for 3 years, cessation was followed by persisting clinical benefit for the 2 years that were monitored.

• The first dose should be administered in a health care setting under observation by a physician, but subsequent doses are taken at home on a once-daily schedule.

• Local administration site adverse reactions, mostly itching and occasional swelling are experienced by about half the patients. They are brief and usually recur only for the first 1–2 weeks.

• Systemic reactions are rare, usually mild to moderate, have never been fatal or near fatal.

• The US FDA has mandated that patients be prescribed and taught how to use an epinephrine auto-injector for use in the event of a systemic reaction.

Notes