Unnatural Allergen Eases Grass Pollen Allergy

Petra Zieglmayer, MD

For reducing grass pollen allergy symptoms, more is better.

A 1-year follow-up of different administration schedules for recombinant grass pollen vaccine (BM32) indicated that more injections provided greater clinical benefit than less, according to a presentation at the joint meeting of the American Academy of Allergy, Asthma and Immunology and the World Allergy Organization (AAAAI/WAO) in Orlando, FL.

Petra Zieglmayer, MD, reported that in a placebo-comparative analysis of 3, 4, and 5 monthly-injection BM32 prior to grass pollen season, the subjects receiving 5 active injections demonstrated the greatest symptom reduction relative to placebo during the peak pollen period.

No group sustained treatment effect into the next season, however.

Zieglmayer has previously commented on the rationale for developing the recombinant product, in an assessment of its mechanisms, safety and efficacy that she published with colleagues.

"Current allergy vaccines are based on natural allergen extracts which are often of poor quality — eg., varying allergen compositions, lack of important allergens, contaminations — and may induce severe immediate and late phase side effects," Zieglmayer and colleagues wrote.

Additional problems associated with the natural allergen extracts that prompted the group to develop a recombinant vaccine alternative included inconvenient treatment schedules, multiple administrations of gradually increasing doses and, in sensitive patients, the possibility of side effects preventing reaching a fully effective maintenance dose.

"Progress made regarding the molecular characterization of the disease-causing allergens has now opened the door for new forms of allergen-specific immunotherapy which allow reduced side effects and targeting of specific pathways of the allergic immune response," researchers wrote.

The researchers describe BM32 as a B cell epitope-based allergy vaccine, which is based on fusion proteins consisting of non-allergenic peptides derived from the IgE binding sites of disease-causing allergens (that do not bind IgE themselves) and PreS, a surface protein from hepatitis B which serves as a non-allergenic carrier protein providing T cell help.

In the trial reported by Zieglmayer at the congress, 124 subjects were randomized to receive a different number of monthly active or placebo injections in a 4-month period prior to the 2016 grass pollen season. Symptoms were evaluated on a 4-point scale comprising 4 nasal symptoms (runny nose; blocked nose; sneezing; itchy nose) and 2 ocular symptoms (itchy/red eyes; watery eyes).

In the primary measure of combined score from the Symptom Scores and Medication Scores (SMS), the mean daily SMS during the pollen peak following 3, 4, or 5 pre-season monthly injections of BM32 improved by 15%, 3%, and 25%, respectively, versus placebo. There was no further treatment effect demonstrated during the grass pollen peak in 2017.

"Five active injections demonstrated the best immediate clinical efficacy, but no sustained effect," Zieglmayer said. "BM32 was safe and well tolerated."

The presentation, "Clinical Efficacy of a Recombinant Grass Pollen Vaccine One Year after a 4 Month Treatment Course," was published online in the Journal of Allergy and Clinical Immunology.