Safety evaluation of a new allergy vaccine containing the adjuvant monophosphoryl lipid a (MPL®) for the treatment of grass pollen allergy

A novel allergy vaccine (Pollinex(R) Quattro) has been developed for the prevention or relief of allergic symptoms caused by a variety of pollens. Within this range, the grass pollen allergy vaccine contains extracts of 12 grass pollens and rye cereal (all chemically modified by glutaraldehyde) that are adsorbed onto L-tyrosine with addition of the immunostimulatory adjuvant monophosphoryl lipid A (MPL(R)). A specific preclinical safety testing strategy was developed to support clinical use, comprising single-dose toxicity, repeat-dose toxicity and local tolerance studies. Dose levels of up to 0.5 ml per animal (mouse) and up to 1.0 ml per animal (rat and rabbit) were used with vaccines containing 2000 or 12 000 standardized units (SU) ml(-1) of grass pollen allergoids, 50 mug ml(-1) of MPL(R) adjuvant and 20 mg ml(-1) of tyrosine. Overall, the product showed no toxicological findings of significance at levels greatly in excess of those proposed for clinical use. A not unexpected, but relatively minor, immunostimulatory effect was seen following repeated dosing (once weekly for 3 weeks) at 1.0 ml per rat. Copyright (C) 2004 John Wiley Sons, Ltd.