(Sharecast News) - Rare disease specialist Shire announced on Friday that the Ministry of Health, Labour and Welfare (MHLW) in Japan has granted manufacturing and marketing authorisation for its 'FIRAZYR' icatibant injection, for the acute treatment of hereditary angioedema (HAE) attacks in adult patients with HAE.The FTSE 100 drugmaker described HAE as a "rare genetic disease", characterised by recurrent attacks of localised oedema.It said the areas of the body most commonly affected were the extremities, skin and gastrointestinal tract, adding that less frequently, HAE could cause life-threatening attacks due to obstruction in the upper airways.Symptoms of HAE often presented in childhood, and while attacks could occur at any age, Shire said early onset could predict a more severe disease course."As a long-term partner to the HAE community, we continually strive to bring treatments to those living with HAE around the world," said Shire's executive vice-president and head of research and development Andreas Busch."HAE attacks can be unpredictable and debilitating and we are delighted that, subject to price listing, we will be able to provide the Japanese HAE community with the first subcutaneous on-demand therapy to treat acute HAE attacks."Shire said that for most people, attacks of HAE were caused by a deficiency of a protein called C1-esterase-inhibitor (C1-INH) - either there was not enough of it, or it did not function properly.Without sufficient or functional C1-INH, plasma kallikrein in the body was not appropriately controlled, it explained.Overactive plasma kallikrein led to excessive release of bradykinin, which caused blood vessels to release fluid, leading to the swelling which characterises HAE.Shire said FIRAZYR worked by blocking bradykinin from binding to certain receptors in the body, thereby treating the symptoms of acute attacks of HAE.The use of FIRAZYR in Japanese patients was examined in an open-label, single-arm, Phase 3 study of eight adult patients with a confirmed diagnosis of HAE who experienced angioedema attacks.During the study, three patients self-administered FIRAZYR and five patients had FIRAZYR administered by a physician.The primary efficacy endpoint was time to onset of symptom relief (TOSR), defined as a 50% reduction from baseline in patient visual analogue scale (VAS) score."The study showed that FIRAZYR was well tolerated and demonstrated symptom relief during an acute HAE attack through a single injection," the Shire board said in its statement."Overall, median TOSR was 1.75 hours, and TOSR was similar for patients who self-administered FIRAZYR or who had FIRAZYR administered by a physician."Symptom relief was attained as early as one hour after FIRAZYR injection and all patients had symptom relief within five hours."The most common adverse events in patients treated with FIRAZYR were injection site reactions such as erythema, or swelling, which were found to be mild to moderate in severity.