(ShareCast News) - Imperial Innovations noted top-line results from a Circassia Pharmaceuticals drug study on Monday, after Circassia's share price plummeted in the wake of the cat allergy treatment's failure to perform against a placebo.At 1230 BST, shares in Imperial were down 3.87% at 418.3p.In the study, both treatment regimens and placebo greatly - and equally - reduced subjects' combined allergy symptom and rescue medication use score from baseline.As a result, despite the improvements in subjects' allergy symptoms and rescue medication use, the very marked placebo effect meant that the treatment did not meet the study's primary endpoint."Although these results are disappointing, we continue to be supportive long-term shareholders in Circassia.," said Imperial CEO Russ Cummings."The experienced management team have diversified the business since its IPO in 2014."Cummings said that in addition to its immunotherapy products, Circassia has a fast-growing asthma diagnostics and management platform and a broad pipeline of respiratory products."Our strategy is to build a portfolio of high quality, well-managed, well-funded businesses with significant potential. Circassia, in which we have a 9.3% stake, continues to be one," he added.Imperial Innovations' portfolio currently comprises 105 companies, of which 45 are "accelerated growth companies" in which Imperial actively invests and takes a seat on the board.