The reset of the Pegcetacoplan review timeline by the European Medicines Agency is a positive regulatory development for Apellis Pharmaceuticals. This decision likely indicates progress in the review process, which can be seen as a positive signal by investors, leading to increased confidence in the company's pipeline and potentially its future revenue prospects. The direct mention of the company and the specific nature of the news suggest a high relevance and importance to the company's stock performance in the short term.