Chroma was founded by Cancer Research Ventures (CRV) to exploit the chromatin biology research of Prof. Tony Kouzarides at the University of Cambridge and Prof. Paul Workman at the Institute of Cancer Research (ICR) in London. Prof. David Allis, now at Rockefeller University, NY, was subsequently approached and agreed to become involved in Chroma. Abingworth became involved in the establishment of Chroma in mid-2000 and was able to contribute the start-up executive management, who had independently approached them with a business plan that overlapped with that of Chroma. Combining these two elements provided Chroma with experienced management and complementary scientific experience.

Chroma became operational in September 2001 with the provision of seed financing from Abingworth and CRV, and the conclusion of pipeline agreements with the University of Cambridge and ICR. A number of patents in the chromatin field originating from the founding institutions were also assigned to the company, including discoveries of Prof. Allis whilst at the University of Virginia.

In November 2003, the company licensed the novel aminopeptidase inhibitor CHR-2797 from Vemalis PLC. In May 2004 the company raised £10 million in a Series B financing lead by the Wellcome Trust, joined by Gilde and Abingworth, and in December 2004 raised a further £5 million from Essex Woodlands Healthcare Ventures in an extension to the Series B financing. Between these two financings, the company entered CHR-2797, into a Phase I trial in solid tumors in October 2004.

Following closing of the Series B financing, Chroma has built a highly experienced management team and R&D organisation, and in February 2005 moved into new premises at Milton Park, providing world-class laboratory facilities to support its burgeoning science base.

In March 2006, the company closed a £30 million Series C financing, providing funding for the further clinical development of CHR-2797 and its chromatin-based development candidates. Around the time of the series C financing, the company entered the first of its internal candidate drugs into development, the HDAC inhibitor CHR-3996.