MPM beat 10 other UK print management companies to the tender and will now produce upwards of 3,000 individual printed products per annum.
GSK said it was looking for a business that could best support its pharmaceutical, consumer healthcare and nutritional business units with business innovation, industry knowledge, and the highest level of personal customer service.
Mayence said that its prices were also proven to be "at least 25% lower than others".
Darren Kopitko, managing director of the print management business, said: "GSK's decision to re-appoint Mayence UK for a further three years is a testimony to the dedication, hard work and the very high standards of customer care my on-site team have delivered over the previous five years.
"As you can imagine, my team and I are extremely proud and enthused to continue our work for GSK."
MPM has a turnover of £50m and employs 100 staff. It specialises in pre-press, post-press, editing, catalogues, POS, gifts and premiums and web cataloguing.
The company counts numerous blue-chip customers, such as Nestlé, Henkel and The Phone House within its client roster.