New client wins for 2015 are: Results with Lucy, the fitness programme from The Only Way Is Essex (TOWIE) star Lucy Mecklenburgh; Asthma UK; the NHS Partners Network; the End of Life Care campaign; and German pharmaceutical company Bayer.
It follows client wins in late 2014 that included the personal genomics service 23andMe and drugs firm Alexion.
Incisive, which was named New Consultancy of the Year at the PRWeek Awards 2014, has increased its staff count from eight to 16 in the past few months by hiring a series of account managers and directors.
Among the account director appointments are Ben Nunn of MHP Communications and Caroline Gordon of Connect Public Affairs.
Mike Birtwistle, founding partner of the London-based agency, said: "The team had an incredibly busy 2014 delivering superb work on some of the biggest health issues facing society. This work is clearly being noticed, leading to new opportunities with a range of clients."