The figure illustrates the influence of the mass loss rate on the evolution of a massive merger object. The dashed line represents the mass evolution during the core helium burning phase (CHeB) if a constant mass loss rate of hydrogen-deficient WR stars is adopted that closely matches our computed rates. In this case the VMS will end its life with a mass greater than 1000   M_⊙ and the formation of an intermediate-mass black hole (IMBH) takes place. In contrast, we also followed the CHeB evolution by using an extrapolation of the mass loss rates presented by Nugis & Lamers (2000) for hydrogen-deficient WR stars (dotted line). In this case the star loses much more mass and therefore the occurrence of a pair-instability supernova is more likely than the formation of an IMBH.