I have had to remove biro about 20 times from my cream leather sofa!! The best i can reccommend is aftershave or perfume on cotton wool or kitchen paper, please try on a hidden area first incase it changes colour. Good luck!
Perfume and nailvarnish remover. We had a biro leak onto our white sofa and although it took several goes and to start with we didn't think it was going to come off as we had a pale bluepatch, eventually it did shift it.As Rachel says though try a little patch first somewhere inconspicuous.