This invention is directed to compounds of the formula (I): wherein one of R.sup.6, R.sup.7, R.sup.8 and R.sup.9 is and X, R.sup.1 to R.sup.12, m, n and o are as defined in the description, and pharmaceutically acceptable salts and/or esters thereof. The invention is also directed to pharmaceutical compositions containing such compounds, to a process for their preparation and to their use for the treatment and/or prevention of diseases which are modulated by PPAR.delta. and/or PPAR.alpha. agonists.