A review.Hyaluronan receptors (CD44, RHAMM) are over-expressed in a wide variety of cancers including bladder and ovarian tumors.Based on this rationale, a hyaluronic acid paclitaxel conjugate, ONCOFID-P, was developed for the treatment of refractory bladder cancer and peritoneal carcinosis.ONCOFID-P has demonstrated improved in vitro and in vivo efficacy in hyaluronan receptor-pos. tumor models and a favorable toxicity profile in rodents.It has been investigated in 15 patients with refractory bladder cancer by intravesical instillation, showing promising antitumor efficacy with 60 % of treated patients achieving a complete response.As a consequence, phase II studies with ONCOFID-P are ongoing in six European countries.In addition, phase I studies have been initiated investigating the maximum tolerated dose (MTD) and the safety profile of ONCOFID-P following IP infusion in patients affected by i.p. carcinosis in ovarian, breast, stomach, bladder and colon cancer.