Objectives To evaluate the activity and toxicity of AEZS-108 (Zoptarelin Doxorubicin Acetate) an LHRH agonist linked to doxorubicin in women with platinum refractory or resistant ovarian cancer expressing LHRH receptors. Methods Women with epithelial ovarian, fallopian tube or primary peritoneal cancer, expressing LHRH receptors were eligible for this trial, when they had progression during treatment with a platinum based regimen or within 6 months after receiving a platinum based regimen and a previous taxane treatment. At least one measurable target lesion (RECIST) or CA-125 levels higher than twice the upper limit of normal range (GCIG-criteria) were required. Patients received AEZS-108 (267 mg/m2 equimolar to 76.8 mg/m2 of free doxorubicin) every 3 weeks as a two hour i.v. infusion. Results Fifty-five of 59 (93%) of ovarian cancer samples screened expressed LHRH receptors. 42 patients were enrolled in this study and received at least 1 infusion of AEZS-108 (ITT population). Of these 42 patients 6 (14.3%) had a partial response, 16 (38%) stable disease, 16 (38%) progressive disease and 4 patients were not evaluable. Median time to progression was 12 weeks (95% CI: 8-20 weeks), and median overall survival was 53 weeks (95% CI: 39-73 weeks). Toxicity profile was favorable. Conclusion AEZS-108 has a clinical activity in platinum refractory/resistant ovarian cancer which seems to be comparable to that of pegylated liposomal doxorubicin or to topotecan. Toxicity was comparably low. These data support the concept of a targeted chemotherapy for tumors expressing LHRH receptors.