Abstract 2673: Relationship between serum hormone levels and pharmacokinetics (PK) of PEGylated liposomal doxorubicin (PLD) in patients with refractory ovarian cancer

Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL Background: Pharmacokinetics (PK) of nanoparticle agents, such as PEGylated liposomes, are dependent upon the carrier and not the encapsulated drug. Previous studies have demonstrated a high degree of interpatient variability in the PK of PEGylated liposomal doxorubicin (PLD). We have previously demonstrated that circulating monocytes play a major role in clearance (CL) of PEGylated liposomes in patients. Estrogen and testosterone, which are largely secreted via the gonads, have been shown to modulate monocyte function and chemotaxis. In addition, estrone is converted from other steroid hormones in adipose tissue. Thus, we evaluated the relationship between serum hormone concentrations in blood samples and PK of PLD in patients with refractory ovarian cancer. Methods: PLD was administered at 30 or 40mg/m2 IV every 28 days with or without concurrent carboplatin at an AUC = 5 in patients (n = 10) with recurrent ovarian cancer. All patients had undergone bilateral salpingo-oophorectomy (BSO). Serial PK samples were obtained from time 0 h to 168 h and day 28 post PLD dose. Plasma was processed to measure encapsulated and released doxorubicin using solid phase separation and HPLC with fluorescence detection. CL of encapsulated doxorubicin in plasma was calculated by non-compartmental methods. Prior to administration of PLD, serum samples were collected and concentrations of estrone, estrogen, testosterone, and dihydrotestosterone were measured. Results: There was a direct linear relationship between encapsulated doxorubicin CL and both testosterone (R2 = 0.72) and estrone concentrations (R2 = 0.54) in all patients. When patients were subdivided based on PLD monotherapy (n = 6) or PLD + carboplatin (n = 4), there was a stronger relationship between encapsulated doxorubicin CL and both testosterone (R2 = 0.88) and estrone concentrations (R2 = 0.86) in patients receiving PLD monotherapy. Estrogen and dihydrotestosterone concentrations were below quantification limits for the majority of patients and thus were not evaluated. There was no relationship between patient body weight and BMI and estrone concentrations (R2 = 0.25 and R2 = 0.13 respectively). Conclusions: These findings indicate that serum hormone concentrations are associated with encapsulated doxorubicin CL and thus may be useful for individualizing PLD therapy in patients with ovarian cancer and other malignancies. Patient body weight and BMI were not associated with estrone concentrations in patients with ovarian cancer, suggesting phenotypic and/or genotypic differences in estrone production in adipose tissue. Low estrogen concentrations are consistent with the patients undergoing BSO surgery as standard treatment of ovarian cancer. The relationship between hormone levels and PK of nanoparticles needs to be further evaluated as a method to individualize nanoparticle therapy. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2673. doi:1538-7445.AM2012-2673