Pharmacogenomics of Paclitaxel in Ovarian Cancer

Paclitaxel is an antineoplastic drug used in the treatment of ovarian cancer. The effect and toxicity is unpredictable in the individual patient. Paclitaxel is removed (eliminated) from the organism by oxidation. CYP2C8 is the enzyme mainly responsible. P-glycoprotein (Pgp) is an efflux transport protein natural to the human organism. Pgp is responsible for excretion of drugs via the bile and the kidneys and is thought to play a role in chemotherapy resistance. Paclitaxel is substrate for Pgp. Single nucleotide polymorphisms are possible causes for variation in both CYP2C8 and Pgp expression/function. We will study a possible role of these genetic variations as predictors of paclitaxel toxicity and effect and the possible implications for individual dosing in the future.

We want to determine the metabolic capacity of approximately 100 ovarian cancer patients and comparing this with genotypes, acute toxicity(eg. bone marrow suppression and neuropathy) and response to treatment(ie. CA125 response, progression free survival and overall survival). The metabolic capacity is estimated using a "sparse sampling" approach applying advanced computerized pharmacokinetic/dynamic modelling as opposed to traditional "frequent sampling" pharmacokinetic studies which burden the individual patient more.

Patients are recruited in collaboration with Oncological departments throughout Scandinavia.

Inclusion criteria

• Clinical diagnose and histology of invasive epithelial ovarian/tuba or peritoneal cancer
• FIGO stage IIb-IV any grade or FIGO Ia-IIa only grade 3 or clear cell carcinoma (any stage and grade)
• Natural candidate for paclitaxel 175mg/m2 + Carboplatin (AUC=5-6)
• Baseline CA125≥70 AND/OR evaluable disease after RECIST (incl ultrasound)
• 18 years or older
• Caucasian (ie.parents and grandparents are Caucasian)
• Performance status 2 or lower (after WHO/ECOG)

Exclusion criteria

• Prior malignant disease apart from cervical carcinoma in situ and basal cell carcinoma of the skin
• Prior chemo / radiotherapy
• Ongoing or imminent other chemotherapies
• Pregnant or lactating
• Fertile woman of childbearing potential not willing to use adequate contraception
• Neurological symptoms (any kind) worse than CTCAE grade 1
• Active infection or other serious disease that could impair on treatment and/or follow-up