Trial Information

Evaluation of Polymorphisms, Mutations, and Protein Expression by Automated Quantitative Immunohistochemistry (AQUA) in the LapatinibTargets and Metabolic Pathway in Samples From E5803

OBJECTIVES:

- To determine the association between polymorphisms in drug metabolizing enzymes and
lapatinib ditosylate-associated toxicity in patients with hormone-sensitive recurrent
prostate cancer receiving lapatinib ditosylate on clinical trial ECOG-E5803.

- To determine the association between mutations in EGFR, HER-2 and Kras; protein
expression of HER2, EGFR, MAPK and AKT; polymorphism controlling androgen synthesis;
and progression-free survival.

OUTLINE: Tissue and blood samples collected from patients enrolled on clinical trial
ECOG-E5803 are analyzed for correlative studies. Samples are assessed for HER2, EGFR, MAPK,
and Akt; EGFR mutations and polymorphisms in CYP3A4; Ras mutations; recently identified
mutations in HER2-neu and Kras; and additional polymorphisms in the lapatinib ditosylate
metabolic pathway by automated quantitative IHC. Predictors of efficacy and toxicity are
analyzed, including markers in the EGFR pathway as predictors of progression-free survival.