In phase I clinical trials escalating doses of PF-00477736 were administered intravenously on Days 2 and 9 and gemcitabine was be administered intravenously on Days 1 and 8 of a 21-day cycle. Doses from 50 - 225 mg were tested.

The proliferation assays were done using an MTT assay. The IC50 assay measures the antiproliferative effects of PF-00477736 on p53-defective human cancer cell lines. Cells in each line were seeded in complete medium at an exponentially growing density in 96-well assay plate and allowed to attach for 16 h. Serial dilutions of PF-00477736 were then done, and appropriate controls were added to each plate. Cells were incubated with drug for 96 h. After incubation, MTT working stock diluted in complete medium was added to each well, and cells were incubated for 4 h. After centrifugation and supernatant removal, DMSO was added to each well and plates were read on SpectraMax plate reader at 540 nm. PF-00477736 was found to be cytotoxic in low-micromolar doses.