MDA-MB-231 cell line derived murine xenografts

Pharmaron (Beijing, P.R. China) was contracted by Pacylex to perform the xenograft experiments. MDA-MB-231 breast cancer cells (1 × 10⁷) were subcutaneously injected into on the right lower flank of thirty 6–8 week old NODscid mice at Pharmaron laboratory facilities (Beijing, China). Once the mean tumor size reached approximately 125 mm³, mice were randomized to receive an oral daily dose of either 35 mg/kg or 50 mg/kg of PCLX-001, or vehicle alone for 21 days. Treatment groups consisted of 10 mice each. Body weight, tumor measurements, and other routine monitoring was performed on all study animals once every other day (once per 2 days) throughout the course of the study. Body weight changes were calculated as:

Tumor measurements were conducted using calipers and tumor volume was estimated as:

where “length” and “width” were the longest and shortest diameters of a tumor, respectively.

Tumor growth inhibition (TGI) was calculated using the formula:

where “T” and “C” was the mean relative volumes (% tumor growth) of the tumors in the treated and the control groups, respectively. All the procedures related to animal handling, care, and treatment were performed according to guidelines approved by the Institutional Animal Care and Use Committee (IACUC) of Pharmaron following the guidance of the Association for Assessment and Accreditation of Laboratory Animal Care (AAALAC).