Dear Marilia,

Attached please find a paper that covers the answer to your question. I have copied some text which I think to be important for quick view:

Neoplasia. 2014 Jul; 16(7): 562–571.

Published online 2014 Aug 9. doi: 10.1016/j.neo.2014.06.004

PMCID: PMC4198828

Co-Treatment with Panitumumab and Trastuzumab Augments Response to the MEK Inhibitor Trametinib in a Patient-Derived Xenograft Model of Pancreatic Cancer1

James M. Lindberg,* Timothy E. Newhook,* Sara J. Adair,* Dustin M. Walters,* Alison J. Kim,* Edward B. Stelow,† J. Thomas Parsons,‡ and Todd W. Bauer*⁎

Tumor Xenografts and Treatment

Tumor pieces (~ 50 mg) were orthotopically implanted onto the pancreata of 6- to 8-week-old male athymic nude mice. Tumors were allowed to grow for 3 to 4 weeks to a volume of 100 to 500 mm3 as assessed by volumetric magnetic resonance imaging (MRI), at which point drug treatment commenced. Mice were treated with either vehicle (0.5% hydroxypropyl methylcellulose in 0.1% Tween 80) or a combination of trametinib, panitumumab, and/or trastuzumab as indicated in the text and figures. Dosing was given as follows: trametinib (0.3 mg/kg orally, once daily), panitumumab (200 μg, intraperitoneal injection, twice weekly), trastuzumab (500 μg, intraperitoneal injection, twice weekly), pertuzumab (200 μg, intraperitoneal injection, twice weekly). In all experiments, volumetric MRI was used to assess changes in tumor volume at 7-day intervals while on drug treatment, as previously described [23]. Mice were then sacrificed, tumors were completely excised, weighed, and measured by calipers, and mice were examined for the presence of metastatic disease. To determine the therapeutic efficacy of drug combinations, an MRI was obtained just before the start of treatment to establish an index tumor volume for each mouse. Subsequent interval MRI studies were used to assess the change in tumor volume while on treatment. The interval tumor volumes were divided by the index tumor volume to calculate the relative change in tumor volume (fold change) for each tumor. Linear regression was used to model a line of best fit for the tumor fold change data plotted relative to time. The slope of that line of best fit served as an estimate of the tumor growth rate for each treatment group expressed as the fold change per week on treatment. Upon completion of the experiment, pieces of tumor were placed in Allprotect (Qiagen, Valencia, CA), snap-frozen in liquid nitrogen, or fixed in formalin for histologic analysis.

Hoping this will be helpful,

Rafik

trametinib (1 mg/kg/day, intraperitoneal injection) or vehicle (0.5% methylcellulose, 0.2% Tween 80, i.p. injection) once per day for 6 days a week for 3 weeks