Core Evidence clinical impact summary for [Panitumumab for metastatic colorectal cancer]

Outcome measure	Evidence	Implications
Disease-oriented evidence
Phase I–II studies	Panitumumab was well tolerated, and no human anti-human antibody formation or infusion-related reactions were observed. Moreover, the use of panitumumab increased overall response rate and seemed to improve PFS and OS.	Panitumumab was evaluated in phase III trials in patients with relapsed or refractory metastatic CRC.
Phase III	Panitumumab significantly improved overall response rate, PFR and OS in mCRC pretreated patients.	Panitumumab monotherapy received FDA approval for the treatment of metastatic colorectal cancer with disease progression while receiving or after receiving fluoropyrimidine, oxaliplatin, and irinotecan chemotherapy regimens.
K-RAS	Clinical efficacy of panitumumab therapy is restricted to patients with wild-type K-RAS tumors. There was no evidence of benefit in patients with mutated K-RAS tumors.	K-RAS genotyping of tumors should be strongly considered to select patients being treated with panitumumab.
Skin Toxicity	The development of skin toxicity during panitumumab monotherapy has been significantly linked with higher response rate and longer survival.	Skin toxicity cannot be used to select patients and it could be useful in the clinical practice to identify patients who may derive greater benefit from panitumumab treatment.
Economic evidence
Role of K-RAS testing in clinical practice.	Screening could cost several thousand dollars per patient and still result in a lower overall cost of care, based on very conservative estimates of the cost reduction associated with treatment avoidance in patients with K-RAS mutations.	Implementing routine K-RAS screening and limiting the use of EGFR inhibitors to patients with wild-type K-RAS actually appears the better strategy for selecting only the patients who could benefit from the therapy with panitumumab and also may have the potential for cost savings.