Open AccessPanitumumab in Patients with KRAS Wild‐Type Colorectal Cancer after Progression on Cetuximab
Author(s) -
Wadlow Raymond C.,
Hezel Aram F.,
Abrams Thomas A.,
Blaszkowsky Lawrence S.,
Fuchs Charles S.,
Kulke Matthew H.,
Kwak Eunice L.,
Meyerhardt Jeffrey A.,
Ryan David P.,
Szymonifka Jackie,
Wolpin Brian M.,
Zhu Andrew X.,
Clark Jeffrey W.
Publication year - 2012
Publication title -
the oncologist
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.176
H-Index - 164
eISSN - 1549-490X
pISSN - 1083-7159
DOI - 10.1634/theoncologist.2011-0452
Subject(s) - cetuximab , medicine , panitumumab , kras , colorectal cancer , oncology , cancer , cancer research
Purpose. Cetuximab and panitumumab are monoclonal antibodies that target the epidermal growth factor receptor (EGFR) and are approved for the treatment of patients with KRAS wild‐type metastatic colorectal cancer. There are no data that describe the activity of panitumumab in patients with progressive disease on cetuximab. We performed a single‐arm phase II trial of panitumumab in patients with KRAS wild‐type metastatic colorectal cancer that had progressed on prior cetuximab. Patients and Methods. We used a two‐stage study design to treat patients with panitumumab at 6 mg/kg every 14 days (cycle length = 28 days). Treatment was continued until disease progression, death, inability to tolerate panitumumab, or study withdrawal. The primary endpoint was response rate; secondary endpoints included progression‐free survival and overall survival. Twenty patients were treated in the first stage, with plans to treat an additional twelve patients if there was at least one objective response. We collected blood samples at baseline and prior to cycles 2 and 3 to evaluate for the presence of anti‐cetuximab and anti‐panitumumab antibodies. Results. We treated twenty patients for a median of two cycles (range 1–4). No patients responded, and 45% had a best response of stable disease (no progression for at least two cycles). Median progression‐free survival was 1.7 months and median overall survival was 5.2 months. Panitumumab was well tolerated. Thirteen patients (65%) had grade 1–2 dry skin or rash, and three patients had treatment‐related grade 3 toxicities (one each with hyperglycemia, hyperbilirubinemia, and hypokalemia). No patients had detectable anti‐cetuximab antibodies at any time point; one patient developed anti‐panitumumab antibodies. Conclusions. Panitumumab has minimal benefit in patients with KRAS wild‐type metastatic colorectal cancer that has progressed on prior cetuximab.