Pre-emptive treatment helped curtail skin toxicity with Panitumumab

With a pre-emptive, prophylactic skin regimen, patients who receive panitumumab for treatment of metastatic colorectal cancer may be able to avoid some of the skin-associated toxicities, according to data presented at the 2009 American Society of Clinical Oncology Gastrointestinal Cancers Symposium in San Francisco.

Edith Mitchell, M.D., a clinical professor in the Department of Medical Oncology at Jefferson Medical College of Thomas Jefferson University, presented data from the study, which was the first prospective study to compare pre-emptive and reactive skin treatment for skin toxicities related to panitumumab. The study was co-led by Dr. Mitchell and Mario Lacouture, M.D., an assistant professor of Dermatology at Northwestern University's Feinberg School of Medicine in Chicago.

Skin toxicities are the most common adverse effects related to panitumumab (Vectibix), which is a fully human monoclonal antibody that targets the epidermal growth factor receptor (EGFR). The toxicities could include erythema, dermatitis, pruritus, pustules, rash, and hair and nail changes.

“Panitumumab and the other EGFR inhibitors are now key components to the treatment strategies for metastatic colorectal cancer,” Dr. Mitchell said. “But the majority of the patients who receive these agents suffer from skin toxicities, and for some patients, the treatment must be interrupted or discontinued. If we can prevent or minimize these toxicities, it would be a significant advance in patient care.”

The researchers studied 95 patients receiving panitumumab in combination with irinotecan-based chemotherapy. The patients were randomized to receive pre-emptive skin toxicity treatment initiated 24 hours prior to the first dose of panitumumab, then given daily through week six, or reactive skin treatment after the skin toxicity developed. The skin treatment included moisturizers, sunscreen, topical steroids and oral doxycycline.

The primary endpoint was the incidence of specific grade 2 or higher skin toxicities during the six week skin treatment period. The incidence of these toxicities was reduced more than 50% in the group that received pre-emptive treatment.

Quality of life was also assessed, using the Dermatology Life Quality Index. Patients who received the pre-emptive, prophylactic skin treatment regimen reported an improved quality of life, even around week three, which was the median time to first grade 2 or higher skin toxicity in the reactive skin treatment group.

"This study supports the notion that, as with other side effects to cancer treatments, it is more advantageous to treat prophylactically, than to wait for the side effect to fully develop," Dr. Lacouture said. "Futhermore, it shows that treating early on does not affect the benefit received from the anticancer therapy.”