Curtailing Skin Toxicity Associated With Colon Cancer Drug
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 being presented at the 2009 ASCO Annual in Orlando.
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 STEPP (Skin Toxicity Evaluation Protocol with Panitumumab) trial, which was the first prospective study to compare pre-emptive and reactive skin treatment for skin toxicities related to panitumumab.
Skin toxicities are the most common adverse effects related to panitumumab (Vectibix) and cetuximab (Erbitux), which are fully human monoclonal antibodies that target the epidermal growth factor receptor (EGFR). The toxicities affect approximately 90 percent of patients who receive panitumumab, and 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, 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. Forty-eight patients received the pre-emptive treatment, which 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. In the six-week period, 29 percent of patients who received pre-emptive treatment developed the skin toxicities, compared with 62 percent of the patients who did not receive 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.