ORLANDO A prophylactic skin care regimen may prevent the severe rashes that afflict cancer patients treated with epidermal growth factor receptor inhibitors, according to a physician who conducted a randomized, controlled trial in 95 colon cancer patients.
Not only did the intervention reduce moderate to severe dermatologic side effects by more than half during the 6-week study, but investigators also were surprised to see adverse events such as diarrhea and neutropenia sharply reduced.
"Everything is cost effective," Dr. Edith P. Mitchell said, listing the generic products in the regimen during a press briefing at the annual meeting of the American Society of Clinical Oncology, where the study was presented.
The regimen includes sunscreen (for patients going out in the sun), a moisturizer, topical 1% hydrocortisone cream, and 100 mg of oral doxycycline, all given twice a day, explained Dr. Mitchell, program leader in gastrointestinal oncology at Thomas Jefferson University in Philadelphia.
Treatment should commence at least 24 hours before the start of anti-epidermal growth factor receptor (EGFR) therapy and continue throughout treatment, she said. One patient stayed on the prophylactic regimen for a year.
All patients in the STEPP (Skin Toxicity Evaluation Plan with Panitumumab) study were being treated with panitumumab (Vectibix), a monoclonal antibody approved as monotherapy for metastatic colorectal carcinoma that has progressed after standard chemotherapy. Although cetuximab (Erbitux), another EGFR inhibitor, was not involved in the trial, Dr. Mitchell said rash is a class effect of EGFR inhibitors. She also uses the regimen in patients receiving cetuximab.
Investigators randomized 48 patients to the prophylactic regimen and 47 patients to receive skin treatment reactively if they developed a rash. Dr. Mitchell reported 14 patients (29%) in the prophylactic group developed grade 2 or higher skin toxicity, compared with 29 patients (62%) in the control group.
Just 3 patients had grade 3 or higher dermatologic toxicity, compared with 10 patients in the control group. Those toxicities included dermatitis acneiform, pruritus, and pustular rash. None of the patients in either group had a grade 4 or 5 event.
Although the prophylactic group received more panitumumab doses (155 vs. 141) during the study, they had fewer doses of panitumumab delayed (1 vs. 9). That is considered important, because EGFR rashes are a problem affecting 90% of patients, causing some to delay and even to stop treatment, according to Dr. Mitchell. There have even been deaths due to infections associated with those rashes, she said.
A concern going into the study was that eliminating rash would interfere with the effectiveness of panitumumab.
Dr. Mitchell reported the regimen had no impact on efficacy of the colon cancer therapy. The overall response rate was 15% in the prophylactic arm and 11% in the control group; progression-free survival was 4.7 and 4.1 months, respectively.
The analysis also saw no difference between the two study arms when patients were analyzed for KRAS status.
Nondermatologic toxicities including grade 3 nausea, vomiting, fatigue, diarrhea, neutropenia, hypomagnesemia, and dehydration occurred less frequently in the prophylactic arm, as did grade 4 neutropenia. Neither group had any grade 5 toxicities.
Dr. Mitchell and many of her co-investigators disclosed financial relationships with Amgen, Inc., which makes panitumumab.
'Everything iscost effective,' and the skin care regimen had no impact on the cancer drug's efficacy. DR. MITCHELL