Nearly all patients who are treated with Vectibix™ (panitumumab) will develop an itchy skin rash that looks something like acne. However, treating the rash preemptively before it appears reduces its severity and lengthens the time before more serious rash appears.
During the STEPP (Skin Toxicity Evaluation Protocol with Panitumumab) trial, researchers randomized patients who were being treated with Vectibix to either preemptive skin rash management at the beginning of chemotherapy or reactive treatment once rash appeared. After six weeks, 70 percent of patients treated preemptively had not developed grade 2 skin rash. Sixty-two percent of the reactive group already had rash that was grade 2 or higher.
Skin rash management included:
- Topical steroids
- Oral doxycycline
After six weeks of treatment, 70 percent of the preemptive group were free of grade 2 rash, while only 38 percent of the reactive group were rash-free. In the reactive group half of patients had developed a grade 2 rash by 2.7 weeks.
More than twice as many people in the reactive group developed a more severe grade 3 rash (62 percent in reactive group versus 29 percent of the preemptive group.)
There was no increase in other side effects in the preemptive group.
Patients in the study were either treated with FOLFIRI chemotherapy and Vectibix every two weeks or Camptosar® (irinotecan) and Vectibix every three weeks.
As in other studies, benefits of Vectibix treatment were limited to patients without KRAS mutations in their tumors (wild-type).
Reflecting on the results of the STEPP study, David Chang, M.D., vice president for oncology clinical development at Amgen said,
Since skin rash is the most common side effect of EGFr therapy, the results of the STEPP trial showing that skin rash may be controlled by a relatively simple preemptive treatment, represent a significant advancement.
STEPP results were presented during the World Congress on Gastrointestinal Cancer in Barcelona, Spain.