"We continue to focus on additional studies involving tremelimumab alone and in combination with other therapies which are currently ongoing in patients with several types of cancer," said Charles Baum, vice president and oncology therapeutic area head at Pfizer Global Research and Development, the AP reported.
Baum also said Pfizer "will continue to assess the study data to understand the clinical benefit seen in some patients who received tremelimumab."
Deadliest Form of Skin Cancer Largely Unknown
Merkel cell carcinoma -- the deadliest form of skin cancer -- hasn't received much scientific scrutiny, and most people probably haven't heard of it, according to the Associated Press.
Funding is a major issue. Researchers investigating the disease have long had to rely on small pilot grants and family fund-raising.
It's only been about 15 years since Merkel cell carcinoma was recognized as distinct from melanoma. Since then, the number of diagnosed cases in the United States has tripled to about 1,500 a year. Merkel cell carcinoma is more aggressive than melanoma and requires different treatment -- intense radiation.
Last month, the first comprehensive report on Merkel cell carcinoma symptoms and risk factors was published. The disease almost exclusively develops on sun-exposed skin on Caucasians over age 50, the AP reported.
In January, University of Pittsburgh scientists announced they'd identified a possible cancer-triggering virus inside Merkel cell tumors.