Ipilimumab, used in combination with radiotherapy, electrochemotherapy, or internal radiotherapy, may significantly prolong overall survival in patients with melanoma compared with treatment with ipilimumab alone, according to research published in the journal Cancer Immunotherapy Research.
“Our results are concordant with those previously reported for 29 patients treated in the United States with ipilimumab and local radiotherapy (Cancer Immunology Research, published online July 25, 2013),” said lead author Sebastian Theurich, MD, lecturer and physician-scientist in the Center of Integrated Oncology (CIO) at the University Hospital of Cologne, Germany.
For this retrospective study, Dr. Theurich and colleagues collected and analyzed data from 127 patients with malignant melanoma treated consecutively at four cancer centers in Germany and Switzerland. In all, 82 patients were treated with ipilimumab only, while 45 received ipilimumab and local peripheral treatment for relief of tumor-related symptoms.
“Having data from different parts of the world improves the validity of the results, especially if you deal with retrospective analyses. Moreover, all our patients were treated with the same dose of ipilimumab, whereas those in the previous study received varying doses because they were being treated in a dose- escalation clinical trial,” he noted.
The 82 patients treated with ipilimumab and local peripheral treatment had a median overall survival of 93 weeks, compared with 42 weeks in the 45 who received ipilimumab only. Researchers then excluded patients with brain metastases for analysis, and found a median overall survival benefit of 117 weeks in patients treated with ipilimumab plus local peripheral treatments compared with 46 weeks in patients treated with ipilimumab only.
“We found that adding local peripheral treatments, including external radiotherapy, electrochemotherapy, or internal radiotherapy, to systemic ipilimumab treatment doubled survival chances in our patient cohort and did not increase immune-related side effects,” said Dr. Theurich.
“Importantly, this survival advantage seemed to overcome even traditional risk factors of poor outcomes. This suggests that this combination could be an option for all patients with malignant melanoma, and this is being tested in ongoing prospective clinical trials,” he said.
Dr. Theurich added that study limitations include that data were not collected prospectively and in a randomized way, but noted that their results are currently undergoing prospective clinical trials for validation.
“We were also able to begin to investigate the potential immunologic mechanism underlying the benefit of adding local peripheral treatment to ipilimumab,” added Dr. Theurich. “It seems that local peripheral treatments activate immune cells, which are then able to attack tumors at sites away from the local treatment site. However, we are investigating this further in prospective studies,” he concluded.
The study was, in part, funded by the University of Cologne (Physician Scientist Program, “Gerok-Rotationsstelle”) and the Freie Akademische Gesellschaft Basel, Switzerland.