Elizabeth Loggers, MD, PhD
Researchers are hoping the immunotherapy revolution occurring across several cancer types will extend to the field of sarcoma.
Results from the phase II SARC028 trial presented at the 2016 Connective Tissue Oncology Society (CTOS) annual meeting showed that the PD-1 inhibitor pembrolizumab (Keytruda) induced a response rate of approximately 20% in the overall cohort of patients with soft tissue and bone sarcomas. In a subgroup of patients with undifferentiated pleomorphic sarcoma, the response rate was 44%.
Also at the CTOS meeting, the Fred Hutchinson Cancer Research Center presented a single institution retrospective analysis of monotherapy with pembrolizumab or the PD-1 inhibitor nivolumab (Opdivo), as well as a combination regimen of nivolumab and the CTLA-4 inhibitor ipilimumab (Yervoy).
Study author Elizabeth Loggers, MD, PhD, discussed the findings of the study with OncLive
in an interview at CTOS. Loggers is an associate member in the clinical research division at Fred Hutch, an assistant clinical professor of Medicine at the University of Washington, and medical director of Supportive and Palliative Care at Seattle Cancer Care Alliance.
OncLive: What have been some of the results that you have seen with these agents in sarcoma?
: Well, in actual facts, one of the problems is that we are still waiting for the results of many studies that have used these agents. What we do know from some of the early results is that there are some subtypes of sarcoma that really don’t have great treatment options that have seen responses such as epithelioid sarcoma, chondrosarcomas, dedifferentiated leiomyosarcoma, and undifferentiated sarcomas.
Are there any new data with these immunotherapy agents that are being presented here at CTOS?
There have been a number of different abstracts presented that were very interesting, looking at the role of different immune infiltrates into the tumors—tumor infiltrating lymphocytes as well as tumor infiltrating macrophages, which I think will be very exciting as this science develops.
Our results were our single institution retrospective study of patients who were receiving either single-agent nivolumab or pembrolizumab or combined therapy with nivolumab and ipilimumab. These patients are of interest because these agents have been very effective in melanoma, lung cancer, renal cancer, and the combined agents have been more effective than the single agent for some conditions. So we were interested in whether that would hold true for sarcoma patients.
What would you say were the next steps with your research?
Well, I think it’s really important to interpret our results with caution because they are just a single institution, non-randomized study. What we were interested in was whether overall survival would be different for individuals who received single-agent, immune-based approaches versus combination.
What our data showed was that people who received single- agent therapy actually lived longer in this small, single institution retrospective analysis. So again, we want to interpret this with caution, but it leads us to interesting questions about which will be better for our patients—single agent or combined agents—especially understanding the toxicities will be greater with combined therapy.
We’ve got the Alliance study results that are going to help us definitively answer this question, but what our study does is underline the importance of understanding really simple things like dose, interval, and the underlying mechanisms by which these agents work, which may be different in sarcoma than in melanoma or in lung cancer.