Multisite SBRT may make immunotherapy more effective in lung cancer
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Multisite stereotactic body radiotherapy, or SBRT, in combination with concurrent ipilimumab and nivolumab was well-tolerated in patients with stage 4 non-small cell lung cancer, according to findings from the COSINR study presented at the virtual ASCO Annual Meeting.
“The idea is that radiation not only cytoreduces cancer and makes a lower volume of cancer more amenable to immunotherapy, but also likely changes the immune environment to make immunotherapy more effective,” Jyoti D. Patel, MD, associate vice chair for clinical research and professor of medicine at Northwestern’s Feinberg School of Medicine, told Healio.
The researchers enrolled 35 treatment-naive patients with advanced stage non-small cell lung cancer (NSCLC) and no driver mutation. Patients received SBRT at one to four metastatic sites. According to the abstract, metastases larger than 65 mL were partially irradiated, and not all metastases were targeted.
“With this paradigm of concurrent radiation and immunotherapy we saw minimal toxicity and really impressive progression-free or time-to-treatment with chemotherapy, as well as overall survival – one that we’ve never really seen before,” Patel said.
According to the abstract, 27% of enrolled patients also had brain metastases. The researchers reported 0% PD-L1 expression in 16 patients, 1% to 49% expression in 10 patients and more than 50% expression in nine patients. Progression-free survival and overall survival were not impacted by patient PDL1 status, the researchers noted.
Oncologists used SBRT to treat a median of 3.2 metastases. Overall, the median PFS was 5.9 months (95% CI; 4.9-13.1), while the PFS for patients treated with immunotherapy and sequential multisite SBRT was 6.2 months (95% CI; 3.5-12.6) and 5.9 months (95% CI; 3.1-18) for patients treated with immunotherapy and concurrent multisite SBRT.
“We are very encouraged about this idea of cytoreduction, getting rid of those rapid progressors and really giving immunotherapy a chance to work is really a great option for patients that want to keep chemotherapy in their back pocket subsequent lines,” Patel said.
The time to the second line therapy of chemotherapy was 17.5 months for patients receiving concurrent multisite SBRT and was not reached for patients receiving sequential multisite SBRT.
“Our next plan is to expand the patient population and get more confidence about that. We can say very clearly that for time to overall survival, the study has not matured. That is going to be at least 21 months for this subset of patients,” Patel concluded. “This is encouraging because we are seeing long and deep responses in patients with really aggressive disease.”
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Patel JD, et al. Abstract 9616. Presented at: ASCO20 Virtual Scientific Program; May 29-31, 2020.
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