A new model containing six basic laboratory and imaging factors predicts survival of patients with advanced urothelial carcinoma who are given the immune checkpoint inhibitor atezolizumab(Tecentriq), investigators reported in a press briefing in advance of the 2018 Genitourinary Cancers Symposium.
“In the past couple of years, there have been five new programmed death 1 [PD-1] and programmed death ligand 1 [PD-L1] inhibitors [checkpoint-inhibitors] approved by the U.S. FDA [Food and Drug Administration] for patients with advanced urothelial carcinoma that progressed during or after platinum-based chemotherapy, and one of these is atezolizumab,” said lead study author, of McMaster University, Hamilton, Ont.
However, “there is no available prognostic model for predicting which patients will have improved overall survival in this setting,” he said. “At the moment, we don’t know which therapy to give to which patient. These sorts of prognostic models will help us identify which patients might benefit the most from which therapy.”
Dr. Pond and colleagues analyzed data from patients with advanced urothelial carcinoma treated with atezolizumab in the postplatinum setting. They developed and trained the model in a cohort of 310 patients from the phase 2trial and validated it in a cohort of 95 patients from the phase 1 trial.
The model ultimately contained six prognostic factors: elevated neutrophil-lymphocyte ratio (5 or higher), impaired functional status (Eastern Cooperative Oncology Group performance status of 1 or higher), elevated platelet count (400 x 109/L or higher), anemia (hemoglobin level less than 10 g/dL), elevated lactate dehydrogenase level (280 U/L or higher), and the presence of liver metastasis.
Main results showed that median overall survival for patients with 0-1, 2-3, and 4 or more factors was 19.6, 5.9, and 2.8 months in the IMvigor210 cohort, and 19.4, 7.2, and 2.6 months in the PCD4989g cohort, respectively.
“We have developed a prognostic model for overall survival, which we now propose for patients with advanced urothelial carcinoma receiving postplatinum atezolizumab,” Dr. Pond summarized. “The initial results of our study are very promising in both the training and validation datasets.
“The model does require further evaluation and further refinements,” he acknowledged. “For example, we need to look at and evaluate how the model performs in larger sample sizes, and we also want to see how it works with other checkpoint inhibitors.” The investigators also plan to assess its performance relative to that of a PD-L1 immunohistochemical assay.
Full results of the study will be reported later this week at the symposium, which is sponsored by the American Society of Clinical Oncology, ASTRO, and the Society of Urologic Oncology.
Findings in context
Response of advanced urothelial carcinoma to immune checkpoint inhibitors ranges widely, with one-quarter of patients or fewer seeing tumor shrinkage, and a small proportion seeing longer-term survival, according to ASCO expert and presscast moderator.
“Until the results of this study, there was no way to easily discern prognosis and identify who might stand to benefit most,” he said. “This easily applied score developed by Dr. Pond and colleagues based on parameters readily available in the patient’s chart provides tremendous input.
“While I would not necessarily withhold therapy on the basis of an anticipated poor prognosis, I would consider using this information in counseling patients who want to be better informed about potential outcomes with immunotherapy,” commented Dr. Pal, who is a medical oncologist and codirector of the Kidney Cancer Program at City of Hope, Duarte, Calif.
Many studies are assessing combinations of immunotherapies with one another and with chemotherapy, he noted. “If these studies are positive, there would be a massive paradigm shift in how we manage advanced bladder cancer. At that point in time, we would have to determine if the model established by Dr. Pond and colleagues remains relevant in that climate.”
Dr. Pond disclosed that an immediate family member is an employee of Roche Canada. Genentech provided data for this study.
SOURCE: Pond GR et al. GU Cancers Symposium, Abstract 413