The search for biomarkers that can help clinicians match patients with effective therapies continues at a torrid pace in oncology. Yet in the parlance of basketball, not all biomarkers translate into slam dunks when it comes to clinical utility. The complexities associated with translating the growing body of knowledge about the cell-signaling networks that drive malignancies are particularly evident in the unfolding story of PD-L1 expression in non–small cell lung cancer (NSCLC).
From the early days of PD-1 research, it seemed that PD-L1 expression levels would serve as a natural biomarker for which patients would be more likely to respond to the immunotherapy agents. Indeed, higher levels of PDL1 expression often indicate greater response rates and, in the case of nivolumab in nonsquamous NSCLC, longer median overall survival.
Yet it has become abundantly clear that PD-L1 is not going to be the kind of straightforward biomarker that EGFR
mutation testing has been for EGFR
targeting therapies in the tumor type.
Indeed, patients with negative PD-L1 expression levels on the tests used in several clinical trials benefited from the therapies at rates similar to those seen with more toxic chemotherapies in second-line settings.
As a result, leading lung cancer experts who spoke at the 10th Annual New York Lung Cancer Symposium are not ready to rule out patients who might benefit from the drug based on their PD-L1 status. Their views are captured in our cover story, “PD-L1 Inhibitors Advance Rapidly for Broad Cohort in NSCLC.”
As problematic as this biomarker conundrum might be with this class of therapies in NSCLC, there is a great likelihood that similar questions will arise as new molecular biomarkers are discovered across the spectrum of cancers. Maurie Markman, MD, our editorin- chief, discusses the uncertain messages that some biomarkers send in his column, “‘All or None’ Approach in Precision Oncology Sometimes Poses a Dilemma.” We believe these questions will become increasingly important as more novel anticancer therapies are introduced at ever-escalating prices. The healthcare system is looking intently for efficacy and value.
We support efforts to integrate valuebased medicine into oncology, but we also believe that potentially beneficial therapies should not be withheld from patients based on a biomarker without the certainty that that marker is telling us what we think it is.
Please let us know your thoughts on these matters and, as always, thank you for reading.