Making the Rounds: Exploring the Role of Circulating Tumor DNA (ctDNA) in Non-Small Cell Lung Cancer.

Advancements in the clinical practice of non-small cell lung cancer (NSCLC) are shifting treatment paradigms towards increasingly personalized approaches. Liquid biopsies using various circulating analytes provide minimally invasive methods of sampling the molecular content within tumor cells. Plasma-derived circulating tumor DNA (ctDNA), the tumor-derived component of cell-free DNA (cfDNA), is the most extensively studied analyte and has a growing list of applications in the clinical management of NSCLC. As an alternative to tumor genotyping, the assessment of oncogenic driver alterations by ctDNA has become an accepted companion diagnostic via both single-gene polymerase chain reactions (PCR) and next-generation sequencing (NGS) for advanced NSCLC. ctDNA technologies have also shown the ability to detect the emerging mechanisms of acquired resistance that evolve after targeted therapy. Furthermore, the detection of minimal residual disease (MRD) by ctDNA for patients with NSCLC after curative-intent treatment may serve as a prognostic and potentially predictive biomarker for recurrence and response to therapy, respectively. Finally, ctDNA analysis via mutational, methylation, and/or fragmentation multi-omic profiling offers the potential for improving early lung cancer detection. In this review, we discuss the role of ctDNA in each of these capacities, namely, for molecular profiling, treatment response monitoring, MRD detection, and early cancer detection of NSCLC.

Immune Checkpoint Inhibitors and Chemoradiation for Limited-Stage Small Cell Lung Cancer.

OPINION STATEMENT: Limited-stage small cell lung cancer (LS-SCLC) is a potentially curable disease. However, most patients develop disease relapse shortly after definitive treatment. The landmark trials IMpower133 and CASPIAN demonstrated a survival benefit with the addition of immunotherapy to first-line platinum/etoposide for extensive-stage small cell lung cancer. Therefore, it is critical to determine whether advancements in overall survival with immunotherapy can be translated earlier into the treatment paradigm for LS-SCLC. Decades of robust preclinical research into the synergism of radiation therapy and immunotherapy set the stage for the combination of these treatment modalities. Recently published data suggests tolerability of single agent immunotherapy concurrent with chemoradiation in LS-SCLC, along with promising efficacy. However, combination immunotherapy in the consolidation setting appears too toxic, although this may be reflective of the dosing schedule rather than inherent to any combination immune checkpoint blockade. Here, we review underlying mechanisms of synergy with the combination of radiation and immunotherapy, the safety and efficacy of respective treatment modalities, and the ongoing trials that are exploring novel therapeutic approaches for LS-SCLC. Pivotal trials in LS-SCLC are ongoing and anticipated to aid in understanding efficacy and safety of immunotherapy with concurrent platinum-based chemoradiotherapy.

A Novel Case of Leflunomide-Induced Thrombotic Thrombocytopenic Purpura.

Leflunomide has not been previously associated with thrombotic thrombocytopenic purpura (TTP), a rare life-threatening clinical syndrome characterized by thrombotic microangiopathy (TMA) due to inability to cleave ADAMTS13. Here, we present the first case of leflunomide-induced TTP. Our patient developed encephalopathy, thrombocytopenia, anemia and hyperbilirubinemia 2 months after starting leflunomide. Schistocytes were noted on peripheral smear and ADAMTS13 activity was low (< 5%), consistent with acquired TTP. He received therapeutic plasma exchange, corticosteroids, rituximab and caplacizumab with normalization of hemolysis labs and ADAMTS13 activity. However, pancytopenia persisted, raising the suspicion for leflunomide toxicity. Oral cholestyramine treatment was empirically started before teriflunomide (a leflunomide metabolite) level was found to be elevated. Blood counts normalized after cholestyramine and have remained normal at last follow-up over a year later. This is the first reported case of TTP precipitated by leflunomide. Our case highlights the importance of recognizing drugs as an etiology of TMA and adds leflunomide to this list.

Immunotherapy for Advanced Non-Small Cell Lung Cancer: A Decade of Progress.

The treatment paradigm for patients with advanced non-small cell lung cancer has substantially changed with the discovery of immunotherapy. The incorporation of immunotherapy into treatment algorithms has resulted in better outcomes for patients, with fewer side effects compared with classic chemotherapeutic agents. Multiple treatment options are now available for patients with advanced non-small cell lung cancer, ranging from single-agent immunotherapy to quadruple therapy, which involves dual immune checkpoint inhibitor plus chemotherapy or immune checkpoint inhibitor plus chemotherapy plus anti-vascular endothelial growth factor drugs. This article will review landmark studies that have led to U.S. Food and Drug Administration approval of immunotherapy agents alone or in combination with chemotherapy or other immunotherapy drugs to treat advanced non-small cell lung cancer.