SHP-2 and PD-L1 Inhibition Combined with Radiotherapy Enhances Systemic Antitumor Effects in an Anti–PD-1–Resistant Model of Non–Small Cell Lung Cancer
Menée à l'aide d'un modèle murin de cancer du poumon non à petites cellules résistant aux traitements anti-PD1, cette étude met en évidence l'intérêt d'une stratégie thérapeutique consistant à combiner radiothérapie et inhibition du ligand PD-L1 et de la phosphatase SHP-2
Immune checkpoint inhibitors, such as anti–PD-1/PD-L1, have emerged as promising therapies for advanced non–small cell lung cancer (NSCLC). However, approximately 80% of patients do not respond to immunotherapy given alone because of intrinsic or acquired resistance. Radiotherapy (XRT) can overcome PD-1 resistance and improve treatment outcomes, but its efficacy remains suboptimal. The tyrosine phosphatase SHP-2, expressed in some cancers and in immune cells, has been shown to negatively affect antitumor immunity. Our hypothesis was that SHP-2 inhibition in combination with anti–PD-L1 would enhance immune-mediated responses to XRT and synergistically boost antitumor effects in an anti–PD-1–resistant mouse model. We treated 129Sv/Ev mice with anti–PD-1–resistant 344SQ NSCLC adenocarcinoma with oral SHP099 (a SHP-2 inhibitor) combined with XRT and intraperitoneal anti–PD-L1. Primary tumors were treated with XRT (three fractions of 12 Gy each), whereas abscopal (out-of-field) tumors were observed but not treated. XRT in combination with SHP099 and anti–PD-L1 promoted local and abscopal responses, reduced lung metastases, and improved mouse survival. XRT also increased SHP-2+ M1 tumor–associated macrophages in abscopal tumors (P = 0.019). The addition of SHP099 also associated with a higher M1/M2 ratio, greater numbers of CD8+ T cells, and fewer regulatory T cells. This triple-combination therapy had strong antitumor effects in a mouse model of anti–PD-1–resistant NSCLC and may be a novel therapeutic approach for anti–PD-1–resistant NSCLC in patients.