Highly aneuploid non-small cell lung cancer shows enhanced responsiveness to concurrent radiation and immune checkpoint blockade.

Over 500 clinical trials are investigating combination radiotherapy and immune checkpoint blockade (ICB) as cancer treatments; however, the majority of trials have found no positive interaction. Here we perform a comprehensive molecular analysis of a randomized phase I clinical trial of patients with non-small cell lung cancer (NSCLC) treated with concurrent or sequential ablative radiotherapy and ICB. We show that concurrent treatment is superior to sequential treatment in augmenting local and distant tumor responses and in improving overall survival in a subset of patients with immunologically cold, highly aneuploid tumors, but not in those with less aneuploid tumors. In addition, radiotherapy alone decreases intratumoral cytotoxic T cell and adaptive immune signatures, whereas radiotherapy and ICB upregulates key immune pathways. Our findings challenge the prevailing paradigm that local ablative radiotherapy beneficially stimulates the immune response. We propose the use of tumor aneuploidy as a biomarker and therapeutic target in personalizing treatment approaches for patients with NSCLC treated with radiotherapy and ICB.

Phase I Study of Stereotactic Body Radiotherapy plus Nivolumab and Urelumab or Cabiralizumab in Advanced Solid Tumors.

PURPOSE: CD137 agonism and CSF1R blockade augment stereotactic body radiotherapy (SBRT) and anti-programmed death-1 in preclinical models. We evaluated the safety and efficacy of SBRT with nivolumab+urelumab (CD137 agonist) or nivolumab+cabiralizumab (CSF1R inhibitor). PATIENTS AND METHODS: This phase I clinical trial enrolled patients with advanced solid tumors that had progressed on standard therapies. SBRT was delivered to 1-4 metastases with nivolumab+urelumab or nivolumab+cabiralizumab given concurrently and following SBRT. Dose-limiting toxicity (DLT) was the primary endpoint with anatomic location-specific SBRT doses deemed safe if ≤33% DLT frequency was observed. Secondary endpoints included RECISTv1.1 response, progression-free survival (PFS), overall survival (OS), and molecular correlative studies. RESULTS: Sixty patients were enrolled, and median follow-up for living patients is 13.8 months. Of these, 23 (38%) received SBRT+nivolumab+urelumab and 37 (62%) received SBRT+nivolumab+cabiralizumab. Seven patients (12%) experienced a DLT (n = 3 grade 3, n = 4 grade 4) in the following anatomic cohorts: abdominal/pelvic (3/17, 18%), liver (1/13, 8%), central lung (2/14, 14%), and peripheral lung (1/12, 8%). Of 41 patients radiographically evaluable for best overall response including 55 radiated and 23 unirradiated RECIST target lesions, 2 had complete responses (5%), 7 had partial responses (17%), 12 had stable disease (29%), and 20 had progression (49%). Median estimated PFS and OS are 3.0 months [95% confidence interval (CI), 2.9-4.8] and 17.0 months (95% CI, 6.8-undetermined), respectively. No patients with elevated pre-SBRT serum IL8 experienced a response. CONCLUSIONS: SBRT to ≤4 sites with nivolumab+urelumab or nivolumab+cabiralizumab for treating advanced solid tumors is feasible with acceptable toxicity and modest antitumor activity.See related commentary by Rodriguez-Ruiz et al., p. 5443.

Improved Survival Associated with Local Tumor Response Following Multisite Radiotherapy and Pembrolizumab: Secondary Analysis of a Phase I Trial.

PURPOSE: Multisite stereotactic body radiotherapy followed by pembrolizumab (SBRT+P) has demonstrated safety in advanced solid tumors (ASTs). However, no studies have examined the relationships between irradiated tumor response, SBRT-induced tumor gene expression, and overall survival (OS). PATIENTS AND METHODS: Patients with AST received SBRT (30-50 Gy in 3-5 fractions) to two to four metastases followed by pembrolizumab (200 mg i.v. every 3 weeks). SBRT was prescribed to a maximum tumor volume of 65 mL. Small metastases received the complete prescribed coverage (complete-Rx), while larger metastases received partial coverage (partial-Rx). Treated metastasis control (TMC) was defined as a lack of progression for an irradiated metastasis. Landmark analysis was used to assess the relationship between TMC and OS. Thirty-five biopsies were obtained from 24 patients: 19 pre-SBRT and 16 post-SBRT (11 matched) prior to pembrolizumab and were analyzed via RNA microarray. RESULTS: Sixty-eight patients (139 metastases) were enrolled with a median follow-up of 10.4 months. One-year TMC was 89.5% with no difference between complete-Rx or partial-Rx. On multivariable analysis, TMC was independently associated with a reduced risk for death (HR, 0.36; 95% confidence interval, 0.17-0.75; P = 0.006). SBRT increased expression of innate and adaptive immune genes and concomitantly decreased expression of cell cycle and DNA repair genes in the irradiated tumors. Elevated post-SBRT expression of DNASE1 correlated with increased expression of cytolytic T-cell genes and irradiated tumor response. CONCLUSIONS: In the context of SBRT+P, TMC independently correlates with OS. SBRT impacts intratumoral immune gene expression associated with TMC. Randomized trials are needed to validate these findings.

The EphB4 receptor tyrosine kinase promotes lung cancer growth: a potential novel therapeutic target.

Despite progress in locoregional and systemic therapies, patient survival from lung cancer remains a challenge. Receptor tyrosine kinases are frequently implicated in lung cancer pathogenesis, and some tyrosine kinase inhibition strategies have been effective clinically. The EphB4 receptor tyrosine kinase has recently emerged as a potential target in several other cancers. We sought to systematically study the role of EphB4 in lung cancer. Here, we demonstrate that EphB4 is overexpressed 3-fold in lung tumors compared to paired normal tissues and frequently exhibits gene copy number increases in lung cancer. We also show that overexpression of EphB4 promotes cellular proliferation, colony formation, and motility, while EphB4 inhibition reduces cellular viability in vitro, halts the growth of established tumors in mouse xenograft models when used as a single-target strategy, and causes near-complete regression of established tumors when used in combination with paclitaxel. Taken together, these data suggest an important role for EphB4 as a potential novel therapeutic target in lung cancer. Clinical trials investigating the efficacy of anti-EphB4 therapies as well as combination therapy involving EphB4 inhibition may be warranted.

Paxillin mutations affect focal adhesions and lead to altered mitochondrial dynamics: relevance to lung cancer.

Cytoskeletal and focal adhesion abnormalities are observed in several types of cancer, including lung cancer. We have previously reported that paxillin (PXN) was mutated, amplified, and overexpressed in a significant number of lung cancer patient samples, that PXN protein was upregulated in more advanced stages of lung cancer compared with lower stages, and that the PXN gene was also amplified in some pre-neoplastic lung lesions. Among the mutations investigated, we previously found that PXN variant A127T in lung cancer cells enhanced cell proliferation and focal adhesion formation and colocalized with the anti-apoptotic protein B Cell Lymphoma 2 (BCL-2), which is known to localize to the mitochondria, among other sites. To further explore the effects of activating mutations of PXN on mitochondrial function, we cloned and expressed wild-type PXN and variants containing the most commonly occurring PXN mutations (P46S, P52L, G105D, A127T, P233L, T255I, D399N, E423K, P487L, and K506R) in a GFP-tagged vector using HEK-293 human embryonic kidney cells. Utilizing live-cell imaging to systematically study the effects of wild-type PXN vs. mutants, we created a model that recapitulates the salient features of the measured dynamics and conclude that compared with wild-type, some mutant clones confer enhanced focal adhesion and lamellipodia formation (A127T, P233L, and P487L) and some confer increased association with BCL-2, Dynamin-related Protein-1 (DRP-1), and Mitofusion-2 (MFN-2) proteins (P233L and D399N). Further, PXN mutants, through their interactions with BCL-2 and DRP-1, could regulate cisplatin drug resistance in human lung cancer cells. The data reported herein suggest that mutant PXN variants play a prominent role in mitochondrial dynamics with direct implications on lung cancer progression and hence, deserve further exploration as therapeutic targets.