Karen L. Reckamp

Nivolumab versus Docetaxel in Advanced Squamous-Cell Non-Small-Cell Lung Cancer.

BACKGROUND Patients with advanced squamous-cell non-small-cell lung cancer (NSCLC) who have disease progression during or after first-line chemotherapy have limited treatment options. This randomized, open-label, international, phase 3 study evaluated the efficacy and safety of nivolumab, a fully human IgG4 programmed death 1 (PD-1) immune-checkpoint-inhibitor antibody, as compared with docetaxel in this patient population. METHODS We randomly assigned 272 patients to receive nivolumab, at a dose of 3 mg per kilogram of body weight every 2 weeks, or docetaxel, at a dose of 75 mg per square meter of body-surface area every 3 weeks. The primary end point was overall survival. RESULTS The median overall survival was 9.2 months (95% confidence interval [CI], 7.3 to 13.3) with nivolumab versus 6.0 months (95% CI, 5.1 to 7.3) with docetaxel. The risk of death was 41% lower with nivolumab than with docetaxel (hazard ratio, 0.59; 95% CI, 0.44 to 0.79; P<0.001). At 1 year, the overall survival rate was 42% (95% CI, 34 to 50) with nivolumab versus 24% (95% CI, 17 to 31) with docetaxel. The response rate was 20% with nivolumab versus 9% with docetaxel (P=0.008). The median progression-free survival was 3.5 months with nivolumab versus 2.8 months with docetaxel (hazard ratio for death or disease progression, 0.62; 95% CI, 0.47 to 0.81; P<0.001). The expression of the PD-1 ligand (PD-L1) was neither prognostic nor predictive of benefit. Treatment-related adverse events of grade 3 or 4 were reported in 7% of the patients in the nivolumab group as compared with 55% of those in the docetaxel group. CONCLUSIONS Among patients with advanced, previously treated squamous-cell NSCLC, overall survival, response rate, and progression-free survival were significantly better with nivolumab than with docetaxel, regardless of PD-L1 expression level. (Funded by Bristol-Myers Squibb; CheckMate 017 ClinicalTrials.gov number, NCT01642004.).

Prostaglandin E2 Induces FOXP3 Gene Expression and T Regulatory Cell Function in Human CD4+ T Cells

Naturally occurring CD4+CD25+ regulatory T cells (T reg) are pivotal in suppressing immune responses and maintaining tolerance. The identification of molecules controlling T reg differentiation and function is important in understanding host immune responses in malignancy and autoimmunity. In this study we show that PGE2 enhances the in vitro inhibitory function of human purified CD4+CD25+ T reg cells. Moreover, PGE2 induces a regulatory phenotype in CD4+CD25− T cells. PGE2-treated T cell-mediated inhibition of anti-CD3-stimulated lymphocyte proliferation did not require cell contact. Phenotypic analysis revealed that PGE2 diminished CD25 expression in both CD4+CD25dim T cells and CD4+CD25bright T reg cells. PGE2 exposure induced the T reg cell-specific transcription factor forkhead/winged helix transcription factor gene (FOXP3) in CD4+CD25− T cells and significantly up-regulated its expression in CD4+CD25+ T reg cells. Similarly, 24-h incubation with supernatants from cyclooxygenase-2-overexpressing lung cancer cells that secrete high levels of PGE2 significantly induced FOXP3 in CD4+CD25− T cells. Finally, PGE2 up-regulated FOXP3 at both mRNA and protein levels and enhanced FOXP3 promoter activity. This is the first report indicating that PGE2 can modulate FOXP3 expression and T reg function in human lymphocytes.

Tumor Cyclooxygenase-2/Prostaglandin E2–Dependent Promotion of FOXP3 Expression and CD4+CD25+ T Regulatory Cell Activities in Lung Cancer

Cyclooxygenase (COX)-2 and its product prostaglandin (PG) E2 underlie an immunosuppressive network that is important in the pathogenesis of non-small cell lung cancer. CD4+ CD25+ T regulatory (Treg) cells play an important role in maintenance of immunologic self-tolerance. CD4+ CD25+ Treg cell activities increase in lung cancer and appear to play a role in suppressing antitumor immune responses. Definition of the pathways controlling Treg cell activities will enhance our understanding of limitation of the host antitumor immune responses. Tumor-derived COX-2/PGE2 induced expression of the Treg cell-specific transcription factor, Foxp3, and increased Treg cell activity. Assessment of E-prostanoid (EP) receptor requirements revealed that PGE2-mediated induction of Treg cell Foxp3 gene expression was significantly reduced in the absence of the EP4 receptor and ablated in the absence of the EP2 receptor expression. In vivo, COX-2 inhibition reduced Treg cell frequency and activity, attenuated Foxp3 expression in tumor-infiltrating lymphocytes, and decreased tumor burden. Transfer of Treg cells or administration of PGE2 to mice receiving COX-2 inhibitors reversed these effects. We conclude that inhibition of COX-2/PGE2 suppresses Treg cell activity and enhances antitumor responses.

Akt inhibitors in clinical development for the treatment of cancer

Importance of the field: The evolution of targeted therapies is dependent upon identification of cellular moieties that can be pharmacologically modulated. As one such example, the serine-threonine kinase Akt was identified nearly two decades ago. Since then, its role in mediating multiple signaling cascades (ultimately leading to cell growth and proliferation) has since been identified. More recently, several agents have been developed that antagonize Akt – these agents are in various stages of clinical testing. Areas covered in this review: Herein, we outline development of several promising Akt inhibitors, including perifosine, MK-2206, RX-0201, PBI-05204, GSK2141795 and others. What the reader will gain: The reader will gain insight into the current pipeline of Akt inhibitors, and the degree to which these agents have been examined both clinically and preclinically. Take home message: With an emerging pipeline of agents targeting Akt, it will be critical to decipher which amongst them holds the greatest promise. Herein, we explore this drug pipeline and provide strategies for determining the future clinical application of these agents.

Prostaglandin E2 Activates Mitogen-Activated Protein Kinase/Erk Pathway Signaling and Cell Proliferation in Non–Small Cell Lung Cancer Cells in an Epidermal Growth Factor Receptor–Independent Manner

Cyclooxygenase 2 (COX-2) overexpression is found in a wide variety of human cancers and is linked to all stages of tumorigenesis. Elevated tumor COX-2 expression is associated with increased angiogenesis, tumor invasion, suppression of host immunity and promotes tumor cell resistance to apoptosis. Previous reports have linked the COX-2 product prostaglandin E2 (PGE2) to the abnormal activation of the mitogen-activated protein kinase/Erk kinase pathway. Here we show that PGE2 is able to rapidly stimulate Erk phosphorylation in a subset of non-small cell lung cancer (NSCLC) cell lines. This effect is not evident in bronchial epithelial cells. In contrast to previous reports in colon cancer, we found that Erk activation as well as cellular proliferation induced by PGE2 was not inhibited by pretreatment of the cells with epidermal growth factor receptor (EGFR) inhibitors. Activation of the Erk pathway by PGE2 was also resistant to src kinase inhibitors but sensitive to the protein kinase C inhibition. PGE2 effects are mediated through four G protein-coupled receptors. Selective inhibition of EP receptors revealed the possible involvement of Ca2+-dependent signaling in PGE2-mediated activation of Erk. Our data indicate the presence of an EGFR-independent activation of the mitogen-activated protein kinase/Erk pathway by PGE2 in NSCLC cells. These findings provide evidence for the possible link between tumor COX-2 overexpression and elevated Erk-mediated cancer cell proliferation and migration. Importantly, these findings suggest that COX-2 overexpression may contribute to EGFR inhibitor resistance in NSCLC.

Stromal Derived Factor-1 (SDF-1/CXCL12) and CXCR4 in renal cell carcinoma metastasis

Renal cell carcinoma (RCC) is characterized by organ-specific metastases. The chemokine stromal derived factor-1 (SDF-1/CXCL12) and its receptor CXCR4 have been suggested to regulate organ-specific metastasis in various other cancers. On this basis, we hypothesized that the biological axis of CXCL12 via interaction with its receptor, CXCR4, is a major mechanism for RCC metastasis. We demonstrated that CXCR4 was significantly expressed on circulating cytokeratin+ RCC cells from patients with known metastatic RCC. We detected up-regulation of CXCR4 mRNA and protein levels on a human RCC cell line by either knockdown of the von Hippel-Lindau (VHL) tumor suppressor protein, or incubating the cells under hypoxic conditions. The enhanced CXCR4 expression was mediated through the interaction of the Hypoxia Inducible Factor-1α (HIF-1α) with the promoter region of the CXCR4 gene. Furthermore, the expression of CXCR4 on human RCC directly correlated with their metastatic ability in vivo in both heterotopic and orthotopic SCID mouse models of human RCC. Neutralization of CXCL12 in SCID mice abrogated metastasis of RCC to target organs expressing high levels of CXCL12; without altering tumor cell proliferation, apoptosis, or tumor-associated angiogenesis. Therefore, our data suggest that the CXCL12/CXCR4 biological axis plays an important role in regulating the organ-specific metastasis of RCC.

The role of CXCR2/CXCR2 ligand biological axis in renal cell carcinoma.

Renal cell carcinoma (RCC) accounts for 3% of new cancer incidence and mortality in the United States. Studies in RCC have predominantly focused on VEGF in promoting tumor-associated angiogenesis. However, other angiogenic factors may contribute to the overall angiogenic milieu of RCC. We hypothesized that the CXCR2/CXCR2 ligand biological axis represents a mechanism by which RCC cells promote angiogenesis and facilitate tumor growth and metastasis. Therefore, we first examined tumor biopsies and plasma of patients with metastatic RCC for levels of CXCR2 ligands, and RCC tumor biopsies for the expression of CXCR2. The proangiogenic CXCR2 ligands CXCL1, CXCL3, CXCL5, and CXCL8, as well as VEGF were elevated in the plasma of these patients and found to be expressed within the tumors. CXCR2 was found to be expressed on endothelial cells within the tumors. To assess the role of ELR+ CXC chemokines in RCC, we next used a model of syngeneic RCC (i.e., RENCA) in BALB/c mice. CXCR2 ligand and VEGF expression temporally increased in direct correlation with RENCA growth in CXCR2+/+ mice. However, there was a marked reduction of RENCA tumor growth in CXCR2−/− mice, which correlated with decreased angiogenesis and increased tumor necrosis. Furthermore, in the absence of CXCR2, orthotopic RENCA tumors demonstrated a reduced potential to metastasize to the lungs of CXCR2−/− mice. These data support the notion that CXCR2/CXCR2 ligand biology is an important component of RCC tumor-associated angiogenesis and tumorigenesis.

Identification of Five Candidate Lung Cancer Biomarkers by Proteomics Analysis of Conditioned Media of Four Lung Cancer Cell Lines

Detection of lung cancer at an early stage is necessary for successful therapy and improved survival rates. We performed a bottom-up proteomics analysis using a two-dimensional LC-MS/MS strategy on the conditioned media of four lung cancer cell lines of different histological backgrounds (non-small cell lung cancer: H23 (adenocarcinoma), H520 (squamous cell carcinoma), and H460 (large cell carcinoma); small cell lung cancer: H1688) to identify secreted or membrane-bound proteins that could be useful as novel lung cancer biomarkers. Proteomics analysis of the four conditioned media allowed identification of 1,830 different proteins (965, 871, 726, and 847 from H1688, H23, H460, and H520, respectively). All proteins were assigned a subcellular localization, and 38% were classified as extracellular or membrane-bound. We successfully identified the internal control proteins (also detected by ELISA), kallikrein-related peptidases 14 and 11, and IGFBP2. We also identified known or putative lung cancer tumor markers such as squamous cell carcinoma antigen, carcinoembryonic antigen, chromogranin A, creatine kinase BB, progastrin-releasing peptide, neural cell adhesion molecule, and tumor M2-PK. To select the most promising candidates for validation, we performed tissue specificity assays, functional classifications, literature searches for association to cancer, and a comparison of our proteome with the proteome of lung-related diseases and serum. Five novel lung cancer candidates, ADAM-17, osteoprotegerin, pentraxin 3, follistatin, and tumor necrosis factor receptor superfamily member 1A were preliminarily validated in the serum of patients with lung cancer and healthy controls. Our results demonstrate the utility of this cell culture proteomics approach to identify secreted and shed proteins that are potentially useful as serological markers for lung cancer.

Brigatinib in Patients With Crizotinib-Refractory Anaplastic Lymphoma Kinase–Positive Non–Small-Cell Lung Cancer: A Randomized, Multicenter Phase II Trial

Purpose Most crizotinib-treated patients with anaplastic lymphoma kinase gene ( ALK)-rearranged non-small-cell lung cancer (ALK-positive NSCLC) eventually experience disease progression. We evaluated two regimens of brigatinib, an investigational next-generation ALK inhibitor, in crizotinib-refractory ALK-positive NSCLC. Patients and Methods Patients were stratified by brain metastases and best response to crizotinib. They were randomly assigned (1:1) to oral brigatinib 90 mg once daily (arm A) or 180 mg once daily with a 7-day lead-in at 90 mg (180 mg once daily [with lead-in]; arm B). Investigator-assessed confirmed objective response rate (ORR) was the primary end point. Results Of 222 patients enrolled (arm A: n = 112, 109 treated; arm B: n = 110, 110 treated), 154 (69%) had baseline brain metastases and 164 of 222 (74%) had received prior chemotherapy. With 8.0-month median follow-up, investigator-assessed confirmed ORR was 45% (97.5% CI, 34% to 56%) in arm A and 54% (97.5% CI, 43% to 65%) in arm B. Investigator-assessed median progression-free survival was 9.2 months (95% CI, 7.4 to 15.6) and 12.9 months (95% CI, 11.1 to not reached) in arms A and B, respectively. Independent review committee-assessed intracranial ORR in patients with measurable brain metastases at baseline was 42% (11 of 26 patients) in arm A and 67% (12 of 18 patients) in arm B. Common treatment-emergent adverse events were nausea (arm A/B, 33%/40%), diarrhea (arm A/B, 19%/38%), headache (arm A/B, 28%/27%), and cough (arm A/B, 18%/34%), and were mainly grades 1 to 2. A subset of pulmonary adverse events with early onset (median onset: day 2) occurred in 14 of 219 treated patients (all grades, 6%; grade ≥ 3, 3%); none occurred after escalation to 180 mg in arm B. Seven of 14 patients were successfully retreated with brigatinib. Conclusion Brigatinib yielded substantial whole-body and intracranial responses as well as robust progression-free survival; 180 mg (with lead-in) showed consistently better efficacy than 90 mg, with acceptable safety.

A Phase I Trial to Determine the Optimal Biological Dose of Celecoxib when Combined with Erlotinib in Advanced Non–Small Cell Lung Cancer

Purpose: Overexpression of cyclooxygenase-2 (COX-2) activates extracellular signal-regulated kinase/mitogen-activated protein kinase signaling in an epidermal growth factor receptor (EGFR) tyrosine kinase inhibition (TKI)–resistant manner. Because preclinical data indicated that tumor COX-2 expression caused resistance to EGFR TKI, a phase I trial to establish the optimal biological dose (OBD), defined as the maximal decrease in urinary prostaglandin E-M (PGE-M), and toxicity profile of the combination of celecoxib and erlotinib in advanced non–small cell lung cancer was done. Experimental Design: Twenty-two subjects with stage IIIB and/or IV non–small cell lung cancer received increasing doses of celecoxib from 200 to 800 mg twice daily (bid) and a fixed dose of erlotinib. Primary end points included evaluation of toxicity and determination of the OBD of celecoxib when combined with erlotinib. Secondary end points investigate exploratory biological markers and clinical response. Results: Twenty-two subjects were enrolled, and 21 were evaluable for the determination of the OBD, toxicity, and response. Rash and skin-related effects were the most commonly reported toxicities and occurred in 86%. There were no dose-limiting toxicities and no cardiovascular toxicities related to study treatment. All subjects were evaluated on intent to treat. Seven patients showed partial responses (33%), and five patients developed stable disease (24%). Responses were seen in patients both with and without EGFR-activating mutations. A significant decline in urinary PGE-M was shown after 8 weeks of treatment, with an OBD of celecoxib of 600 mg bid. Conclusions: This study defines the OBD of celecoxib when combined with a fixed dose of EGFR TKI. These results show objective responses with an acceptable toxicity profile. Future trials using COX-2 inhibition strategies should use the OBD of celecoxib at 600 mg bid.