TROP2 Is Associated with Primary Resistance to Immune Checkpoint Inhibition in Patients with Advanced Non-Small Cell Lung Cancer

PURPOSE

Mechanisms of primary resistance to inhibitors of the programmed cell death-1 (PD-1)/programmed death-ligand 1 (PD-L1) signaling axis in non-small cell lung cancer (NSCLC) are still poorly understood. While some studies suggest the involvement of trophoblast cell surface antigen 2 (TROP2) in modulating tumor cell resistance to therapeutic drugs, its specific role in the context of PD-1/PD-L1 axis blockade is not definitively established.

EXPERIMENTAL DESIGN

We performed high-throughput analysis of transcriptomic data from 891 NSCLC tumors from patients treated with either the PD-L1 inhibitor atezolizumab or chemotherapy in two large randomized clinical trials. To confirm our results at the protein level, we complemented this transcriptional approach by performing a multiplex immunofluorescence analysis of tumor tissue samples as well as a proteomic profiling of plasma.

RESULTS

We observed a significant association of TROP2 overexpression with worse progression-free survival and overall survival on PD-L1 blockade, independent of other prognostic factors. Importantly, we found increased TROP2 expression to be predictive of survival in patients treated with atezolizumab but not chemotherapy. TROP2 overexpression was associated with decreased T-cell infiltration. We confirmed these results at the proteomic level both on tumor tissue and in plasma.

CONCLUSIONS

Our results suggest an important contribution of TROP2 expression to the primary resistance to PD-L1 blockade in NSCLC. TROP2-biomarker-based strategy may be relevant in selecting patients with NSCLC who are more likely to benefit from a combination of immunotherapy and an anti-TROP2 agent.

Upregulation of Indoleamine 2,3-Dioxygenase 1 in Tumor Cells and Tertiary Lymphoid Structures is a Hallmark of Inflamed Non-Small Cell Lung Cancer

PURPOSE

Overexpression of the tryptophan-catabolizing enzyme indoleamine 2,3-dioxygenase 1 (IDO1) has been reported in several tumor types, including non-small cell lung cancer (NSCLC), and has been shown to promote tumor-immune evasion and inhibit T-cell activation through increased tryptophan degradation and the production of several immunosuppressive metabolites collectively known as kynurenines. However, it remains unclear whether IDO1 expression by tumor cells is detrimental specifically in the context of programmed cell death protein 1 (PD-1)/programmed death ligand 1 (PD-L1) axis blockade.

EXPERIMENTAL DESIGN

We analyzed the transcriptome of 891 NSCLC tumor samples from patients enrolled in two large randomized clinical trials investigating the safety and activity of atezolizumab, a humanized IgG1 mAb that targets PD-L1, versus docetaxel in patients with advanced NSCLC. We complemented these transcriptomics results at the protein level by using multiplex immunofluorescence and at the functional level with in vitro experiments.

RESULTS

The increased expression of the tryptophan-catabolizing enzyme IDO1 was significantly associated with improved objective response, progression-free survival, and overall survival in patients treated with PD-L1 inhibitors, but not in those treated with chemotherapy. Strikingly, inflamed tumors had higher levels of IDO1, and IDO1 was also expressed in tertiary lymphoid structures (TLS) by mature follicular dendritic cells. L-kynurenine impaired the differentiation of antibody-producing B cells induced by follicular helper T (Tfh)/B-cell interactions, a hallmark process within TLS.

CONCLUSIONS

IDO1 pathway in NSCLC is driven by the immune system rather than by tumor cells. Targeting IDO1 in combination with anti-PD-1/PD-L1 might be beneficial only in patients with inflamed tumors and particularly in those bearing TLS.

Evaluating video-based consultations in routine clinical practice at a comprehensive cancer center

INTRODUCTION

Integrating telemedicine into cancer care remains a major challenge. There are little clinical evidence for teleconsultation efficacy and safety in daily oncology practice. This study as a pioneering experience, aimed to analyze patient and physician opinions regarding the implementation of telemedicine consultations, and to identify major limitations of telehealth spread in an oncology institute.

MATERIAL AND METHODS

During COVID-19 lockdown, patients and physicians who took part to at least one video-based teleconsultation between March and May 2020, were enrolled in this observational study. All eligible patients received an anonymous online questionnaire. On the other hand, all physicians eligible to participate were asked through email to complete a questionnaire.

RESULTS

In this study, 31 physicians and 304 patients consented to participate in this study by answering the questionnaire and were included. Regarding telemedicine satisfaction, 65.8% of patients were satisfied. The lack of clinical examination was the major limitation reported by 77% of patients. Patients belonging to a high socio-professional category were statistically more dissatisfied with the relationship with their doctor (OR = 2.31 and 95% CI [1.12; 4.74]).

CONCLUSION

This study showed promising results of incorporating video-based teleconsultations into cancer patient management. Randomized clinical trials are needed in order to accelerate the digital implementation in clinical practice.

Urachal carcinoma: a large retrospective multicentric study from the French Genito-Urinary Tumor Group

Introduction

Urachal cancer (UrC) is a rare, non-urothelial malignancy. Its natural history and management are poorly understood. Although localized to the bladder dome, the most common histological subtype of UrC is adenocarcinoma. UrC develops from an embryonic remnant, and is frequently diagnosed in advanced stage with poor prognosis. The treatment is not standardized, and based only on case reports and small series. This large retrospective multicentric study was conducted by the French Genito-Urinary Tumor Group to gain a better understanding of UrC.

Material and Methods

data has been collected retrospectively on 97 patients treated at 22 French Cancer Centers between 1996 and 2020.

Results

The median follow-up was 59 months (range 44-96). The median age at diagnosis was 53 years (range 20-86), 45% were females and 23% had tobacco exposure. For patients with localized disease (Mayo I-II, n=46) and with lymph-node invasion (Mayo III, n=13) median progression-free-survival (mPFS) was 31 months (95% CI: 20-67) and 7 months (95% CI: 6-not reached (NR)), and median overall survival (mOS) was 73 months (95% CI: 57-NR) and 22 months (95% CI: 21-NR) respectively. For 45 patients with Mayo I-III had secondary metastatic progression, and 20 patients were metastatic at diagnosis. Metastatic localization was peritoneal for 54% of patients. Most patients with localized tumor were treated with partial cystectomy, with mPFS of 20 months (95% CI: 14-49), and only 12 patients received adjuvant therapy. Metastatic patients (Mayo IV) had a mOS of 23 months (95% CI: 19-33) and 69% received a platin-fluorouracil combination treatment.

Conclusion

UrC is a rare tumor of the bladder where patients are younger with a higher number of females, and a lower tobacco exposure than in standard urothelial carcinoma. For localized tumor, partial cystectomy is recommended. The mOS and mPFS were low, notably for patients with lymph node invasion. For metastatic patients the prognosis is poor and standard therapy is not well-defined. Further clinical and biological knowledge are needed.

Circulating L-Arginine predicts the survival of cancer patients treated with immune checkpoint inhibitors

BACKGROUND

The discovery of immune checkpoint inhibitors (ICIs) has revolutionized the systemic approach to cancer treatment. However, most patients receiving ICIs do not derive benefits. Therefore, it is crucial to identify reliable predictive biomarkers of response to ICIs. One important pathway in regulating immune cell reactivity is L-arginine (ARG) metabolism, essential to T-cell activation. We therefore aimed to evaluate the association between baseline plasma ARG levels and the clinical benefit of ICIs.

PATIENTS AND METHODS

The correlation between ARG levels and clinical ICI activity was assessed by analyzing plasma samples obtained before treatment onset in two independent cohorts of patients with advanced cancer included in two institutional molecular profiling programs (BIP, NCT02534649, n = 77; PREMIS, NCT03984318, n = 296) and from patients in a phase 1 first-in-human study of budigalimab monotherapy (NCT03000257). Additionally, the correlation between ARG levels and ICI efficacy in preclinical settings was evaluated using a syngeneic mouse model of colorectal cancer responsive to ICIs. Using matched PBMC plasma samples, we analyzed the correlation between ARG levels and PBMC features through multiplexed flow cytometry analysis.

RESULTS

In both discovery and validation cohorts, low ARG levels at baseline (<42 μM) were significantly and independently associated with a worse clinical benefit rate, progression-free survival, and overall survival. Moreover, at the preclinical level, the tumor rejection rate was significantly higher in mice with high baseline ARG levels than in those with low ARG levels (85.7% versus 23.8%; P = 0.004). Finally, PBMC immunophenotyping showed that low ARG levels were significantly associated with increased PD-L1 expression in several immune cell subsets from the myeloid lineage.

CONCLUSION

We demonstrate that baseline ARG levels predict ICI response. Plasma ARG quantification may therefore represent an attractive biomarker to tailor novel therapeutic regimens targeting the ARG pathway in combination with ICIs.

Identification of super-exhausted T cells: A novel population predictive of response to immunotherapy

2596

Background: Given that most of cancer patients treated with anti-PD1/PD-L1 immune checkpoint blockers (ICB) do not derive benefit, there is a crucial need to identify reliable predictive biomarker of response. Besides PD-1, several key immune checkpoints, such as CTLA4, LAG3, TIM3 and TIGIT, are associated with a T cell exhausted phenotype and play a crucial role in leading to cancer immune evasion. The impact of simultaneous expression by T cells of distinct inhibitory receptors on outcome of patients treated with ICB is still unknown. Methods: We analyzed the tissue samples, collected before ICB initiation, from patients with solid tumors and included in an institutional molecular profiling program (NCT02534649). We used multiplexed-immunohistofluorescence with the following panel CD3/PD1/TIM3/LAG3/TIGIT/CTLA4, and performed immune cell characterization using multispectral images analysis. We then investigated the correlation between coexpression of T cell-associated exhaustion markers, clinical response rate, progression-free survival (PFS) and overall survival (OS) by Cox proportional hazards models. Results: Four hundred thirty five patients were included in the analysis (NSCLC: n=207, 47.6%; sarcoma: n=42, 9.7%; urothelial: n=30, 6.9%; others: n=156, 35.9%). Digital pathology analysis allowed us to identify a population of “super-exhausted” T cells characterized by the co-expression of PD1, LAG3, TIGIT and TIM3 which was enriched in 125 cases (28.7%), and was significantly associated with better PFS (HR 1.60, CI95 1.26-2.04, p<0.001) and OS (HR 1.42, CI95 1.07-1.89, p=0.016) in the whole cohort. Patients with super-exhausted high tumors had higher objective response rate (38.4%) compared to super-exhausted low tumors (19.7%, p<0.001). The presence of super-exhausted T cells was significantly higher in responders (10%) versus non responders (4%, p<0.001). Correlation with better outcome was observed whatever the subgroup considered (NSCLC vs other tumors, CD8 T cells density and presence of tertiary lymphoid structure [TLS]). In multivariate analysis (n=372, 85.5%), increased tumor infiltration by super-exhausted T cells (>1 %) was significantly associated with better PFS (HR 0.61, CI95 0.46-0.81, p<0.001, Table) and OS (HR 0.68, CI95 0.48-0.97, p=0.033, Table). Conclusions: The presence of super-exhausted T cells may represent a new predictive biomarker of response to ICB and pave the way for the development of effective ICB combinations. Data from an independent validation cohort will be presented at the meeting. [Table: see text]

Impact of acetaminophen on the efficacy of immunotherapy in patients with cancer

12000

Background: Pain is the most common symptom experienced by patients with advanced cancer. Acetaminophen (APAP, commonly known as paracetamol) alone or in combination with a weak opioid, such as codeine or tramadol, is usually considered as the first-line strategy to manage mild-to-moderate pain in this setting. Although generally considered to be safe, several evidences suggest that APAP may have negative immunomodulatory effects. Randomized studies have shown that APAP use is associated with blunted vaccine immune responses. Given its potential to impair vaccine effectiveness, the World Health Organization stated in 2015 that administration of APAP before or at the time of vaccination is not recommended. This study aimed to assess APAP impact on efficacy of immunotherapy in patients with cancer. Methods: Exposure to APAP was assessed by plasma analysis and was correlated with clinical outcome in three independent cohorts of patients with advanced cancer who were treated with immune checkpoint blockers (ICB): the CheckMate 025 trial, n = 297 (NCT01668784, sponsor: Bristol Myers Squibb), the institutional biomarker program BIP n = 34 (NCT02534649, sponsor: Institut Bergonié, Bordeaux, France) and the institutional biomarker program PREMIS n = 297 (NCT03984318, sponsor: Gustave Roussy, Villejuif, France). APAP immunomodulatory effects were evaluated on a pre-clinical tumor model (MC38) and on human peripheral blood mononuclear cells (PBMCs) from healthy donors. Results: Detectable plasma APAP levels at treatment onset was associated with a significantly worse clinical outcome in ICB-treated cancer patients (HR for progression-free survival : 1.43, 95% CI 1.07–1.91, p = 0.015; HR for overall survival: 1.78 95% CI 1.18–2.68, p = 0.006), independently of other prognostic factors (age, performance status, number of previous lines of treatment, tumor type, number of metastatic sites, presence of liver metastases, LDH levels). APAP significantly reduced ICB efficacy in the pre-clinical MC38 model, as well as the production of PD1 blockade-related interferon-γ secretion by human PBMCs. Moreover, reduction of ICB efficacy in vivo was associated with significantly increased tumor infiltration by regulatory T cells (Tregs). Administration of APAP over 24 h induced a significant expansion of peripheral Tregs in healthy individuals. In addition, interleukin-10, a crucial mediator of Treg-induced immune suppression, was significantly upregulated upon treatment with ICB in cancer patients taking APAP. Conclusions: This study provides strong pre-clinical and clinical evidence of the role of APAP as a potential suppressor of antitumor immunity. Hence, APAP should be used with caution in patients treated with ICB.

Impact of acetaminophen on the efficacy of immunotherapy in cancer patients

BACKGROUND

Acetaminophen (APAP) use has been associated with blunted vaccine immune responses. This study aimed to assess APAP impact on immunotherapy efficacy in patients with cancer.

PATIENTS AND METHODS

Exposure to APAP was assessed by plasma analysis and was correlated with clinical outcome in three independent cohorts of patients with advanced cancer who were treated with immune checkpoint blockers (ICB). APAP immunomodulatory effects were evaluated on a pre-clinical tumor model and on human peripheral blood mononuclear cells (PBMCs) from healthy donors.

RESULTS

Detectable plasma APAP levels at treatment onset was associated with a significantly worse clinical outcome in ICB-treated cancer patients, independently of other prognostic factors. APAP significantly reduced ICB efficacy in the pre-clinical MC38 model, as well as the production of PD1 blockade-related interferon-γ secretion by human PBMCs. Moreover, reduction of ICB efficacy in vivo was associated with significantly increased tumor infiltration by regulatory T cells (Tregs). Administration of APAP over 24 h induced a significant expansion of peripheral Tregs in healthy individuals. In addition, interleukin-10, a crucial mediator of Treg-induced immune suppression, was significantly upregulated upon treatment with ICB in cancer patients taking APAP.

CONCLUSION

This study provides strong pre-clinical and clinical evidence of the role of APAP as a potential suppressor of antitumor immunity. Hence, APAP should be used with caution in patients treated with ICB.

Mature tertiary lymphoid structures predict immune checkpoint inhibitor efficacy in solid tumors independently of PD-L1 expression

Only a minority of patients derive long-term clinical benefit from anti-PD1/PD-L1 monoclonal antibodies. The presence of tertiary lymphoid structures (TLS) has been associated with improved survival in several tumor types. Here, using a large-scale retrospective analysis of three independent cohorts of cancer patients treated with anti-PD1/PD-L1 antibodies, we showed that the presence of mature TLS was associated with improved objective response rate, progression-free survival, and overall survival independently of PD-L1 expression status and CD8+ T-cell density. These results pave the way for using TLS detection to select patients who are more likely to benefit from immune checkpoint blockade.

Is There a Role for Percutaneous Ablation for Early Stage Lung Cancer? What Is the Evidence?

PURPOSE OF REVIEW

For patients with early stage non-small-cell lung cancer (NSCLC), thermal ablation (TA) has become in the least two decades an option of treatment used worldwide for patients with comorbidities who are not surgical candidates. Here, we review data published with different TA techniques: radiofrequency ablation (RFA), microwave ablation (MWA) and cryoablation. This paper reviews also the comparison that has been made between TA and stereotactic radiotherapy (SBRT).

RECENT FINDINGS

A majority of retrospective studies, the absence of comparative studies, and the variety of techniques make difficult to get evident data. Nevertheless, these stand-alone techniques have demonstrated local efficacy for tumors less than 3 cm and good tolerance on fragile patients. Many recent reviews and database analyses show that outcomes after TA (mainly RFA and MWA) are comparable to SBRT in terms of survival rates. For patients who are unfit for surgery, TA has demonstrated interesting results for safety, benefits in overall survival, and acceptable local control.

Prostate cancer and PARP inhibitors: progress and challenges

Despite survival improvements achieved over the last two decades, prostate cancer remains lethal at the metastatic castration-resistant stage (mCRPC) and new therapeutic approaches are needed. Germinal and/or somatic alterations of DNA-damage response pathway genes are found in a substantial number of patients with advanced prostate cancers, mainly of poor prognosis. Such alterations induce a dependency for single strand break reparation through the poly(adenosine diphosphate-ribose) polymerase (PARP) system, providing the rationale to develop PARP inhibitors. In solid tumors, the first demonstration of an improvement in overall survival was provided by olaparib in patients with mCRPC harboring homologous recombination repair deficiencies. Although this represents a major milestone, a number of issues relating to PARP inhibitors remain. This timely review synthesizes and discusses the rationale and development of PARP inhibitors, biomarker-based approaches associated and the future challenges related to their prescription as well as patient pathways.

Impact of 18FDG-PET CT in the management of invasive bladder cancer

444

Background: Guidelines do not recommend FDG-Positron Emission Tomography (PET) Computed Tomography (CT) for the staging of Muscle Invasive Bladder Cancer (MIBC), but rather CT scan for lymph node (LN) and metastatic staging, despite its low accuracy. We performed a retrospective analysis of patients (pts) with MIBC who had a FDG-PET CT for staging, indicated by multidisciplinary team, in two centers, and analyzed its utility in this setting. Methods: All pts who had a FDG-PET CT performed at the time of diagnosis of MIBC from 01/2005 to 12/2017 in Bordeaux (Bergonie Institute and University Hospital) were retrospectively reviewed. Nodal and metastatic staging on CT and FDG-PET CT were done independently according to the 8th TNM classification. The aims of the study were to evaluate the accuracy of the FDG-PET CT for LN staging and to determine the rate of treatment modification (neoadjuvant chemotherapy for curative intent, no surgery for metastatic disease), according to FDG-PET CT results. Results: Among the 130 pts included, with a median age of 65 years, 74% were considered free from nodal metastasis (N0) by CT whereas only 44% were N0 from FDG-PET CT. Based on CT results, 88% of pts were free from distant metastasis (M0) but only 75% were classified M0, on FDG-PET CT. Accuracy of LN staging for CT and FDG-PET CT at initial diagnosis were analyzed for 85 pts (including 70 pts treated with neoadjuvant chemotherapy) and compared to pathological examination of resected LN. Sensitivity of FDG-PET CT was better than CT (respectively 80.8% versus 26.9%) but the specificity was low (respectively 54.2% versus 83.1%). Youden index was better for FDG-PET CT (0.35; 0.1 for CT), being more accurate for determining LN staging of MIBC. FDG-PET CT findings allowed a treatment decision modification in 34/130 pts (26.1%): therapeutic intensification in 12 pts (9.2%), including surgery not previously indicated, modified radiotherapy; or de-escalation in 22 pts (16.9%), mostly avoiding surgery. Conclusions: FDG-PET CT is more sensitive to detect LN involvement at initial diagnosis of MIBC than standard CT scan. Moreover, in the present study, treatment decisions were modified, according to FDG-PET CT results, in a quarter of pts according to LN and distant metastatic staging.

Sensitization of EGFR Wild-Type Non-Small Cell Lung Cancer Cells to EGFR-Tyrosine Kinase Inhibitor Erlotinib

The benefit of EGFR-TKI in non-small cell lung cancer has been demonstrated in mutant EGFR tumors as first-line treatment but the benefit in wild-type EGFR tumors is marginal as well as restricted to maintenance therapy in pretreated patients. This work aimed at questioning the effects of cisplatin initial treatment on the EGFR pathway in non-small cell lung cancer and the functional consequences in vitro and in in vivo animal models of patient-derived xenografts (PDX). We establish here that cisplatin pretreatment specifically sensitizes wild-type EGFR-expressing cells to erlotinib, contrary to what happens in mutant EGFR cells and with a blocking EGFR antibody, both in vitro and in vivo The sensitization entails the activation of the kinase Src upstream of EGFR, thereafter transactivating EGFR through a ligand-independent activation. We propose a combination of markers that enable to discriminate between the tumors sensitized to erlotinib or not in PDX models, which should be worth testing in patients. These markers might be useful for the selection of patients who would benefit from erlotinib as a maintenance therapy. Mol Cancer Ther; 16(8); 1634-44. ©2017 AACR.

Bevacizumab Efficacy Is Influenced by Primary Tumor Resection in First-Line Treatment of Metastatic Colorectal Cancer in a Retrospective Multicenter Study

INTRODUCTION

There is no predictive factor of response to bevacizumab in metastatic colorectal cancer. Nevertheless, preclinical studies demonstrated an interaction between primary tumor and metastatic sites for the neoangiogenesis regulation. The primary objective of our study was to identify an effect of up-front primary tumor resection (UPTR) on bevacizumab efficacy.

PATIENTS AND METHODS

Between 2008 and 2010, we retrospectively analyzed progression-free survival (PFS) and overall survival (OS) of 316 patients with synchronous and metachronous metastatic colorectal cancer according to bevacizumab addition to first-line chemotherapy and UPTR.

RESULTS

Among 206 patients with UPTR, the addition of bevacizumab to chemotherapy significantly improved OS compared to chemotherapy alone (29.8 vs. 23.9 months respectively; hazard ratio [HR] 0.58; 95% confidence interval [CI], 0.40-0.83; P = .003). This effect was confirmed in multivariate analysis. There was also a nonsignificant trend toward improved PFS (9.7 vs. 8.4 months respectively; HR 0.71; 95% CI, 0.50-1.02; P = .062). Conversely, among 110 patients without UPTR, the addition of bevacizumab to chemotherapy had no effect on OS compared to chemotherapy alone (18.2 vs. 19.3 months respectively; HR 0.96; 95% CI, 0.65-1.42; P = .853). Bevacizumab significantly improved PFS (8.1 vs. 5.7 months respectively; HR 0.66; 95% CI, 0.45-0.96; P = .032) without confirmation in multivariate analysis.

CONCLUSION

In this retrospective study, bevacizumab seems to improve OS only in patients with UPTR, which could suggest a complementarity of both therapeutic modalities for antiangiogenic effect.

[KRAS mutation does not influence oxaliplatin or irinotecan efficacy, in association with bevacizumab, in first line treatment of metastatic colorectal cancer]

INTRODUCTION

The identification of RAS status (KRAS and NRAS) has changed the management of metastatic colorectal cancer (mCRC). The impact of the RAS mutation on cytotoxic chemotherapy efficacy has not yet been determined. Nevertheless, several retrospective studies suggest a greater efficacy of oxaliplatin in mCRC with KRAS mutation.

METHODS

We analyzed retrospectively the progression free survival (PFS) and overall survival (OS) in 216 patients with mCRC receiving first line treatment between 2008 and 2010 according to KRAS status and chemotherapy regimen used (oxaliplatin- or irinotecan-based, in association with fluoropyrimidine and bevacizumab).

RESULTS

In KRAS mutated tumors, median OS was 23.4 months with oxaliplatin-based regimen, and 23.6 months with irinotecan-based regimen, with no significant difference (HR 1.30; 95 % CI 0.81-2.09; P=0.27). In KRAS wild-type tumors, median OS was 30.3 months with oxaliplatin-based regimen, and 25.4 months with irinotecan-based regimen, with no significant difference (HR 0.81; 95 % CI 0.52-1.24; P=0.33). Similarly, KRAS mutational status had no significant effect on efficacy of oxaliplatin or irinotecan regarding PFS.

DISCUSSION

In this retrospective study, KRAS mutational status does not influence the efficacy of first line cytotoxic chemotherapy in association with bevacizumab.

Abstract 2559: Optimisation of EGFR TKI efficiency wild-type EGFR lung cancer

Background : Lung cancer is the first cause of cancer death worldwide. EGFR tyrosine kinase inhibitors (EGFR-TKI) have improved the survival of patient harboring EGFR activating mutations. Besides, EGFR-TKIs have shown clinical activity for patients with wild type EGFR (wtEGFR) tumors as maintenance treatment and for a fraction of them as second line treatment. These observations impel us to objective and document the mechanisms implicated in order to optimize the use of EGFR-TKI in the treatment of wtEGFR lung cancer.

Methods : In vitro experiments rely on lung cancer cell lines expressing either wtEGFR or mutated EGFR. Their sensitivity to erlotinib in control conditions or short after a sublethal cisplatin treatment was studied. In vitro results were validated on lung patients-derived xenografts (PDX) with four wtEGFR human adenocarcinomas.

Results : Cisplatin pretreatment enhances erlotinib toxicity in wtEGFR cells (providing its robust expression) but not in EGFR-mutated cells. Cisplatin priming increases erlotinib toxicity either through apoptosis or autophagy depending on the cell line. This sensitization correlates with an increase in EGFR expression and phosphorylation and a raise in AKT and Erk phosphorylation. The sensitization is also observed during long-term cisplatin treatment in a cisplatin-resistant subpopulation, together with concomitant EGFR pathway activation.

The in vivo experiments conducted in PDX confirm that cisplatin pretreatment potentiates erlotinib in three of the four wtEGFR lung tumors models.

Of note, the sensitization to erlotinib occured independently from KRas status.

Conclusion : The sensitivity of the wtEGFR lung cancer cells and lung cancer xenografts to erlotinib is enhanced by cisplatin pretreatment, whatever the type of induced cell death. Cisplatin induces activation of EGFR and his downstream kinases AKT and Erk. This sensitization is independent from the tumor K-Ras status. EGFR phosphorylation could be a potential marker of this sensitization and might be predicitive of the optimal efficiency of EGFR TKI. In vivo validation of this marker is still ongoing.

This study was supported by Roche laboratory and by the foundation for medical research.

Citation Format: Judith Raimbourg, Mathilde Cabart, Marie-Pierre Joalland, Didier Decaudin, Ludmilla Deplater, Didier Lanoe, Jean-Yves Douillard, Jaafar Bennouna, François Vallette, Lisenn Lalier. Optimisation of EGFR TKI efficiency wild-type EGFR lung cancer. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 2559. doi:10.1158/1538-7445.AM2015-2559

Optimisation of EGFR TKI efficiency in the therapeutic scheme of EGFR wild-type lung cancer

e18532

Background: EGFR tyrosine kinase inhibitors (EGFR TKI) have improved the therapeutic care of lung cancer patients but only a small sub-population of patients, namely those harboring EGFR-mutated tumors, benefit from this therapy. The observation that EGFR TKI enhance prognosis and quality of life in all patients when used as second line or maintenance treatment impelled us into the search of potential markers of the optimal introduction kinetics of EGFR TKI in the therapeutic scheme. Methods: We used lung cancer cell lines harboring either wild-type or mutated EGFR (NCI-H1650, NCI-H1975) to study the consequences of cisplatin treatment in vitro on the consecutive sensitivity to erlotinib. Results: Sub-lethal cisplatin pretreatment (3µM) enhances erlotinib toxicity in EGFR wild-type, but not EGFR mutated cells (A549 IC50 drops from 28 to 15µM for short-term or 12µM for long-term exposure). This correlates with EGFR activation following short-term or prolonged cisplatin treatment through the secretion of EGFR ligands. This activation of EGFR is concomitant to the decrease in other receptor tyrosine kinases phosphorylation including Met. Conclusions: The sensitivity of EGFR wild-type lung cancer cells to erlotinib in vitro is enhanced by cisplatin pretreatment. We identified potential markers of this sensitization, namely EGFR ligands, which serum level might be predicitive of the optimal efficiency of EGFR TKI. In vivo validation of these markers is under investigation. The concomitant decrease in other receptor tyrosine kinases phosphorylation suggests that the targeting of other receptor tyrosine kinases might potentiate EGFR TKI efficiency.