Turning Concept Into Reality: Modulating the Immune System to Treat NSCLC

Patrick M. Forde, MD

Fellow in the Thoracic Oncology Research Program,

Sidney Kimmel Comprehensive Cancer Center at

Johns Hopkins, Baltimore, MD

Corresponding Author:

Julie R. Brahmer, MD, MSc

Associate Professor of Oncology,

Sidney Kimmel Comprehensive Cancer Center at

Johns Hopkins, Baltimore, MD;

brahmju@jhmi.edu

Abstract

For many years non—small cell lung cancer (NSCLC), unlike melanoma and renal cell carcinoma, was thought to be a nonimmunogenic tumor unlikely to benefit from therapies aimed at augmenting endogenous antitumor immunity. Recent early-phase trial data with several agents that target immune checkpoint molecules responsible for suppression of T-cell– mediated immunity have challenged this perception. Antibodies targeting cytotoxic T-lymphocyte antigen-4 (CTLA-4) and programmed death-1 (PD-1) are currently undergoing phase III investigation for advanced NSCLC. Vaccines targeting molecules expressed on NSCLC tumors have shown promise in earlyphase trials, and phase III studies are ongoing. In this article, we summarize early-phase trial results in NSCLC with immune checkpoint inhibitors and vaccines, and look forward to future developments in this rapidly expanding field.

Therapy for advanced non—small cell lung cancer (NSCLC) has shown incremental improvement over the past two decades with median overall survival (OS) in phase III trials now typically exceeding 12 months for patients with nonsquamous disease, and approaching 15 months in the most recently reported studies.^1-3In addition, OS for the 10% to 15% of patients who have a targetable driver mutation in the epidermal growth factor receptor (EGFR) and are treated with EGFR tyrosine kinase inhibitor (TKI) therapy has ranged from 22.9 to 27.7 months in recent studies.^4,5Results from trials enrolling patients with squamous NSCLC, which rarely has driver mutations that can be targeted with current FDA-approved agents, have been less encouraging, with typical median survival figures of 9 to 12 months.^6,7For earlier-stage disease, approximately 50% to 75% of patients will eventually relapse and die from lung cancer despite apparently curative resection.⁸

Vaccines

Melanoma-Associated Antigen A3 Vaccine

In this setting, novel treatments such as immunotherapy are of great interest, particularly if new biomarkers of response can be developed, allowing their use to cross the boundaries of histology and mutational status.Vaccine-based strategies currently in phase III development in NSCLC are summarized inTable 1.^9-18Melanoma-associated antigen A3 (MAGE-A3) is a tumorspecific gene product that is recognized by cytotoxic T cells and frequently upregulated in the early development of NSCLC.^19,20MAGE-A3 is expressed in 30% to 50% of NSCLC tumors and at a higher frequency in squamous tumors, poorly differentiated tumors, and advanced disease.^21,22Expression has also been associated with poorer disease-free survival (DFS) for resected NSCLC.²³Given the specificity of MAGE-A3 expression for tumor cells, MAGE-A3 vaccine has been created containing MAGE-A3 recombinant protein combined with a ASO2B immunologic adjuvant system, which appears to potentiate the immunologic effect. This vaccine has shown preliminary efficacy in metastatic melanoma, with five responses from 26 patients in a phase I/II study.²³

Initial studies in patients post-resection of early-stage NSCLC demonstrated that seven of eight vaccinated patients attained a rise in serum anti-MAGE-A3 antibodies, and repeated vaccination augmented this response.²⁴In a double-blind phase II study, 182 patients with resected stage IB or II NSCLC, expressing MAGE-A3 by quantitative reverse transcriptase—polymerase chain reaction, were randomized 2:1 to receive adjuvant MAGE-A3 vaccine intramuscular injections or placebo.9 Analysis showed a positive trend favoring the MAGE-A3 vaccine with hazard ratios of 0.76 (95% CI, 0.48-1.21) for DFS and 0.81 (95% CI, 0.47-1.40) for OS; however, these figures did not reach statistical significance. The investigators developed a gene signature from this study, of immune-related genes that appeared to predict benefit from the vaccine, and indeed may be predictive of response to immune-based therapeutics in general.²⁵

Liposomal BLP25

TABLE 1. Vaccines in Phase III Clinical Development for NSCLC

Vaccine

Antigen/ Formulation

Phase II

Phase III

Post-surgical resection of early-stage NSCLC

MAGE-A3

Full protein ASO2B/AS15

Trend for increased DFS vs placebo (HR = 0.74; P = .107)⁹

MAGRIT study, stage IB-IIIA, MAGEA3- positive, vaccine or placebo after surgery alone/surgery + adjuvant chemo; completed accrual 2012¹⁰

Post-CRT for unresectable stage III NSCLC

Liposomal-BLP25(Stimuvax)

MUC1 peptide, liposomal

Trend for increased OS vs BSC (HR = 0.75; P = .112)¹¹

START study, stage IIIA/B, after definitive CRT, reportedly negative for OS¹²; formal results awaited

Advanced NSCLC

Belagenpumatucel-L(Lucanix)

Allogeneic cell vaccine transfected with TGF-β2 antisense gene

Response in 15%, higher dose correlated with survival¹³

STOP study, stage III/IV, vaccine vs placebo after first-line platinum doublet chemo; completed accrual 2012¹⁴

rHu-EGF(CIMAvax-EGF)

EGF fused to carrier protein

Trend for increased OS in patients developing antibody response¹⁵

Stage III/IV, vaccine vs BSC¹⁶

TG4010

MUC1, recombinant viral vector coding human MUC1 and hIL-2

Chemo + TG4010 vs chemo alone, trend for improved RR for vaccine, no difference in OS¹⁷

First-line MUC1-positive stage III/IV, chemo + vaccine vs chemo alone¹⁸

MAGE-A3, melanoma-associated antigen-A3; DFS, disease-free survival; OS, overall survival; BSC, best supportive care; chemo, chemotherapy; CRT, chemoradiation; TGF- β2, transforming growth factor-β2; rHu-EGF, recombinant human epidermal growth factor; MUC1, mucin glycoprotein 1; hIL-2, recombinant human interleukin-2; RR, response rate by RECIST 1.0.

Belagenpumatucel-L

The MAGE-A3 vaccine is currently being investigated in a large phase III trial, NCT00480025, that has enrolled over 3000 patients with stage IB-IIIA resected NSCLC (MAGRIT study) and includes patients who receive adjuvant chemotherapy.¹⁰The primary endpoint for this study is DFS, and initial efficacy data are expected in mid-2013.Mucin glycoprotein 1 (MUC 1) is a membrane-associated glycoprotein that is overexpressed in human cancers including NSCLC, and has been associated with a poor prognosis.²⁶Liposomal BLP25 (Stimuvax) is a peptide vaccine that targets MUC 1 and has elicited T-cell responses in phase I studies.²⁷In a phase IIb study, 171 patients with advanced NSCLC were randomized to receive either a single dose of low-dose cyclophosphamide followed by 8 weekly doses of liposomal BLP25 vaccine or best supportive care.11 Results showed a nonsignificant trend toward improved survival for patients who received liposomal BLP25 (17.2 vs 13.0 months; hazard ratio [HR] = 0·745; 95% CI, 0.533-1.042). Adverse events included flu-like symptoms and injection site reaction, and were generally grade 1-2.Two international phase III studies of liposomal BLP25 are ongoing.28,29 The START study (Stimulating Targeted Antigenic Responses to NSCLC), NCT00409188, in Europe and the United States, randomized 1300 patients with stage IIIA/B NSCLC to vaccine or placebo after definitive chemoradiation,28 while a similar study in Asia has commenced enrollment.29 Merck Serono, the pharmaceutical company responsible for liposomal BLP25, recently announced that START did not meet its primary endpoint of improving OS; however, detailed results of this study are awaited.12Belagenpumatucel-L is an allogeneic cell vaccine consisting of four NSCLC lines (2 adenocarcinoma, 1 squamous, and 1 large cell). Allogeneic vaccines do not have the logistical concerns associated with manufacture that are seen with autologous agents such as the prostate cancer vaccine, sipuleucel-T30; however, more uncertainty exists with allogeneic vaccines regarding the degree of true antitumor activity elicited. Belagenpumatucel-L downregulates transforming growth factor-β2 (TGF-β2) by transfecting cells with a TGF-β2 antisense gene, thus enhancing tumor antigen recognition.¹³

Epidermal Growth Factor

Immune Checkpoints

TABLE 2. Immune Checkpoint Blockade in NSCLC

Target

Agent

Early-Phase Results

Phase III

CTLA-4

Ipilimumab

Phase II study, phased schedule with chemotherapy showed prolonged irPFS vs chemo alone³¹

First-line, advanced squamous NSCLC, chemo +/- phased ipilimumab32

PD-1

Nivolumab (BMS- 936558)

Phase I study included 121 evaluable, pretreated patients with advanced NSCLC; RR, 16%^33,34

Second-line, advanced NSCLC, single-agent chemo vs nivolumab

PD-L1

BMS- 936559

Phase I study included 49 evaluable, pretreated patients with advanced NSCLC; RR, 10%³⁵

NSCLC, non—small cell lung cancer; chemo, chemotherapy; CTLA-4, cytotoxic T-lymphocyte antigen-4; irPFS, progression-free-survival by immune response; PD-1, programmed death-1; RR, response rate by RECIST 1.0; PD-L1, programmed death-ligand 1.

CTLA-4

Clinical Pearls

• Immunotherapy is showing unexpected promise in NSCLC, with numerous large phase III trials under way or planned.
• Results from vaccine trials in both the adjuvant and advanceddisease settings are awaited. Important vaccines in development include the MAGE-A3 vaccine, liposomal BLP25 targeting MUC1, an allogeneic vaccine, belagenpumatucel-L, and a vaccine targeting epidermal growth factor.
• Agents modulating immune checkpoint molecules are entering phase III investigation in NSCLC, including ipilimumab targeting CTLA-4 and nivolumab (BMS-936558) targeting PD-1.

PD-1

In a phase II dose-variable study of 75 patients with stage II-IV NSCLC, a response rate of 15% was noted in 61 patients with stage III-IV disease.¹³OS appeared to be prolonged in patients who received higher doses of the vaccine (OS, 47% at 2 years vs 18% for lower dose), and patients who had a humoral and cellular response to the vaccine had improved OS (32.5 months vs 11.6 months;P= .011). The phase III STOP trial, NCT00676507, is comparing belagenpumatucel-L with placebo for patients with advanced NSCLC who have stable disease or a response after first-line platinum doublet chemotherapy. The primary endpoint of this study is OS.¹⁴This study completed enrollment of over 700 patients in 2012.CIMAvax-EGF is a therapeutic cancer vaccine comprising human recombinant epidermal growth factor (EGF) conjugated to a carrier protein, P64K from Neisseria Meningitides.¹⁵After promising phase II results in advanced NSCLC, enrollment was completed on a phase III study, NCT01444118, with results expected within the next year.¹⁶To date, agents targeting two immune checkpoint molecules, CTLA-4 and PD-1, have entered phase III clinical trial investigation in NSCLC. In addition, early-phase studies of an antibody targeting the ligand of PD-1, programmed death-ligand 1 (PD-L1), have also shown promising results in NSCLC. Studies to date incorporating these agents are summarized inTable 2.^31-35CTLA-4 is a transmembrane receptor whose expression is induced by T cell activation, leading to downregulation of T cell responses and suppression of the innate immune response to tumor.³⁶Ipilimumab is a fully human monoclonal antibody that blocks CTLA-4, thus releasing innate antitumor immunity.³⁷In a phase II study, 204 patients with advanced NSCLC were randomized to firstline platinum doublet chemotherapy with placebo versus chemotherapy with concurrent or phased-schedule ipilimumab.³¹The phased schedule of two induction chemotherapy cycles followed by four cycles of chemotherapy concurrent with ipilimumab met the primary endpoint of improved progression-free survival by immune response (irPFS),³⁸(5.7 months vs 4.6 months;P= .05), whereas the concurrent schedule did not. The benefit of ipilimumab in this study appeared to be confined to patients with squamous histology, leading to activation of an ongoing phase III study, NCT01285609, in this cohort.³²PD-1 is a coinhibitory molecule, widely expressed on immune cells after antigen exposure, that acts to dampen the T-cell—mediated immune response to tumors and other antigens.³⁹In a large phase I study incorporating 296 patients with melanoma, renal cell carcinoma, and advanced NSCLC (76 patients evaluable for response at the time of report), single-agent anti-PD-1 (nivolumab [BMS-936558]) was responsible for a 16% response rate by RECIST 1.0 in patients with heavily pretreated NSCLC.^33,34In addition, 33% of patients with NSCLC were free from tumor progression at 6 months. Responses were noted in nine of 48 patients with squamous NSCLC and 11 of 73 patients with nonsquamous NSCLC, suggesting activity in both subsets. Immunohistochemical expression of PD-L1 on tumor cells appeared to correlate with response to anti-PD-1, with no responses seen in tumors lacking PD-L1 expression; however, only 10 patients with NSCLC were included in this analysis. Pneumonitis was noted as a potential immune-related serious toxicity associated with anti-PD-1 therapy, occurring in 3% of the overall study population, with cessation of therapy and early institution of steroids leading to the resolution of several cases. Currently, a phase III study, NCT01642004, of single-agent nivolumab compared with second-line, single-agent chemotherapy in advanced NSCLC is ongoing.

PD-L1

Conclusion

Several other agents targeting PD-1 are currently either undergoing or in the planning stages of early clinical development, including MK-3475 (Merck), MEDI4736 (Medimmune), MPDL-3280A (Genentech), AMP-224 (Amplimmune/GSK), and AUR-012 (Aurigene).In a phase I study of anti-PD-L1 (BMS-936559) that included 75 heavily pretreated patients with advanced NSCLC, anti-PD-L1 induced a 10% response rate in the 49 patients evaluable for response; an additional 12% of patients had stable disease lasting more than 6 months.³⁵Strategies aimed at augmenting endogenous antitumor immunity have shown significant promise in earlyphase studies in NSCLC. Results are awaited from large phase III studies of vaccine-based therapies. Immune checkpoint inhibition has led to responses and prolonged remissions for some patients with advanced NSCLC, and phase III studies of anti-CTLA-4 and anti-PD-1 therapies are planned or in progress. Challenges remain, in particular validating biomarkers of response to immunotherapy in order to maximize benefit. Elucidating the optimal sequence and combinations of immune-based treatments with traditional cytotoxic chemotherapy and other targeted agents will be the next step in the development of these exciting new therapies.

References

1. Kabbinavar FF, Miller VA, Johnson BE, et al. Overall survival (OS) in ATLAS, a phase IIIb trial comparing bevacizumab (B) therapy with or without erlotinib (E) after completion of chemotherapy (chemo) with B for firstline treatment of locally advanced, recurrent, or metastatic non-small cell lung cancer (NSCLC).J Clin Oncol. 2010;28(15 suppl; abstr 7526).
2. Lara PN Jr, Douillard JY, Nakagawa K, et al. Randomized phase III placebo-controlled trial of carboplatin and paclitaxel with or without the vascular disrupting agent vadimezan (ASA404) in advanced non-smallcell lung cancerJ Clin Oncol. 2011;29(22):2965-2971.
3. Cancergrace.org. My Four Key Points from the PointBreak Trial. Available at: http://cancergrace.org/lung/2012/09/07/4-key-points-frompointbreak- trial/. Accessed March 22, 2013.
4. Rosell R, Carcereny E, Gervais R, et al. Erlotinib versus standard chemotherapy as first-line treatment for European patients with advanced EGFR mutation-positive non-small-cell lung cancer (EURTAC): a multicentre, open-label, randomised phase 3 trial.Lancet Oncol. 2012;13(3):239-246.
5. Inoue A, Kobayashi K, Maemondo M, et al. Updated overall survival results from a randomized phase III trial comparing gefitinib with carboplatin-paclitaxel for chemo-naïve non-small cell lung cancer with sensitive EGFR gene mutations (NEJ002).Ann Oncol. 2013;24(1):54-59.
6. Pirker R, Pereira JR, Szczesna A, et al. Cetuximab plus chemotherapy in patients with advanced non-small-cell lung cancer (FLEX): an openlabel randomised phase III trial.Lancet. 2009;373(9674):1525-1531.
7. Socinski MA, Bondarenko I, Karaseva NA, et al. Weekly nab-paclitaxel in combination with carboplatin versus solvent-based paclitaxel plus carboplatin as first-line therapy in patients with advanced nonsmall- cell lung cancer: final results of a phase III trial.J Clin Oncol. 2012;30(17):2055-2062.
8. Chansky K, Sculier JP, Crowley JJ, et al. The International Association for the Study of Lung Cancer Staging Project: prognostic factors and pathologic TNM stage in surgically managed non-small cell lung cancer.J Thorac Oncol. 2009;4(7):792-801.
9. Vansteenkiste J, Zielinski M, Linder A, et al. Final results of a multicenter, double-blind, randomized, placebo-controlled phase II study to assess the efficacy of MAGE-A3 immunotherapeutic as adjuvant therapy in stage IB/II non-small cell lung cancer. Presented at: 2007 ASCO Annual Meeting; June 1-5, 2007; Chicago, IL.
10. Clinicaltrials.gov identifier: NCT00480025.
11. Butts C, Murray N, Maksymiuk A, et al. Randomized phase IIB trial of BLP25 liposome vaccine in stage IIIB and IV non-small-cell lung cancer.J Clin Oncol. 2005;23(27):6674-6681.
12. EMD Serono. Available at: http://www.emdserono.com/.
13. Nemunaitis J, Dillman RO, Schwarzenberger PO, et al. Phase II study of belagenpumatucel-L, a transforming growth factor beta-2 antisense gene-modified allogeneic tumor cell vaccine in non-small cell lung cancer.J Clin Oncol. 2006;24(29):4721-4730.
14. Clinicaltrials.gov identifier: NCT00676507.
15. Neninger Vinageras E, de la Torre A, Osorio Rodríguez M, et al. Phase II randomized controlled trial of an epidermal growth factor vaccine in advanced non-small-cell lung cancer.J Clin Oncol. 2008;26(9):1452-1458.
16. Clinicaltrials.gov identifier: NCT01444118.
17. Quoix E, Ramlau R, Westeel V, et al. Therapeutic vaccination with TG4010 and first-line chemotherapy in advanced non-small-cell lung cancer: a controlled phase 2B trial.Lancet Oncol. 2011;12(12):1125-1133.
18. Clinicaltrials.gov identifier: NCT01383148.
19. Kobayashi H, Song Y, Hoon DS, et al. Tumor-reactive T helper lymphocytes recognize a promiscuous MAGE-A3 epitope presented by various major histocompatibility complex class II alleles.Cancer Res. 2001;61(12):4773-4778.
20. Jang SJ, Soria JC, Wang L, et al. Activation of melanoma antigen tumor antigens occurs early in lung carcinogenesis.Cancer Res. 2001;61(21):7959-7963.
21. Bolli M, Kocher T, Adamina M, et al. Tissue microarray evaluation of Melanoma antigen E (MAGE) tumor-associated antigen expression: potential indications for specific immunotherapy and prognostic relevance in squamous cell lung carcinoma.Ann Surg. 2002;236(6):785-793.
22. Gure AO, Chua R, Williamson B, et al. Cancer-testis genes are coordinately expressed and are markers of poor outcome in non-small cell lung cancer.Clin Cancer Res. 2005;11(22):8055-8062.
23. Kruit WH, van Ojik HH, Brichard VG, et al. Phase 1/2 study of subcutaneous and intradermal immunization with a recombinant MAGE- 3 protein in patients with detectable metastatic melanoma.Int J Cancer. 2005;117(4):596-604.
24. Atanackovic D, Altorki NK, Stockert E, et al. Vaccine-induced CD4+ T cell responses to MAGE-3 protein in lung cancer patients.J Immunol. 2004;172(5):3289-3296.
25. Vansteenkiste JF, Zielinski M, Dahabreh IJ, et al. Association of gene expression signature and clinical efficacy of MAGE-A3 antigen-specific cancer immunotherapeutic as adjuvant therapy in resected stage IB/II non-small cell lung cancer.J Clin Oncol. 2008;26(15S). Abstract 7501.
26. Kelly RJ, Giaccone G. Lung cancer vaccines.Cancer J. 2011;17(5):302-308.
27. Butts C, Murray RN, Smith CJ, et al. A multicenter open-label study to assess the safety of a new formulation of BLP25 liposome vaccine in patients with unresectable stage III non-small-cell lung cancer.Clin Lung Cancer. 2010;11(6):391-395.
28. Clinicaltrials.gov identifier: NCT00409188.
29. Clinicaltrials.gov identifier: NCT01015443.
30. Di Lorenzo G, Ferro M, Buonerba C. Sipuleucel-T (Provenge®) for castration-resistant prostate cancer.BJU Int. 2012;110(2 Pt 2):E99-E104.
31. Lynch TJ, Bondarenko I, Luft A, et al. Ipilimumab in combination with paclitaxel and carboplatin as first-line treatment in stage IIIB/IV non-small-cell lung cancer: results from a randomized, double-blind, multicenter phase II study.J Clin Oncol. 2012;30(17):2046-2054.
32. ClinicalTrials.gov Identifier: NCT01285609.
33. Topalian SL, Hodi FS, Brahmer JR, et al. Safety, activity, and immune correlates of anti-PD-1 antibody in cancerN Engl J Med. 2012;28;366(26):2443-2454.
34. Topalian SL, Brahmer JR, Hodi, FS, et al. Anti-programmed death-1 (PD-1) (BMS-936558/MDX-1106/ONO in patients (pts) with advanced solid tumors: clinical activity, safety, and molecular markers. Presented at the 2012 European Society for Medical Oncology Annual Meeting; September 28-October 2, 2012; Vienna, Austria. Abstract 1391. Available at: http://abstracts.webges.com/viewing/view.php?congress=esmo2012&congress_id=370&publication_id=1391. Accessed April 12, 2013.
35. Brahmer JR, Tykodi SS, Chow LQ, et al. Safety and activity of anti-PD-L1 antibody in patients with advanced cancer.N Engl J Med. 2012;366:2455-2465.
36. Krummel MF, Allison JP. CD28 and CTLA-4 have opposing effects on the response of T cells to stimulation.J Exp Med. 1995;182(2):459-465.
37. Wolchok J. How recent advances in immunotherapy are changing the standard of care for patients with metastatic melanoma.Ann Oncol. 2012;23(suppl 8):viii15-21.
38. Wolchok JD, Hoos A, O’Day S, et al. Guidelines for the evaluation of immune therapy activity in solid tumors: immune-related response criteriaClin Cancer Res. 2009;15(23):7412-7420.
39. Dong H, Strome SE, Salomao DR, et al. Tumor-associated B7-H1 promotes T-cell apoptosis: a potential mechanism of immune evasionNat Med. 2002;8(8):793-800.

Author Disclosures

Dr. Forde has no conflicts of interest to report.