A Phase II trial of alternating osimertinib and gefitinib therapy in advanced EGFR-T790M positive non-small cell lung cancer: OSCILLATE

In this phase II, single arm trial (ACTRN12617000720314), we investigate if alternating osimertinib and gefitinib would delay the development of resistance to osimertinib in advanced, non-small cell lung cancer (NSCLC) with the epidermal growth factor receptor (EGFR) T790M mutation (n = 47) by modulating selective pressure on resistant clones. The primary endpoint is progression free-survival (PFS) rate at 12 months, and secondary endpoints include: feasibility of alternating therapy, overall response rate (ORR), overall survival (OS), and safety. The 12-month PFS rate is 38% (95% CI 27.5-55), not meeting the pre-specified primary endpoint. Serial circulating tumor DNA (ctDNA) analysis reveals decrease and clearance of the original activating EGFR and EGFR-T790M mutations which are prognostic of clinical outcomes. In 73% of participants, loss of T790M ctDNA is observed at progression and no participants have evidence of the EGFR C797S resistance mutation following the alternating regimen. These findings highlight the challenges of treatment strategies designed to modulate clonal evolution and the clinical importance of resistance mechanisms beyond suppression of selected genetic mutations in driving therapeutic escape to highly potent targeted therapies.

Lurbinectedin in small cell lung cancer: real-world experience of a multicentre national early access programme

BACKGROUND AND AIMS

Lurbinectedin is a novel oncogenic transcription inhibitor active in several cancers, including small cell lung cancer (SCLC). We aimed to describe the first Australian experience of the clinical efficacy and tolerability of lurbinectedin for the treatment of SCLC after progression on platinum-containing therapy.

METHODS

Multicentre real-world study of individuals with SCLC initiating lurbinectedin monotherapy (3.2 mg/m2 three-weekly) on an early access programme between May 2020 and December 2021. Key outcomes were clinical utilisation, efficacy and tolerability. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method. Outcome data were collected within the AUstralian Registry and biObank of thoRacic cAncers (AURORA).

RESULTS

Data were analysed for 46 individuals across seven sites. Lurbinectedin was given as second- (83%, 38/46) or subsequent- (17%, 8/46) line therapy, mostly with prior chemoimmunotherapy (87%, 40/46). We report dose modifications (17%, 8/46), interruptions/delays (24%, 11/46), high-grade toxicities (28%, 13/46) and hospitalisations (54%, 25/46) during active treatment. The overall response rate was 33% and the disease control rate was 50%. Six-month OS was 44% (95% confidence interval (CI): 29.0-57.1). Twelve-month OS was 15% (95% CI: 6.5-26.8). From lurbinectedin first dose, the median PFS was 2.5 months (95% CI: 1.8-2.9) and OS was 4.5 months (95% CI: 3.5-7.2). From SCLC diagnosis, the median OS was 12.9 months (95% CI: 11.0-17.2). Individuals with a longer chemotherapy-free interval prior to lurbinectedin had longer PFS and OS.

CONCLUSION

This real-world national experience of lurbinectedin post-platinum chemotherapy and immunotherapy for individuals with SCLC was similar to that reported in clinical trials.

Implementation of a nurse-led, multidisciplinary model of care for older adults with cancer: a process evaluation protocol

INTRODUCTION

Cancer is predominantly a disease of older adults, with an increasing number of cancer diagnoses in individuals aged 65 or older. Multiple geriatric factors have been shown to impact patient outcomes in cancer treatment. However, oncology specialists are not well adapted to incorporate geriatric assessment into practice due to a lack of resources and knowledge of the specialty.The primary aim of this study is to implement and evaluate a nurse-led, multidisciplinary model of care for older adults with cancer at two public tertiary hospitals in Melbourne, Australia.

METHODS AND ANALYSIS

This study will aim to assess 200 patients across 2 sites. Both sites will assess individuals with lung cancer; the second site will also include individuals with genitourinary, upper gastrointestinal and colorectal cancers.This process evaluation will use quantitative and qualitative methods to explore the reach, effectiveness, adoption, implementation, and maintenance (RE-AIM) of the nurse-led, multidisciplinary model of care.

ETHICS AND DISSEMINATION

Ethical approval and local governance approvals have been obtained by Austin Health and Monash Health Human Research Ethics committees. Dissemination will occur via publications, conferences, social medical and local engagement with clinicians, consumers and managers.

Real-World Analysis of Clinical Characteristics and Survival Outcomes in Patients With Extensive-Stage SCLC Treated With First-Line Chemoimmunotherapy

Introduction

There are no clinically validated prognostic biomarkers in the management of extensive-stage SCLC (ES-SCLC). We explored the association between clinical characteristics and survival outcomes in patients with ES-SCLC treated with chemoimmunotherapy.

Methods

In this retrospective cohort study, patients with ES-SCLC treated with first-line platinum-etoposide chemotherapy and atezolizumab were identified from medical records. Pretreatment clinical characteristics, biochemical parameters, and tumor and treatment characteristics were collected. Univariate and multivariate Cox regression were used to evaluate treatment effect on progression-free survival (PFS) and overall survival (OS).

Results

We evaluated 75 patients in total. The median PFS and OS were 6.1 months and 9.2 months, respectively. Statistically significant associations were found with lower lactate dehydrogenase and improved OS (hazard ratio [HR] = 1.0, 95% confidence interval [CI]: 1.0-1.01, p = 0.006), whereas higher age (HR = 0.94, 95% CI: 0.90-0.98, p = 0.006) and lower neutrophil-to-lymphocyte ratio (HR = 1.08, 95% CI: 1.02-1.14, p = 0.005) were associated with improved PFS. The number of chemotherapy cycles received were associated with both an improved PFS (HR = 0.57, 95% CI: 0.37-0.89, p = 0.011) and OS (HR = 0.5, 95% CI: 0.30-0.84, p = 0.008).

Conclusions

This study highlights the important effect of chemotherapy on survival. Furthermore, the association between lactate dehydrogenase and neutrophil-to-lymphocyte ratio on survival further suggests that baseline tumor burden and optimizing sarcopenia are important factors for clinicians to consider as we seek to develop personalized treatment for this disease.

Real-world challenges in undertaking NTRK fusion testing in non-small cell lung cancer

BACKGROUND

We performed a retrospective analysis to determine the incidence of neurotrophic tropomyosin-receptor kinase (NTRK) fusion in non-small cell lung cancer (NSCLC).

METHODS

Archival NSCLC tissues between 2018-2020 were screened by immunohistochemistry (IHC) with IHC-positive cases undergoing confirmatory molecular analysis. Correlative clinicopathologic parameters were collected.

RESULTS

Of 289 samples analyzed, 10 (3.5%) cases had NTRK expression on IHC. The median age of patients with NTRK-positivity on IHC was 74.9 (range, 44-88) years and 70% had a smoking history. The cohort included seven adenocarcinomas and one each squamous cell carcinoma, large-cell neuroendocrine and not otherwise specified histologies. PDL1 expression was ≤50% in five cases. Concurrent EGFR mutations were detected in three cases, with two cases also showing a PIK3CA E542K mutation and MET amplification, respectively. Due to insufficient tumor material, RNA-sequencing was undertaken in only one IHC-positive case, with the other nine cases analyzed by Fluorescent in-situ Hybridisation. A NTRK fusion, EML4-NTRK3 gene fusion was detected in one patient, a frequency of 0.35%.

CONCLUSIONS

NTRK fusions in NSCLC are rare. This study highlights real world diagnostic challenges regarding NTRK testing, such as requirements of adequate tumor tissue and appropriate testing methodologies.

Antibody drug conjugates for glioblastoma: current progress towards clinical use

INTRODUCTION

Antibody drug conjugates (ADCs) are now a proven therapeutic class for many cancers, combining highly specific targeting with the potency of high effective payloads. This review summarizes the experience with ADCs in brain tumors and examines future paths for their use in these tumors.

AREAS COVERED

This review will cover all the key classes of ADCs which have been tested in primary brain tumors, including commentary on the major trials to date. The efficacy of these trials, as well as their limitations, will put in context of the overall landscape of drug development in brain tumors. Importantly, this review will summarize key learnings and insights from these trials that help provide the basis for rational ways in which these drugs can be effectively and appropriate developed for patients with primary brain tumors.

EXPERT OPINION

ADC development in brain tumors has occurred in two major phases to date. Key learnings from previous trials provide a strong rationale for the continued development of these drugs for primary brain tumors. However, the unique biology of these tumors requires development strategies specifically tailored to maximize their optimal development.

LOREALAUS: LOrlatinib REAL world AUStralian experience in advanced anaplastic lymphoma kinase rearranged non-small cell lung cancer

Introduction

Over the past decade, ALK tyrosine kinase inhibitors have delivered unprecedented survival for individuals with ALK-positive (ALK+) lung cancers. Real-world data enhance the understanding of optimal drug sequencing and expectations for survival.

Methods

Multicenter real-world study of individuals with pretreated advanced ALK+ lung cancers managed on a lorlatinib access program between 2016 and 2020. Key outcomes were lorlatinib efficacy, tolerability, and treatment sequencing. Progression-free survival (PFS) and overall survival (OS) were calculated using the Kaplan-Meier method among all individuals (PFSa and OSa), with at least 30 days (one-cycle) lorlatinib exposure (PFSb and OSb), and with good performance status (PFSc and OSc). Subgroups of interest were analyzed to assess signals of potential clinical applicability. Two OS index dates were analyzed, from lorlatinib initiation and advanced ALK+ diagnosis.

Results

The population (N = 38, 10 sites) was heavily pretreated (23 had ≥2 previous treatment lines) with a high disease burden (26 had 2-4 sites and 11 had >4 sites of metastatic disease, 19 had brain metastases). The overall response rate was 44% and the disease control rate was 81%. Lorlatinib dose reduction (18%), interruption (16%), and discontinuation (3%) were consistent with the trial experience. From advanced ALK+ diagnosis, the median OS for populations a, b, and c was 45.0 months, 69.9 months and 61.2 months respectively. From lorlatinib initiation, the median PFSa, PFSb and PFSc was 7.3 months, 13.2 months and 27.7 months and the median OSa, OSb and OSc was 19.9 months, 25.1 months and 27.7 months. The median PFSa with versus without brain metastases was 34.6 months versus 5.8 months (p = 0.09). The intracranial median PFS was 14.2 months. Previous good response versus poor response to the first ALK-directed therapy median PFSa was 27.7 months versus 4.7 months with a hazard ratio of 0.3 (p = 0.01).

Conclusions

Lorlatinib is a potent, highly active brain-penetrant third-generation ALK tyrosine kinase inhibitors with benefits for most individuals in the later-line setting in a real-world evaluation, consistent with clinical trial data.

A Multi-Center Real-World Experience of IMpower150 in Oncogene Driven Tumors and CNS Metastases

BACKGROUND

There are limited real world data on the IMpower150 regimen in oncogene driven tumors and central nervous system metastases; this study aims to address this gap.

MATERIALS AND METHODS

Retrospective analysis of patients with advanced non-small cell lung cancer treated with the IMpower150 regimen across 12 Australian sites between July 2018 and April 2021. Clinicopathologic and treatment parameters were correlated with efficacy and toxicity.

RESULTS

A total of 106 patients identified with median follow up of 8 months (range 0-72). Median age was 61 years (range 33-83), 34% Asian and 58% never-smokers. An oncogene was reported in 94 (89%) patients, EGFR in 72 (68%). At treatment commencement, 50 (47%) patients had brain metastases, 21 (20%) leptomeningeal disease (LMD) and 47 (44%) liver metastases. 27% were treatment-naïve and pemetrexed was substituted for paclitaxel in 44 (42%). The overall response rate was 51% for all patients; 52% in patients with EGFR mutations. Patients with untreated brain metastases prior to commencing IMpower150 had a similar intracranial response as those with treated brain metastases (55% vs. 53%). The median time to treatment failure and overall survival from commencement of IMpower150 was 5.7 and 11.4 months respectively for the entire cohort and 5.2 and 10.5 months in those with an EGFR sensitizing mutation. Overall survival in patients with liver, brain metastases and LMD was 11.0, 11.4, and 7.1 months respectively. No new safety signals seen.

CONCLUSION

In this largely oncogene positive, pre-treated population the IMpower150 regimen demonstrated clinically-meaningful responses, including in patients with CNS disease.

ImmunoPET: IMaging of cancer imMUNOtherapy targets with positron Emission Tomography: a phase 0/1 study characterising PD-L1 with 89Zr-durvalumab (MEDI4736) PET/CT in stage III NSCLC patients receiving chemoradiation study protocol

BACKGROUND

ImmunoPET is a multicentre, single arm, phase 0-1 study that aims to establish if ⁸⁹Zr-durvalumab PET/CT can be used to interrogate the expression of PD-L1 in larger, multicentre clinical trials.

METHODS

The phase 0 study recruited 5 PD-L1+ patients with metastatic non-small cell lung cancer (NSCLC). Patients received 60MBq/70 kg ⁸⁹Zr-durva up to a maximum of 74 MBq, with scan acquisition at days 0, 1, 3 or 5±1 day. Data on (1) Percentage of injected ⁸⁹Zr-durva dose found in organs of interest (2) Absorbed organ doses (µSv/MBq of administered ⁸⁹Zr-durva) and (3) whole-body dose expressed as mSv/100MBq of administered dose was collected to characterise biodistribution.The phase 1 study will recruit 20 patients undergoing concurrent chemoradiotherapy for stage III NSCLC. Patients will have ⁸⁹Zr-durva and FDG-PET/CT before, during and after chemoradiation. In order to establish the feasibility of ⁸⁹Zr-durva PET/CT for larger multicentre trials, we will collect both imaging and toxicity data. Feasibility will be deemed to have been met if more than 80% of patients are able complete all trial requirements with no significant toxicity.

ETHICS AND DISSEMINATION

This phase 0 study has ethics approval (HREC/65450/PMCC 20/100) and is registered on the Australian Clinical Trials Network (ACTRN12621000171819). The protocol, technical and clinical data will be disseminated by conference presentations and publications. Any modifications to the protocol will be formally documented by administrative letters and must be submitted to the approving HREC for review and approval.

TRIAL REGISTRATION NUMBER

Australian Clinical Trials Network ACTRN12621000171819.

Poor correlation between preclinical and patient efficacy data for tumor targeted monotherapies in glioblastoma: the results of a systematic review

PURPOSE

Limited progress has been made in treating glioblastoma, and we hypothesise that poor concordance between preclinical and clinical efficacy in this disease is a major barrier to drug development. We undertook a systematic review to quantify this issue.

METHODS

We identified phase I trials (P1Ts) of tumor targeted drugs, subsequent trial results and preceding relevant preclinical data published in adult glioblastoma patients between 2006-2019 via structured searches of EMBASE/MEDLINE/PUBMED. Detailed clinical/preclinical information was extracted. Associations between preclinical and clinical efficacy metrics were determined using appropriate non-parametric statistical tests.

RESULTS

A total of 28 eligible P1Ts were identified, with median ORR of 2.9% (range 0.0-33.3%). Twenty-three (82%) had published relevant preclinical data available. Five (18%) had relevant later phase clinical trial data available. There was overall poor correlation between preclinical and clinical efficacy metrics on univariate testing. However, drugs that had undergone in vivo testing had significantly longer median overall survival (7.9 vs 5.6mo, p = 0.02). Additionally, drugs tested in ≥ 2 biologically-distinct in vivo models ('multiple models') had a significantly better median response rate than those tested using only one ('single model') or those lacking in vivo data (6.8% vs 1.2% vs. 0.0% respectively, p = 0.027).

CONCLUSION

Currently used preclinical models poorly predict subsequent activity in P1Ts, and generally over-estimate the anti-tumor activity of these drugs. This underscores the need for better preclinical models to aid the development of novel anti-glioblastoma drugs. Until these become widely available and used, the use of multiple biologically-distinct in vivo models should be strongly encouraged.

Adult medulloblastoma in an Australian population

Medulloblastoma in adult patients is a rare condition with limited contemporary demographic and treatment outcome data available in an Australian population. We conducted a retrospective review of patterns of care and outcomes of adult patients diagnosed with medulloblastoma treated at major neuro-oncology centres across Australia between January 2010 and December 2019. A total of 80 patients were identified and the median follow-up after diagnosis was 59.2 (range 0.5-204) months. A variety of chemotherapy regimens were used in the adjuvant and recurrent settings. The median overall survival (mOS) was 78 months (IQR 17.5-94.8). Patients who had no residual disease post-resection or with SHH-subtype tumours had a numerically longer 5-year survival rate than those with residual disease post resection or non-SHH subtypes respectively. The median time to recurrence from diagnosis was 18.4 months. The median OS from 1st relapse was 22.1 months (95% CI 11.7-31.4) and mOS from second relapse was 10.2 months (95% CI 6.6 - NR). This is the largest dataset examining patterns of care of adult patients with medulloblastoma in an Australian population. Substantial variation existed in the chemotherapy agents used in the adjuvant and recurrent setting. As has been demonstrated in a paediatric population, trials such as the upcoming EORTC 1634-BTG/NOA-23 trial (PersoMed-1 study) which are tailoring treatments to molecular profiles are likely to improve outcome in adult medulloblastoma.

Antibody-drug conjugates: beyond current approvals and potential future strategies

The recent approvals for antibody-drug conjugates (ADCs) in multiple malignancies in recent years have fuelled the ongoing development of this class of drugs. These novel agents combine the benefits of high specific targeting of oncogenic cell surface antigens with the additional cell kill from high potency cytotoxic payloads, thus achieving wider therapeutic windows. This review will summarise the clinical activity of ADCs in tumour types not covered elsewhere in this issue, such as gastrointestinal (GI) and genitourinary (GU) cancers and glioblastoma (GBM). In addition to the ongoing clinical testing of existing ADCs, there is substantial preclinical and early phase testing of newer ADCs or ADC incorporating strategies. This review will provide selected insights into such future development, focusing on the development of novel ADCs against new antigen targets in the tumour microenvironment (TME) and combination of ADCs with immuno-oncology (IO) agents.

Radiolabeled Antibodies for Cancer Imaging and Therapy

Simple Summary

Monoclonal antibodies (mAbs) have the ability to specifically target tumor-cell antigens. This unique property has led to their use in the delivery of radioisotopes to tumor sites (scintigraphic imaging and radioimmunotherapy (RIT)). The choice of the radionuclide depends on its unique physical properties and intended use. Using radiolabeled mAbs with imaging techniques provides critical data that are essential for predicting side effects and determining an optimal antibody dose and treatment schedule. While RIT has been successful in the management of hematological malignancies, the treatment of solid tumors remains challenging. Various strategies are being investigated to improve the efficacy of RIT in solid tumors.

Abstract

Radioimmunoconjugates consist of a monoclonal antibody (mAb) linked to a radionuclide. Radioimmunoconjugates as theranostics tools have been in development with success, particularly in hematological malignancies, leading to approval by the US Food and Drug Administration (FDA) for the treatment of non-Hodgkin’s lymphoma. Radioimmunotherapy (RIT) allows for reduced toxicity compared to conventional radiation therapy and enhances the efficacy of mAbs. In addition, using radiolabeled mAbs with imaging methods provides critical information on the pharmacokinetics and pharmacodynamics of therapeutic agents with direct relevance to the optimization of the dose and dosing schedule, real-time antigen quantitation, antigen heterogeneity, and dynamic antigen changes. All of these parameters are critical in predicting treatment responses and identifying patients who are most likely to benefit from treatment. Historically, RITs have been less effective in solid tumors; however, several strategies are being investigated to improve their therapeutic index, including targeting patients with minimal disease burden; using pre-targeting strategies, newer radionuclides, and improved labeling techniques; and using combined modalities and locoregional application. This review provides an overview of the radiolabeled intact antibodies currently in clinical use and those in development.

The systemic management of central nervous system metastases and leptomeningeal disease from advanced lung, melanoma, and breast cancer with molecular drivers: An Australian perspective

The advent of systemic therapies with high intracranial efficacy in recent years is changing the therapeutic paradigm and renewing interest in the management of central nervous system (CNS) and leptomeningeal metastases from solid organ tumors. CNS metastases have traditionally heralded a dismal prognosis with median survival of 3-10 months, and were primarily treated with local therapeutic modalities, such as surgery or radiation therapy. Although these modalities still have a role in the management of CNS disease, newer agents, such as small molecule tyrosine kinase inhibitors and immune-checkpoint inhibitors, are now paving the way as an alternative therapeutic option for those with oligometastatic or low-volume intracranial disease, potentially eliminating or delaying the need for local treatment modalities in this setting. Herein, we summarize the systemic treatments with proven intracranial efficacy, currently approved for use in Australia for advanced mutation-driven non-small cell lung cancer, melanoma, and breast cancer, as well as novel agents in preclinical and clinical trial development.

Standard-Dose Osimertinib in EGFR-Mutated Non-Small-Cell Lung Adenocarcinoma With Leptomeningeal Disease

PURPOSE

Leptomeningeal disease (LMD) in epidermal growth factor receptor (EGFR)-mutant lung adenocarcinoma is associated with a poor prognosis and limited treatment options. Osimertinib is a potent third-generation EGFR tyrosine kinase inhibitor with confirmed CNS penetration. This study reports on outcomes of patients with EGFR-mutated non-small-cell lung cancer who developed LMD and were subsequently treated with osimertinib.

METHODS

We identified patients treated with osimertinib 80 mg PO daily under a compassionate access scheme across nine tertiary Australian institutes between July 2017 and July 2020. Patient demographics, tumor characteristics, and treatment history were collected. Median overall survival, median progression-free survival, disease control rates (DCR), and overall response rates (ORR) were assessed. Kaplan-Meier analysis was performed and descriptive statistics were used.

RESULTS

Thirty-nine patients were analyzed of which 74% were female. Exon 19 deletions (49%) and L858R point mutations (41%) were the most common EGFR mutations. Forty-nine percentage of patients were Eastern Cooperative Oncology Group 1. The median duration of osimertinib therapy was 6 months. The extracranial DCR and ORR were 60% and 54%, and the intracranial DCR and ORR were 68% and 53%, respectively. Median overall survival was 10.5 months (95% CI, 8.17 to 15.05 months).

CONCLUSION

There are limited treatment options for LMD in EGFR-positive lung cancer, and osimertinib at a dose of 80 mg daily is an active therapeutic option for these patients.

Multicellular Effects of STAT3 in Non-small Cell Lung Cancer: Mechanistic Insights and Therapeutic Opportunities

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and accounts for 85% of lung cancer cases. Aberrant activation of the Signal Transducer and Activator of Transcription 3 (STAT3) is frequently observed in NSCLC and is associated with a poor prognosis. Pre-clinical studies have revealed an unequivocal role for tumor cell-intrinsic and extrinsic STAT3 signaling in NSCLC by promoting angiogenesis, cell survival, cancer cell stemness, drug resistance, and evasion of anti-tumor immunity. Several STAT3-targeting strategies have also been investigated in pre-clinical models, and include preventing upstream receptor/ligand interactions, promoting the degradation of STAT3 mRNA, and interfering with STAT3 DNA binding. In this review, we discuss the molecular and immunological mechanisms by which persistent STAT3 activation promotes NSCLC development, and the utility of STAT3 as a prognostic and predictive biomarker in NSCLC. We also provide a comprehensive update of STAT3-targeting therapies that are currently undergoing clinical evaluation, and discuss the challenges associated with these treatment modalities in human patients.

Antibody Drug Conjugates in Glioblastoma - Is There a Future for Them?

Glioblastoma (GBM) is an aggressive and fatal malignancy that despite decades of trials has limited therapeutic options. Antibody drug conjugates (ADCs) are composed of a monoclonal antibody which specifically recognizes a cellular surface antigen linked to a cytotoxic payload. ADCs have demonstrated superior efficacy and/or reduced toxicity in a range of haematological and solid tumors resulting in nine ADCs receiving regulatory approval. ADCs have also been explored in patients with brain tumours but with limited success to date. While earlier generations ADCs in glioma patients have had limited success and high toxicity, newer and improved ADCs characterised by low immunogenicity and more effective payloads have shown promise in a range of tumour types. These newer ADCs have also been tested in glioma patients, however, with mixed results. Factors affecting the effectiveness of ADCs to target the CNS include the blood brain barrier which acts as a physical and biochemical barrier, the pro-cancerogenic and immunosuppressive tumor microenvironment and tumour characteristics like tumour volume and antigen expression. In this paper we review the data regarding the ongoing the development of ADCs in glioma patients as well as potential strategies to overcome these barriers to maximise their therapeutic potential.

456 A phase 1b/2 umbrella study of anti-PD-1 sasanlimab in combination with other therapies for patients with stage IIIB/IV non-small cell lung cancer (NSCLC): The LANDSCAPE 1011 trial in progress

Background

Programmed cell death protein 1 (PD-1) inhibitors as monotherapy or in combination with chemotherapy have become a standard of care first-line therapy for Stage IIIB/IV non-small cell lung cancer (NSCLC). However, many patients experience disease progression and require subsequent therapy within the first year of treatment.1 For patients requiring salvage chemotherapy, prognosis is poor, with a median progression-free survival (PFS) and overall survival (OS) of 4.0 and 8.5 months, respectively.2 Combinations of PD-1 blockade using sasanlimab (PF-06801591) and other immune and/or targeted therapies may be able to achieve clinical response in patients who have progressed on standard chemoimmunotherapy.

Methods

LANDSCAPE 1011 (NCT04585815) is a prospective, open-label, multi-center, parallel group, phase 1b/2 umbrella study evaluating the safety, efficacy, pharmacokinetics, and pharmacodynamics of sasanlimab in combination with other therapies, in patients with Stage IIIB/IV NSCLC. The study is expected to enrol ~375 patients age 18 years or older diagnosed with stage IIIB/IV NSCLC. During phase 1b, the safety of each sub-study combination with subcutaneous sasanlimab will be assessed and the recommended phase 2 dose determined for each combination. Phase 2 will further evaluate safety and anti-tumor activity of each combination using the respective recommended phase 2 dose (figure 1). Up to 5 parallel sub-studies are planned. Currently, 2 sub-studies are ongoing. Sub-Study A will investigate sasanlimab, encorafenib (a BRAF inhibitor), and binimetinib (a MEK inhibitor) in patients with BRAF^V600E mutations (only including treatment-naïve patients in phase 2). Sub-Study B will investigate sasanlimab, axitinib (a vascular endothelial growth factor receptor inhibitor), and SEA-TGT (an anti-TIGIT antibody). In phase 2, this will involve treatment-naïve patients without oncogene drivers who have PD ligand 1-positive tumors or whose disease has progressed on prior immune checkpoint inhibitor-containing regimens. The primary phase 1b endpoint is the dose-limiting toxicity during the first cycle (28 days). The primary phase 2 endpoint in Sub-Study A is durable objective response (OR) defined as confirmed complete response or partial response lasting 10 or more months; and in Sub-Study B, OR defined as confirmed complete response or partial response, according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Secondary endpoints include adverse events and laboratory abnormalities, duration of response, time to tumor response, PFS, OS, OR by PD-L1 expression at baseline, pharmacokinetic parameters, incidence of anti-drug antibodies and neutralizing antibodies, and health-related quality of life. The first patient was enrolled in November 2020.

Abstract 456 Figure 1

LANDSCAPE 1011 study overview

Acknowledgements

This study was sponsored by Pfizer. Medical writing and editorial support was provided by Simon Stones at Engage Scientific Solutions, and funded by Pfizer. The authors would like to acknowledge the late Aron Thall, who was highly devoted to the execution and success of this study.

Trial Registration

ClinicalTrials.

gov NCT04585815

References

Gandhi L, Rodriguez-Abreu D, Gadgeel S, et al. Pembrolizumab plus Chemotherapy in Metastatic Non-Small-Cell Lung Cancer. N Engl J Med 2018;378:2078–92.

Herbst RS, Baas P, Kim DW, et al. Pembrolizumab versus docetaxel for previously treated, PD-L1-positive, advanced non-small-cell lung cancer (KEYNOTE-010): a randomised controlled trial. Lancet 2016;387:1540–50.

Ethics Approval

The study is approved at each study site according to local regulations.

Tumor volumes as a predictor of response to the anti-EGFR antibody drug conjugate depatuxizumab mafadotin

Background

The adverse impact of increasing brain tumor size on the efficacy of antibody-drug conjugates (ADCs) was investigated preclinically then validated with clinical data.

Methods—Preclinical study

The impact of tumor size on ADC tumor delivery and treatment response was evaluated in an EGFR-amplified patient-derived glioblastoma (GBM) model following treatment with Depatuxizumab mafadotin (Depatux-M). Biodistribution and imaging studies correlated drug distribution with starting treatment volume and anti-tumor activity.

Methods—Clinical study

M12-356 was a Phase I study of Depatux-M in patients with GBM. Blinded volumetric analysis of baseline tumor volumes of M12-356 patients was undertaken by two reviewers and results correlated with response and survival.

Results

Preclinically, imaging and biodistribution studies showed specific and significantly higher tumor uptake of zirconium-89 labeled Depatux-M (⁸⁹Zr-Depatux-M) in mice with smaller tumor volume (~98 mm³) versus those with larger volumes (~365 mm³); concordantly, mice with tumor volumes ≤100 mm³ at treatment commencement had significantly better growth inhibition by Depatux-M (93% vs 27%, P < .001) and significantly longer overall survival (P < .0001) compared to tumors ≥400 mm³. Clinically, patients with tumor volumes <25 cm³ had significantly higher response rates (17% vs. 0%, P = .009) and longer overall survival (0.5 vs 0.89 years, P = .001) than tumors above 25 cm³.

Conclusion

Both preclinical and clinical data showed intra-tumoral concentration and efficacy of Depatux-m inversely correlated with tumor size. This finding merit further investigation with pretreatment tumor volume as a predictor for response to ADCs, in both gliomas and other solid tumors.

Protein disulphide isomerase (PDI) is protective against amyotrophic lateral sclerosis (ALS)-related mutant Fused in Sarcoma (FUS) in in vitro models

Mutations in Fused in Sarcoma (FUS) are present in familial and sporadic cases of amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). FUS is localised in the nucleus where it has important functions in DNA repair. However, in ALS/FTD, mutant FUS mislocalises from the nucleus to the cytoplasm where it forms inclusions, a key pathological hallmark of neurodegeneration. Mutant FUS also inhibits protein import into the nucleus, resulting in defects in nucleocytoplasmic transport. Fragmentation of the neuronal Golgi apparatus, induction of endoplasmic reticulum (ER) stress, and inhibition of ER-Golgi trafficking are also associated with mutant FUS misfolding in ALS. Protein disulphide isomerase (PDI) is an ER chaperone previously shown to be protective against misfolding associated with mutant superoxide dismutase 1 (SOD1) and TAR DNA-binding protein-43 (TDP-43) in cellular and zebrafish models. However, a protective role against mutant FUS in ALS has not been previously described. In this study, we demonstrate that PDI is protective against mutant FUS. In neuronal cell line and primary cultures, PDI restores defects in nuclear import, prevents the formation of mutant FUS inclusions, inhibits Golgi fragmentation, ER stress, ER-Golgi transport defects, and apoptosis. These findings imply that PDI is a new therapeutic target in FUS-associated ALS.

Response Evaluation and Survival Prediction After PD-1 Immunotherapy in Patients with Non-Small Cell Lung Cancer: Comparison of Assessment Methods

Immunotherapy using programmed death-1 blockers is a promising modality for non-small cell lung cancer (NSCLC). Therefore, defining the most accurate response criteria for immunotherapy monitoring is of great importance in patient management. This study aimed to compare the correlation between survival outcome and response assessment by PERCIST, version 1.0; immunotherapy-modified PERCIST (imPERCIST); RECIST, version 1.1; and immunotherapy-modified RECIST (iRECIST) in NSCLC patients. Methods: Seventy-two patients with NSCLC who were treated with nivolumab or pembrolizumab and had baseline and follow-up ¹⁸F-FDG PET/CT data were analyzed. The patients were categorized into responders (complete or partial response) and nonresponders (stable or progressive disease) according to PERCIST1 and PERCIST5 (analyzing the peak SUV normalized by lean body mass [SUL_peak] of 1 or up to 5 lesions), imPERCIST1, imPERCIST5, RECIST, and iRECIST. The correlation between achieved response and overall survival (OS) was compared. Results: The overall response rate and the overall disease control rate of the study population were 29% and 74%, respectively. The OS and progression-free survival (PFS) of patients with complete and partial response were statistically comparable. The OS and PFS were significantly different between responders and nonresponders (20.3 vs. 10.6 mo, P = 0.001, for OS and 15.5 vs. 2.2 mo, P < 0.001, for PFS, respectively). Twenty-three (32%) patients with progressive disease according to PERCIST5 had controlled disease according to imPERCIST5; follow-up of patients showed that 22% of these patients had pseudoprogression. The overall incidence of pseudoprogression was 7%. The response rate was 25% and 24% according to PERCIST1 and PERCIST5 (P = 0.2) and 32% and 29% according to imPERCIST1 and imPERCIST5 (P = 0.5), respectively, indicating no significant difference between analyzing the SUL_peak of only the most ¹⁸F-FDG-avid lesion and analyzing up to the 5 most ¹⁸F-FDG-avid lesions. Conclusion: The achieved response by all conventional and immunotherapy-modified methods correlated strongly with patients' survival outcome, with significantly longer OS and PFS in responders than in nonresponders according to all assessed definitions. The most ¹⁸F-FDG-avid lesion according to PERCIST and imPERCIST accurately reflects the overall metabolic response.

PDCD1 Polymorphisms May Predict Response to Anti-PD-1 Blockade in Patients With Metastatic Melanoma

A significant number of patients (pts) with metastatic melanoma do not respond to anti-programmed cell death 1 (PD1) therapies. Identifying predictive biomarkers therefore remains an urgent need. We retrospectively analyzed plasma DNA of pts with advanced melanoma treated with PD-1 antibodies, nivolumab or pembrolizumab, for five PD-1 genotype single nucleotide polymorphisms (SNPs): PD1.1 (rs36084323, G>A), PD1.3 (rs11568821, G>A), PD1.5 (rs2227981, C>T) PD1.6 (rs10204225, G>A) and PD1.9 (rs2227982, C>T). Clinico-pathological and treatment parameters were collected, and presence of SNPs correlated with response, progression free survival (PFS) and overall survival (OS). 115 patients were identified with a median follow up of 18.7 months (range 0.26 – 52.0 months). All were Caucasian; 27% BRAF V600 mutation positive. At PD-1 antibody commencement, 36% were treatment-naïve and 52% had prior ipilimumab. The overall response rate was 43%, 19% achieving a complete response. Overall median PFS was 11.0 months (95% CI 5.4 - 17.3) and median OS was 31.1 months (95% CI 23.2 - NA). Patients with the G/G genotype had more complete responses than with A/G genotype (16.5% vs. 2.6% respectively) and the G allele of PD1.3 rs11568821 was significantly associated with a longer median PFS than the AG allele, 14.1 vs. 7.0 months compared to the A allele (p=0.04; 95% CI 0.14 – 0.94). No significant association between the remaining SNPs and responses, PFS or OS were observed. Despite limitations in sample size, this is the first study to demonstrate an association of a germline PD-1 polymorphism and PFS in response to anti-PD-1 therapy in pts with metastatic melanoma. Extrinsic factors like host germline polymorphisms should be considered with tumor intrinsic factors as predictive biomarkers for immune checkpoint regulators.

Inefficiencies in phase II to phase III transition impeding successful drug development in glioblastoma

Background

Improving outcomes of patients with glioblastoma (GBM) represents a significant challenge in neuro-oncology. We undertook a systematic review of key parameters of phase II and III trials in GBM to identify and quantify the impact of trial design on this phenomenon.

Methods

Studies between 2005 and 2019 inclusive were identified though MEDLINE search and manual bibliography searches. Phase II studies (P2T) were restricted to those referenced by the corresponding phase III trials (P3T). Clinical and statistical characteristics were extracted. For each P3T, corresponding P2T data was “optimally matched,” where same drug was used in similar schedule and similar population; “suboptimally matched” if dis-similar schedule and/or treatment setting; or “lacking.” Phase II/III transition data were compared by Pearson Correlation, Fisher’s exact or chi-square testing.

Results

Of 20 P3Ts identified, 6 (30%) lacked phase II data. Of the remaining 14 P3T, 9 had 1 prior P2T, 4 had 2 P2T, and 1 had 3 P2T, for a total of 20 P3T-P2T pairs (called dyads). The 13 “optimally matched” dyads showed strong concordance for mPFS (r² = 0.95, P < .01) and mOS (r² = 0.84, P < .01), while 7 “suboptimally matched” dyads did not (P > .05). Overall, 7 P3Ts underwent an ideal transition from P2T to P3T. “Newly diagnosed” P2Ts with mPFS < 14 months and/or mOS< 22 months had subsequent negative P3Ts. “Recurrent” P2Ts with mPFS < 6 months and mOS< 12 months also had negative P3Ts.

Conclusion

Our findings highlight the critical role of optimally designed phase II trials in informing drug development for GBM.

Expression of EGFR and conformational forms of EGFR in malignant pleural mesothelioma and its impact on survival

AIM

Conformational forms of the epidermal growth factor receptor (EGFR) are pro-tumorigenic. The prevalence and impact of conformational forms of EGFR in malignant mesothelioma (MM) is unknown. We investigated expression of EGFR and conformational forms of EGFR by immunohistochemistry using EGFR-targeting monoclonal antibodies (mAb). In addition, EGFR gene amplification was investigated by fluorescent in-situ hybridization (FISH). Findings were correlated with survival.

METHODS

Patients treated between 1988 and 2014 were identified from the thoracic surgery database of the Austin Hospital, Melbourne, Australia. Tissue microarrays (TMAs) were constructed, subjected to wild type (wt) EGFR IHC staining and FISH analysis. Conformational and mutation forms of EGFR were detected by IHC using mAb806, and LMH-151 which detects EGFRVIII. `H-scores` were derived and EGFR expression correlated with survival by Kaplan-Meier and log rank analysis.

RESULTS

WtEGFR expression was seen in 93 % (299/321) of cases with overexpression (defined as an H-score ≥200) seen in more than half of cases (64 %). EGFR overexpression in MM was seen more commonly in the epithelioid subtype. EGFR overexpression was not associated with true EGFR amplification, although multiple copies were appreciated in samples with polysomy. EGFR expression did not correlate with survival. A conformational form of EGFR associated with EGFR dysregulation was found in 8.2 % of cases, and patients with these tumors had a trend towards a poorer outcome. No cases of the EGFRVIII mutation were identified.

CONCLUSION

MM consistently demonstrated high expression of EGFR, with a subset of tumors showing conformational EGFR forms consistent with EGFR dysregulation, but withoutEGFR amplification or EGFR VIII mutation. wtEGFR expression did not influence survival. The impact of EGFR conformation on survival warrants further investigation.

Immune Checkpoint Inhibition With Chemoradiotherapy in Stage III Non-small-cell Lung Cancer: A Systematic Review and Meta-analysis of Safety Results

The role of immune checkpoint inhibitors (ICIs) administered concurrently with or after definitive chemoradiation (CRT) in stage III non-small-cell lung cancer (NSCLC) has been detailed in several studies. We performed a systematic review to determine pneumonitis rates using ICIs with CRT. MEDLINE and EMBASE databases were searched using keywords and MeSH terms. Studies using anti-programmed cell death protein 1 (PD-1) or anti-programmed death-ligand 1 (PD-L1) therapy, either sequentially or concurrently with CRT, for patients with stage III NSCLC were included. A meta-analysis of pneumonitis rates was performed based on weighted pooled proportion, using random-effects models. Weighting was performed by the inverse variance or standard error of event rates. Comparative analysis between groups was performed. Odds ratios (OR) were used as the primary summary statistics. A total of 13 studies were identified (6 prospective clinical trials and 7 real-world reports). Rates of grade ≥ 3 pneumonitis were significantly higher in clinical trials using anti-PD-1 therapy compared with PD-L1 inhibitors (8.6%; 95% confidence interval [CI], 6.2%-11.9% vs. 4.4%; 95% CI, 3.0%-6.6%; OR, 2.0; P = .01). Clinical trials using concurrent ICI therapy with CRT had greater rates of grade 2 pneumonitis compared with sequential administration (23.0%; 95% CI, 15.8%-32.3% vs. 11.0%; 95% CI, 6.6%-17.8%; OR, 0.42; P = .02). Higher rates of grade ≥ 3 pneumonitis were observed in real-world studies compared with clinical trials involving sequential PD-L1 therapy (9.9%; 95% CI, 5.3%-17.9% vs. 4.4%; 95% CI, 2.9%-6.7%; OR, 0.43; P < .01). The suggestion of increased pneumonitis with a concurrent ICI strategy and using anti-PD-1 therapies warrants further consideration in future comparative studies.

EXTH-38. ORTHOGONAL IN VIVO MODELS WERE THE SOLE PRECLINICAL PREDICTOR OF CLINICAL EFFICACY IN PHASE 1 TRIALS OF TARGETED THERAPIES FOR GLIOBLASTOMA: RESULTS OF A SYSTEMATIC REVIEW

INTRODUCTION

No drug has improved survival in recurrent glioblastoma despite encouraging activity preclinically. We undertook a systematic review of matched preclinical and Phase 1 trials (P1Ts) of targeted agents to investigate potential preclinical predictors of clinical efficacy.

METHODS

We identified all adult glioblastoma monotherapy P1Ts of targeted agents & preceding preclinical data published between 2006–2019 via structured searches of EMBASE/MEDLINE/PUBMED. For preclinical studies, data regarding in vitro models, in vivo models (species, implantation site, cell-line type) and efficacy (growth inhibition, regression rate, survival) were extracted. For P1T, response rate (RR) data were collected as absolute (%) and categorical (RR&lt; 5% vs. RR≥ 5%) variables. Associations were compared by chi-square/Fisher’s exact test, Kruskal-Wallis or Mann-Whitney U testing as appropriate with 2-sided p-values.

RESULTS

We found 28 P1Ts with median RR 2.9% (range 0.0–33.3%) and mOS 8.0mo (range 4.6–13.0mo). Seven (25%) had ‘minimal’ published pre-clinical data (5 missing entirely; 2 in vitro only); 12 (43%) utilised one cell line in vivo (‘single model’ group); and 9 (32%) used 2+ biologically distinct in vivo models (‘orthogonal’ group). There was strong reliance on U87-based cell lines (14/21 (71%)) in the latter groups. None of the variables tested were associated with RR except for use of ‘orthogonal models’. Compared to the ‘orthogonal’ group, the P1T RR rate was lower in ‘single’ and ‘minimal’ groups (6.8% vs 1.2%, p= 0.043 and 6.8% vs 0.0%, p= 0.026 respectively). The frequency of P1T with a RR &gt; 5% was also higher in the ‘orthogonal’ compared to the same two groups (78% vs 20%, p= 0.042 and 78% vs 17%, p= 0.041).

CONCLUSION

The availability of good quality pre-clinical data, especially the use of orthogonal models in vivo, was significantly associated with P1T response rates and warrants further investigation as a minimal threshold of evidence in future drug development.

Antibody-Drug Conjugates for Cancer Therapy

Antibody-drug conjugates (ADCs) are novel drugs that exploit the specificity of a monoclonal antibody (mAb) to reach target antigens expressed on cancer cells for the delivery of a potent cytotoxic payload. ADCs provide a unique opportunity to deliver drugs to tumor cells while minimizing toxicity to normal tissue, achieving wider therapeutic windows and enhanced pharmacokinetic/pharmacodynamic properties. To date, nine ADCs have been approved by the FDA and more than 80 ADCs are under clinical development worldwide. In this paper, we provide an overview of the biology and chemistry of each component of ADC design. We briefly discuss the clinical experience with approved ADCs and the various pathways involved in ADC resistance. We conclude with perspectives about the future development of the next generations of ADCs, including the role of molecular imaging in drug development.

Targeting and Efficacy of Novel mAb806-Antibody-Drug Conjugates in Malignant Mesothelioma

Epidermal growth factor receptor (EGFR) is highly overexpressed in malignant mesothelioma (MM). MAb806 is a novel anti-EGFR antibody that selectively targets a tumor-selective epitope. MAb806-derived antibody drug conjugates (ADCs), ABT-414, ABBV-221 and ABBV-322, may represent a novel therapeutic strategy in MM. EGFR and mAb806 epitope expressions in mesothelioma cell lines were evaluated using an array of binding assays, and the in vitro cell effects of ABT-414 and ABBV-322 were determined. In vivo therapy studies were conducted in mesothelioma xenograft and patient-derived xenograft (PDX) tumor models. We also performed biodistribution and imaging studies to allow the quantitative targeting of MM by mAb806 using a 89Zr-labeled immunoconjugate-ch806. A high EGFR expression was present in all mesothelioma cell lines evaluated and mAb806 binding present in all cell lines, except NCIH-2452. ABT-414 and ABBV-322 resulted in significant tumor growth inhibition in MM models with high EGFR and mAb806 epitope expressions. In contrast, in an EGFR-expressing PDX model that was negative for the mAb806 epitope, no growth inhibition was observed. We demonstrated the specific targeting of the mAb806 epitope expressing MM tumors using 89Zr-based PET imaging. Our data suggest that targeting EGFR in MM using specific ADCs is a valid therapeutic strategy and supports further investigation of the mAb806 epitope expression as a predictive biomarker.

A pilot study of intrahepatic yttrium-90 microsphere radioembolization in combination with intravenous cisplatin for uveal melanoma liver-only metastases

BACKGROUND

Metastatic uveal melanoma is a highly aggressive disease with no standard of care treatment option. A large proportion of patients have liver-only metastatic disease which raises the question if liver-directed therapy can be efficacious in this subpopulation.

AIMS

The study aims to evaluate the safety and efficacy of radiosensitizing chemotherapy in combination with yttrium-90 microspheres in patients with uveal melanoma with liver-only metastases.

METHODS AND RESULTS

This single arm, open labeled, non-randomized study enrolled 10 patients with liver-only metastatic uveal melanoma between November 2012 and January 2018. Eligible patients received intrahepatic yttrium-90 microspheres followed by intravenous cisplatin (20 mg/m²) for 5 days. Ten patients were enrolled, but nine patients received treatment who were included in the final analysis with a median follow-up of 30 months (range 7 to 44). Five (50%) were female, five (50%) had an elevated lactate dehydrogenase (LDH), and one (10%) had prior anti-PD-1 therapy. The combination was well tolerated with no greater than or equal to grade 3 toxicity observed. The liver objective response rate (ORR) was 33% (3/9), the median progression-free survival (PFS) in the liver was 3 months (95% CI, 3-NA), and the extrahepatic PFS was 3 months (95% CI, 3-NA). Seventy-eight percent (7/9) received an immune checkpoint inhibitor on disease progression, with no responses seen. The median overall survival (OS) was 10 months (95% CI, 7-NA).

CONCLUSION

The combination of cisplatin with yttrium-90 microspheres was well tolerated; however, it was associated with intrahepatic disease control of relatively short duration. No responses were seen in patients treated with immune checkpoint inhibitors post radioembolization.

Impact of Radiotherapy on the Efficacy and Toxicity of anti-PD-1 Inhibitors in Metastatic NSCLC

BACKGROUND

The impact of radiotherapy (RT) on the efficacy and toxicity of immune checkpoint inhibitors (ICIs) in patients with metastatic non-small-cell lung cancer (NSCLC) is unclear.

MATERIALS AND METHODS

We identified patients with metastatic NSCLC treated with the anti-programmed death 1 antibodies nivolumab or pembrolizumab between January 2016 and May 2019 at 3 tertiary centers, who were also treated with palliative RT either during or within 3 months of starting anti-programmed death 1 treatment. Patient demographics, tumor characteristics, and treatment history were collected. Response rates, progression-free survival (PFS), and overall survival (OS) were analyzed and correlated with RT use.

RESULTS

A total of 269 patients were identified, with a median follow-up of 19.4 months. The median age was 70 years (range, 35-90 years), and they were 63% male, 60% smokers, and 65% had adenocarcinoma histology. At the commencement of ICI treatment, the majority (86%) had ≥ 1 line of prior therapy and 34% had brain metastases. A total of 102 (38%) patients received RT within 3 months of starting ICI or subsequently during ICI treatment. Of patients that received RT, 86 (84%) received conventional hypofractionated RT, and, in the majority, 81 (79%) the intent of RT was symptom control. The use of RT did not increase grade 3/4 immune-related adverse events. The overall median PFS was 2.0 months (95% confidence interval, 1.3-2.6 months) and the median OS was 9.0 months (95% confidence interval, 6.4-9.5 months). There were no significant differences in median PFS (3.0 vs. 2.0 months; P = .515) and median OS (9.0 vs. 9.0 months; P = .917) in the patients who received RT versus those that did not.

CONCLUSIONS

In patients with metastatic NSCLC, the addition of RT to ICI was not associated with increased toxicity or improved survival.

Inefficiencies in the phase II to phase III transition as a modifiable factor that is impeding successful drug development for glioblastoma

2516

Background: Improving the outcomes of patients with glioblastoma (GBM) represents one of the most significant challenges in neuro-oncology. We have observed inefficiencies in the availability and use of phase 2 data when planning phase 3 studies, and have undertaken a detailed review of key design parameters of phase 2 and 3 trials in GBM to identify and quantify the impact of this phenomenon. Methods: Studies between 2005-2019 inclusive were identified though MEDLINE search using keywords and MeSH terms, and manual bibliography searches. P2Ts were restricted to those referenced by the corresponding P3Ts. Clinical, statistical and sponsor characteristics were extracted by two reviewers (AB&AG). For each P3T, corresponding Phase 2 trial (P2T) data was “optimally matched” (OM) where same drug was used in similar schedule and similar GBM population; “partially matched” (PM) where dis-similar schedule and/or treatment setting; and “lacking” in all other circumstances. The statistical data used in the P2/3 transition were compared by Pearson Correlation, Fisher’s Exact or Chi-square testing as appropriate. Results: Of 20 P3Ts identified, 6 (30%) lacked any phase 2 data. Of the remaining 14 P3T, 9 had 1 prior P2T, 4 had 2 P2T and 1 had 3 P2T, for a total of 20 P3T-P2T pairs (called dyads). Further, there were 13 OM dyads and 7 PM dyads. OM dyads showed strong concordance for mPFS (r2= 0.95, p < 0.01) and mOS (r2= 0.84, p < 0.01), whilst PM dyads did not (p > 0.05). We identified several inefficiencies in translation from P2T to P3T. Firstly, 3 P3T had statistical assumptions of primary endpoint that may have been too optimistic. 2 of these P3Ts aimed for an expected endpoint that was higher than the actual outcomes from a matched P2T. 1 P3T was unable to reach the desired sample size. We note that 4 P3Ts had actual primary endpoint HRs that were < 0.9 but with P > 0.05. Finally, we investigated whether there were absolute thresholds for efficacy in P2Ts to inform whether to proceed with P3Ts. For P2Ts in the newly diagnosed setting, all those with mPFS < 14 months and/or mOS < 22 months had subsequent negative P3Ts. For P2Ts in recurrent disease, all those with mPFS < 6 months and mOS < 12 months had negative P3Ts. Applying these thresholds to the studies in our review, 10 of the 12 negative P3Ts (83%) with matched P2Ts need not have been initiated, sparing 4739 patients’ from unnecessary trial participation. Conclusions: Our data strongly supports the vital role of properly designed P2Ts in informing P3Ts for drug development for primary CNS tumours.

A phase I study of AK112, a bispecific antibody that targets PD-1 and VEGF co-expressing T cells, in patients with advanced solid tumors

TPS3155

Background: AK112 is a humanized IgG1 bispecific anti-PD-1/VEGF antibody. VEGF blockade potentiates PD-1 inhibition by, inter alia, opposing the immunosuppressive effects of VEGF-A, which include suppression of dendritic cell activity and enhancement of checkpoint molecule expression on CD8+ T cells and proliferation of regulatory T cells. Combination therapies involving PD-(L)1 and VEGF inhibitors have been approved for the treatment of selected patients with metastatic non-small cell lung carcinoma, advanced renal cell carcinoma and advanced endometrial carcinoma. A supplemental Biologics License Application has been submitted for an anti-PD-L1 + anti-VEGF combination for the first-line treatment of unresectable hepatocellular carcinoma. Given the strong correlation between VEGF and PD-1 expression in the tumor microenvironment, the simultaneous blockade of these 2 targets by AK112 as a single agent might achieve higher target binding specificities and synergistically produce enhanced antitumor activity compared to co-administration of anti-PD-(L)1 and anti-VEGF therapies. Methods: This is a Phase 1a/1b, first-in-human, multicenter, open-label study in patients with advanced or metastatic solid tumor that is refractory/relapsed to standard therapies. The primary objective is to assess safety, tolerability and DLTs; and to determine the Maximum Tolerated Dose (MTD) or Maximum Administered Dose of AK112. Antitumor activity, PK and immunogenicity of AK112 will be studied as secondary objectives. As exploratory endpoints, tumor tissue samples may be evaluated for PD-L1 expression, mRNA expression profile and biomarkers (e.g. CD8+, FoxP3, Granzyme B, apelin and EPHB4). PD-1 receptor occupancy on circulating T-cells and serum VEGF level may also be measured as indications of target engagement. The dose-escalation phase will evaluate 5 dose levels of AK112 (up to 20 mg/kg Q2W IV) using a 3+3+3 study design. Additional subjects (up to 18 subjects) may be enrolled at any dose level not exceeding the MTD for additional PK, PD and safety evaluations to determine the optimal dose level for the dose-expansion phase. Cohorts 1 and 2 have been completed and enrollment to Cohort 3 began in January 2020. The dose-expansion phase will be performed in patients with selected advanced solid tumors who had no prior exposure to drugs targeting T-cell co-stimulation or immune checkpoint pathways. Clinical trial information: NCT04047290 .

Sensitization of Cancers Resistant to HER2 Antibodies

Human epidermal growth factor receptor 2 (HER2) oncogene addiction has led to the development of anti-HER2 therapies which have revolutionized the management of patients with HER2-positive cancers, with trastuzumab being the cornerstone of treatment of HER2-positive breast cancer. Despite the success of these biologics in breast cancer patients, not all patients with HER2-positive tumors respond to treatment, and many eventually develop resistance to therapy. Developing therapies that that circumvent current resistance mechanisms and improve patient outcomes further remains an area of unmet clinical need. Based on insights gained from established anti-HER2 therapies and our understanding of known resistance mechanisms a number of novel anti-HER2 treatments are being developed. These include novel HER2 antibody-drug conjugates that have shown activity in HER2 high and low tumors, novel HER2 antibodies, T cell bispecific antibodies, and HER2 antibodies in combination with phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) inhibitors, immunotherapy and cyclin-dependent kinase 4/6 (CDK4/6) inhibitors. In this article, we review resistance mechanisms to approved HER2 antibodies and provide an overview of emerging therapeutic agents.

HOUT-13. CLINICAL TRIALS IN GLIOBLASTOMA: LEARNING FROM PREVIOUS EXPERIENCES TOWARDS OPTIMAL DEVELOPMENT OF TRIAL DESIGN

INTRODUCTION

We undertook a literature review testing the hypothesis that inefficiencies in the Phase 2/3 transition contributes to most GBM Phase 3 trials (P3T’s) being negative.

METHODS

Studies between 2005–2019 inclusive were identified though MEDLINE(R) using keywords and MeSH terms, and manual bibliography searches. Clinical, statistical and sponsor characteristics were extracted by two reviewers (AB&AG). For each P3T, Phase 2 trial (P2T) data was “optimally matched” where same drug was used in similar schedule and GBM population; “partially matched” where dis-similar schedule and/or treatment setting; and “lacking” in all other circumstances. Data were compared by Pearson Correlation, t-test or chi-square as appropriate.

RESULTS

18 relevant P3T’s and 15 P2T’s were identified. Median values for median progression free survival (mPFS) and median overall survival (mOS) in P3T’s were 7.9 and 17.9 mths respectively for first line studies; 2.2 and 7.9 mths for recurrent studies. These were 11.8 and 20.4 mths for 1st line P2T’s, suggesting selection bias, and 3.3 and 7.5 mths for recurrent studies. 50% of P3T had optimally matched P2D, with high concordance for mPFS (r2= 0.90, p< 0.01) and mOS (r2= 0.84, p< 0.01) between corresponding P3T and P2T. The remain 50% of P3T had ‘partially matched’ (22.2%) or lacked P2T data (27.8%). ‘Partially matched’ trials also had a high concordance for mPFS (r2= 0.92, p< 0.01) and mOS (r2= 0.83, p< 0.01). However, 80% of P3T planned for HR didn’t meet expected benefit. All first-line P2T with mPFS< 15 months and/or OS< 22 months had negative P3T. All recurrent P2T with mPFS< 5 months and mOS< 12 months had negative P3T. Impact of sponsors and molecular subtypes will be presented.

CONCLUSIONS

This review identified issues (selection bias, lack of appropriate P2T and possible underpowered P3T’s) at the Phase 2/3 interface and provides data for future trial design.

Current Development of Monoclonal Antibodies in Cancer Therapy

Exploiting the unique specificity of monoclonal antibodies has revolutionized the treatment and diagnosis of haematological and solid organ malignancies; bringing benefit to millions of patients over the past decades. Recent achievements include conjugating antibodies with toxic payloads resulting in superior efficacy and/or reduced toxicity, development of molecular imaging techniques targeting specific antigens for use as predictive and prognostic biomarkers, the development of novel bi- and tri-specific antibodies to enhance therapeutic benefit and abrogate resistance and the success of immunotherapy agents. In this chapter, we review an overview of antibody structure and function relevant to cancer therapy and provide an overview of pivotal clinical trials which have led to regulatory approval of monoclonal antibodies in cancer treatment. We further discuss resistance mechanisms and the unique side effects of each class of antibody and provide an overview of emerging therapeutic agents.

Rab-dependent cellular trafficking and amyotrophic lateral sclerosis

Rab GTPases are becoming increasingly implicated in neurodegenerative disorders, although their role in amyotrophic lateral sclerosis (ALS) has been somewhat overlooked. However, dysfunction of intracellular transport is gaining increasing attention as a pathogenic mechanism in ALS. Many previous studies have focused axonal trafficking, and the extreme length of axons in motor neurons may contribute to their unique susceptibility in this disorder. In contrast, the role of transport defects within the cell body has been relatively neglected. Similarly, whilst Rab GTPases control all intracellular membrane trafficking events, their role in ALS is poorly understood. Emerging evidence now highlights this family of proteins in ALS, particularly the discovery that C9orf72 functions in intra transport in conjunction with several Rab GTPases. Here, we summarize recent updates on cellular transport defects in ALS, with a focus on Rab GTPases and how their dysfunction may specifically target neurons and contribute to pathophysiology. We discuss the molecular mechanisms associated with dysfunction of Rab proteins in ALS. Finally, we also discuss dysfunction in other modes of transport recently implicated in ALS, including nucleocytoplasmic transport and the ER-mitochondrial contact regions (MAM compartment), and speculate whether these may also involve Rab GTPases.

Real-world efficacy and toxicity of combined nivolumab and ipilimumab in patients with metastatic melanoma

BACKGROUND

There is limited real-world data on the efficacy and safety of combination programmed cell death protein-1 (PD-1) inhibitor, nivolumab and the cytotoxic T-lymphocyte antigen (CTLA-4) inhibitor ipilimumab.

METHOD

We retrospectively identified patients (pts) with metastatic melanoma treated with three-weekly nivolumab (1 mg/kg) in combination with ipilimumab (3 mg/kg) for four cycles followed by nivolumab monotherapy (3 mg/kg) fortnightly. Patient demographics and treatment parameters were collected and outcomes determined.

RESULTS

A total of 45 pts received combination treatment with a median follow up of 8.7 months (range 0.33-25.9 months). A total of 67% were male, and BRAF V600 mutations detected in 38%. At treatment commencement, 14 (31%) pts had brain metastases, 51% had an elevated LDH and 18 (40%) were treatment-naive. Almost a third (30%) required corticosteroids for symptom control or management of prior toxicities. Nineteen (42%) patients had prior anti-PD-1 therapy. The disease control rate (DCR) was 54% and objective response rate (ORR) was 29%. Of pts treated with prior immune checkpoint inhibitors, the DCR and ORR were 50% and 33%, respectively. Intracranial responses were observed in 18% (n = 2). The median progression-free survival (PFS) was 5.8 months (95% Confidence interval (CI), 2.9-14.1 months). PFS was higher in treatment naïve patients compared to those who had prior immunotherapy (6.2 months vs 4.9 months, P = 0.59). The median OS was 17.4 months (95% CI, 7.1-NR). pts requiring corticosteroids had a shorter PFS (4.9 months vs 6.8 months) and OS (7.1 months vs NR, P = 0.01).Treatment-related adverse events of any grade were experienced by 88% of pts, with 54% having grade 3-4 adverse events. Treatment discontinuation due to adverse events occurred in 44% of pts.

CONCLUSION

In this study, responses to combination immunotherapy were lower than reported. Patients treated with prior immunotherapy had similar responses as treatment-naïve pts. The toxicity profile seen in this study is similar to those reported in clinical trials.

Molecular imaging of T cell co-regulator factor B7-H3 with 89Zr-DS-5573a

B7-H3 is a transmembrane protein widely expressed in a variety of cancers and has been shown to play a role in anti-tumor immunity. This study aims to develop a molecular imaging probe to identify B7-H3 expression in tumors and to develop ⁸⁹Zr-DS-5573a as a theranostic that could aid patient selection in clinical Phase I studies. Methods: The anti-B7-H3 humanised monoclonal antibody DS-5573a was labeled with zirconium-89 (⁸⁹Zr-), and assessed for radiochemical purity, immunoreactivity (Lindmo analysis), antigen binding affinity (Scatchard analysis), and serum stability in vitro. In vivo biodistribution and imaging studies were performed with positron emission tomography and magnetic resonance imaging (PET/MRI) studies to identify and quantitate ⁸⁹Zr-DS-5573a tumor uptake in a B7-H3-positive breast cancer model (MDA-MB-231) and a B7-H3-negative murine colon cancer model (CT26). Imaging and biodistribution studies were also performed in MDA-MB-231 tumor-bearing SCID mice in the absence and presence of therapeutic DS-5573a antibody dose (3 mg/kg DS-5573a). Results:⁸⁹Zr-DS-5573a showed high and specific binding to B7-H3-expressing MDA-MB-231 cells (immunoreactivity on day 0, 75.0 ± 2.9%), and low binding to B7-H3-negative CT26 cells (immunoreactivity on day 0, 10.85 ± 0.11%) in vitro. ⁸⁹Zr-DS-5573a demonstrated good serum stability in vitro with 57.2 ± 2.0% of immunoreactivity remaining on day 7. In vivo biodistribution studies showed high uptake of ⁸⁹Zr-DS-5573a in B7-H3-expressing MDA-MB-231 tumor-bearing mice, achieving 32.32 ± 6.55 %ID/g on day 7 post injection in BALB/c nu/nu mice and 25.76 ± 1.79 %ID/g in SCID mice, with minimal evidence of non-specific uptake in normal tissues, and excellent tumor localization on PET/MRI. In a combined imaging/therapy study, receptor saturation was demonstrated in tumors responding to therapy. Conclusion:⁸⁹Zr-DS-5573a demonstrates specific and prolonged targeting of B7-H3-expressing tumors in vivo. Saturation of binding sites was demonstrated in tumors responding to DS-5573a therapy. These results indicate that ⁸⁹Zr-DS-5573a has potential to target B7-H3-expressing tumors in cancer patients. Furthermore ⁸⁹Zr-DS-5573a has the potential to provide important insights into T cell biology through its specific binding to B7-H3.

Novel Approaches To Undergraduate Oncology Education

With the increasing incidence of cancer and related survival, junior doctors are more commonly involved the management of oncology patients. A comprehensive oncology curriculum has been developed and adopted across medi-cal schools in Australia. However, it was not designed to inform how medical students should be taught, and whether curriculum content translates to knowledge and competency can depend on its implementation. We have conducted a literature review of PubMed, Embase and Cochrane databases to identify and summarise the evidence for novel approaches to delivering the undergraduate oncology curriculum. Numerous effective approaches have been developed across areas of prevention, clinical examination through simulation, the multidisciplinary team, psycho-oncology, palliative care and even research. There is growing focus on a holistic and multidisciplinary approach to cancer education although direct clinical exposure and interactions with cancer patients is still crucial. Medical schools may also have an under-recognised role in promoting positive health behaviour if their graduates are to convey these preventative measures to their patients. Application of such methods relies upon clinicians and medical educators to consider the practicability and relevance of specific implementation in their local context.

Delayed Autoimmune Toxicity Occurring Several Months After Cessation of Anti-PD-1 Therapy

Treatment with anti-programmed cell death protein 1 (PD-1) antibodies has demonstrated clinical efficacy in a whole range of malignancies including advanced melanoma, renal cell cancer, bladder cancer, and non-small cell lung cancer. Immune-related adverse events are a unique side effect of checkpoint regulator therapy including anti-PD-1 antibodies. Treatment-related autoimmunity can occur in any organ system, with the median onset usually within 5-15 weeks from the commencement of therapy, depending on the organ system involved. This study describes for the first time a case of delayed autoimmunity occurring 8 months after discontinuing treatment with the anti-PD-1 antibody nivolumab in a patient with metastatic melanoma. The case highlights the need for ongoing surveillance of patients treated with immune checkpoint inhibitors even after cessation of therapy, especially as patients increasingly stop treatment after achieving durable responses.