The dream and reality of histology agnostic cancer clinical trials

Agnostic Administration of Targeted Anticancer Drugs: Looking for a Balance between Hype and Caution

Many tumors have well-defined vulnerabilities, thus potentially allowing highly specific and effective treatment. There is a spectrum of actionable genetic alterations which are shared across various tumor types and, therefore, can be targeted by a given drug irrespective of tumor histology. Several agnostic drug-target matches have already been approved for clinical use, e.g., immune therapy for tumors with microsatellite instability (MSI) and/or high tumor mutation burden (TMB), NTRK1-3 and RET inhibitors for cancers carrying rearrangements in these kinases, and dabrafenib plus trametinib for BRAF V600E mutated malignancies. Multiple lines of evidence suggest that this histology-independent approach is also reasonable for tumors carrying ALK and ROS1 translocations, biallelic BRCA1/2 inactivation and/or homologous recombination deficiency (HRD), strong HER2 amplification/overexpression coupled with the absence of other MAPK pathway-activating mutations, etc. On the other hand, some well-known targets are not agnostic: for example, PD-L1 expression is predictive for the efficacy of PD-L1/PD1 inhibitors only in some but not all cancer types. Unfortunately, the individual probability of finding a druggable target in a given tumor is relatively low, even with the use of comprehensive next-generation sequencing (NGS) assays. Nevertheless, the rapidly growing utilization of NGS will significantly increase the number of patients with highly unusual or exceptionally rare tumor-target combinations. Clinical trials may provide only a framework for treatment attitudes, while the decisions for individual patients usually require case-by-case consideration of the probability of deriving benefit from agnostic versus standard therapy, drug availability, associated costs, and other circumstances. The existing format of data dissemination may not be optimal for agnostic cancer medicine, as conventional scientific journals are understandably biased towards the publication of positive findings and usually discourage the submission of case reports. Despite all the limitations and concerns, histology-independent drug-target matching is certainly feasible and, therefore, will be increasingly utilized in the future.

Histology agnosticism: Infra-molecularizing disease?

The term "molecularization" has been used by historians and sociologists of science to describe the transition from an anatomic view of the body to a submicroscopic one, where health and illness, indeed life itself, are increasingly defined in terms of an individual's "genetic landscape." Here we introduce the notion of the infra-molecular as a way of extending and nuancing the molecularization trope as it applies to the domain of (post)genomic oncology. In particular we look at how infra-molecularity is enacted in practice as part of the so-called "histology-agnostic" turn in clinical cancer research and care. Drawing on fieldwork in North American oncology settings, we analyze how histology agnosticism partially reconfigures knowledge and practice across the linked domains of drug development and clinical trials, therapeutic decision making, and regulation, and the implications of this for an ongoing revision of how we understand the biopathology and temporality of cancer. We show how, in practice, the inframolecular gaze entails a "return" of histology as a modulator of histology-agnostic drugs and background for interpretation of mutational complexity.

Organizing precision medicine: A case study of Memorial Sloan Kettering Cancer Center's engagement in/with genomics

Recent decades have seen a dramatic rise of in the number of initiatives designed to promote precision oncology, a domain that has played a pioneering role in the implementation of post-genomic approaches and technologies such as innovative clinical trial designs and molecular profiling. In this paper, based on fieldwork carried out at the Memorial Sloan-Kettering Cancer Center from 2019 onwards, we analyze how a world-leading cancer center has adapted, responded, and contributed to the challenge of "doing" precision oncology by developing new programs and services, and building an infrastructure that has created the conditions for genomic practices. We do so by attending to the "organizing" side of precision oncology and to the nexus between these activities and epistemic issues. We situate the work that goes into making results actionable and accessing targeted drugs within the larger process of creating a precision medicine ecosystem that includes purpose-built institutional settings, thus simultaneously experimenting with bioclinical matters and, reflexively, with organizing practices. The constitution and articulation of innovative sociotechnical arrangements at MSK provides a unique case study of the production of a large and complex clinical research ecosystem designed to implement rapidly evolving therapeutic strategies embedded in a renewed and dynamic understanding of cancer biology.

Histology-Agnostic Drugs: A Paradigm Shift-A Narrative Review

Cancer diagnosis and therapeutics have been traditionally based on pathologic classification at the organ of origin. The availability of an unprecedented amount of clinical and biologic data provides a unique window of opportunity for the development of new drugs. What was once treated as a homogeneous disease with a one-size-fits-all approach was shown to be a rather heterogeneous condition, with multiple targetable mutations that can vary during the course of the disease. Clinical trial designs have had to adapt to the exponential growth of targetable mechanisms and new agents, with ensuing challenges that are closer to those experienced with rare diseases and orphan medicines. To face these problems, precision/enrichment and other novel trial designs have been developed, and the concept of histology-agnostic targeted therapeutic agents has emerged. Patients are selected for a specific agent based on specific genomic or molecular alterations, with the same compound used to potentially treat a multiplicity of cancers, granted that the actionable driver alteration is present. There are currently approved drugs for such indications, but this approach has raised issues on multiple levels. This review aims to address the challenges of this new concept and provide insights into possible solutions and frameworks on how to tackle them.

Systematic review of neurotrophic tropomyosin-related kinase inhibition as a tumor-agnostic management strategy

Aim: To conduct a systematic review and meta-analysis feasibility of clinical, quality of life and economic evidence for neurotrophic tropomyosin-related receptor tyrosine kinases (NTRK) inhibitors in patients with NTRK gene fusion-positive tumors. Materials & methods: Databases were searched for studies on NTRK inhibitors in adult and pediatric patients. Results: 27 publications reported clinical data for seven interventions. Efficacy/safety data were available for two interventions only. Four trials each reported data for larotrectinib and entrectinib with pooled analyses reporting objective response rates of 75% (95% CI: 61-85) and 57.4% (43.2-70.8), respectively. No publications reported economic or quality of life evidence. Conclusion: Preliminary data demonstrate that NTRK inhibitors are well tolerated and show impressive clinical benefit; corroboration of existing studies and real-world data are required.

Encyclopedic tumor analysis for guiding treatment of advanced, broadly refractory cancers: results from the RESILIENT trial

RESILIENT (CTRI/2018/02/011808) was a single arm, open label, phase II/III study to test if label agnostic therapy regimens guided by Encyclopedic Tumor Analysis (ETA) can offer meaningful clinical benefit for patients with relapsed refractory metastatic (r/r-m) malignancies. Patients with advanced refractory solid organ malignancies where disease had progressed following ≥2 lines of systemic treatments were enrolled in the trial. Patients received personalized treatment recommendations based on integrational comprehensive analysis of freshly biopsied tumor tissue and blood. The primary end points were Objective Response Rate (ORR), Progression Free Survival (PFS) and Quality of Life (QoL). Objective Response (Complete Response + Partial Response) was observed in 54 of 126 patients evaluable per protocol (ORR = 42.9%; 95% CI: 34.3%–51.4%, p < 0.0001). At study completion, Disease Control (Complete Response + Partial Response + Stable Disease) was observed in 114 out of 126 patients evaluable per protocol (CBR = 90.5%; 95% CI: 83.9% - 95.0%, p < 0.00001) and Disease Progression in 12 patients. Median duration of follow-up was 138 days (range 31 to 379). Median PFS at study termination was 134 days (range 31 to 379). PFS rate at 90 days and 180 days were 93.9% and 82.5% respectively. The study demonstrated that tumors have latent vulnerabilities that can be identified via integrational multi-analyte investigations such as ETA. This approach identified viable treatment options that could yield meaningful clinical benefit in this cohort of patients with advanced refractory cancers.

Contribution of bladder cancer pathology assessment in planning clinical trials

Bladder cancer is a heterogeneous disease that demonstrates a wide spectrum of histologic features. The modern classification of bladder cancer is largely based on pathologic analysis, which assesses tumor grade, stage, type, size, and other features that are essential for understanding the biological behavior of bladder cancer. Bladder cancers with similar histologic features are likely to show comparable responses to a new therapeutic agent in clinical trial. Furthermore, pathologic analysis also evaluates the quality of tissue samples in clinical trial to ensure the integrity of various molecular tests. In spite of the emerging role of genomic and molecular studies, pathology remains the cornerstone in the diagnosis, prognosis, and treatment of bladder cancer. Herein, the pathologic considerations for bladder cancer clinical trial planning are reviewed.

Network science in clinical trials: A patient-centered approach

There has been a paradigm shift in translational oncology with the advent of novel molecular diagnostic tools in the clinic. However, several challenges are associated with the integration of these sophisticated tools into clinical oncology and daily practice. High-throughput profiling at the DNA, RNA and protein levels (omics) generate a massive amount of data. The analysis and interpretation of these is non-trivial but will allow a more thorough understanding of cancer. Linear modelling of the data as it is often used today is likely to limit our understanding of cancer as a complex disease, and at times under-performs to capture a phenotype of interest. Network science and systems biology-based approaches, using machine learning and network science principles, that integrate multiple data sources, can uncover complex changes in a biological system. This approach will integrate a large number of potential biomarkers in preclinical studies to better inform therapeutic decisions and ultimately make substantial progress towards precision medicine. It will however require development of a new generation of clinical trials. Beyond discussing the challenges of high-throughput technologies, this review will develop a framework on how to implement a network science approach in new clinical trial designs in order to advance cancer care.

Estimation of treatment effect in two-stage confirmatory oncology trials of personalized medicines

A personalized medicine may benefit a subpopulation with certain predictive biomarker signatures or certain disease types. However, there is great uncertainty about drug activity in a subpopulation when designing a confirmatory trial in practice, and it is logical to take a two-stage approach with the study unless credible external information is available for decision-making purpose. The first stage deselects (or prunes) non-performing subpopulations at an interim analysis, and the second stage pools the remaining subpopulations in the final analysis. The endpoints used at the two stages can be different in general. A key issue of interest is the statistical property of the test statistics and point estimate at the final analysis. Previous research has focused on type I error control and power calculation for such two-stage designs. This manuscript will investigate estimation bias of the treatment effect, which is implicit in the adjustment of nominal type I error for multiplicity control in such two-stage designs. Previous work handles the treatment effect of an intermediate endpoint as a nuisance parameter to provide the most conservative type I error control. This manuscript takes the same approach to explore the bias. The methodology is applied to the two previously studied designs. In the first design, patients with different biomarker levels are enrolled in a study, and the treatment effect is assumed to be in an order. The goal of the interim analysis is to identify a biomarker cut-off point for the subpopulations. In the second design, patients with different tumour types but the same biomarker signature are included in a trial applying a basket design. The goal of the interim analysis is to identify a subset of tumour types in the absence of treatment effect ordering. Closed-form equations are provided for the estimation bias as well as the variance under the two designs. Simulations are conducted under various scenarios to validate the analytic results that demonstrated that the bias can be properly estimated in practice. Worked examples are presented. Extensions to general adaptive designs and operational considerations are discussed. Copyright © 2017 John Wiley & Sons, Ltd.

Translational research in surgical oncology

Surgeons need to get involved

Adaptive Design for a Confirmatory Basket Trial in Multiple Tumor Types Based on a Putative Predictive Biomarker

Increasingly, tumors are defined on a molecular basis rather than only on histology, and targeted agents, which address these molecular subtypes, are being approved. This profusion of molecular subtypes creates "rare" diseases as subsets of common cancers, leading to difficulties in enrolling sufficiently large cohorts for confirmatory trials. However, if the molecular subtype is shared across various histologies, these may be pooled into a basket trial. To date, basket trials have been primarily for exploratory early development. In this perspective, we consider qualitative designs for confirmatory basket trials. These confirmatory basket designs will provide patients in niche indications with enhanced access to novel therapies, facilitate development and full approval for niche indications, allow accelerated approval for indications within a basket based on a surrogate endpoint, reduce development cost by combining trials, and enhance the ability of regulatory authorities to evaluate risk and benefit in niche indications.

cMET Exon 14 Skipping: From the Structure to the Clinic

The abnormal stimulation of the multiple signal transduction pathways downstream of the receptor tyrosine kinase mesenchymal-epithelial transition factor (cMET) promotes cellular transformation, tumor motility, and invasion. Therefore, cMET has been the focus of prognostic and therapeutic studies in different tumor types, including non-small cell lung cancer. In particular, several cMET inhibitors have been developed as innovative therapeutic candidates and are currently under investigation in clinical trials. However, one of the challenges in establishing effective targeted treatments against cMET remains the accurate identification of biomarkers for the selection of responsive subsets of patients. Recently, splice site mutations have been discovered in cMET that lead to the skipping of exon 14, impairing the breakdown of the receptor. Patients with NSCLC who are carrying this splice variant typically overexpress the cMET receptor and show a response to small molecule inhibitors of cMET. Here, we review the main differences at the structural level between the wild-type and the splice variants of cMET and their influence on cMET signaling. We clarify the reason why this variant responds to small molecule inhibitors and their prognostic/predictive role.

The dream and reality of histology agnostic cancer clinical trials

Emerging technologies and progress in data processing allowed for new insights on gene expression, genomics and epigenomics, and mechanisms of cancer genesis and progression. The development of new therapeutic strategies should therefore be triggered by the understanding of the underlying biology through sophisticated clinical trials. Therefore, the methodology and the design of cancer clinical trials as well as the methods of their implementation are under profound changes. Targeting specific pathways has open the hope of a more focused and personalized medicine which has the potential to bring more efficient and tailored treatments to patients. It has been questioned therefore whether clinical trials traditionally designed for specific tumor types could not re-visited towards trials gathering patients based on molecular features rather than pure pathology criteria. The complexity of the cancer biology being the result of so many different interactive mechanisms whether driving or not the process of cancer cells is an additional level of complexity to approach more inclusive clinical trial access. Nevertheless, a number of innovative solutions to address biological challenges across histologies have been initiated and the question of whether histology agnostic trials could be conceived is a logical next question. This paper questions the advantages and the limits of clinical trials performed across tumor types bearing similar selected molecular features and looks further into the feasibility of such histology agnostic trials.