Which Metrics Are Appropriate to Describe the Value of New Cancer Therapies?

Comparative overall survival of CDK4/6 inhibitors plus an aromatase inhibitor in HR+/HER2- metastatic breast cancer in the US real-world setting

BACKGROUND

Randomized controlled trials have shown inconsistent overall survival (OS) benefit among the three cyclin-dependent kinase 4/6 inhibitors (CDK4/6i) as first-line (1L) treatment of patients with hormone receptor-positive (HR+)/human epidermal growth factor receptor 2-negative (HER2-) metastatic breast cancer (mBC). Several real-world studies compared CDK4/6i effectiveness, with inconsistent findings. This study compared overall survival (OS) of patients with HR+/HER2- mBC receiving 1L palbociclib, ribociclib, or abemaciclib, in combination with an aromatase inhibitor (AI), in US clinical practice.

PATIENTS AND METHODS

This retrospective study used real-world data from the Flatiron Health electronic health record-derived deidentified longitudinal database. Patients with HR+/HER2- mBC aged ≥18 years at mBC diagnosis started 1L CDK4/6i therapy (index treatment) between February 2015 and November 2023, with a potential ≥6-month follow-up. OS was defined as months from start of index treatment to death. Stabilized inverse probability of treatment weighting (sIPTW; primary analysis) was used to balance baseline patient characteristics. Multivariable Cox proportional hazards model was carried out as a sensitivity analysis.

RESULTS

Of 9146 eligible patients, 6831, 1279, and 1036 received palbociclib plus AI, ribociclib plus AI, or abemaciclib plus AI, respectively. After sIPTW, baseline characteristics were balanced between treatment groups. After sIPTW, no significant OS differences were found between treatment groups [ribociclib versus palbociclib: adjusted hazard ratio (aHR) 0.98, 95% confidence interval (CI) 0.87-1.10, P = 0.7531; abemaciclib versus palbociclib: aHR 0.95, 95% CI 0.84-1.08, P = 0.4292; abemaciclib versus ribociclib: aHR 0.97, 95% CI 0.82-1.14, P = 0.6956]. Sensitivity analysis including a subanalysis of patients who started index treatment in 2017 or later also showed no significant OS differences between treatment groups.

CONCLUSIONS

This large real-world study suggested that there were no significant OS differences between 1L ribociclib, abemaciclib, and palbociclib in combination with an AI for patients with HR+/HER2- mBC. These findings together with other factors such as safety and quality of life are helpful in the selection of CDK4/6i combination therapy for patients with HR+/HER2- mBC.

Tumor therapy by targeting extracellular hydroxyapatite using novel drugs: A paradigm shift

BACKGROUND

It has been shown that tumor microenvironment (TME) hydroxyapatite (HAP) is typically associated with many malignancies and plays a role in tumor progression and growth. Additionally, acidosis in the TME has been reported to play a key role in selecting for a more aggressive tumor phenotype, drug resistance and desensitization to immunotherapy for many types of cancers. TME-HAP is an attractive target for tumor detection and treatment development since HAP is generally absent from normal soft tissue. We provide strong evidence that dissolution of hydroxyapatite (HAP) within the tumor microenvironment (TME-HAP) using a novel therapeutic can be used to kill cancer cells both in vitro and in vivo with minimal adverse effects.

METHODS

We developed an injectable cation exchange nano particulate sulfonated polystyrene solution (NSPS) that we engineered to dissolve TME-HAP, inducing localized acute alkalosis and inhibition of tumor growth and glucose metabolism. This was evaluated in cell culture using 4T1, MDA-MB-231 triple negative breast cancer cells, MCF10 normal breast cells, and H292 lung cancer cells, and in vivo using orthotopic mouse models of cancer that contained detectable microenvironment HAP including breast (MMTV-Neu, 4T1, and MDA-MB-231), prostate (PC3) and colon (HCA7) cancer using 18 F-NaF for HAP and 18 F-FDG for glucose metabolism with PET imaging. On the other hand, H292 lung tumor cells that lacked detectable microenvironment HAP and MCF10a normal breast cells that do not produce HAP served as negative controls. Tumor microenvironment pH levels following injection of NSPS were evaluated via Chemical Exchange Saturation (CEST) MRI and via ex vivo methods.

RESULTS

Within 24 h of adding the small concentration of 1X of NSPS (~7 μM), we observed significant tumor cell death (~ 10%, p < 0.05) in 4T1 and MDA-MB-231 cell cultures that contain HAP but ⟨2% in H292 and MCF10a cells that lack detectable HAP and in controls. Using CEST MRI, we found extracellular pH (pHe) in the 4T1 breast tumors, located in the mammary fat pad, to increase by nearly 10% from baseline before gradually receding back to baseline during the first hour post NSPS administration. in the tumors that contained TME-HAP in mouse models, MMTV-Neu, 4T1, and MDA-MB-231, PC3, and HCA7, there was a significant reduction (p<0.05) in 18 F-Na Fuptake post NSPS treatment as expected; 18 F-  uptake in the tumor = 3.8 ± 0.5 %ID/g (percent of the injected dose per gram) at baseline compared to 1.8 ±0.5 %ID/g following one-time treatment with 100 mg/kg NSPS. Of similar importance, is that 18 F-FDG uptake in the tumors was reduced by more than 75% compared to baseline within 24 h of treatment with one-time NSPS which persisted for at least one week. Additionally, tumor growth was significantly slower (p < 0.05) in the mice treated with one-time NSPS. Toxicity showed no evidence of any adverse effects, a finding attributed to the absence of HAP in normal soft tissue and to our therapeutic NSPS having limited penetration to access HAP within skeletal bone.

CONCLUSION

Dissolution of TME-HAP using our novel NSPS has the potential to provide a new treatment paradigm to enhance the management of cancer patients with poor prognosis.

Selection of the optimal personalized treatment from multiple treatments with right-censored multivariate outcome measures

We propose a novel personalized concept for the optimal treatment selection for a situation where the response is a multivariate vector that could contain right-censored variables such as survival time. The proposed method can be applied with any number of treatments and outcome variables, under a broad set of models. Following a working semiparametric Single Index Model that relates covariates and responses, we first define a patient-specific composite score, constructed from individual covariates. We then estimate conditional means of each response, given the patient score, correspond to each treatment, using a nonparametric smooth estimator. Next, a rank aggregation technique is applied to estimate an ordering of treatments based on ranked lists of treatment performance measures given by conditional means. We handle the right-censored data by incorporating the inverse probability of censoring weighting to the corresponding estimators. An empirical study illustrates the performance of the proposed method in finite sample problems. To show the applicability of the proposed procedure for real data, we also present a data analysis using HIV clinical trial data, that contained a right-censored survival event as one of the endpoints.

What proportion of patients with stage 3 ovarian cancer are potentially cured following intraperitoneal chemotherapy? Analysis of the long term (≥10 years) survivors in NRG/GOG randomized clinical trials of intraperitoneal and intravenous chemotherapy in stage III ovarian cancer

OBJECTIVE

Patients with advanced epithelial ovarian cancer (EOC) alive without progression at a landmark time-point of 10 years from diagnosis are likely cured. We report the proportion of patients with Stage III EOC who were long-term disease-free survivors (LTDFS≥10 years) following either intraperitoneal (IP) or intravenous (IV) chemotherapy as well as the predictors of LTDFS.

METHODS

Data from 3 mature NRG/GOG trials (104, 114, 172) were analyzed and included demographics, clinicopathologic details, route of administration, and survival outcomes of patients living ≥10 years assessed according to the Kaplan-Meier method. Cox regression survival analysis was performed to evaluate independent prognostic predictors of LTDFS.

RESULTS

Of 1174 patients randomized, 10-year overall survival (OS) was 26% (95% CI, 23-28%) and LTDFS ≥10 years was 18% (95% CI, 16-20%). Patients with LTDFS ≥10 years had a median age of 54.6 years (p < 0.001). Younger age (p < 0.001) was the only independent prognostic factor for LTDFS≥10 years on multivariate Cox analysis.

CONCLUSIONS

Approximately 18% of patients were LTDFS ≥10 years. They form the tail end of the survival curve and are likely cured. Our results provide a comparative benchmark to evaluate the impact of PARP inhibitors in 1st line maintenance trials on survival outcomes.

Quantiles based personalized treatment selection for multivariate outcomes and multiple treatments

In this work, we propose a method for individualized treatment selection when there are correlated multiple responses for the K treatment ( K ≥ 2 ) scenario. Here we use ranks of quantiles of outcome variables for each treatment conditional on patient-specific scores constructed from collected covariate measurements. Our method covers any number of treatments and outcome variables using any number of quantiles and it can be applied for a broad set of models. We propose a rank aggregation technique for combining several lists of ranks where both these lists and elements within each list can be correlated. The method has the flexibility to incorporate patient and clinician preferences into the optimal treatment decision on an individual case basis. A simulation study demonstrates the performance of the proposed method in finite samples. We also present illustrations using two different datasets from diabetes and HIV-1 clinical trials to show the applicability of the proposed procedure for real data.

Optimal Personalized Treatment Selection with Multivariate Outcome Measures in a Multiple Treatment Case

In this work we propose a novel method for individualized treatment selection when there are correlated multiple treatment responses. For the K treatment (K ≥ 2) scenario, we compare quantities that are suitable indexes based on outcome variables for each treatment conditional on patient-specific scores constructed from collected covariate measurements. Our method covers any number of treatments and outcome variables, and it can be applied for a broad set of models. The proposed method uses a rank aggregation technique that takes into account possible correlations among ranked lists to estimate an ordering of treatments based on treatment performance measures such as the smooth conditional mean. The method has the flexibility to incorporate patient and clinician preferences into the optimal treatment decision on an individual case basis. A simulation study demonstrates the performance of the proposed method in finite samples. We also present data analyses using HIV clinical trial data to show the applicability of the proposed procedure for real data.

The Importance of Disease-Free Survival as a Clinical Trial Endpoint: A Qualitative Study Among Canadian Survivors of Lung Cancer

BACKGROUND

In lung cancer trials, overall survival is a well-validated and widely used endpoint; yet, in the context of adjuvant or curative intent treatments, disease-free survival (DFS) may be a better indicator of transformative patient outcomes. Although use of DFS is growing, patient perceptions of its relevance have not been established.

OBJECTIVE

We aimed to understand the importance of DFS as a trial endpoint, from the perspective of survivors of lung cancer.

METHODS

Web-based qualitative interviews were conducted with Canadian survivors of stage Ib-IIIa lung cancer. Participants described their experiences of cancer diagnosis and treatment, including their treatment goals and priorities. Participants then provided their perspectives on DFS and overall survival, and how well each aligned with their treatment priorities. Thematic analysis was used to explore patterns in responses.

RESULTS

Among the 18 participants (mean age, 64 years), 83% were female, most (89%) had received surgery, and 56% received chemotherapy. Most participants viewed DFS as an intrinsically meaningful treatment outcome, for reasons such as alignment with treatment goals, and the perception that DFS would help maintain a high quality of life. One individual was interested in DFS only as a potential surrogate for overall survival. Participants desired access to new treatments that improve DFS and emphasized this within the context of promoting patient agency in treatment decision making.

CONCLUSIONS

These findings suggest DFS is a meaningful endpoint from the perspective of survivors of lung cancer; and may help inform decisions regarding regulatory approval and reimbursement of new treatments based on DFS data.

Assessing potential cures: are there distinctive elements of value beyond health gain?

Assessing the 'value' of potential cures can be challenging, as some have suggested that cures may offer distinctive benefits from noncurative treatments. We explore what these - previously unspecified - additional benefits may be. We suggest that three new elements of value seem distinctive to cures: liberation from the identity of being diseased, liberation from the stigma associated with the disease and liberation from the burden of ongoing therapy. However, including additional elements of value in health technology assessment may result in double counting and requires consideration of potential opportunity costs. We suggest health technology assessment should explore the relevance of these three elements of value and may have good reasons to - judiciously - integrate them through the deliberative process.

Effect of Treatment with the PD-1/PD-L1 Inhibitors on Key Health Outcomes of Cancer Patients

BACKGROUND

Recent studies have shown that treatment with the programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1) inhibitor class could significantly improve survival outcomes in several oncology indications. However, there is some clinical uncertainty.

OBJECTIVE

This study aimed to obtain high-level estimates of the impact of treatment with PD-1/PD-L1 inhibitor class to oncology treatment on key health outcomes in real-world situations and to inform public health policy decisions about cancer care after reducing uncertainties around new immuno-oncology therapy options in South Korea.

METHODS

A model was developed to estimate the impact of PD-1/PD-L1 inhibitors on outcomes in situations wherein both anti-PD-1/PD-L1s and standard of care (SOC) were available versus SOC only. A partitioned survival model was utilized to estimate the impact of introducing anti-PD-1/PD-L1s on outcomes, including life-years gained, quality-adjusted life-years gained, progression-free survival-years obtained, and grade 3 or higher adverse events avoided for six indications over 5 years. An exponential distribution was fitted to the survival function of the SOC based on visual inspection. Outcomes associated with anti-PD-1/PD-L1s were estimated using a piecewise modeling approach with Kaplan-Meier analysis followed by best-fitting survival analysis. The incident number of patients and market share of anti-PD-1/PD-L1s during 2020-2024 were projected using published literature and Korean market survey data. Sensitivity analyses were performed to test the uncertainty of input parameters.

RESULTS

During the next 5-year period (2020-2024), introducing the anti-PD-1/PD-L1 class led to a gain of 22,001 life-years (+ 31%), 19,073 quality-adjusted life-years (+ 38%), and 22,893 progression-free survival-years (+ 82%); it also avoided 3610 adverse events (- 11%) compared with SOC alone. Most adverse events associated with anti-PD-1/PD-L1s were attributed to combination therapy with cytotoxic chemotherapy (91%). In a scenario wherein the time to reimbursement of the anti-PD-1/PD-L1s was accelerated by 1 year, the life-years gained increased by 14% compared with the base-case scenario.

CONCLUSIONS

Anti-PD-1/PD-L1 therapy is expected to provide marked survival benefits for patients with cancer. This study demonstrated the potentially beneficial health impacts of utilizing the anti-PD-1/PD-L1 class at the population level. The findings could inform health policy decision makers about cancer care and ultimately enhance population health through rapid access to innovative cancer drugs.

Clinical Challenges of Immune Checkpoint Inhibitors

Even though the immuno-oncology (IO) era has achieved many successes, some signs of research development deceleration are arising. Recently, the number of FDA immunotherapy approvals has decreased concurrently with a decline in the relative number of patients recruited to these trials. Identifying the unique features of IO treatments and taking them into consideration on clinical research will lead to a better evaluation of these agents and patient outcomes. In this review, we discuss current challenges and new potential approaches to implement rationally designed clinical trials of IO drugs, particularly those targeting immune checkpoints.

Patients' understanding of oncology clinical endpoints: A literature review

OBJECTIVES

Oncology clinical trials use a variety of clinical endpoints. Patients' understanding of the differences between clinical endpoints is important because misperceptions of treatment efficacy may affect treatment decisions. The objective of this literature review is to find and synthesize available empirical publications assessing patients' understanding of common oncology clinical endpoints.

METHODS

We conducted a literature search of 5 databases and 3 conferences, limiting the search to articles and abstracts published in English through September 2018. We reviewed the titles and abstracts for inclusion, then reviewed full texts to determine if they reported empirical research studies focused on (1) clinical endpoints, (2) oncology, and (3) patient understanding. The original search identified 497publications, of which 13 met the inclusion criteria.

RESULTS

Available literature yields little information on this topic.The few publications that do exist suggest that healthcare professionals and cancer patients generally do not discuss clinical endpoint concepts and that patients can be confused about the purpose of a treatment based on misperceptions about endpoints.

CONCLUSIONS

Research is needed on how to discuss oncology clinical endpoints with patients.

PRACTICE IMPLICATIONS

Patient-friendly definitions of clinical endpoints may help healthcare providers communicate important information about treatments to patients.

Clinicians' Perspectives on Cure in Adult Patients with Acute Lymphoblastic Leukemia with Minimal Residual Disease: A Delphi Study

Hematologic complete remission (CR) is achievable for most adults with B cell precursor acute lymphoblastic leukemia (BCP-ALL). However, minimal residual disease (MRD) in patients with hematologic CR is associated with increased risk of relapse, shorter survival, and poorer transplantation outcomes. This study explored the concept of cure in adults with Philadelphia chromosome-negative (Ph−) BCP-ALL by MRD status at first hematologic CR (CR1) to inform evaluation of the clinical and economic benefits of new agents, where the concept of cure is important but long-term data are not available. The study used modified Delphi methodology involving clinicians experienced in the treatment of adult ALL. Participants completed a questionnaire, which was followed by country-specific panel discussions to discuss results and identify consensus on concepts and definitions. Clinicians from France (n = 4), Germany (n = 4), and the UK (n = 5) took part. Participants described cure in terms of the probability of future relapse. Relapse-free survival (RFS) was the preferred outcome measure to describe cure for the three patient groups considered (patients with MRD at CR1; patients who become negative for MRD after further treatment; patients who continue to have MRD). Consensus was reached on definitions of cure: that cure would begin to be considered at 3 years’ RFS and/or would be highly likely at 5 years’ RFS. Participants agreed that patients with MRD should usually undergo hematopoietic stem cell transplantation to have the best chance of survival; consensus was reached that alternatives are required when transplantation is not an option. Panels agreed that patients who achieve cure have a higher mortality rate and lower health-related quality of life than the general population. This study provides quantitative and qualitative information on the concept of cure in Ph− BCP-ALL in CR by MRD status applicable to interpreting the value of new therapies.

Funding: Amgen.

Plain Language Summary: Plain language summary available for this article.

Clinician Concepts of Cure in Adult Relapsed and Refractory Philadelphia-Negative B Cell Precursor Acute Lymphoblastic Leukemia: A Delphi Study

INTRODUCTION

Despite the poor prognosis for adults with relapsed or refractory (RR) Philadelphia chromosome (Ph)-negative B cell precursor acute lymphoblastic leukemia (ALL), long-term survival is possible and may even be considered as "cure".

METHODS

This study used a Delphi panel approach to explore concepts of cure in RR Ph-negative B cell precursor ALL. Ten European experts in this disease area participated in a survey and face-to-face panel meeting.

RESULTS

Findings showed that clinicians conceptualize "cure" as a combination of three broad treatment outcomes that vary depending on the treatment stage: complete remission early in treatment (1-3 months) indicates initial success; eradicating cancer cells (minimal residual disease negative status) consolidates the early clinical response; leukemia-free survival is required in the long term.

CONCLUSIONS

Although such terminology remains contested, clinicians would begin considering "cure" as early as 2 years provided the patient is off therapy, with most considering the term applicable by the third year.

FUNDING

Amgen Inc.

Alternative metrics for assessing clinical benefit with immunotherapy in oncology

Therapies for cancer have traditionally been assessed with metrics such as the response rate, hazard ratio, or median survival. Such metrics have value in measuring the outcomes of conventional therapies, but may not be the most appropriate for new therapies. Immuno-oncology therapies offer a new approach to treating cancer by stimulating patients' immune systems to fight cancer. The value of these novel therapies has so far been assessed with traditional metrics, but the different ways in which immuno-oncology therapies work can mean the full value is not captured. Immuno-oncology therapies can produce longer survival times but this effect can be delayed or even preceded by an apparent phase of progression, which median survival or response rates may not reflect. This paper discusses a range of traditional and alternative metrics and their benefits or disadvantages in measuring the effects of immuno-oncology therapies, using examples of several novel drugs as case studies.

Measuring the Value of New Drugs: Validity and Reliability of 4 Value Assessment Frameworks in the Oncology Setting

BACKGROUND

Several organizations have developed frameworks to systematically assess the value of new drugs.

OBJECTIVE

To evaluate the convergent validity and interrater reliability of 4 value frameworks to understand the extent to which these tools can facilitate value-based treatment decisions in oncology.

METHODS

Eight panelists used the American Society of Clinical Oncology (ASCO), European Society for Medical Oncology (ESMO), Institute for Clinical and Economic Review (ICER), and National Comprehensive Cancer Network (NCCN) frameworks to conduct value assessments of 15 drugs for advanced lung and breast cancers and castration-refractory prostate cancer. Panelists received instructions and published clinical data required to complete the assessments, assigning each drug a numeric or letter score. Kendall's Coefficient of Concordance for Ranks (Kendall's W) was used to measure convergent validity by cancer type among the 4 frameworks. Intraclass correlation coefficients (ICCs) were used to measure interrater reliability for each framework across cancers. Panelists were surveyed on their experiences.

RESULTS

Kendall's W across all 4 frameworks for breast, lung, and prostate cancer drugs was 0.560 (P= 0.010), 0.562 (P = 0.010), and 0.920 (P < 0.001), respectively. Pairwise, Kendall's W for breast cancer drugs was highest for ESMO-ICER and ICER-NCCN (W = 0.950, P = 0.019 for both pairs) and lowest for ASCO-NCCN (W = 0.300, P = 0.748). For lung cancer drugs, W was highest pairwise for ESMO-ICER (W = 0.974, P = 0.007) and lowest for ASCO-NCCN (W = 0.218, P = 0.839); for prostate cancer drugs, pairwise W was highest for ICER-NCCN (W = 1.000, P < 0.001) and lowest for ESMO-ICER and ESMO-NCCN (W = 0.900, P = 0.052 for both pairs). When ranking drugs on distinct framework subdomains, Kendall's W among breast cancer drugs was highest for certainty (ICER, NCCN: W = 0.908, P = 0.046) and lowest for clinical benefit (ASCO, ESMO, NCCN: W = 0.345, P = 0.436). Among lung cancer drugs, W was highest for toxicity (ASCO, ESMO, NCCN: W = 0. 944, P < 0.001) and lowest for certainty (ICER, NCCN: W = 0.230, P = 0.827); and among prostate cancer drugs, it was highest for quality of life (ASCO, ESMO: W = 0.986, P = 0.003) and lowest for toxicity (ASCO, ESMO, NCCN: W = 0.200, P = 0.711). ICC (95% CI) for ASCO, ESMO, ICER, and NCCN were 0.800 (0.660-0.913), 0.818 (0.686-0.921), 0.652 (0.466-0.834), and 0.153 (0.045-0.371), respectively. When scores were rescaled to 0-100, NCCN provided the narrowest band of scores. When asked about their experiences using the ASCO, ESMO, ICER, and NCCN frameworks, panelists generally agreed that the frameworks were logically organized and reasonably easy to use, with NCCN rated somewhat easier.

CONCLUSIONS

Convergent validity among the ASCO, ESMO, ICER, and NCCN frameworks was fair to excellent, increasing with clinical benefit subdomain concordance and simplicity of drug trial data. Interrater reliability, highest for ASCO and ESMO, improved with clarity of instructions and specificity of score definitions. Continued use, analyses, and refinements of these frameworks will bring us closer to the ultimate goal of using value-based treatment decisions to improve patient care and outcomes.

DISCLOSURES

This work was funded by Eisai Inc. Copher and Knoth are employees of Eisai Inc. Bentley, Lee, Zambrano, and Broder are employees of Partnership for Health Analytic Research, a health services research company paid by Eisai Inc. to conduct this research. For this study, Cohen, Huynh, and Neville report fees from Partnership for Health Analytic Research. Outside of this study, Cohen receives grants and direct consulting fees from various companies that manufacture and market pharmaceuticals. Mei reports a grant from Eisai Inc. during this study. The other authors have no disclosures to report. Study concept and design were contributed by Bentley and Broder, with assistance from Elkin and Cohen. Bentley took the lead in data collection, along with Elkin, Huynh, Mukherjea, Neville, Mei, Popescu, Lee, and Zambrano. Data interpretation was performed by Bentley and Broder, along with Elkin, Cohen, Copher, and Knoth. The manuscript was written primarily by Bentley, along with Elkin and Broder, and revised by Bentley, Broder, Elkin, Cohen, Copher, and Knoth. Select components of this work's methods were presented at ISPOR 19th Annual European Congress held in Vienna, Austria, October 29-November 2, 2016, and Society for Medical Decision Making 38th Annual North American Meeting held in Vancouver, Canada, October 23-26, 2016.