Defining treatment regimens and lines of therapy using real-world data in oncology

Tackling Challenges in Assessing the Economic Value of Tumor-Agnostic Therapies: A Cost-Effectiveness Analysis of Pembrolizumab as a Case Study

OBJECTIVES

Assessing the value of tumor-agnostic drugs (TAD) is challenging given the potential variability in treatment effects, trials with small sample sizes, different standards of care (SoC), and lack of comparative data from single-arm basket trials. Our study developed and applied novel methods to assess the value of pembrolizumab compared with SoC to inform coverage decisions.

METHODS

We developed a partitioned survival model to evaluate the cost-utility of pembrolizumab for previously treated patients with 8 advanced or metastatic microsatellite instability-high or mismatch repair-deficient cancers from a US commercial payer perspective. Efficacy of pembrolizumab was based on data from trials directly or with adjustment using Bayesian hierarchical models. Eight chemotherapy-based external control arms were constructed from the TriNetX electronic health record databases. Tumor-specific health-state utility values were applied. All costs were adjusted to 2022 US dollars.

RESULTS

At a lifetime horizon, pembrolizumab was associated with increased effectiveness compared with chemotherapies in colorectal (quality-adjusted life years [QALYs]: +0.64, life years [LYs]: +0.64), endometrial (QALYs: +3.79, LYs: +5.47), and small intestine cancers (QALYs: +1.73, LYs: +2.48), but not for patients with metastatic gastric, cholangiocarcinoma, pancreatic, ovarian, and brain cancers. Incremental cost-effectiveness ratios varied substantially across tumor types. Pembrolizumab was found to be cost-effective in treating colorectal and endometrial cancers (incremental cost-effectiveness ratios: $121 967 and $139 257, respectively), and not cost-effective for other assessed cancers at a $150 000 willingness-to-pay/QALY threshold, compared with SoC chemotherapies.

CONCLUSIONS

The cost-effectiveness of TADs can vary by cancers. Using analytic tools such as external controls and Bayesian hierarchical models can tackle several challenges in assessing the value of TADs and uncertainties from basket trials.

First- vs second-line CDK 4/6 inhibitor use for patients with hormone receptor positive, human epidermal growth-factor receptor-2 negative, metastatic breast cancer in the real world setting

PURPOSE

To compare CDK4/6 inhibitor (CDK4/6i) with endocrine therapy (ET) in the first- versus second-line setting for treatment of hormone receptor positive (HR+), HER2 negative, metastatic breast cancer (MBC) using real-world evidence.

METHODS

Patients with HR+, HER2 negative MBC, diagnosed between 2/3/2015 and 11/2/2021 and having ≥ 3 months follow-up were identified from the nationwide electronic health record-derived Flatiron Health de-identified database. Treatment cohorts included: (1) first-line ET with a CDK 4/6i (1st-line CDK4/6i) versus (2) first-line ET alone followed by second-line ET with a CDK4/6i (2nd-line CDK4/6i). Differences in baseline characteristics were tested using chi-square tests and two-sample t-tests. Time to third-line therapy, time to start of chemotherapy, and overall survival were compared using Kaplan-Maier method.

RESULTS

The analysis included 2771 patients (2170 1st-line CDK4/6i and 601 2nd-line CDK4/6i). Patients receiving 1st-line CDK4/6i were younger (75% vs 68% < 75 years old, p = 0.0001), less likely uninsured or not having insurance status documented (10% vs. 13%, p = 0.04), of better performance status (50% vs 43% with ECOG 0, p = 0.03), and more likely to have de novo MBC (36% vs. 24%, p < 0.001). Time to third-line therapy (49 vs 22 months, p < 0.001) and time to chemotherapy (68 vs 41 months, p < 0.001) were longer in those receiving first-line CDK4/6i. Overall survival (54 vs 49 months, p = 0.33) was similar between groups.

CONCLUSION

Use of CDK4/6i with first-, vs second-, line ET was associated with longer time to receipt of 3rd-line therapy and longer time to receipt of chemotherapy.

Extraction of Unstructured Electronic Health Records to Evaluate Glioblastoma Treatment Patterns

PURPOSE

Data on lines of therapy (LOTs) for cancer treatment are important for clinical oncology research, but LOTs are not explicitly recorded in electronic health records (EHRs). We present an efficient approach for clinical data abstraction and a flexible algorithm to derive LOTs from EHR-based medication data on patients with glioblastoma multiforme (GBM).

METHODS

Nonclinicians were trained to abstract the diagnosis of GBM from EHRs, and their accuracy was compared with abstraction performed by clinicians. The resulting data were used to build a cohort of patients with confirmed GBM diagnosis. An algorithm was developed to derive LOTs using structured medication data, accounting for the addition and discontinuation of therapies and drug class. Descriptive statistics were calculated and time-to-next-treatment (TTNT) analysis was performed using the Kaplan-Meier method.

RESULTS

Treating clinicians as the gold standard, nonclinicians abstracted GBM diagnosis with a sensitivity of 0.98, specificity 1.00, positive predictive value 1.00, and negative predictive value 0.90, suggesting that nonclinician abstraction of GBM diagnosis was comparable with clinician abstraction. Of 693 patients with a confirmed diagnosis of GBM, 246 patients contained structured information about the types of medications received. Of them, 165 (67.1%) received a first-line therapy (1L) of temozolomide, and the median TTNT from the start of 1L was 179 days.

CONCLUSION

We described a workflow for extracting diagnosis of GBM and LOT from EHR data that combines nonclinician abstraction with algorithmic processing, demonstrating comparable accuracy with clinician abstraction and highlighting the potential for scalable and efficient EHR-based oncology research.

Concepts of lines of therapy in cancer treatment: findings from an expert interview-based study

OBJECTIVE

The concept of lines of therapy (LOT) in cancer treatment is often considered for decision making in tumor boards and clinical management, but lacks a common definition across medical specialties. The complexity and heterogeneity of malignancies and treatment modalities contribute to an inconsistent understanding of LOT among physicians. This study assesses the heterogeneity of understandings of the LOT concept, its major dimensions, and criteria from the perspective of physicians of different specialties with an oncological focus in Germany. Semi-structured expert interviews with nine physicians were conducted and evaluated using qualitative content analysis.

RESULTS

Most interviewees agreed that there is no single definition for LOT and found it difficult to explicate their understanding. A majority of experts stated that they had already encountered misunderstandings with colleagues regarding LOT and that they had problems with deciphering LOT from the medical records of their patients. Disagreement emerged about the roles of the following within the LOT concept: maintenance therapy, treatment intention, different therapy modalities, changing pharmaceutical agents, and therapy breaks. Respondents predominantly considered the same criteria as decisive for the definition of LOT as for a change in LOT (e.g., the occurrence of a progression event or tumor recurrence).

Prevalence and Spectrum of AR Ligand-Binding Domain Mutations Detected in Circulating-Tumor DNA Across Disease States in Men With Metastatic Castration-Resistant Prostate Cancer

PURPOSE

Metastatic castration-resistant prostate cancer (mCRPC) is typically treated with agents directly or indirectly targeting the androgen receptor (AR) pathway. However, such treatment is limited by resistance mechanisms, including the development of activating mutations in the AR ligand-binding domain (AR-LBD).

METHODS

This study evaluated a database of over 15,000 patients with advanced prostate cancer (PC) undergoing comprehensive circulating-tumor DNA analysis (Guardant360, Redwood City, CA) between 2014 and 2021, with associated clinical information from administrative claims (GuardantINFORM database).

RESULTS

Of 15,705 patients with PC included, 54% had mCRPC at the time of their blood draw. Of those, 49% had previous treatment with an AR pathway inhibitor (ARPi). AR-LBD mutation prevalence was 15% in patients with mCRPC who were untreated with a next-generation ARPi, 22% in those after one line of ARPi therapy, and 24% in those after two lines of ARPi treatment. Next-generation ARPi treatment yielded an increase in AR L702H and T878A/S mutations after abiraterone, and an increase in AR L702H and F877L mutations after enzalutamide. AR-LBD+ patients demonstrated unique biology, including increased concurrent mutations in the cell-cycle, wingless-related integration site, homologous recombination repair, and phospho-inositide 3-kinase pathways (all P < .0005), and greater low-level (copy number <10) AR amplifications (P = .0041). AR-LBD+ patients exhibited worse overall survival (OS) relative to a matched cohort of AR-LBD- patients (50.1 v 60.7 months, unadjusted log-rank P = .013).

CONCLUSION

This large database analysis demonstrates that AR-LBD mutation prevalence increases after next-generation ARPi use. AR-LBD+ tumors demonstrate unique biology (more oncogenic pathway mutations and low-level AR amplification) and reduced OS. These findings inform the development of novel therapies designed to circumvent AR-mediated therapeutic resistance.

Incidence and risk factors of immune-related adverse events induced by immune checkpoint inhibitors among older adults with non-small cell lung cancer

BACKGROUND

Immune checkpoint inhibitor (ICI) treatment has been linked to a variety of immune-related adverse events (irAEs), which can affect any organ system. The incidence and risk factors of irAEs have not been adequately evaluated among older adults with NSCLC.

METHODS

A cohort study was conducted using 1999-2019 SEER-Medicare data among beneficiaries aged ≥65 years with a diagnosis of NSCLC who received nivolumab, pembrolizumab, or atezolizumab. Incident irAEs were identified post-ICI initiation. Demographic, cancer-related characteristics, and clinical history risk factors of irAEs were evaluated with competing events considered.

RESULTS

A total of 8175 older NSCLC patients were included (with 46.8% experiencing irAEs). Pneumonitis (16.5%), hypothyroidism (10.5%), arrhythmia (11.18%), and acute kidney injury (AKI) (5.8%) were the most common irAEs. The median time to first irAE was 82 days (IQR: 29-182 days). The earliest onset of irAE occurrence was for hematologic irAEs, while the latest were gastrointestinal, dermatologic, and musculoskeletal irAEs. Fine-Gray regression modeling revealed significantly greater hazards of irAE occurrence in patients who received pembrolizumab at index, did not have CNS metastases, had a history of autoimmune disorder, and had chemotherapy in combination with ICI. Race, socioeconomic status, previous radiation therapy, and comorbidity burden were found to be associated with the occurrence of certain type of irAEs.

CONCLUSION

A significant proportion of older patients with NSCLC develop an irAE after receiving ICI treatment. Factors related to cancer and treatment as well as demographics contribute to the increased risk of irAEs. Close monitoring and prediction of irAE among older patients receiving ICI is warranted.

Framework for the Use of External Controls to Evaluate Treatment Outcomes in Precision Oncology Trials

Advances in genomics have enabled anticancer therapies to be tailored to target specific genomic alterations. Single-arm trials (SATs), including those incorporated within umbrella, basket, and platform trials, are widely adopted when it is not feasible to conduct randomized controlled trials in rare biomarker-defined subpopulations. External controls (ECs), defined as control arm data derived outside the clinical trial, have gained renewed interest as a strategy to supplement evidence generated from SATs to allow comparative analysis. There are increasing examples demonstrating the application of EC in precision oncology trials. The prospective application of EC in conducting comparative studies is associated with distinct methodological challenges, the specific considerations for EC use in biomarker-defined subpopulations have not been adequately discussed, and a formal framework is yet to be established. In this review, we present a framework for conducting a prospective comparative analysis using EC. Key steps are (1) defining the purpose of using EC to address the study question, (2) determining if the external data are fit for purpose, (3) developing a transparent study protocol and a statistical analysis plan, and (iv) interpreting results and drawing conclusions on the basis of a prespecified hypothesis. We specify the considerations required for the biomarker-defined subpopulations, which include (1) specifying the comparator and biomarker status of the comparator group, (2) defining lines of treatment, (3) assessment of the biomarker testing panels used, and (4) assessment of cohort stratification in tumor-agnostic studies. We further discuss novel clinical trial designs and statistical techniques leveraging EC to propose future directions to advance evidence generation and facilitate drug development in precision oncology.

Real-World Treatment Patterns and Economic Burden Following First-Line Trastuzumab in Patients with Metastatic Gastric Cancer in the USA

BACKGROUND

Trastuzumab in combination with chemotherapy is the standard first-line (1L) treatment for HER2+ metastatic gastric cancer (mGC) in the USA.

OBJECTIVE

This study characterizes the real-world treatment patterns, healthcare resource use (HRU), and costs in patients with HER2+ mGC post-1L trastuzumab before approval of fam-trastuzumab deruxtecan-nxki.

PATIENTS AND METHODS

This retrospective study used the IQVIA PharMetrics® Plus Database (October 2014-September 2019) to identify adults with HER2+ mGC who discontinued trastuzumab-based regimens in 1L. Patient characteristics, second-line (2L) treatment patterns, and treatment duration were summarized. HRU and costs before and after discontinuation of 1L trastuzumab-based regimens as well as during 2L treatment were described.

RESULTS

Of the 190 HER2+mGC patients who discontinued 1L trastuzumab-based regimens, 136 (71.58%) initiated 2L treatments. Trastuzumab-based regimens were the most common in 2L (50.74%), followed by ramucirumab + paclitaxel (19.85%). The median time to 2L discontinuation was 2.37 months. During a mean follow-up of 9.8 months, mean per-patient-per-month (PPPM) healthcare costs post-1L trastuzumab-based regimens were higher in patients receiving 2L treatment than those without subsequent treatment (US$25,178 vs. US$14,812). The mean PPPM cost during 2L treatment was US$30,838, primarily driven by outpatient infusion costs (US$22,262).

CONCLUSIONS

The short duration of 2L treatment observed in this study is consistent with a lack of effective treatments post-1L trastuzumab prior to 2020. Re-use of trastuzumab treatment was common despite its limited efficacy and high treatment cost. The findings highlight the unmet medical needs and substantial burden faced by patients with HER2 +mGC previously treated with trastuzumab.

Incidence of second primary malignancies in relapsed/refractory B-cell non-Hodgkin's lymphoma patients in England

BACKGROUND

Treatments for relapsed/refractory (r/r) B-cell non-Hodgkin's lymphoma (NHL) may be associated with an increased risk of second primary malignancies (SPMs). Currently available SPM incidence benchmarks are unreliable due to small sample sizes.

METHODS

The Cancer Analysis System (CAS), a population-level cancer database in England, was used to identify patients with incident B-cell NHL diagnosed during 2013-2018 with evidence of r/r disease. Incidence rates (IRs) of SPMs after r/r disease diagnosis were calculated per 1000 person-years (PYs) and stratified by age, sex, and SPM type.

RESULTS

We identified 9444 patients with r/r B-cell NHL disease. Of those who were eligible for SPM analysis, nearly 6.0% (470/7807) developed at least one SPM after r/r disease diagnosis (IR: 44.7; 95% confidence interval [CI]: 40.9-48.9). Of note, 205 (2.6%) had a non-melanoma skin cancer (NMSC) SPM. IR of SPMs was the highest for patients with r/r chronic lymphocytic leukemia/small lymphocytic leukemia (80.0) and lowest for diffuse large B-cell lymphoma (DLBCL) (30.9). Patients with DLBCL had the shortest overall survival after r/r disease diagnosis.

CONCLUSIONS

This real-world data study suggests that the IR of SPM among patients with r/r B-cell NHL is 44.7 per 1000 PY and that most SPMs diagnosed after r/r disease diagnosis are NMSCs, establishing a basis for the comparison of safety outcomes for new treatments being developed for r/r B-cell NHL.

Real-World Molecular Biomarker Testing Patterns and Results for Advanced Gastroesophageal Cancers in the United States

The decision to treat advanced gastroesophageal cancers (GECs) with targeted therapy and immunotherapy is based on key biomarker expression (human epidermal growth factor receptor 2 (HER2), programmed cell death-ligand 1 (PD-L1), microsatellite instability (MSI), and/or mismatch repair (MMR)). Real-world data on testing, results, and treatment patterns are limited. This retrospective observational study used a nationwide electronic health record-derived de-identified database of patients from the United States. The analysis included adult patients with advanced GECs who initiated systemic treatment between 2017 and 2020. Biomarker testing patterns, timing, assays, tissue collection site, results, and treatment sequences were assessed. Of 1142 eligible patients, adenocarcinoma was the most prevalent histology (83% of patients). Overall, 571 (50%) patients were tested for PD-L1, 582 (51%) were tested for MMR/MSI, and 857 (75%) were tested for HER2. Between 2017 and 2020, the PD-L1 testing rate increased from 39% to 58%, and the MMR/MSI testing rate increased from 41% to 58%; the median time from initial diagnosis to first test decreased for both biomarkers. Programmed cell death receptor-1 inhibitor use was observed among patients with positive PD-L1 or MMR-deficient/MSI-High results. These results supplement data reported in key clinical trials and may inform decision-making as treatment options for advanced GECs evolve.

Multi-state survival models with treatment effects and biomarkers: Simulations for study design assessment

BACKGROUND

Comparative effectiveness studies of cancer therapeutics in observational data face confounding by patterns of clinical treatment over time. The validity of survival analysis in longitudinal health records depends on study design choices including index date definition and model specification for covariate adjustment.

METHODS

Overall survival in cancer is a multi-state transition process with mortality and treatment switching as competing risks. Parametric Weibull regression quantifies proportionality of hazards across lines of therapy in real-world cohorts of 12 solid tumor types. Study design assessments compare alternative analytic models in simulations with realistic disproportionality. The multi-state simulation framework is adaptable to alternative treatment effect profiles and exposure patterns.

RESULTS

Event-specific hazards of treatment-switching and death are not proportional across lines of therapy in 12 solid tumor types. Study designs that include all eligible lines of therapy per subject showed lower bias and variance than designs that select one line per subject. Confounding by line number was effectively mitigated across a range of simulation scenarios by Cox proportional hazards models with stratified baseline hazards and inverse probability of treatment weighting.

CONCLUSION

Quantitative study design assessment can inform the planning of observational research in clinical oncology by demonstrating the potential impact of model misspecification. Use of empirical parameter estimates in simulation designs adapts analytic recommendations to the clinical population of interest.

Health care resource utilization and treatment variability in the care of patients with advanced or metastatic colorectal or gastric cancer

AIMS

This study was designed to describe health care resource utilization (HCRU) of patients with metastatic colorectal cancer (CRC) or gastric cancer to test the hypothesis that greater treatment variability would be associated with increased HCRU.

METHODS

A retrospective observational study using Marketscan claims data was conducted. Eligible patients had a first diagnosis of metastatic CRC or gastric cancer between 2004 and 2015 and must have received systemic anti-cancer therapy after diagnosis. Treatment variability was measured using the Herfindahl-Hirschman Index (HHI). HHI scores were stratified by quartile. HCRU variables were evaluated throughout the follow-up period and described by 6-month periods. Chi-square test was used for categorical variables and ANOVA for continuous variables.

RESULTS

A total of 55,403 CRC and 9,073 gastric cancer patients were eligible. First-line HHI scores ranged from 0.1304-0.2778 for CRC and 0.0383-0.1778 for gastric cancer by state of residence. Statistically significant differences by HHI quartiles for HCRU in CRC included hospitalizations (p = 0.0003), ER visits (p < 0.0001), ER visits leading to hospitalization (p < 0.0001), and supportive care (all agents studied, p < 0.01). For gastric cancer, significant differences by HHI quartile were observed for ER visits (p = 0.002) and selected supportive care (G-CSF, erythropoiesis-stimulating agents, bisphosphonates, nutritional support, and antiemetics, each p < 0.05). No consistent increasing or decreasing trends were observed across the quartiles for either cohort.

LIMITATIONS

Large sample sizes could lead to statistical significance without being clinically meaningful. High treatment heterogeneity in the gastric cancer cohort and lack of a homogeneous quartile for comparisons limited the ability to evaluate HCRU by different levels of treatment variability.

CONCLUSIONS

Statistically significant relationships were observed between treatment variability as measured by HHI and increased HCRU, but no consistent directional trends in HCRU variables were observed. Therefore, this study failed to reject the null hypothesis of equivalent HCRU by level of treatment variability.