AbstractIntroductionStructured data capture requires defined languages such as minimal Common Oncology Data Elements (mCODE). This pilot assessed the feasibility of capturing 5 mCODE categories (stage, disease status, performance status (PS), intent of therapy and intent to change therapy).MethodsA tool (SmartPhrase) using existing and custom structured data elements was Built to capture 4 data categories (disease status, PS, intent of therapy and intent to change therapy) typically documented as free‐text within notes. Existing functionality for stage was supported by the Build. Participant survey data, presence of data (per encounter), and time in chart were collected prior to go‐live and repeat timepoints. The anticipated outcome was capture of >50% sustained over time without undue burden.ResultsPre‐intervention (5‐weeks before go‐live), participants had 1390 encounters (1207 patients). The median percent capture across all participants was 32% for stage; no structured data was available for other categories pre‐intervention. During a 6‐month pilot with 14 participants across three sites, 4995 encounters (3071 patients) occurred. The median percent capture across all participants and all post‐intervention months increased to 64% for stage and 81%–82% for the other data categories post‐intervention. No increase in participant time in chart was noted. Participants reported that data were meaningful to capture.ConclusionsStructured data can be captured (1) in real‐time, (2) sustained over time without (3) undue provider burden using note‐based tools. Our system is expanding the pilot, with integration of these data into clinical decision support, practice dashboards and potential for clinical trial matching.
Abstract Antibody-drug conjugates (ADCs) are increasingly being used in clinic, and many novel ADCs are being tested in clinical trials. Most ADCs act by delivering cytotoxic payloads into target cells. The activity of most ADCs is predicated upon internalization to release the cytotoxic payloads intracellularly to act on the malignant cells. The degree of ADC internalization is incomplete or absent for many cell surface targets, limiting the activity of ADCs. PROTACs are heterobifunctional molecules that result in the polyubiquitylation of their targets by inducing proximity with E3 ligases. The proteasome then recognizes the poly-ubiquitin chains and degrades these targets. We hypothesized that PROTACs that act on the same targets as ADCs could improve the internalization and efficacy of these ADCs. Using multiple cell lines derived from breast, lung or pancreatic cancers that express the oncogenic cell surface proteins EGFR (ERBB1), HER2 (ERBB2) or MET (HGF), we measured antibody internalization with live cell imaging. Antibodies were labeled with a pH sensitive reagent that fluoresces red (640 nm) upon exposure to acidic environments. Fluorescence was measured over time to create an area under the curve which was compared between the cell lines that were treated with and without PROTACs. Antibody internalization was observed in all cell lines that expressed the targets recognized by the antibodies. The addition of PROTACs targeting the same oncogenic cell surface proteins as the antibodies significantly increased antibody internalization beyond that observed without PROTACs. Internalization of antibodies was confirmed by measuring intracellular immunoglobulins by Western blot. Antibody internalization with PROTACs was dose-dependent, increased over time and was blocked by either the clatharin inhibitor Dyngo4a or the proteasome inhibitor MG132. In the case of HER2 for which there are FDA-approved anti-HER2 ADCs, the cytotoxicity of trastuzumab emtansine (TDM1) significantly increased with the addition of a HER2-targeting PROTAC across a range of doses. PROTACs that target the same oncogenic cell surface proteins as antibodies improve antibody internalization and ADC cytotoxicity, in a process dependent upon clatharin and the proteasome. This novel application of PROTACs may impact the use of ADCs, and provides a rationale to combine these agents in clinical trials. Citation Format: Ezequiel J. Tolosa, Lin Yang, Jennifer Ayers-Ringler, Jayapal Mallareddy, Janet Schaefer-Klein, Farhad Kosari, Amar Natarajan, Aaron S. Mansfield. Proteolysis targeting chimera (PROTAC)-driven internalization of antibodies targeting oncogenic cell surface receptors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 4518.
Ki-67 Proliferation Index Is Associated With Tumor Grade and Survival in Pleural Epithelioid Mesotheliomas
Pleural epithelioid mesothelioma (PEM) is divided into low and high grades based on nuclear atypia, mitoses, and necrosis in the tumor. Assessing mitoses and nuclear atypia tend to be labor-intensive with limited reproducibility. Ki-67 proliferation index was shown to be a prognostic factor in PEM, but its performance has not been directly correlated with tumor grade or mitotic score. This study evaluated the potential of Ki-67 index as a surrogate of tumor grade. We also compared the predictability of mitoses and Ki-67 index for overall survival (OS). Ninety-six PEM samples from 85 patients were identified from the surgical pathology file during 2000-2021 at our institution, and all glass slides were reviewed by 2 pulmonary pathologists to confirm the diagnosis and assign the tumor grade. Digital image analysis (DIA) was done for Ki-67 index. The agreement on tumor grading between 2 reviewers was moderate (kappa value = 0.47). The correlation between mitotic count (average count by 2 reviewers) and Ki-67 index was 0.65. The areas under the curve for predicting tumor grade by mitotic score and Ki-67 index were 0.84 and 0.74 (reviewer 1) and 0.85 and 0.81 (reviewer 2), respectively. High Ki-67 index and mitoses were significantly associated with poor OS (P=0.03 and 0.0005, using 30% and 10/2 mm2 as cutoffs, respectively). In conclusion, Ki-67 index by DIA was associated with tumor grade as well as mitotic count, and its predictability for OS was comparable to that of mitotic score, thus being a potential surrogate for tumor grade.
Pegargiminase Plus First-Line Chemotherapy in Patients With Nonepithelioid Pleural Mesothelioma
ImportanceArginine deprivation using ADI-PEG20 (pegargiminase) combined with chemotherapy is untested in a randomized study among patients with cancer. ATOMIC-Meso (ADI-PEG20 Targeting of Malignancies Induces Cytotoxicity-Mesothelioma) is a pivotal trial comparing standard first-line chemotherapy plus pegargiminase or placebo in patients with nonepithelioid pleural mesothelioma.ObjectiveTo determine the effect of pegargiminase-based chemotherapy on survival in nonepithelioid pleural mesothelioma, an arginine-auxotrophic tumor.Design, Setting, and ParticipantsThis was a phase 2-3, double-blind randomized clinical trial conducted at 43 centers in 5 countries that included patients with chemotherapy-naive nonepithelioid pleural mesothelioma from August 1, 2017, to August 15, 2021, with at least 12 months’ follow-up. Final follow-up was on August 15, 2022. Data analysis was performed from March 2018 to June 2023.InterventionPatients were randomly assigned (1:1) to receive weekly intramuscular pegargiminase (36.8 mg/m2) or placebo. All patients received intravenous pemetrexed (500 mg/m2) and platinum (75-mg/m2 cisplatin or carboplatin area under the curve 5) chemotherapy every 3 weeks up to 6 cycles. Pegargiminase or placebo was continued until progression, toxicity, or 24 months.Main Outcomes and MeasuresThe primary end point was overall survival, and secondary end points were progression-free survival and safety. Response rate by blinded independent central review was assessed in the phase 2 portion only.ResultsAmong 249 randomized patients (mean [SD] age, 69.5 [7.9] years; 43 female individuals [17.3%] and 206 male individuals [82.7%]), all were included in the analysis. The median overall survival was 9.3 months (95% CI, 7.9-11.8 months) with pegargiminase-chemotherapy as compared with 7.7 months (95% CI, 6.1-9.5 months) with placebo-chemotherapy (hazard ratio [HR] for death, 0.71; 95% CI, 0.55-0.93; P = .02). The median progression-free survival was 6.2 months (95% CI, 5.8-7.4 months) with pegargiminase-chemotherapy as compared with 5.6 months (95% CI, 4.1-5.9 months) with placebo-chemotherapy (HR, 0.65; 95% CI, 0.46-0.90; P = .02). Grade 3 to 4 adverse events with pegargiminase occurred in 36 patients (28.8%) and with placebo in 21 patients (16.9%); drug hypersensitivity and skin reactions occurred in the experimental arm in 3 patients (2.4%) and 2 patients (1.6%), respectively, and none in the placebo arm. Rates of poststudy treatments were comparable in both arms (57 patients [45.6%] with pegargiminase vs 58 patients [46.8%] with placebo).Conclusions and RelevanceIn this randomized clinical trial of arginine depletion with pegargiminase plus chemotherapy, survival was extended beyond standard chemotherapy with a favorable safety profile in patients with nonepithelioid pleural mesothelioma. Pegargiminase-based chemotherapy as a novel antimetabolite strategy for mesothelioma validates wider clinical testing in oncology.Trial RegistrationClinicalTrials.gov Identifier: NCT02709512
Molecular Tumor Board Improves Outcomes for Hispanic Patients With Advanced Solid Tumors
PURPOSE Multidisciplinary molecular tumor boards (MTBs) decode complex genomic data into clinical recommendations. Although MTBs are well-established in the oncology practice in developed countries, this strategy needs to be better explored in developing countries. Herein, we describe the possible benefits and limitations of the first MTB established in Colombia. METHODS Demographic, clinical, and genomic information was collected between August 2020 and November 2021. By mid-2020, an MTB strategy was created to discuss clinical cases with one or more genomic alterations identified by next-generation sequencing using an open-access virtual platform. We characterized the patient population as benefiting from the recommended treatment option. We assessed the benefits and access to available targeted therapies that have the potential to change clinical management by making recommendations to treating oncologists on the basis of genomic profiling. However, we did not assess the treatment oncologists' compliance with MTB recommendations because they were not intended to replace clinical judgment/standard of care. RESULTS A total of 146 patients were included in the discussions of the MTB. The median age was 59 years, and 59.6% were women. Genomic results prompting a change in therapeutic decisions were obtained in 53.1% of patients (95% CI, 44.9 to 61.3). The most prevalent malignancy was non–small-cell lung cancer (51%). Other malignancies represented 60%, 50%, and 30% of patients with soft-tissue sarcomas, brain tumors, and breast cancer, respectively. CONCLUSION Using an open-access virtual platform, MTBs were feasible in low- and middle-income countries on the basis of the capability to provide the benefits and access to available targeted therapies that are not standard of care. Furthermore, MTB recommendations were made available to the treating oncologist in different locations across Colombia, providing the option to modify clinical management in most of these patients.
Pralsetinib in Patients with Advanced/Metastatic Rearranged During Transfection (RET)-Altered Thyroid Cancer: Updated Efficacy and Safety Data from the ARROW Study
Background: Rearranged during transfection ( RET ) alterations are targetable oncogenic drivers in thyroid cancer. Primary data from the open-label, phase 1/2 ARROW study demonstrated clinical activity and manageable safety with pralsetinib, a selective RET inhibitor, in patients with advanced/metastatic RET -altered thyroid cancer. We present an updated analysis with more patients and longer follow-up. Methods: Adult patients with advanced/metastatic RET -mutant medullary thyroid cancer (MTC) or RET fusion-positive thyroid cancer who initiated oral pralsetinib at 400 mg once daily were included. Primary endpoints were overall response rate (ORR) by blinded independent central review (per RECIST v1.1) and safety. Secondary endpoints included duration of response (DoR), progression-free survival (PFS), and overall survival. Responses were assessed in three cohorts of patients with baseline measurable disease: patients with RET -mutant MTC who had received prior cabozantinib and/or vandetanib (C/V), treatment-naïve patients with RET -mutant MTC, and patients with previously treated RET fusion-positive thyroid cancer. Patient-reported outcomes (PROs) were an exploratory endpoint. Results: As of October 18, 2021, the measurable disease population comprised of 61 patients with RET -mutant MTC and prior C/V, 62 treatment-naïve patients with RET -mutant MTC, and 22 patients with RET fusion-positive thyroid cancer who had received prior systemic therapy, including radioactive iodine. The ORR was 55.7% [confidence interval; 95% CI: 42.4–68.5] in patients with RET -mutant MTC and prior C/V, 77.4% [95% CI: 65.0–87.1] in treatment-naïve patients with RET -mutant MTC, and 90.9% [95% CI: 70.8–98.9] in patients with previously treated RET fusion-positive thyroid cancer. Median DoR and median PFS were both 25.8 months in patients with RET -mutant MTC and prior C/V, not reached in treatment-naïve patients with RET -mutant MTC, and 23.6 and 25.4 months, respectively, in patients with previously treated RET fusion-positive thyroid cancer. In the RET -altered thyroid cancer safety population ( N = 175), 97.1% of patients reported a treatment-related adverse event (TRAE); these led to discontinuation in 5.7% and dose reduction in 52.6% of patients. There was one death (0.6%) due to a TRAE. PROs improved or remained stable after pralsetinib treatment. Conclusions: In this updated analysis of the ARROW study, pralsetinib continued to show deep and durable clinical activity and a manageable safety profile in patients with advanced/metastatic RET- altered thyroid cancer. Clinical Trial Registration: NCT03037385
Salvage therapy expands highly cytotoxic and metabolically fit resilient CD8
+
T cells via ME1 up-regulation
Patients with advanced cancers who either do not experience initial response to or progress while on immune checkpoint inhibitors (ICIs) receive salvage radiotherapy to reduce tumor burden and tumor-related symptoms. Occasionally, some patients experience substantial global tumor regression with a rebound of cytotoxic CD8 + T cells. We have termed the rebound of cytotoxic CD8 + T cells in response to salvage therapy as T cell resilience and examined the underlying mechanisms of resilience. Resilient T cells are enriched for CX3CR1 + CD8 + T cells with low mitochondrial membrane potential, accumulate less reactive oxygen species (ROS), and express more malic enzyme 1 (ME1). ME1 overexpression enhanced the cytotoxicity and expansion of effector CD8 + T cells partially via the type I interferon pathway. ME1 also increased mitochondrial respiration while maintaining the redox state balance. ME1 increased the cytotoxicity of peripheral lymphocytes from patients with advanced cancers. Thus, preserved resilient T cells in patients rebound after salvage therapy and ME1 enhances their resiliency.
EXTH-37. FUNCTIONAL GENOMICS IDENTIFIES THERAPEUTIC VULNERABILITIES OF GLIOMA SUBTYPES AND YAP/TAZ-ENRICHED TUMORS
Abstract Sequencing efforts have identified key oncogenic drivers and transcriptomic subtypes of high-grade gliomas (HGGs), but this knowledge has not resulted in individualized therapy or improved patient outcomes. Here, we used a functional genomics approach combining integrated genomic/transcriptomic analyses with patient-derived 3D micro-cancers (mCancers) to rapidly identify individualized therapeutic vulnerabilities and determine predictive response biomarkers. 30 primary/recurrent HGGs, including 20 glioblastomas, 5 astrocytomas, and 5 oligodendrogliomas, were included for drug testing. mCancers recapitulated the structural and molecular alterations, cellularity, and heterogeneity, of parental patient tumors. A total of 119 single-agent drugs and 183 drug combinations were tested, while a pre-selected drug panel comprising 25 glioma-relevant treatment strategies was tested across all cases. In general, mCancer efficacy corresponded well to historical responses to previously tested agents (EGFR, HDAC inhibitors, etc.). Combined, strong efficacy (i.e. >70% growth inhibition at Cmax) of single treatments targeting deregulated receptor tyrosine kinase (RTK), p53/apoptosis, cell cycle, DNA damage repair, IDH, or telomere maintainance pathways, was observed in 14 out of 30 cases. Surprisingly, transcriptional signatures, but not specific genetic alterations, were found to stratify drug responses. For example, mCancers enriched for the most aggressive mesenchymal (MES) and glycolytic/plurimetabolic (GPM) transcriptional subtypes exhibited stronger response to the BET inhibitor JQ1 (and other clinical BET inhibitors) and the DNA-PKcs/mTOR dual inhibitor CC-115. This therapeutic vulnerability was associated with enrichment of YAP/TAZ signaling, and the glioblastoma stem cell G-STEM signature. Notably, individual combination strategies were effective across tumors, with strong responses ranging from 38% to 77% of all tumors tested. Overall, this study underscores the value of functional genomics in identifying novel vulnerabilities of HGGs and associated response biomarkers. It also highlights the need for further clinical validation of several novel therapies and especially drug combination strategies with strong efficacy in the ex vivo setting.
CTNI-03. EFFICACY OF WSD0922-FU IN OSIMERTINIB-RESISTANT NSCLC WITH CENTRAL NERVOUS SYSTEM (CNS) METASTASES – UPDATES FROM THE DOSE ESCALATION COHORT OF A FIRST-IN-HUMAN PHASE 1 CLINICAL TRIAL (MC1914)
Abstract WSD0922-Fu is an oral, CNS-penetrant, small molecule EGFR inhibitor which potently inhibits EGFR aberrations specific to non-small cell lung cancer (NSCLC) and high-grade astrocytoma (HGA). MC1914 (NCT04197934) is a first-in-human phase 1 trial in patients with EGFR aberrant recurrent HGA and NSCLC. Adult patients with either recurrent EGFR mutant NSCLC with CNS metastases or recurrent EGFR aberrant HGA were enrolled and treated across six cohorts (40 mg once daily to 320 mg twice daily, 28-day cycles) to determine the maximum tolerated dose (MTD). 25 patients (17 HGA, 8 NSCLC) were enrolled (median age = 57 years; 24% female; 36% ECOG 0). All patients with HGA received prior radiation and temozolomide. All patients with NSCLC had previous disease progression on EGFR inhibitor therapy (prior osimertinib 88%). The median duration of WSD0922-Fu exposure among all patients was 55 days (range 3 to >279 days) [NSCLC median = 131 days; HGA median = 51 days]. Common treatment-related adverse events are comparable to other EGFR inhibitors (fatigue, acneiform rash, diarrhea, nausea, pruritis). At Cycle 1 Day 15 for patients treated at MTD (160 mg twice daily), the mean terminal elimination half-life (%CV) in the plasma was 31.6 h (102%) (median 14.5 h). The mean Cmax, Tmax, oral clearance at steady state, and AUC (0-12 h) (%CV) were 4513 ng/mL (50%), 2.0 hr (69%), 6.9 L/hr/m2 (42%), and 28084 h*ng/mL (52%), respectively. Among patients with NSCLC treated at MTD or higher dose levels and with available response data, 100% (5/5) of patients demonstrated clinical benefit (SD + PR) while 60% of patients had partial responses. Intracranial and extracranial efficacy was concordant. Furthermore, prolonged stable disease (9 cycles) was observed in a patient with EGFRvIII mutant GBM. Expansion cohorts are in progress to optimize WSD0922-Fu dose and schedule for future phase 2 development.
Pralsetinib in Patients with RET Fusion–Positive Non-Small-Cell Lung Cancer: A Plain Language Summary of the ARROW Study