Cytotoxic Regimens Research Articles

Real-world treatment costs of first-line treatment for metastatic colorectal cancer: a survey of the JCOG colorectal cancer study group.

Although treatment outcomes for metastatic colorectal cancer (mCRC) have dramatically improved over the past few decades, drug costs have also significantly increased. This study aimed to investigate which first-line treatment regimens for mCRC are actually used (frequency) in Japanese practice and at what cost. We collected data on patients with mCRC who received first-line treatment at 37 institutions of the Japan Clinical Oncology Group Colorectal Cancer Study Group from July 2021 to June 2022, and calculated the cost of regimens. The cost per month of each regimen was estimated based on standard usage, assuming a patient with a weight of 70kg and a body surface area of 1.8m2. We categorized the regimens into very high-cost (≥1 000 000 Japanese yen [JPY]/month), high-cost (≥500 000 JPY/month), and others (<500 000 JPY/month). The study included 1880 participants, 24% of whom were≥75years. Molecular targeted containing regimens were received by 78% of the patients. The most frequently used regimen was the doublet regimen (fluoropyrimidine with either oxaliplatin or irinotecan) plus bevacizumab (43%), followed by doublet plus cetuximab or panitumumab (21%). The cost of molecular targeted drugs-containing regimens (ranging from 85 406 to 843 602 JPY/month) is much higher than that of only cytotoxic drug regimens (ranging from 17 672 to 51 004 JPY/month). About 16% received high-cost treatments that included panitumumab-containing regimens and pembrolizumab (17% of patients aged ≤74years and 11% of patients aged ≥75years). About 16% of mCRC patients received first-line treatment with regimens costing >500 000JPY/month, and molecular targeted drugs being the main drivers of cost.

Targeting CDC42 reduces skeletal degeneration after hematopoietic stem cell transplantation

AbstractOsteopenia and osteoporosis are common long-term complications of the cytotoxic conditioning regimen for hematopoietic stem cell transplantation (HSCT). We examined mesenchymal stem and progenitor cells (MSPCs), which include skeletal progenitors, from mice undergoing HSCT. Such MSPCs showed reduced fibroblastic colony-forming units frequency, increased DNA damage, and enhanced occurrence of cellular senescence, whereas there was a reduced bone volume in animals that underwent HSCT. This reduced MSPC function correlated with elevated activation of the small Rho guanosine triphosphate hydrolase CDC42, disorganized F-actin distribution, mitochondrial abnormalities, and impaired mitophagy in MSPCs. Changes and defects similar to those in mice were also observed in MSPCs from humans undergoing HSCT. A pharmacological treatment that attenuated the elevated activation of CDC42 restored F-actin fiber alignment, mitochondrial function, and mitophagy in MSPCs in vitro. Finally, targeting CDC42 activity in vivo in animals undergoing transplants improved MSPC quality to increase both bone volume and trabecular bone thickness. Our study shows that attenuation of CDC42 activity is sufficient to attenuate reduced function of MSPCs in a BM transplant setting.

Enfortumab vedotin (EV) in triple-negative breast cancer (TNBC) and HR+/HER2- breast cancer (BC) cohorts of EV-202.

1005 Background: EV, a Nectin-4–directed antibody–drug conjugate, is approved for use in urothelial cancer. Nectin-4 is expressed in several solid tumors, including BC. EV monotherapy was evaluated in TNBC and HR+/HER2- BC in EV-202 (NCT04225117). Methods: In this open-label, multicohort, phase 2 trial, eligible adults had locally advanced or metastatic (la/m) solid tumors, measurable disease, and ECOG PS 0–1. In BC cohorts, patients (pts) had prior taxanes or anthracyclines, ≥1 standard-of-care cytotoxic regimen and ≤2 lines (L) of cytotoxic therapy for la/mBC, and prior PD-1/L1 inhibitor (TNBC) or endocrine treatment (tx) with a CDK4/6 inhibitor (HR+/HER2- BC). Nectin-4 expression was not required but was assessed retrospectively. Pts received EV 1.25 mg/kg intravenously days 1, 8, and 15 of each 28-d cycle until discontinuation criteria (eg, disease progression, unacceptable toxicity) were met. Primary endpoint was confirmed objective response rate (ORR); ≥10 (TNBC) or ≥12 (HR+/HER2- BC) responders out of 40 evaluable pts were needed to claim promising antitumor activity. Secondary endpoints were duration of response (DOR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS), and safety/tolerability. Antitumor activity was investigator-assessed per RECIST v1.1. Results: In the TNBC cohort, 42 female pts received EV as of Mar 3, 2023 (median follow-up, 11.8 mo). Median age was 53 y, 64% had ≥2L systemic tx for metastatic BC, and 33% had prior sacituzumab govitecan. ORR was 19.0%. Grade ≥3 tx-related adverse events (TRAEs) in &gt;1 pt were decreased neutrophil count (n=3, 7%), decreased white blood cell count (n=2, 5%), and increased aspartate aminotransferase (n=2, 5%). Selected TRAEs of special interest were skin reactions (n=25, 60%), peripheral neuropathy (n=11, 26%), and hyperglycemia (n=2, 5%). In the HR+/HER2- BC cohort (median age, 57.0 y), 45 female pts received EV as of Dec 3, 2022 (median follow-up, 11.2 mo). Most (73%) had ≥3L systemic tx for metastatic BC. ORR was 15.6%. Grade ≥3 TRAEs in &gt;1 pt were maculopapular rash (n=7, 16%), pruritus and increased aspartate aminotransferase (both n=3, 7%), and abdominal pain and erythema (both n=2, 4%). Selected TRAEs of special interest were skin reactions (n=28, 62%), peripheral neuropathy (n=12, 27%), and hyperglycemia (n=5, 11%). Additional efficacy data for both cohorts are in the table. Conclusions: EV showed antitumor activity in heavily pretreated TNBC. Safety in both cohorts was manageable and consistent with previous reports. Clinical trial information: NCT04225117 . [Table: see text]

TOPOLOGY: A phase II study to evaluate the efficacy and toxicities of PLX038, in patients with locally advanced or metastatic triple-negative breast cancer.

TPS1142 Background: Sacituzumab govitecan (SG) is an anti-TROP2 antibody-drug conjugate (ADC) with an SN-38 payload (topoisomerase I inhibitor) that was recently approved for use in advanced triple-negative breast cancer (TNBC). The rapid spontaneous linker hydrolysis in sacituzumab-govitecan releases a very large amount of SN-38 cargo systemically, which may in part contribute to efficacy and also in part be responsible for systemic side effects (1). PLX038 is a 40 kDa 4-arm PEG-SN38 conjugate with a half-life of 5 days. It has a controlled, slow-release rate which allows high SN-38 exposure over an extended period of time with a low Cmax, and very low levels of SN-38-glucuronide. The PLX038 nanomolecule also penetrates large pores of tumor vasculature, and accumulates and is retained in the tumor for long periods. The prolonged exposure of tumors to SN-38 may result in increased efficacy without resulting in severe gastrointestinal toxicity. We hypothesize that PLX038 may be effective in patients with advanced TNBC who have been previously treated with standard chemotherapy regimens. Methods: This is an open label, multi-centric phase II study designed to evaluate the safety, tolerability, pharmacokinetics, pharmacodynamics and efficacy of PLX038 in locally advanced or metastatic TNBC previously treated with at least two prior cytotoxic chemotherapy regimens for locally advanced or metastatic breast cancer including an anthracycline, taxane and sacituzumab govitecan. Patients will be treated at a dose of 1730mg/m2 IV infusion on Day 1 of each cycle Q3W (every 21 days, 1 cycle = 1 injection) after at least a first cycle at 1300mg/m2. At the discretion of the treating physician, the PLX038 dose will be increased to 1730 mg/m2 for patients who tolerate at least 1 cycle. All included patients will receive PLX038 as single agent as long as study is ongoing or until progression of disease, unacceptable toxicity, patient withdrawal of consent, Investigator decision, lost to follow-up, death, patient non-compliance, or study termination by Sponsor. The primary endpoint is the best tumor response (defined as partial or complete response in the first 6 months of treatment) assessed by investigators per RECIST v1.1 criteria, with tumor assessments every 8 weeks (± 7 days). Secondary endpoints include i) efficacy criteria (time to response, duration of response, progression-free survival, overall survival), ii) toxicity criteria (AE/SAEs), iii) association between PLX038 efficacy and biomarkers (homologous recombination defect, replication stress-related biomarkers such as SFLN11 expression, RB1 loss), iv) PK/PD analysis. A Simon's two-stage optimum design will be used, and a maximum of N=44 patients will be included, 1. Santi et al., Biodrugs 2024. Clinical trial information: NCT06162351 .

281P Comparison of efficacy & safety of two frontline cytotoxic chemotherapy regimens in newly diagnosed metastatic cancer of biliary tract: A randomized control study

281P Comparison of efficacy & safety of two frontline cytotoxic chemotherapy regimens in newly diagnosed metastatic cancer of biliary tract: A randomized control study

Impact of DNA damage repair alterations on real-world response to therapy in metastatic colorectal cancer.

e15557 Background: Alterations in the DNA damage repair (DDR) pathway genes contribute to tumor development. These alterations can be exploited by cytotoxic chemotherapy regimens that induce DNA damage. Platinum chemotherapy agents have been shown to be particularly effective in breast and ovarian cancer patients with alterations in the DDR pathway. However, the clinical impact of DDR alterations in metastatic colorectal cancer (mCRC) is still poorly understood. In this study, we utilize a large national database to evaluate clinical outcomes in patients with mCRC and alterations in DDR pathway genes. Methods: We reviewed 5602 patients that received standard fluorouracil based first-line chemotherapy regimens for mCRC using the nationwide Flatiron Health EHR-derived de-identified database. Chemotherapy regimens were categorized as a platinum-based doublet (FOLFOX, CAPOX), irinotecan-based doublets (FOLFIRI), or triplet (FOLFOXIRI). Overall survival (OS) was summarized within groups via Kaplan-Meier survival estimates. OS was compared between groups in the context of univariable and multivariable Cox proportional hazards models controlling for age, gender, DDR status, stage at diagnosis, ECOG, RAS/RAF status, MMR status, albumin and CEA at diagnosis. OS was defined as the time in months between date of first line therapy initiation to death. Results: DDR gene alterations were indentified in 35.7% (2001) patients.The most frequent mutations were in ATM (13.3%) and BRCA2 (8.3%). There was no significant difference in OS based on DDR mutation status. Within DDR altered patients, there was no difference in OS between those who received a platinum-based doublet, irinotecan-based doublet or triplet first-line therapy. Time to next treatment or death (TTNTD) was significantly improved with an irinotecan-containing doublet regimen and triplet regimen compared to a platinum-based doublet in a multivariable model (HR 0.79, p = 0.001 and HR 0.68, p = 0.002, respectively). There was no difference in OS in DDR-mutated patients that received an irinotecan-based regimen in the first line followed by an oxaliplatin-based regimen in the second line or the reverse sequence. When evaluating the impact of commonly co-mutated genes on survival we observed a worse OS in patients with a KRAS mutation in addition to a DDR mutation (HR 1.19, p = 0.045). An APC mutation was associated with an improved OS in the entire cohort, regardless of DDR status (HR 0.76, p &lt; 0.001). Conclusions: In this real-world population, approximately one third of patients with mCRC harbored an alteration in a DDR pathway gene. In these patients, TTNTD was greater with irinotecan-containing first line therapies (doublet or triplet). However, OS was similar regardless of which first-line chemotherapy was used.

Extracellular release of damaged mitochondria induced by prehematopoietic stem cell transplant conditioning exacerbates GVHD

AbstractDespite therapeutic advancements, graft-versus-host disease (GVHD) is a major complication of hematopoietic stem cell transplantation (HSCT). In current models of GVHD, tissue injury induced by cytotoxic conditioning regimens, along with translocation of microbes expressing pathogen-associated molecular patterns, result in activation of host antigen-presenting cells (APCs) to stimulate alloreactive donor T lymphocytes. Recent studies have demonstrated that in many pathologic states, tissue injury results in the release of mitochondria from the cytoplasm to the extracellular space. We hypothesized that extracellular mitochondria, which are related to archaebacteria, could also trigger GVHD by stimulation of host APCs. We found that clinically relevant doses of radiation or busulfan induced extracellular release of mitochondria by various cell types, including cultured intestinal epithelial cells. Conditioning-mediated mitochondrial release was associated with mitochondrial damage and impaired quality control but did not affect the viability of the cells. Extracellular mitochondria directly stimulated host APCs to express higher levels of major histocompatibility complex II (MHC-II), costimulatory CD86, and proinflammatory cytokines, resulting in increased donor T-cell activation, and proliferation in mixed lymphocyte reactions. Analyses of plasma from both experimental mice and a cohort of children undergoing HSCT demonstrated that conditioning induced extracellular mitochondrial release in vivo. In mice undergoing MHC-mismatched HSCT, administration of purified syngeneic extracellular mitochondria increased host APC activation and exacerbated GVHD. Our data suggest that pre-HSCT conditioning results in extracellular release of damaged mitochondria, which increase alloreactivity and exacerbate GVHD. Therefore, decreasing the extracellular release of damaged mitochondria after conditioning could serve as a novel strategy for GVHD prevention.

Abstract PO5-16-07: Unveiling the Landscape of PD-L1 Expression and Tumor-Infiltrating Lymphocyte Subtypes in Advanced Triple-Negative Breast Cancer

Abstract Background: Triple-negative breast cancer (TNBC) is known for its aggressive behavior with poor survival outcomes. Influenced by different expression levels of Programmed Death-Ligand 1 (PD-L1) and several subtypes of tumor-infiltrating lymphocytes (TILs), tumor microenvironment (TME) plays a crucial role in TNBC response to treatment and progression. Objective: To assess the prevalence and prognostic role of PD-L1 expression in advanced TNBC, defined as unresectable stage III or stage IV disease, in patients treated with a standard cytotoxic chemotherapy regimen. TILs composition was also evaluated as an exploratory objective. Methods: The internal database of the Brazilian National Cancer Institute was queried out for women diagnosed and treated with advanced TNBC from January 2018 to December 2022. Formalin-fixed paraffin-embedded samples of a maximum of four years old were analyzed. PD-L1 expression using 22C3 pharmDX assay was estimated through combined positive score (CPS) dichotomization (CPS &amp;lt; 10 vs. CPS≥10). Tissue microarrays comprising the samples of biopsies were subjected to immunohistochemistry, targeting specific markers including CD3, CD4, CD8, CD56, CD68, CD117, FOXP3, PD-1, the immune cell profiles were carefully examined and their correlation with the PD-L1 CPS was determined. Results: A total of 150 patients were included. The expression of PD-L1 was undetermined in 2 cases. The median age was 51.5 years (IQR 41.8-60.2) and 20.9% of the cases had CPS≥10. Most patients were &amp;lt; 65 years (73.0%), were postmenopausal (56.8%) and belonged to non-white ethnicity (70.3%). Postmenopausal women predominated in the CPS≥10 subgroup (74.2%) (Table 1). No significant differences in demographic characteristics and clinicopathological variables were observed based on PD-L1 subgroups, 117 patients (79.1%) had CPS &amp;lt; 10, with 91 (77.8%) being de novo stage IV metastatic disease. CD3+ (p=0.037), CD4+ (p=0.005) and CD8+ (p=0.001) TILs had higher expression in tumors with PD-L1 CPS≥10 (Table 2). According to the treatment received, almost half of the patients only received first-line chemotherapy (47%), as the following second line was applied to 28.8% of the total group. The third and fourth lines were administered in 12.9% and 9.1% of patients, respectively. Only 2 patients went through five palliative chemotherapy lines, and only one received up to 6 treatment lines. Between the subgroups CPS≥10 versus CPS &amp;lt; 10 no statistically significant differences were observed in the median progression-free survival (PFS) (5.1 vs. 5.0 months, p=0.89) and overall survival (OS) (8.7 vs. 8.8 months, p=0.6). Conclusion: This study offers insights into the expression patterns of PD-L1 and TILs subtypes in advanced TNBC cases in Brazil. PD-L1 CPS did not influence survival outcomes for this cohort of patients treated with cytotoxic chemotherapy only. The composition of TILs subtypes within the TME appears to vary based on PD-L1 CPS. Table 1. Advanced TNBC population characteristic by CPS (Nf148). Table 2. Tumor Infiltrating Lymphocytes characterization (CD3, CD4, CD8, CD56, CD68, CD 117, FOXP3 and PD-1) and its correlation with CPS status. Citation Format: Alexssandra Lima Siqueira dos Santos, Jesse Lopes da Silva, Lucas Zanetti de Albuquerque, Antônio Lucas Araújo Neto, Cecília Ferreira da Silva, Luana Aguiar Mesquita Cerva, Isabele Ávila Small, Cicera Pimenta Marcelino, Paula de Mendonça Batista, Maria Aparecida do Carmo Rego, Maria Amélia Carlos Souto Maior Borba, Andreia Cristina de Melo. Unveiling the Landscape of PD-L1 Expression and Tumor-Infiltrating Lymphocyte Subtypes in Advanced Triple-Negative Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-16-07.

Abstract PO3-19-07: AC699-001, a first in human Phase 1 trial utilizing a novel estrogen receptor chimeric degrader in patients with advanced or metastatic breast cancer

Abstract Background Estrogen receptors (ER) are hormone-regulated transcription factors that play a critical role in breast cancer initiation and proliferation. Modulation of estrogen activity with therapeutics such as tamoxifen and aromatase inhibitors have been the mainstay therapeutic strategy for ER-positive breast cancer. Several ER-directed therapies have been developed to antagonize the oncogenic ER function, including Selective ER Degraders (SERDs) such as fulvestrant which is approved to treat patients with advanced or metastatic breast cancer. However, it requires intramuscular injection and has poor solubility, thereby limiting its administered dose and therefore its efficacy. In addition to SERDs, a newly emerging technology, E3 ligase-engaged chimeric degraders, has been used to induce potent and deeper ER degradation. Empowered by Accutar's proprietary Protein-Protein Interaction Targeting Chimeras (PPI-TAC) platform, AC699 was meticulously designed as a chimeric degrader to target and degrade the protein of interest, ERα. By effectively linking an ER ligand to an E3-ligase recruiting ligand, AC699 brings ERα in proximity to an E3 ligase, thereby inducing subsequent ubiquitination and degradation of ERα. Notably, chimeric ER degraders possess the unique advantage of degrading the ER protein without the inherent risk of activating an ER signal. Moreover, these molecules are not degraded alongside the target protein allowing for their efficient recycling within the cell. This direct mechanism enables chimeric ER degraders to achieve potent ER degradation with increased specificity, thereby potentially providing a higher therapeutic index compared to SERDs. This abstract describes a first-in-human Phase 1 trial of AC699, a novel ER degrader. Study Description The AC699-001 Phase 1 dose escalation study will enroll up to 60 patients with locally advanced or metastatic ER-positive, human epidermal growth factor receptor 2-negative, breast cancer. Patients must have progressed on standard treatment including at least two prior endocrine regimens or at least one prior line of therapy if combined with a CDK4/6 inhibitor. Prior chemotherapy is not required but must not exceed three prior cytotoxic regimens. Patients must have at least one measurable lesion or at least one predominantly lytic bone lesion. AC699 is given orally, once daily, with doses ranging from 100 mg to 600 mg in a standard 3+3 dose escalation design. The primary objective is to evaluate the safety and tolerability of AC699 using CTCAE 5.0. Secondary objectives include assessing preliminary anti-tumor activity according to RECIST 1.1 and characterizing the pharmacokinetic profile of single and multiple doses of AC699. Enrollment began in December 2022 with five sites in the United States planned. NCT05654532. Citation Format: Manish R Patel, Rachel Layman, Joy Nolte Fong, Hui Zhang, Su Kim, Erika Hamilton. AC699-001, a first in human Phase 1 trial utilizing a novel estrogen receptor chimeric degrader in patients with advanced or metastatic breast cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO3-19-07.

Abstract 4033: Leukocyte-based biomimetic nanoparticles for combined targeted and immunotherapy in osteosarcoma

Abstract Osteosarcoma is the most diffuse bone cancer in the pediatric population, with most patients showing resistance to therapy. All patients are administered systemic high-dose cytotoxic chemotherapy regimens. Many targeted and immune therapy approaches are currently in clinical trials for treating osteosarcoma, but single treatments are not showing promise. While combined targeted and immunotherapy appears to be a possible avenue, developing solutions for patients who show intolerable toxicity or lack of synergy is critical. Nanoparticles (NPs) have successfully been used to prolong the half-life of drugs, favor extended release, reduce systemic toxicity, and reach beyond biological barriers. Biomimetic NPs represent an emerging class of NPs as a system to mimic naturally occurring processes. One class of biomimetic NPs is leukosomes, leukocyte-based biomimetic NPs that target inflamed tissues. Leukosomes are synthesized by integrating proteins isolated from the membranes of circulating leukocytes in the NPs' wall. Leukosomes' biomolecular profile helps them adhere to tumor-inflamed vasculature and promotes their self-tolerance and ability to evade immune clearance from the mononuclear phagocyte system (MPS). We have demonstrated the feasibility of a "one-two punch" approach for leukosome-mediated bone cancer treatment. Specifically, the first "punch" (a multi tyrosine kinase inhibitor, mTKI) induces an immunogenic response, which is subsequently targeted by leukosomes delivering a second class of compounds (immunomodulating nucleic acids, second "punch"). Indeed, even a single mTKI administration increases the amount of leukosomes localized to tumors, which is amplified by a second dosage in a dose-dependent manner. Importantly, leukosome infiltration was paralleled by an increase in immune infiltration, especially in Cd8+ T-cell abundance and macrophages. After several iterations and protocol adjustments, leukosome compositions and microfluidic parameters have been optimized to load either siRNA or mRNA. Current experiments are optimizing the "second punch" targeting immune checkpoint inhibitors (siRNAs vs. PD1/PDL-1). Interestingly, we showed the leukosomes produced using the membranes of human or mouse macrophages pre-treated with LPS show increased surface concentration of adhesion molecules (e.g., Siglec-1) that further enhance their localization at the inflamed site while decreasing filtration by the MPS. In addition to increased delivery to the tumor site, this strategy reduces the therapeutic strain because it is sequential ("one-two punch") and uses nucleic acids instead of antibodies to target immune checkpoints. Overall, our work describes a novel rationale-based sequential approach that can be paradigm-shifting in the field as it harnesses treatment-induced inflammation to boost intratumoral drug delivery. Citation Format: Gabriele Romano, Binh Ha, Jason T. Yustein, Francesca Taraballi. Leukocyte-based biomimetic nanoparticles for combined targeted and immunotherapy in osteosarcoma [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 4033.

Dual-targeted regimens for the frontline treatment of CLL.

The treatment landscape of chronic lymphocytic leukemia (CLL) has evolved considerably over the past decade due to the development of effective novel agents with varying mechanisms of action, including Bruton tyrosine kinase (BTK) and B-cell lymphoma 2 (BCL2) inhibitors. Extrapolating upon the success of anti-CD20-directed chemoimmunotherapy, a dual-targeted approach has been explored in treatment-naive patients with CLL. Anti-CD20 monoclonal antibody combinations with BTK inhibitors as well as BCL2 inhibitors have demonstrated superiority over traditional cytotoxic chemoimmunotherapy regimens such as fludarabine, cyclophosphamide, and rituximab; bendamustine-rituximab; and obinutuzumab-chlorambucil. Impressive clinical benefit is seen in both younger and older patients, those with comorbidities, and, most importantly, those with poor prognostic features. Given this success, combinations of BTK inhibitors and venetoclax have been explored in clinical trials. These dual-targeted regimens provide remarkable efficacy while allowing for an all-oral approach and fixed duration of treatment. Current investigations under way are evaluating the utility of a triplet approach with the addition of obinutuzumab in comparison to a doublet approach.

Abordare multidisciplinară în oncologia pediatrică

Children’s cancer is par excellence a disease of a multidisciplinary nature. It is therefore unrealistic to expect a single person with a single qualification to have the skills and capabilities to carry out a comprehensive assessment and institute competent interventions in all these areas. Decisions and interventions will be in accordance with the decision of the multidisciplinary committee of therapeutic indications.According to the WHO, every year approximately 400,000 children and adolescents between the ages of 0 and 19 develop cancer. The most common childhood cancers include leukemias, brain cancers, lymphomas, and solid tumors such as neuroblastoma and Wilms tumors [1, 2, 3]. In 2019 globally there were 291.3 thousand new cases and 98.8 thousand deaths from childhood cancer worldwide, with a prevalence of 1.8 million [4]. However, the 5-year survival of childhood cancer patients has increased impressively to more than 80% in recent decades, mainly attributed to improved diagnostic technologies and multiagent cytotoxic regimens.

Longitudinal Noninvasive Surveillance & Fragmentomic Characterization of Follicular Lymphoma

Introduction While cell-free DNA (cfDNA) plays an increasingly defined role in aggressive lymphomas, its characteristics in indolent lymphomas are less established. Many follicular lymphoma (FL) patients experience durable remissions and late relapses ( Fig A). We therefore explored circulating tumor DNA (ctDNA) kinetics during long-term blood-based surveillance in patients with FL. In addition to noninvasive detection using somatic mutations, we also evaluated gene expression inference from cfDNA utilizing a novel fragmentomic method to detect histological transformation (tFL). Methods We studied 121 serial samples in a cohort of 17 FL patients (median 7 per patient) with long term clinical and blood-based MRD monitoring (median 5.6 years, max 10.8). We considered serial ctDNA status at 4 milestones: baseline/pre-treatment, post-treatment, in radiographic remission (MRD), and at relapse. We also profiled pre-treatment cfDNA for 9 tFL cases. Cases were genotyped to identify somatic mutations from diagnostic tumor or baseline plasma, with matched PBMCs used to censor germline variants and clonal hematopoiesis. ctDNA status in subsequent samples was evaluated via CAPP-Seq (SNVs) and PhasED-Seq (PVs). The cfDNA fragmentation profiles of pre-treatment FL and control samples were evaluated for inferred gene expression via EPIC-seq (Esfahani Nat Biotech 2022) using a novel 1676-gene panel focused on lymphoid neoplasms, including classic and transformed FL. Results Treatment &amp; Relapse Kinetics Most patients had advanced disease (88% stage III-IV) and Low to Intermediate risk FLIPI (71% 0-2). At first cfDNA evaluation, 9/17 (53%) were previously untreated. Median pre-treatment ctDNA levels were 73.4 hGE/mL in FL, as compared to 236 hGE/mL in DLBCL (Kurtz JCO 2018). Post-treatment, median ctDNA levels dropped to 1.2 hGE/mL. Depth of response was similar between rituximab monotherapy and cytotoxic regimens, with median -2.2 log10 fold change from baseline. MRD Detection PVs were observed in all tumors, consistent with expected aberrant somatic hypermutation in FL. To evaluate MRD detection via PhasED-Seq, we considered plasma timepoints with undetectable ctDNA by CAPP-Seq (n=26) from patients (n=9) with subsequent clinical relapse. MRD was detected in 11 additional specimens (42%) by PhasED-Seq. Among FL patients tested for MRD while in radiographic remission, low-level ctDNA was detectable in 62% of plasma specimens (8/13) obtained within 1 month of negative PET/CT, suggesting potential additional utility for surveillance. Long-term Genomic Stability Sequential biopsies of FL tumors have shown genomic heterogeneity between diagnosis and relapse. We therefore evaluated ctDNA concordance across variant classes &amp; regions. Relative AF was calculated pre-treatment and at relapse (median 2 years between samples, range 1-8 years), normalized by total ctDNA levels. The most stable lesions included missense mutations in CREBBP and TP53, nonsense KMT2D mutations, and BCL2 5'-UTR variants. BCL6 intronic mutations and chr2/chr14 SHM varied between diagnosis/relapse. Plasma versus Cellular Concentrations In contrast to DLBCL, circulating FL cells are frequently detectable at low levels in blood. To compare relative FL concentrations in the cellular versus plasma compartments, we profiled 10 paired specimens from patients with radiographic disease. While tumor-confirmed variants were detected in 7 of 10 cellular specimens, mean allelic frequency (AF) was 5.3x higher in plasma. Fragmentomic Assessment of Transformation We compared gene expression profiles inferred from cfDNA from pre-treatment lymphoma (FL=15, tFL=9) versus control (n=20) samples ( Fig B). Considering genes associated with FL (Huet Lancet Onc 2018), FL patients had significantly higher inferred expression than healthy adults (p=0.036). Likewise, patients with tFL showed higher inferred expression of genes associated with histologic transformation (Gentles Blood 2009, p=0.025). Conclusions Sensitive methods are required for effective MRD assessment in FL given lower ctDNA shedding as compared with DLBCL. Frequent detectable MRD in radiographic remission suggests that integrating molecular surveillance may augment serial imaging in the long-term management of FL. Simultaneous inferred gene expression from FL cfDNA appears to hold promise, including for noninvasive detection of transformation.

Naked Antibody-Based Conditioning Targeting CD47 and CD117 Plus Janus Kinase Inhibition Enables Toxin-Free, Radiation-Free, and Chemotherapy-Free Fully Mismatched Allogeneic Hematopoietic Stem Cell Transplantation

INTRODUCTION: Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is a potentially curative therapy for numerous malignant and non-malignant hematologic diseases. To enable engraftment of donor hematopoietic stem cells (HSCs), recipients undergo conditioning with chemotherapy and irradiation to make marrow space for incoming donor HSCs and suppress host immune responses that may lead to graft rejection. These cytotoxic conditioning regimens carry risks of severe toxicities which prevents many patients from accessing the lifesaving benefit of allo-HSCT. Previously, we developed fully ablative CD45- and cKit-targeted antibody-drug conjugates (ADC) which, when combined with Janus kinase 1/2 (JAK1/2) inhibitors, enabled fully mismatched allo-HSCT with full donor chimerism and minimal toxicity while providing durable antileukemia activity (Persaud et al (2022), ASH Abstract). However, even ADCs carry potential risks of acute and chronic toxicities that may preclude their common use as HSCT conditioning agents. Moreover, unlike malignant diseases, allo-HSCT for non-malignant diseases does not require the conditioning regimen to provide antitumor benefit and partial donor chimerism may be sufficient for cure, strongly favoring the use of less intense conditioning strategies with the fewest possible toxicities. We hypothesized that naked antibody-based conditioning strategies can achieve the therapeutic benefits of allo-HSCT for non-malignant hematologic diseases, obviating exposure to toxic ADC payloads. METHODS: We combined unconjugated antibodies targeting CD47 and cKit with JAK1/2 inhibition to perform minor histocompatibility antigen (miHA)-mismatched (129/Sv→B6-Ly5.1) and fully mismatched (BALB/c→B6) murine allo-HSCT. In some full mismatch HSCT experiments, recipients included B6-gp91phox -/- mice, which serve as a model of chronic granulomatous disease (CGD) due to their deficiency in a catalytic subunit of NADPH oxidase. Mice received 100 µg anti-CD47 (clone mIAP410; BioXcell) 8 days before HSCT (d-8) as a priming dose to reduce the severity of CD47 blockade-induced anemia. Next, mice received 500 µg anti-cKit (clone ACK2; BioLegend) on d-6 and daily 500 µg doses of anti-CD47 from d-6 through d-2. For JAK1/2 inhibition, mice received oral ruxolitinib (Incyte; 2 mg drug/g chow) starting d-3 or d-1 and continuing until d+28. On d0, recipients were transplanted with 20 x 10 6 whole bone marrow cells from 129/Sv (miHA) or BALB/c (fully mismatched) mice. Peripheral blood donor chimerism was followed monthly by flow cytometry for CD45.2 + (miHA) or H-2D d+ (fully mismatched) cells. Oxidative burst among granulocytes in B6-gp91phox -/- recipients was assessed by dihydrorhodamine 123 (DHR123) staining after phorbol 12-myristate 13-acetate (PMA) stimulation. RESULTS: CD47 and cKit antibodies plus ruxolitinib enabled multilineage engraftment in both miHA and fully mismatched allo-HSCT, including myeloid lineage donor chimerism of 95-99% (Figure 1A). As expected, CD47 blockade induced significant but transient morbidity from anemia during the peritransplant period; notably, a shorter duration of ruxolitinib treatment before HSCT (starting d-1 instead of d-3) improved the tolerability of the regimen without impacting engraftment success. Allo-HSCT of B6-gp91phox -/- mice led to near complete replacement of host granulocytes in peripheral blood with donor granulocytes, whose DHR123 positivity upon PMA stimulation indicated an intact oxidative burst capacity (Figure 1B). CONCLUSIONS: Combination of antibodies targeting CD47 and cKit with JAK1/2 inhibition provides a novel conditioning strategy for allo-HSCT in mouse models, achieving high-level, stable multilineage engraftment without radiation, chemotherapy, or exposure to toxic ADC payloads. The near complete donor chimerism among granulocytes made it particularly well suited to correcting phagocyte oxidase function in the gp91phox -/- model of CGD. Future studies seek to 1) mitigate the peritransplant anemia caused by CD47 blockade using Fc-silenced anti-CD47 reagents, 2) determine the proportions of donor- versus recipient-derived myeloid cells in non-hematopoietic tissues of allo-HSCT recipients, and 3) use murine infection models to evaluate the impact of allo-HSCT on host defense in transplanted B6-gp91phox -/- recipients.

Role of Nutrition Support in Improving Outcomes in Allogeneic Stem Cell Transplant Patients

Introduction: Allogeneic hematopoietic stem cell transplant (Allo-SCT) can be associated with several complications related to the cytotoxic conditioning regimen, infections associated with immune suppression, and GVHD. Malnutrition amongst Allo-SCT patients has been reported to be an independent negative prognostic factor. It may be evident on presentation or develop as a sequela of decreased appetite, mucositis, and digestive GVHD. Whether supportive nutrition (enteral feeding or total parenteral nutrition (TPN)) contributes to favorable transplant outcomes is yet to be determined. Methods: We conducted a retrospective single-center study that evaluated patients who underwent Allo-SCT from Jan 2018 through Sept 2021. A chart review was conducted, and relevant data was collected. Primary outcomes were the impact of nutrition support (enteral feeding, TPN or both) among malnourished patients during the first 100 days post-transplant (T+100) on mortality and the composite outcome of acute GVHD incidence, infection rate, and days to engraftment. A higher composite score indicated worse outcomes. GVHD grading was based on the CIBMTR grading system (I-IV). The data was analyzed using Chi-Square and two-sample t-test. Results: A total of 70 Allo-SCT patients were identified. Of them, 42 (60%) were diagnosed with malnutrition, of which 23 (55%) received nutrition support. The mortality rate in patients who required nutrition support was significantly higher compared to those who did not receive nutrition support (83% (19/23) vs 11% (2/19)) with an odds ratio of 40 for this association (CI 6.5-248.9, p-value &amp;lt; 0.0001). The composite outcome was statistically higher amongst patients requiring nutrition support (mean 2.0, median score 1.8, SD 0.6) compared to those who did not need nutritional support (mean 1.6, median score 1.5, SD 0.4). These differences were found to be statistically significant using the Satterthwaite method (p-value 0.0218). Conclusion: Based on this data, we found that a reactive approach of nutrition support in the setting of malnutrition had no benefit on mortality and our pre-defined composite outcome during the first 100 days of allogeneic stem cell transplantation. This is fuel for conducting a prospective study using a preemptive enteral feeding approach to prevent the development of malnutrition and related complications.

Understanding the Role of Bispecific Antibodies in the Management of B-Cell Non-Hodgkin Lymphoma: A New Immunotherapy That Is Here to Stay

Non-Hodgkin lymphomas (NHLs) represent a diverse group of hematologic malignancies derived from various cells. B-cell NHLs represent the largest fraction of lymphomas diagnosed and treated in the United States. Standard chemo-immunotherapies with rituximab and multiagent cytotoxic regimens have proven to be effective in the management of these lymphoproliferative neoplasms; nonetheless, a considerable fraction of patients still experience relapse or have treatment-refractory disease. Therapeutic advances using novel immunotherapeutic agents as well as cell-based treatments, such as chimeric antigen receptor (CAR) T-cell therapies, have improved the outcomes of relapsed/refractory (R/R) B-cell NHL. Most of these new treatment strategies are not curative and most patients succumb to R/R disease, leaving this population with an unmet need for effective and well-tolerated therapeutic options. One of these up-and-coming options are bispecific antibodies (BsAb), either as single agent or in combination with other medications. Conclusion: BsAbs offer a novel “off the shelf” chemotherapy-free approach in the management of R/R B-cell NHL. Advancements in antibody construct design along with improved safety profile and clinical effectiveness of the most recent BsAbs suggest that these agents are a promising new option in the management of R/R B-cell NHL.

Managing Metastatic Extrapulmonary Neuroendocrine Carcinoma After First-Line Treatment.

Extrapulmonary neuroendocrine carcinoma (EP-NEC) is a rare, aggressive malignancy that can arise from any organ and frequently presents with distant metastases. Advanced disease has a poor prognosis with median overall survival (OS) rarely exceeding 1 year even with systemic therapy. The management paradigm of advanced/metastatic EP-NEC has been extrapolated from small cell lung cancer (SCLC) and commonly consists of 1st line therapy with etoposide and platinum (cisplatin or carboplatin), followed by alternative cytotoxic regimens at the time of progression. Only a minority of patients are able to receive 2nd line therapy, and cytotoxics derived from the SCLC paradigm such as topotecan or lurbinectedin have very limited activity. We aimed to evaluate emerging therapeutic options in the 2nd and later lines and survey potential future developments in this space. After a long period of stagnation in treatment options and outcomes, more promising regimens are gradually being utilized in the 2nd line setting including systemic therapy combinations such as FOLFIRI, FOLFOX, modified FOLFIRINOX, CAPTEM, and, more recently, novel checkpoint inhibitors such as nivolumab and ipilimumab. Simultaneously, advances in the understanding of disease biology are helping to refine patient selection and identify commonalities between NEC and their sites of origin which may eventually lead to additional targeted therapy options. While many questions remain, contemporary developments give grounds for optimism that improved outcomes for EP-NEC will soon be within reach.

Abstract IA028: Renal medullary carcinoma: Discovery and validation of tailored treatment strategies

Abstract Renal medullary carcinoma (RMC) is a rare but highly aggressive malignancy that predominantly afflicts young individuals of African descent harboring the sickle cell trait and is defined by loss of the SMARCB1 tumor suppressor. Notably, the anti-VEGF and mTOR targeted therapies and standard immune checkpoint inhibitor strategies developed for clear cell renal cell carcinoma (ccRCC) are completely ineffective against RMC. Conversely, platinum-based cytotoxic chemotherapy regimens are the preferred first-line therapy yielding a response rate of 29% and median survival of 13 months from diagnosis. There is clearly a need for tailored treatment strategies for this deadly disease. To meet this challenge, we have developed a dedicated research and clinical team and bench-to-bedside pipeline that supported the comprehensive profiling of patient samples and the development of multiple RMC cell lines, three patient-derived xenografts, and the first genetically engineered mouse model of RMC. These tools informed the development of the first three clinical trials dedicated to RMC (NCT03587662, NCT03274258, and NCT05347212 at clinicaltrials.gov), as well as the establishment of effective second-line, and more recently third-line, therapeutic strategies that produce objective responses and occasionally cures for this deadly disease. Using these approaches, the majority of patients diagnosed with RMC today will survive beyond a year from diagnosis. The progress made has been supported by a passionate patient advocacy group and the awareness raised has resulted in our current clinical volume of caring for 3-5 patients with RMC per week. Emerging insights into the pathophysiology of RMC have allowed us to uncover an "exercise paradox" whereby the hypoxia induced by high-intensity exercise in the setting of sickle cell trait may be the strongest modifiable risk factor for RMC. The unique biological processes behind the exercise paradox also underlie the distinct biological adaptation of RMC to true hypoxia via the loss of SMARCB1, as opposed to the pseudohypoxia observed in ccRCC driven by VHL loss. Whereas pseudohypoxic tumors are sensitive to VEGF targeting, SMARCB1 loss confers resistance to the hypoxia induced by in vivo inhibition of angiogenesis. These insights have allowed us to identify immediately actionable therapeutic targets paving the way for the next generation of clinical trials for RMC. The benchmark goal is to improve the median survival of patients with RMC to 24 months by 2025 and to 5 years by 2030. Citation Format: Pavlos Msaouel. Renal medullary carcinoma: Discovery and validation of tailored treatment strategies [abstract]. In: Proceedings of the AACR Special Conference: Advances in Kidney Cancer Research; 2023 Jun 24-27; Austin, Texas. Philadelphia (PA): AACR; Cancer Res 2023;83(16 Suppl):Abstract nr IA028.

Real-world treatment trends and outcomes in elderly patients with metastatic colorectal cancer in the United States.

3591 Background: Prospective data to guide management of elderly patients with metastatic colorectal cancer (mCRC) is limited. Whether elderly patients derive the same degree of benefit from doublet chemotherapy as younger patients is not well understood. In this study we utilized real-world data from patients in the United States (US) to evaluate treatment trends and compare overall survival (OS) in younger versus older patients with mCRC who receive first-line (1L) chemotherapy. Methods: The nationwide Flatiron Health electronic health record-derived de-identified database was used to select patients ≥50 years old (yo) with mCRC treated with 1L fluoropyrimidine-based chemotherapy with or without the addition of targeted therapy. Overall survival from the initiation of 1L therapy, stratified by receipt of a doublet or single agent cytotoxic chemotherapy regimen was assessed independently within three age cohorts (50-69; 70-74, ≥75) using both a cox proportional hazard model and a propensity score weighted analysis to control for potential confounding variables. A subgroup analysis was performed in patients receiving bevacizumab as part of 1L therapy. Results: Of 14,440 patients who received 1L chemotherapy, 5,874 (40.7%) were ≥70 yo, including 3,656 (25.4%) who were 75 or older. Doublet chemotherapy was received by 7,505 (87.6%) patients age 50-64 yo, 1892 (85.3%) patients age 70-74 yo, and 2297 (62.2%) patients age 75 and above. In all three groups, multivariate analysis of single agent chemotherapy vs doublet chemotherapy showed a benefit to doublet chemotherapy with a hazard ratio of 1.14, (95% CI 1.04-1.24, p = 0.006), 1.22 (95% CI 1.05-1.42, p = 0.011) and 1.19 (95% CI 1.10-1.29, p &lt; 0.001), respectively. Similar results were noted when comparing doublet to single agent chemotherapy in the age 70-74 and ≥75 groups using a propensity score weighted analysis. In the subgroup of patients age ≥70 who received 1L bevacizumab, 2,604 received doublet chemotherapy and 441 received single agent chemotherapy. Median OS was 19 mos (95% CI: 18-20) vs 13 (95% CI: 11-15) vs with a propensity score weighted HR of 1.35 (95% CI 1.12-1.63, p = 0.001). Conclusions: A smaller percentage of patients over age 75 receive 1L doublet chemotherapy for mCRC in the US compared to patients age 50-69 or 70-74. Regardless of age, patients who receive doublet fluoropyrimidine-based chemotherapy appear to have improved overall survival compared to single agent chemotherapy. This retrospective US data is in contrast with recently presented data from a prospective phase III trial in Japan (JCOG1018). Elderly patients in the US should not be excluded from receiving doublet chemotherapy for mCRC without further prospective data.

Modified FOLFOXIRI plus cetuximab and avelumab as initial therapy in RAS wild-type unresectable metastatic colorectal cancer: Results of the phase II AVETRIC trial by GONO.

3575 Background: The modified schedule of FOLFOXIRI (mFOLFOXIRI) in combination with an anti-EGFR agent showed a manageable safety profile and remarkable activity in RAS wild-type (wt) metastatic colorectal cancer (mCRC). The association of an active cytotoxic regimen with cetuximab (cet) may increase the exposure of tumour-associated neoantigens and induce immunogenic cell death and antibody-dependent cell-mediated cytotoxicity thus enabling the effect of immune checkpoint inhibitors. The AVETRIC study aimed at exploring the efficacy and safety of first-line mFOLFOXIRI plus cet and avelumab (ave) in RAS wt mCRC patients (pts). Methods: AVETRIC is a prospective, open label, multicenter, phase II, single arm trial in which initially unresectable and previously untreated RAS wt mCRC pts received mFOLFOXIRI (irinotecan 150 mg/sqm, oxaliplatin 85 mg/sqm, folinate 200 mg/sqm leucovorin [LV], and 5-fluorouracil [5FU] 2400 mg/sqm) plus cet (500 mg/sqm) and ave (800 mg) every 2 weeks up to 12 cycles followed by maintenance with 5FU/LV plus cet and ave until disease progression. A safety run-in phase including the first 6 enrolled pts was planned. Due to the occurrence of grade 3-4 diarrhoea in 2 (33%) pts, the protocol study was amended to reduce the irinotecan dose to 130 mg/sqm. Primary endpoint was Progression Free Survival (PFS). Fifty-eight pts were needed to detect an increase in median PFS (mPFS) from 10.0 to 19.4 months (mos), setting one-sided α and β errors at 0.05 and 0.10, respectively. The trial is registered at Clinicaltrial.gov, NCT04513951. Results: Between Jun 2020 and Dec 2021, 62 pts were enrolled in 16 Italian centres. Main pts' characteristics were: median age 56 yrs, ECOG PS 0 87%, synchronous metastases 94%, liver-only disease 42%, left-sided primary tumour 89%; all pts had BRAF wt and proficient MMR (pMMR) tumours. The primary endpoint was met. At a median follow-up of 16.0 months, 39 (63%) events were recorded and mPFS was 14.1 months (90% CI 12.0-16.7, Brookmeyer-Crowley test p &lt; 0.001). Response rate and disease control rate were 82% and 98%, respectively, and R0 resection rate was 21% (27% in liver-only subgroup). Early tumour shrinkage was achieved in 74% pts and median deepness of response was 56%. In pts treated after study amendment (n = 56), main grade 3-4 adverse events were neutropenia (27%), diarrhoea (27%), skin rash (14%), asthenia (14%), nausea (11%), stomatitis (7%), febrile neutropenia (2%). Grade 3-4 immune-related adverse events occurred in 6% of pts. Overall survival results are still immature. Conclusions: AVETRIC study met its primary endpoint, showing that combining mFOLFOXIRI plus cet and ave achieves promising results in terms of PFS as well as response rate, in pts with pMMR RAS and BRAF wt mCRC. Translational analyses to evaluate the impact of immune-related biomarkers are ongoing. Clinical trial information: NCT04513951 .