Citations

Background The Woven EndoBridge (WEB) device is a prevalent treatment for intracranial aneurysms. While many studies have assessed the obliteration rate post-WEB embolization, few have focused on long-term outcomes in partially thrombosed aneurysms. Objective To assess whether partially thrombosed aneurysms are at higher risk of recurrence or retreatment following WEB embolization compared with non-thrombosed aneurysms. Methods We evaluated data from 22 academic institutions, focusing on previously untreated cerebral aneurysms treated with the WEB device. Logistic regression was utilized to analyze factors predicting long-term aneurysm obliteration and retreatment necessity. Results Among 1303 patients, 26 presented with a partially thrombosed aneurysm. In the partially thrombosed group, the mean aneurysm maximal diameter was 10.7±4 mm with a neck ratio of 1.99±1.19 mm, larger than in the control group where the mean aneurysm maximal diameter was 6.81±2.37 mm with a neck ratio of 1.64±0.51 mm (P<0.001 for both maximal diameter and neck ratio). At the final follow-up, partially thrombosed aneurysms treated by the WEB device had a 38.5% retreatment rate, compared with 7.0% for non-thrombosed aneurysms (P<0.001). Among partially thrombosed aneurysms, the Raymond-Roy type IIIa/b occlusion rate was higher (38.5% vs 9.9%, P<0.001). On multivariate analysis, partially thrombosed aneurysms compared with non-thrombosed aneurysms had an increased rate of retreatment (OR 3.64, 95% CI 1.28 to 10.1). Conclusion Partially thrombosed aneurysms are associated with a poorer occlusion rate and a higher rate of retreatment following WEB embolization. For partially thrombosed aneurysms, the WEB device appears suboptimal as a first-line treatment, and therefore alternative techniques should be prioritized.

Abstract Clonal hematopoiesis (CH) of indeterminate potential (CHIP), driven by somatic mutations in leukemia-associated genes, confers increased risk of hematologic malignancies, cardiovascular disease, and all-cause mortality. In blood of healthy individuals, small CH clones can expand over time to reach 2% variant allele frequency (VAF), the current threshold for CHIP. Nevertheless, reliable detection of low-VAF CHIP mutations is challenging, often relying on deep targeted sequencing. Here, we present UNISOM, a streamlined workflow for enhancing CHIP detection from whole-genome and whole-exome sequencing data that are underpowered, especially for low VAFs. UNISOM utilizes a meta-caller for variant detection, in couple with machine learning models which classify variants into CHIP, germline, and artifact. In whole-exome sequencing data, UNISOM recovered nearly 80% of the CHIP mutations identified via deep targeted sequencing in the same cohort. Applied to whole-genome sequencing data from Mayo Clinic Biobank, it recapitulated the patterns previously established in much larger cohorts, including the most frequently mutated CHIP genes and predominant mutation types and signatures, as well as strong associations of CHIP with age and smoking status. Notably, 30% of the identified CHIP mutations had &lt; 5% VAFs, demonstrating its high sensitivity toward small mutant clones. This workflow is applicable to CHIP screening in population genomic studies. The UNISOM pipeline is freely available at https://github.com/shulanmayo/UNISOM and https://ngdc.cncb.ac.cn/biocode/tool/7816.

Abstract Glioblastoma (GBM) is a deadly brain cancer with near-universal recurrence despite maximal treatment for which new innovations are sorely needed. Immunotherapy has yet to make significant gains in GBM treatment despite revolutionizing other cancer therapies, due in part to GBM-mediated immune suppression. This immune derangement proceeds through several mechanisms, but increasing evidence points to critical roles for tumor-derived extracellular vesicles (EVs) and immunosuppressive myeloid cells as key factors in this process. In the present study, we demonstrate broad expression of TIGIT across myeloid cell populations in the GBM microenvironment, a finding recapitulated by conditioning healthy monocytes with GBM-derived EVs. Further, knockdown of TIGIT expression reduced the immunosuppressive polarization of monocytes, resulting in improvement in T cell function. This finding proceeded in an NLRP3-dependent manner, with substantial co-localization of TIGIT and NLRP3 expression prior to knockdown. These findings point to a novel role for TIGIT expression in diverse myeloid cells in the GBM microenvironment as a marker of immunosuppressive activity and further indicate a hierarchy of immunomodulatory protein activity in these myeloid cells, with TIGIT knockdown unmasking the pro-inflammatory activity of NLRP3. This study bolsters understanding of the immunosuppressive complexities of myeloid cells in the GBM microenvironment, while lending further support to prevention or attenuation of immunosuppressive myeloid cell activity as a means of restoring immune function in GBM. Graphical abstract (Created in BioRender. Asad, M. (2025) https://BioRender.com/euiljoq Key Points Tumor-mediated immune suppression is a key barrier to the development of effective immunotherapies for GBM. TIGIT is broadly expressed in myeloid cells within the GBM microenvironment and can be induced by GBM-derived extracellular vesicles. Knockdown of TIGIT reduces immunosuppressive polarization of monocytes and enhances T cell activity via NLRP3 signaling, implicating TIGIT expression as a targetable modifier of immunosuppressive activity in GBM-associated myeloid cells. Importance of the Study Glioblastoma (GBM) remains a formidable clinical challenge, with poor prognosis and limited response to current immunotherapies. This study uncovers a novel immunosuppressive axis involving TIGIT expression in myeloid cells, which are key players in the GBM tumor microenvironment. By demonstrating GBM-derived extracellular vesicles induce TIGIT in healthy monocytes and TIGIT knockdown diminishes immunosuppressive polarization in an NLRP3-dependent manner, this study highlights TIGIT as both a marker and modulator of immune dysfunction in GBM. These findings introduce a functional hierarchy of immunoregulatory proteins in tumor-associated myeloid cells, positioning TIGIT as a potential checkpoint target. Restoring immune activity by disrupting this axis could enhance the efficacy of immunotherapy in GBM. Thus, this research not only advances our understanding of tumor-induced immune suppression but also opens a promising therapeutic avenue to reinvigorate anti-tumor immunity in a cancer type historically resistant to immunotherapeutic approaches.

Abstract Background: Savo is an oral, potent and highly selective MET-TKI. In the Phase 2 SAVANNAH study (NCT03778229), savo + osi had a high rate of durable responses in pts with EGFRm advanced NSCLC and high MET OverExp and/or Amp levels. Early clearance of plasma EGFRm may predict outcomes. We report an exploratory analysis of plasma EGFRm clearance and its association with MET tissue biomarker status, ORR and PFS. Methods: Pts with EGFRm advanced NSCLC and MET OverExp and/or Amp with PD on 1L+ osi received savo 300 mg QD, 300 mg BID or 600 mg QD + osi 80 mg QD. MET OverExp/Amp was centrally confirmed (by IHC [Roche], 3+ intensity in ≥50% of tumor cells [MET IHC3+/≥50%]; by FISH [Abbott Molecular], MET gene copy number ≥5 or MET:CEP7 ratio ≥2 [FISH5+], or at higher thresholds of MET IHC3+/≥90% or FISH10+). Baseline (BL) and Wk 3 plasma EGFRm (Ex19del/L858R) were analyzed by ddPCR (Biodesix) as an estimate of tumor burden. MET Amp was not monitored in ctDNA due to low detection sensitivity. Clearance was defined as undetected EGFRm ctDNA at Wk 3, when detected at BL. PFS was investigator-assessed (RECIST 1.1). DCO: Aug 23, 2024. Results: Of 344 pts with evaluable BL ctDNA, 259 (75%) had detected EGFRm ctDNA. Of these, 225 had evaluable ctDNA at Wk 3 (82 [36%] had EGFRm clearance at Wk 3). Confirmed ORR was higher in pts with EGFRm Wk 3 clearance (56/82; 68%) vs non-clearance (38/143; 27%). PFS was longer in pts with vs without EGFRm clearance at Wk 3 (Table). Across all pts evaluable for ctDNA at Wk 3, clearance rates were higher in pts with vs without high MET (69/162 [43%] vs 13/63 [21%]; odds ratio [95% CI] 0.35 [0.16, 0.72]). Similar results were seen in the savo 300 mg QD + osi subgroup. Conclusions: In SAVANNAH, among pts with detected EGFRm ctDNA at BL, clearance at Wk 3 was associated with improved ORR and PFS. Plasma EGFRm clearance at Wk 3 is enriched in pts with MET IHC3+/≥90% or FISH10+ status, consistent with improved efficacy in this biomarker subgroup. Citation Format: Jonathan W. Riess, Filippo de Marinis, Benjamin Levy, Tae Min Kim, Laura Bonanno, Quincy Chu, Marcello Tiseo, Adrian Sacher, Silvia Novello, Christina Baik, Lyudmila Bazhenova, Jacques Cadranel, Giulio Metro, Cheng-Ta Yang, Tsung-Ying Yang, Gee-Chen Chang, Konstantinos Leventakos, Lorenzo Livi, James Chih-Hsin Yang, Lecia V. Sequist, John Argue, Wanning Xu, Aleksandra Markovets, Ryan Hartmaier, Myung-Ju Ahn. SAVANNAH: Clearance of plasma EGFRm in patients with EGFRm MET-overexpressed (OverExp) and/or -amplified (Amp) NSCLC post-osimertinib (osi) treated with savolitinib (savo) + osi [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr LB416.

Abstract Background: Given the dramatic rise in incidence of colorectal cancer in young adults, there remain limited treatment options effective in metastatic disease. Although T cell-based therapies have been successful in treating highly antigenic cancers, like melanoma and lung, they have not yet been shown to induce consistent and durable tumor regression in common epithelial malignancies, including metastatic colorectal cancer (mCRC). CISH (Cytokine inducible SH2 containing protein) is a novel intracellular checkpoint target demonstrating PD-L1 ligand independent mechanisms of enhanced anti-cancer activity. Given that CISH is not currently tractable via antibody or small molecule drug modalities, we employed CRISPR for precise inhibition of CISH in tumor infiltrating lymphocytes (TILs). Here, we provide the first clinical report of safety and anti-tumor activity of CISH edited TILs in 12 patients with metastatic gastrointestinal cancers (NCT04426669), including a clinical complete response (CR) in a young-adult patient with immunotherapy-refractory mCRC. Methods: Tumors were surgically resected for TIL harvest, followed by a rapid expansion protocol and CRISPR/Cas9 knockout (KO) CISH. CISH KO, neoantigen-reactive TILs were expanded, then infused following non-myeloablative lymphocyte depleting (LD) chemotherapy (cyclophosphamide & fludarabine) followed by high-dose IL-2. To establish mechanistic attribution of the CR, we used iR-RepSeq+ for serial analysis of the TCR immune repertoire. Results: Our CRISPR engineering led to KO of CISH in T cells with high-efficiency (&gt;90%) without detectable off-target editing. We safely dosed patients at all five dose levels (range: 1.91e8 to 9.93e10 cells). No dose-limiting toxicities attributable to the CISH-KO TIL product were observed. Adverse events were consistent with established risks of LD chemotherapy, IL-2, or disease progression. A durable ongoing complete response (&gt;21 months) was achieved in a patient with microsatellite instability-high (MSI-H) mCRC refractory to anti-PD1/CTLA-4 combination therapy. Conclusions: We provide the first clinical report of CISH checkpoint targeting via genetically modified T cell therapy, with complete response in a patient with mCRC. Persistence and expansion of unique TCR clonotypes detected in neoantigen responsive TIL was temporally consistent with spikes in CISH edited alleles detected by NGS assay; in the patient with CR, four of the clonotypes exhibiting prolonged persistence greater than one-year post-infusion exhibited significantly reduced or undetectable expression of CISH compared to the total infused TIL population. Given these findings, further investigation of CISH checkpoint inhibition, via gene and cell therapy, and next-generation small molecule drugging modalities, is underway. Citation Format: Emil Lou, Modassir S. Choudhry, Timothy K. Starr, Timothy Folsom, Jason Bell, Blaine Rathmann, Anthony P. DeFeo, Ji Hyun Kim, Nicholas Slipek, Zhaohui Jin, Darin Sumstad, Christopher A. Klebanoff, Katherine Ladner, Akshat Sarkari, R Scott McIvor, Thomas A. Murray, Jeffrey Miller, Madhuri Rao, Eric Jensen, Jacob Ankeny, Mahmoud A. Khalifa, Anil Chauhan, Benjamin Spilseth, Ajay Dixit, Paolo P. Provenzano, Wenjing Pan, Daniel Weber, Miranda Byrne-Steele, Tom Henley, David H. McKenna, Matthew J. Johnson, Beau R. Webber, Branden S. Moriarity. First-in-human trial in patients with metastatic colorectal cancer using CRISPR-engineered tumor infiltrating lymphocytes in which the intracellular immune checkpoint CISH is inhibited [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_2):Abstract nr CT269.

Abstract Background In 2021, the American Academy of Physical Medicine and Rehabilitation established the Multi‐Disciplinary Post‐Acute Sequelae of SARS‐CoV‐2 Infection Collaborative to provide guidance from established Long COVID clinics for the evaluation and management of Long COVID. The collaborative previously published eight Long COVID consensus guidance statements using a primarily symptom‐based approach. However, Long COVID symptoms most often do not occur in isolation. Aims This compendium aims to equip clinicians with an efficient, up‐to‐date clinical resource for evaluating and managing adults experiencing Long COVID symptoms. The primary intended audience includes physiatrists, primary care physicians, and other clinicians who provide first‐line assessment and management of Long COVID symptoms, especially in settings where subspecialty care is not readily available. This compendium provides a holistic framework for assessment and management, symptom‐specific considerations, and updates on prevalence, health equity, disability considerations, pathophysiology, and emerging evidence regarding treatments under investigation. Because Long COVID closely resembles other infection‐associated chronic conditions (IACCs) such as myalgic encephalomyelitis/chronic fatigue syndrome, the guidance in this compendium may also be helpful for clinicians managing these related conditions. Methods Guidance in this compendium was developed by the collaborative's established modified Delphi approach. The collaborative is a multidisciplinary group whose members include physiatrists, primary care physicians, pulmonologists, cardiologists, psychiatrists, neuropsychologists, neurologists, occupational therapists, physical therapists, speech and language pathologists, patients, and government representatives. Over 40 Long COVID centers are represented in the collaborative. Results Long COVID is defined by the National Academies of Sciences, Engineering, and Medicine as “an IACC that occurs after SARS‐CoV‐2 infection and is present for at least 3 months as a continuous, relapsing and remitting, or progressive disease state that affects one or more organ systems.” The current global prevalence of Long COVID is estimated to be 6%. Higher prevalence has been identified among female gender, certain racial and ethnic groups, and individuals who live in nonurban areas. However, anyone can develop Long COVID after being infected with the SARS‐CoV‐2 virus. Long COVID can present as a wide variety of symptom clusters. The most common symptoms include exaggerated fatigue and diminished energy windows, postexertional malaise (PEM)/postexertional symptom exacerbation (PESE), cognitive impairment (brain fog), dysautonomia, pain/myalgias, and smell and taste alterations. Holistic assessment should include a traditional history, physical examination, and additional diagnostic testing, as indicated. A positive COVID‐19 test during acute SARS‐CoV‐2 infection is not required to diagnose Long COVID, and currently, there is no single laboratory finding that is definitively diagnostic for confirming or ruling out the diagnosis of Long COVID. A basic laboratory assessment is recommended for all patients with possible Long COVID, and consideration for additional labs and diagnostic procedures is guided by the patient's specific symptoms. Current management strategies focus on symptom‐based supportive care. Critical considerations include energy conservation strategies and addressing comorbidities and modifiable risk factors. Additionally, (1) it is essential to validate the patient's experience and provide reassurance that their symptoms are being taken seriously because many patients have had their symptoms dismissed by loved ones and clinicians; (2) physical activity recommendations must be carefully tailored to the patient's current activity tolerance because overly intense activity can trigger PEM/PESE and worsened muscle damage; and (3) treatment recommendations should be delivered with humility because there are many persistent unknowns related to Long COVID. To date, there are limited data to guide medication management specifically in the context of Long COVID. As such, medication use generally follows standard practice regarding indications and dosing, with extra attention to prioritize (1) patient preference via shared decision‐making and (2) cautious use of medications that may improve some symptoms (eg, cognitive/attention impairment) but may worsen other symptoms (eg, PEM/PESE). Numerous clinical trials are investigating additional treatments. The return‐to‐work process for individuals with Long COVID can be challenging because symptoms can fluctuate, vary in nature, affect multiple functional areas (eg, physical and cognitive), and often manifest as an “invisible disability” that may not be readily acknowledged by employers or coworkers. Clinicians can help patients return to work by identifying suitable workplace accommodations and resources, providing necessary documentation, and recommending occupational or vocational therapy when needed. If these efforts are unsuccessful and work significantly worsens Long COVID symptoms or impedes recovery, applying for disability may be warranted. Long COVID is recognized as a potential disability under the Americans with Disabilities Act. Conclusion To contribute to the overall health and well‐being for all patients, Long COVID care should be delivered in a holistic manner that acknowledges challenges faced by the patient and uncertainties in the field. For more detailed information on assessment and management of specific Long COVID symptoms, readers can reference the collaborative's symptom‐specific consensus guidance statements.

Abstract Background: Targeted agents, such as nanobodies, can be covalently linked to radionuclide chelators for theranostics. Nanobodies are single-domain immunoglobulin variable regions with a short blood half-lives and high specificity. Calreticulin (CALR) is endoplasmic reticular (ER) protein that translocates to the cell surface upon induction with certain agents, namely doxorubicin. We hypothesized surface CALR on tumors could be targeted using a novel nanobody after induction with doxorubicin. Methods: Studies were conducted using in vitro and in vivo models of pancreatic ductal adenocarcinoma (PDAC). Surface CALR expression was determined by western blot on fractionated lysates, flow cytometry, or immunofluorescence (IF). Doxorubicin was administered by intraperitoneal injection to mouse models of PDAC. The anti-CALR nanobody was developed via the panning of a synthetic nanobody phage display library. The top CALR-binding nanobody was confirmed by ELISA, immunohistochemistry (IHC), and flow cytometry. For in vivo studies, the nanobody was conjugated with the chelator NOTA and radiolabeled with 64Cu. PET images were acquired 1-hour after injection. Significance was determined using an independent t-test and p values &lt; 0.05 were considered statistically significant. Results: PDAC cells treated with doxorubicin showed peak surface CALR expression between 24 and 48 hours. Flow cytometry revealed that 61.7% of live PDAC cultured cells treated for 24 hours expressed surface CALR, compared to 2.2% in controls (p &lt; 0.001). In a subcutaneous syngeneic PDAC mouse model, two doses of doxorubicin 48 hours apart significantly increased surface CALR, with 30.4% of live-cells expressing CALR in treated tumors versus 1.5% in controls (p &lt; 0.001). Similarly, doxorubicin-treated tumors from a PDAC patient derived xenograft (PDX) model had a 6.7-fold increase in live-cells expressing surface CALR compared to controls (p &lt; 0.01). IF confirmed a 1.4-fold increase in CALR expression in doxorubicin-treated tumors from the subcutaneous PDAC mouse model (p &lt; 0.01) and a 1.7-fold increase in the PDAC PDX model (p &lt; 0.01). Our anti-CALR nanobody has an apparent 37 nM affinity for recombinant CALR and successfully detected surface CALR by IHC and flow cytometry. In vivo PET imaging showed significant increased uptake of the 64Cu-NOTA-nanobody in tumors from doxorubicin-treated mice over controls, with no significant changes in heart, kidney, or liver accumulation by PET quantification and flow cytometry (p &lt; 0.05). Conclusions: Systemic doxorubicin treatment induces CALR surface translocation in tumors that can be successfully targeted with a radiolabeled nanobody for PET imaging. Targeting chemotherapy-induced surface CALR using our radiolabeled nanobody could provide a theragnostic strategy for the detection and treatment of PDAC. Citation Format: Rachael Guenter, Yuvasri Golivi, Lucinda Hall, Amro Abdelrahman, Chloe La Prairie, Caleb Miller, Tejeshwar C. Rao, Danielle M. Carlson, Mark J. Truty, Benjamin Larimer, J. Bart Rose. Detection of tumor cell surface calreticulin after doxorubicin treatment using a novel radiolabeled nanobody [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 574.

Observational studies have demonstrated that aspirin and/or PTSG2 inhibitor (e.g., celecoxib) use, before or after colon cancer (CC) diagnosis, is associated with a lower risk of recurrence. However, a randomized trial of adjuvant celecoxib therapy in stage III CC did not show improved survival compared to placebo treatment. We therefore hypothesized that immune microenvironment features may identify patient subgroups with stronger survival benefits from anti-inflammatory celecoxib treatment. Drawing from an NCI-Intergroup trial (Cancer and Leukemia Group B [now Alliance for Clinical Trials in Oncology]/SWOG 80702) for patients with stage III resected CC that compared 3 versus 6 months of adjuvant fluorouracil, leucovorin, and oxaliplatin ± 3 years of celecoxib, we conducted tissue-based tumor microenvironment profiling on 1,098 resected tumors using a custom 9-plex, T-cell multiplex immunofluorescence assay coupled with digital image analysis and supervised machine learning. The Kaplan-Meier method was used to describe disease-free survival, based on T cell density, and log-rank testing was performed. Cox proportional hazards models were used to examine unadjusted and adjusted associations between T cell density and disease-free survival (DFS). Two-sided P values ≤0.05 were considered statistically significant. We found that higher CD3+ T cell density was associated with longer DFS with an adjusted hazard ratio (HR) of 0.69 (95% confidence interval [CI] 0.52-0.91) for patients with densities in the highest tertile as compared the lowest tertile (P=0.01). T cell subset analysis showed that stromal regulatory T helper cells (HR 0.42 comparing highest to lowest tertile, CI 0.31-0.58, P&lt;0.001) and stromal memory cytotoxic T cells (HR 0.55 comparing highest to lowest tertile, CI 0.42-0.74, P&lt;0.001) were most strongly associated with longer DFS. Compared to the placebo group, adjuvant celecoxib use associated with improved DFS for patients with low but not high stromal CD3+ T cell density (adjusted HRs of 0.45 [CI 0.31-0.65] for lowest tertile and 1.13 [CI 0.73-1.74] for highest tertile; Pinteraction=0.01). This association was also seen when the analysis was restricted to microsatellite stable tumors (HR 0.50 [CI 0.32-0.80] for lowest density tertile and 1.50 [CI 0.87-2.59] for highest density tertile; Pinteraction=0.01). T cell subset analysis showed that DFS benefit for celecoxib use most strongly associated with stromal memory helper T cell density (HR 0.38 [CI 0.26-0.56] for lowest density tertile and 1.26 [CI 0.80-1.97] for highest density tertile; Pinteraction&lt;0.001). Together, these results show that while higher T cell infiltration is associated with improved DFS, lower T cell infiltration is associated with improved DFS for patients treated with celecoxib. This unexpected finding may inform immunomodulatory treatment strategies for CC. Citation Format: Yasutoshi Takashima, Chao Ma, Qian Shi, Andressa Dias Costa, Tyler Twombly, Juha P. Väyrynen, Melissa Zhao, Ardaman Shergill, Pankaj Kumar, Felix Couture, Philip Kuebler, Smitha Krishnamurthi, Benjamin Tan, Eileen M. O'Reilly, Anthony F. Shields, Shuji Ogino, Charles S. Fuchs, Jeffrey A. Meyerhardt, Jonathan A. Nowak. Prognostic and predictive role of T cell infiltration in stage III colon cancer (CC) treated with celecoxib: CALGB/SWOG 80702 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 5858.

Abstract Introduction: The success of CAR-T in multiple myeloma suggests potential in other challenging plasma cell disorders like systemic AL amyloidosis (AL) and plasma cell leukemia (PCL). CAR-T experience in these indications is limited by the rarity of these diseases. Methods: A systematic review examined publications and clinical trials from 2014 to 2024 to gauge clinical outcomes and safety of CAR-T in AL and PCL. Studies of plasma cell-directed CAR-T with safety and efficacy outcomes were included. Results: We identified a total of 21 AL patients from 6 publications and 23 PCL patients from 5 publications. All patients were treated with anti-BCMA CAR-T; 9 different products were administered. Among AL patients, 12 had cardiac amyloidosis, and 6 had at least stage 3. At a median follow-up of 9 months (2.5-26.4), 16 of 21 AL patients (76%) had a response of VGPR or better: 2 had MRD-negative sCR with organ response, 8 CR, 6 VGPR, 1 PR, and 3 not evaluable. From a safety standpoint, CRS occurred in 71%, with 57% experiencing grades 1-2 and 14% grade 3. ICANS occurred in 2 patients (10%): one grade 1, one grade unknown. Of 11 patients treated with HBI0101, 5 patients died of cardiac disease within 1 year of CAR-T (3 PD, 1 VGPR, 1 PR). Hematologic events were common, with neutropenia in 76% (52% grades 3-4), anemia in 38% (19% grade 2-3, 5% grade 1), and thrombocytopenia in 24% (10% grade 2, 5% grade 3, and one grade 4 worsening thrombocytopenia). Infections were also seen, including BK virus hemorrhagic cystitis, SARS-CoV-2 pneumonia, severe respiratory infection, respiratory viral infection, and sepsis, each affecting 5-14%. A review of CAR-T in PCL included 6 patients with primary PCL and 17 with secondary PCL, with a median of 4.5 (range: 0-15) prior lines of therapy. Overall response at a median follow-up of 6.5 (range: 0-15) months was 17/23 (78%): 2 patients with sCR, 2 CR, 7 VGPR, and 7 PR. Adverse events were only described in 20 of the 23 PCL patients. CRS was frequent, with any grade CRS occurring in 18 of 20 (90%); CRS grade was only reported in 10 (4 grade 1, 3 grade 2, 1 grade 3, 2 grade 4, 8 grade unknown). ICANS grade 1 was reported in 4 patients (20%), and infection (any grade) in 8 (40%). Hematologic events of any grade were frequent: neutropenia in 90% of patients (35% grade ≥ 3), anemia in 80% (40% grade ≥ 3), and thrombocytopenia in 70% (40% grade ≥ 3). Three deaths were reported, two due to infection (pneumonia and pulmonary aspergillosis) and one due to GI hemorrhage. Conclusions: BCMA-directed CAR-T has been used in AL and PCL with encouraging responses, though the durability of these responses is unknown. Our review suggests that CAR-T may be safe in AL in patients without significant cardiac disease. Patients with PCL may be at an increased risk of serious adverse events, especially in the setting of active progressive disease. Careful patient selection and potential dose adjustment may be warranted in these orphan indications. Citation Format: Heather T. Morgan, Benjamin Derman, Hong Ma, Shaji K. Kumar. CAR-T in high-risk plasma cell dyscrasias: A systematic review of AL amyloidosis and plasma cell leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2025; Part 1 (Regular Abstracts); 2025 Apr 25-30; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2025;85(8_Suppl_1):Abstract nr 3180.