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Abstract Introduction Cigarette smoking is highly prevalent among Asian American immigrant subgroups. Previously, Asian-language telephone Quitline services were only available in California. In 2012, the Centers for Disease Control and Prevention (CDC) funded the national Asian Smokers’ Quitline (ASQ) to expand Asian-language Quitline services nationally. However, there are relatively few calls to the ASQ from outside California. Aims and Methods This pilot study assessed the feasibility of two proactive outreach interventions to connect Vietnamese-speaking participants who smoke to the ASQ. Both interventions, (1) proactive telephone outreach with a counselor trained in motivational interviewing (PRO-MI) and (2) proactive telephone outreach with interactive voice response (PRO-IVR), were adapted to be culturally and linguistically appropriate for Vietnamese-speaking participants. Participants were randomly assigned 2:1 to PRO-IVR versus PRO-MI. Assessments were conducted at baseline and 3 months post-enrollment. Feasibility indicators were the recruitment rate and initiation of ASQ treatment. Results Using the HealthPartners electronic health record, a large health system in Minnesota, we identified approximately 343 potentially eligible Vietnamese participants who were mailed invitation letters and baseline surveys with telephone follow-up. We enrolled 86 eligible participants (25% recruitment rate). In the PRO-IVR group 7/58 participants were directly transferred to the ASQ (12% initiation rate) and in the PRO-MI group 8/28 participants were warm transferred to the ASQ (29% initiation rate). Conclusions This pilot study demonstrates the feasibility of our recruitment methods and of implementing proactive outreach interventions to promote the initiation of smoking cessation treatment with the ASQ. Implications This pilot study contributes novel data on the uptake of Asian Smokers’ Quitline (ASQ) services among Vietnamese-speaking people who smoke (PWS) with two proactive outreach interventions: (1) proactive telephone outreach with a counselor trained in motivational interviewing (PRO-MI) and (2) proactive telephone outreach with interactive voice response (PRO-IVR). We found that it is feasible to implement these proactive outreach interventions to promote the initiation of ASQ cessation treatment among Vietnamese-language speaking PWS. Future large trials are needed to rigorously compare PRO-MI and PRO-IVR and conduct budget impact analyses to understand the most efficient strategies for incorporation into health system settings.

Injection of A-MSC-derived EVs harvested from patients who are lean can resolve myocardial injury in mice with experimental renovascular hypertension more effectively than A-MSC-derived EVs from patients with obesity. These observations underscore and might have important ramifications for the self-healing capacity of patients with obesity and for the use of autologous EVs as a regenerative tool.

AbstractAlthough pathogenic variants in PSEN1 leading to autosomal‐dominant Alzheimer disease (ADAD) are highly penetrant, substantial interindividual variability in the rates of cognitive decline and biomarker change are observed in ADAD. We hypothesized that this interindividual variability may be associated with the location of the pathogenic variant within PSEN1. PSEN1 pathogenic variant carriers participating in the Dominantly Inherited Alzheimer Network (DIAN) observational study were grouped based on whether the underlying variant affects a transmembrane (TM) or cytoplasmic (CY) protein domain within PSEN1. CY and TM carriers and variant non‐carriers (NC) who completed clinical evaluation, multimodal neuroimaging, and lumbar puncture for collection of cerebrospinal fluid (CSF) as part of their participation in DIAN were included in this study. Linear mixed effects models were used to determine differences in clinical, cognitive, and biomarker measures between the NC, TM, and CY groups. While both the CY and TM groups were found to have similarly elevated Aβ compared to NC, TM carriers had greater cognitive impairment, smaller hippocampal volume, and elevated phosphorylated tau levels across the spectrum of pre‐symptomatic and symptomatic phases of disease as compared to CY, using both cross‐sectional and longitudinal data. As distinct portions of PSEN1 are differentially involved in APP processing by γ‐secretase and the generation of toxic β‐amyloid species, these results have important implications for understanding the pathobiology of ADAD and accounting for a substantial portion of the interindividual heterogeneity in ongoing ADAD clinical trials.

AbstractBackgroundAbsolute dosimetry measurement is an integral part of Treatment Planning System (TPS) commissioning and it involves measuring the integrated absorbed dose to water for all energies in a pencil beam scanning delivery system. During the commissioning of Singapore's first proton therapy center, a uniform scanned field with an Advanced Markus chamber method was employed for this measurement, and a large dose fluctuation of at least 5% was observed for 10% of the energy layers during repeated measurements.PurposeThis study aims to understand the root cause of this fluctuation by relating the actual delivered spot information in the log file with the charge measurement by the ion chambers.MethodsA dedicated pencil beam dose algorithm was developed, taking into account the log file parameters, to calculate the dose for a single energy layer in a homogeneous water phantom. Three energies, 70.2, 182.7, and 228.7 MeV were used in this study, with the 182.7 MeV energy exhibiting large dose fluctuation. The dose fluctuation was investigated as a function of detector's sizes (pinpoint 3D, Advanced Markus, PTW 34070, and PTW 34089) and water depth (2 , 6, and 20 cm). Twelve ion chambers measurements were performed for each chamber and depth. The comparison of the theoretically predicted integrated dose and the charge measurement served as a validation of the algorithm.ResultsAbout 5.9% and 9.6% dose fluctuation were observed in Advanced Markus and pinpoint 3D measurements at 2 cm depth for 182.7 MeV, while fluctuation of 1.6% and 1.1% were observed in Advanced Markus with 228.7 and 70.2 MeV at similar depth. Fluctuation of less than 0.1% was observed for PTW34070 and PTW 34089 for all energies. The fluctuation was found to diminish with larger spot size at 20 cm depth to 1.3% for 182.7 MeV. The theoretical and measured charge comparison showed a high linear correlation of for all datasets, indicating the fluctuation originated from the delivered spot characteristics. The cause of fluctuation was identified to be due to the spill change occurring close to the detector, and since the spot positional deviation profiles were different between two spills, this resulted in local hot spots between columns of spots. The actual position of spill change varies randomly during measurement, which led to a random occurrence of hot spot within the detector's sensitive volume and a fluctuating dose measurement.ConclusionThis is the first report of a dose fluctuation greater than 5% in absolute dosimetry measurement with a uniform scanned field and the cause of the fluctuation has been conclusively determined. It is important to choose the MU and scanning pattern carefully to avoid spill change happening when the spot delivery is near the detector.

Abstract Purpose: Non-invasive monitoring of circulating tumor DNA (ctDNA) has the potential to be a readily available measure for early prediction of clinical response. Here, we report on early ctDNA changes of KRAS G12C in a Phase 2 trial of adagrasib in patients with advanced, KRAS G12C-mutant lung cancer. Experimental Design: We performed serial droplet digital PCR (ddPCR) and plasma NGS on 60 KRAS G12C-mutant patients with lung cancer that participated in cohort A of the KRYSTAL-1 clinical trial. We analyzed the change in ctDNA at 2 specific intervals: Between cycles 1 and 2 and at cycle 4. Changes in ctDNA were compared with clinical and radiographic response. Results: We found that, in general, a maximal response in KRAS G12C ctDNA levels could be observed during the initial approximately 3-week treatment period, well before the first scan at approximately 6 weeks. 35 patients (89.7%) exhibited a decrease in KRAS G12C cfDNA >90% and 33 patients (84.6%) achieved complete clearance by cycle 2. Patients with complete ctDNA clearance at cycle 2 showed an improved objective response rate (ORR) compared with patients with incomplete ctDNA clearance (60.6% vs. 33.3%). Furthermore, complete ctDNA clearance at cycle 4 was associated with an improved overall survival (14.7 vs. 5.4 months) and progression-free survival (HR, 0.3). Conclusions: These results support using early plasma response of KRAS G12C assessed at approximately 3 weeks to anticipate the likelihood of a favorable objective clinical response.

12100 Background: The safety profiles of novel agents are mainly based on clinician-reported adverse events (AEs) from clinical trials. Patient-reported outcomes (PROs) may better represent the treatment burden experienced by patients (pts) compared with clinician-reported AEs. Using data from POLARIX, a double-blind, placebo-controlled, randomized Phase 3 international study (NCT03274492), we previously presented PRO and clinician-reported data showing similar rates of neuropathy (Trněný et al. 2022). Here, we evaluate the reporting of other common symptoms using PRO and clinician-reported data in POLARIX. Methods: POLARIX methods were previously described (Tilly et al. 2022); this analysis included all pts with PRO data. PRO and clinician-reported data described the incidence and severity of fatigue, constipation, diarrhea, nausea, and vomiting. Clinician-reported severity grading was based on the NCI Common Terminology Criteria for Adverse Events (NCI-CTCAE) v4.0. PROs were collected using the European Organisation Research and Treatment of Cancer Quality of Life-Core 30 questionnaire (EORTC QLQ-C30), which was administered to pts at clinic visits on Day 1 of Cycles 1 (baseline), 2, 3, and 5, and end of treatment (EOT). PRO severity scores included ‘A little’, ‘Quite a bit’, and ‘Very much’. Results: Overall, 825 pts were evaluable. From baseline to EOT, PROs showed a higher incidence of symptoms compared with clinicians for fatigue (98% vs 27%), constipation (68% vs 29%), diarrhea (56% vs 26%), nausea (58% vs 40%), and vomiting (24% vs 15%). PRO severity scores of ‘Quite a bit’ or ‘Very much’ were reported in 33% of pts for fatigue, 29% for constipation, 17% for diarrhea, 19% for nausea, and 7% for vomiting. Clinicians reported Grade ≥2 symptoms in 11% of pts for fatigue, 11% for constipation, 11% for diarrhea, 14% for nausea, and 6% for vomiting. Conclusions: In POLARIX, pts reported a higher incidence and severity of symptoms compared with clinicians. Although distinct scales were used, the differences in symptom rates reported by pts and clinicians were clinically meaningful. These data may have implications for symptom management, including physician evaluation and communication of symptom expectations for pts. Reporting of symptoms by PROs should be incorporated into clinical trials as an adjunct to standard AE reporting to better characterize the patient experience. Clinical trial information: NCT03274492 . [Table: see text]

e21030 Background: Docetaxel +/- ramucirumab remains the standard of care therapy after progression on platinum doublet and immune checkpoint blockade (ICB) in patients with metastatic non-small cell lung cancer (NSCLC). However, the clinical benefit from docetaxel is short-lived with substantial toxicity. Additionally, whether cancer gene mutation status impacts the benefit from docetaxel has not been systemically studied. In this real-world study, we aim to investigate whether cancer gene mutation status is associated with benefit from docetaxel. We also explored whether IMPOWER150-based regimens (ABCP-atezolizumab + bevacizumab + carboplatin + paclitaxel; ACP-atezolizumab + carboplatin + paclitaxel; BCP-bevacizumab + carboplatin+paclitaxel) may serve as alternative options with better efficacy in this patient population. Methods: We retrospectively queried MD Anderson Cancer Center GEMINI database for patients with metastatic NSCLC who received docetaxel, docetaxel+ramucirumab, or one of the above-mentioned IMPOWER150-based regimens after progression on concomitant or sequential platinum-doublet and ICI. Primary endpoints include progression-free survival (PFS) and overall survival (OS). Results: 274 patients were analyzed (docetaxel n = 99; docetaxel +ramucirumab n = 142; ABCP n = 28; BCP n = 4, ACP n = 1). No significant difference was observed in mPFS (3.00m versus 3.93m, P = 0.156) or mOS (8.40m vs.8.67m, P = 0.737) between patients from docetaxel monotherapy group and docetaxel+ ramucirumab group. Cancer gene mutations in EGFR, KRAS, TP53 or PD-L1 expression (0-1%; 1-49%; ≥50%) were not associated with PFS or OS in the 241 patients treated with docetaxel +/- ramucirumab. Furthermore, there was no difference in mPFS (5.50m versus 3.47m, P = 0.516) or mOS (10.40m versus 8.83m, P = 0.737) in patients who received IMPOWER 150-based regimens compared to those who were treated with docetaxel+/- ramucirumab. The median treatment duration was 1.60m (0.70m-20.23m), 1.90m (0.70m-32.90m), 4.80m(0.70m-33.47m) and 11 patients (11.11%), 20 patients (14.08%), and 3 patients (9.09%) discontinued treatment due to adverse events in the patients treated with docetaxel monotherapy, docetaxel+ramucirumab combined therapy, and the IMPOWER150 regimens, respectively. Conclusions: These results from this real-world study suggested that unlike for ICI therapy, where onco-driver mutations have profound impact on the clinical benefit, the cancer gene mutation status does not impact the benefit from docetaxel +/- ramucirumab in NSCLC patients who progressed on platinum doublets and ICI. Furthermore, the clinical benefit from docetaxel +/- ramucirumab is short-lived. Novel treatment regimens are urgently needed in this clinical setting.

9065 Background: Rearranged during transfection ( RET) gene alterations are the oncogenic driver in diverse tumor types, including RET fusions identified in 1-2% of non-small cell lung cancers (NSCLC). While RET-selective tyrosine kinase inhibitors (TKIs) selpercatinib and pralsetinib are effective, acquired drug resistance remains a challenge. Here, we report the initial results from the RETgistry, an international consortium aimed at elucidating mechanisms of resistance to RET TKIs across RET-altered solid tumors. Methods: This was a retrospective analysis performed across 16 institutions. Patients (pts) were eligible if they had advanced solid tumor harboring an oncogenic RET alteration, received ≥1 RET TKI with disease progression, and underwent resistant tumor or liquid biopsy for next-generation sequencing (NGS). Results: A total of 103 time-distinct biopsies (62 tissue, 30 plasma, 11 paired tissue/plasma) were included in analysis, obtained from 88 pts with progression on a RET-selective TKI [selpercatinib (n = 70), pralsetinib (n = 14), selpercatinib and pralsetinib sequentially (n = 4)]. Pts had the following tumor types: 72 NSCLC (69% KIF5B-RET, 21% CCDC6-RET, 10% other RET fusion), 13 medullary thyroid cancer (TC) (54% RET M918T, 46% other RET mutation), and 2 papillary and 1 anaplastic TC (all, RET fusion). Median age was 58 (range, 21-86); 48% were male with 89% never/light smokers. Median duration of RET TKI preceding biopsies [first-line, n = 32 (31%); second-line, n = 42 (41%); third-/greater-line, n = 29 (28%)] was 16.5 months (mos) (95% CI, 14.0-19.6); median PFS was 14.1 mos (95% CI, 9.3-17.0). Resistant biopsies were obtained at median 15.0 mos from TKI initiation (range, 1.8-58.8). Acquired RET mutations were detected in 14 (14%), most common being G810 substitutions in 12 (12%). Potential off-target resistance gene alterations identified in 43 cases (42%) included MET amplification (14%), BRAF V600E or fusion (2%), KRAS gain or mutation (5%), ERBB2 amplification (2%), EGFR amplification (3%), ROS1 fusion (1%), and activating PIK3CA mutation or PTEN loss (4%). No resistant lung cancer biopsy demonstrated small cell transformation. The duration of TKI therapy (HR 0.64, p = 0.11) or PFS (HR 0.75, p = 0.33) did not differ according to the presence of on-target vs off-target resistance. NGS analyses of pre-RET-selective TKI tumors (n = 92) revealed frequent co-occurring alterations in TP53 (29%) and CDKN2A/B (12%). Conclusions: On-target resistance to RET inhibition due to acquired RET mutations was less common than off-target resistance, identified in 14%. The majority of RET TKI resistance is mediated by off-target mechanisms such as bypass receptor tyrosine kinase activation. Further studies are warranted to enable the development of therapeutic strategies to address resistance in pts with RET-altered tumors. The RETgistry accrual and data analyses continue.

e19501 Background: Relapsed and/or refractory (R/R) disease is observed in patients who receive CD19 targeting chimeric antigen receptor (CAR)-T cells to treat B-cell lymphoid leukemias and lymphomas. We generated a novel CAR, MC10029 that targets B-cell activating factor receptor (BAFF-R) to address this unmet medical need. Methods: We engineered a second-generation BAFF-R CAR (MC10029 CAR). The construct includes the single chain variable fragment (scFv) of our newly developed BAFF-R antibody with CD28 costimulatory and CD3ζ signaling domains. We confirmed MC10029 CAR-T cell antigen-specific activation with in vitro degranulation assays and a direct cytolytic assay. We used BAFF-R positive leukemia and lymphoma cell lines in both in vitro and in vivo models to further characterize MC10029 CAR-T cells, and finally, we enriched tumor primary cells from chronic lymphocytic leukemia (CLL) patients as a target for MC10029 CAR-T cells. In preparation for our Phase I clinical trial, we have manufactured three batches of CAR-T cells using a MC10029-encoding lentiviral vector produced under GMP conditions. The production batches of MC10029 CAR-T cells were evaluated for product quality with Viability, Identity and Potency as well as Safety from adventitious viral agents. Antigen specific cytotoxicity of the MC10029 CAR-T cells was confirmed using our standard degranulation assay. Results: MC10029 CAR-T cells elicited in vitro antigen-specific cytotoxicity against Nalm-6 cells, Z138 cells, MEC-1 cells, and a CD19 knock out Nalm-6 model designed to mimic CD19-negative R/R disease. We demonstrated in vivo antitumor effects of MC10029 CAR-T cells in NSG mice challenged with these same cell lines. We showed cytotoxicity of MC10029 CAR-T cells against CLL patients’ tumors. We also showed our quality control results to highlight our clinical trial trajectory. Conclusions: Novel MC10029 CAR-T cells showed broad utility against BAFF-R positive B-cell lymphoid malignancies in a series of in vitro, in vivo, and ex vivo models. With these robust data, we have moved forward to generate clinical grade MC10029 CAR-T cells using cGMP manufacturing and quality protocols in preparation of a MC10029 CAR-T cell Phase I clinical trial.

TPS3640 Background: Recent data have demonstrated that in locally advanced rectal cancer (LARC), a total neoadjuvant therapy (TNT) approach improves compliance with chemotherapy and increases rates of tumor response compared to neoadjuvant chemoradiation (CRT) alone. They further indicate that the optimal sequencing of TNT involves consolidation (rather than induction) chemotherapy to optimize complete response rates. Data, largely from retrospective studies, have also shown that patients (pts) with clinical complete response (cCR) after neoadjuvant therapy may be managed safely with the watch and wait approach (WW) instead of preemptive total mesorectal resection (TME). However, the optimal consolidation chemotherapy regimen to achieve cCR has not been established, and a randomized clinical trial has not robustly evaluated it as a primary endpoint. Collaborating with a multidisciplinary oncology team and pt groups, we designed this NCI-sponsored study of chemotherapy intensification to address these issues and to drive up cCR rates, to provide opportunity for organ preservation and improve quality of life for pts. Methods: In this Alliance for Clinical Trials in Oncology randomized phase II trial (1:1), up to 312 pts with microsatellite stable LARC, clinical stage T4N0, any T, N+ or T3N0 requiring abdominoperineal resection or coloanal anastomosis and distal margin within 12 cm of anal verge will be enrolled. Stratification factors include tumor stage (T4 vs T1-3), nodal stage (N+ vs N0) and distance from anal verge (0-4; 4-8; 8-12 cm). Pts will be randomized to receive neoadjuvant long course CRT (LCRT) followed by consolidation doublet (mFOLFOX6 or CAPOX) or triplet chemotherapy (mFOLFIRINOX) for 4 months. LCRT in both arms involves 4500 cGy in 25 fractions over 5 weeks (w) + 900 cGy boost in 5 fractions with a fluoropyrimidine (capecitabine preferred). Pts will undergo assessment 8-12 w post-TNT completion for the primary endpoint of cCR per previously validated criteria and recommended WW and surveillance if cCR is achieved or TME if an incomplete response is noted. Secondary objectives include time-to event outcomes (disease-free and overall survival, organ preservation time and time to distant metastasis) and adverse effects. Statistical power, based on cCR, incorporates a one-sided alpha = 0.048 and power = 90% yielding 312 patients (156 per arm). Biospecimens including archival tumor tissue, matched / normal blood samples and serial rectal MRI will be collected for exploratory correlative research. This study, activated in late 2022, is open across the NCTN and is actively recruiting. Support: U10CA180821, U10CA180882, U24 CA196171; https://acknowledgments.alliancefound.org . U10CA180868 (NRG); U10CA180888 (SWOG); Clinicaltrials.gov ID: NCT05610163 Clinical trial information: NCT05610163 .