Citations

3077 Background: ATR protein kinase is activated by replication stress and recruited to stalled forks or single strand DNA defects in various cancers. The topoisomerase-I (Top1) inhibitor irinotecan induces DNA damage. The ATR inhibitor BAY1895344 (elimusertib) has demonstrated cytotoxic potential in SCLC and GI cancer xenografts when combined with Top1 inhibitors . Methods: This phase Ia trial assessed elimusertib in combination with irinotecan in adult patients with refractory advanced solid tumors for whom irinotecan can be considered standard care. Patients with previous irinotecan exposure were excluded. Two dosing schedules were used: 1) Biweekly - irinotecan IV (starting at 150 mg/m2) D1 + elimusertib (starting dose 20 mg PO BID) D1,D2 (cycle=14 days); 2) Weekly - irinotecan (starting at 50 mg/m2) IV on D1,8,15 with elimusertib (starting at 20 mg PO daily) on D2,D3,D9,D10 and D16,D17 (cycle=21 days). Dose escalation utilized a 3+3 design. Primary objectives were to assess safety and tolerability and estimate the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D). Secondary objectives included estimating pharmacokinetic (PK) profiles and assessing anti-tumor activity. Results: A total of 21 patients were enrolled in dose escalation (N=9 [Biweekly] and N=12 [Weekly], median age 58 and 2 lines of prior therapy. For the Biweekly cohort: 3/3 patients enrolled at dose level (DL) 1 experienced hematologic dose-limiting toxicity (DLT); 6 patients received DL-1 without any DLTs. The weekly regimen escalation comprised of 12 patients: 6 enrolled in DL1 with 2/6 having hematologic DLT and 5/6 unable to complete ≥75% of cycle 1 dosing; 6 enrolled in DL-1 with no DLTs observed. Notable grade 3+ treatment-related adverse events and summary best response are summarized (Table 1). The majority of evaluable patients in both schedules had initial disease control (56% [biweekly] and 67% [weekly]). One confirmed partial response was seen in the biweekly RP2D. Median progression-free survival was 2.1 mo [biweekly] and 2.5 mo [weekly]. PK results will be presented at time of meeting. Conclusions: Both RP2D and MTD of elimusertib in combination with irinotecan were reached for both dosing schedules: irinotecan 150 mg/m2 IV D1 + elimusertib 10 mg BID PO D1,D2 (biweekly) and irinotecan 25 mg/m2 IV on D1 + elimusertib (20 mg PO daily) on D2,D3 (weekly). Dose escalation was notably limited by myelotoxicity. Due to sponsor decision, the study was halted prior to planned expansion but the concept of ATR + topo I combination remains scientifically relevant. Clinical trial information: NCT04514497 . [Table: see text]

3076 Background: Ataxia telangiectasia and Rad3-related (ATR) protein kinase is activated by replication stress and recruited to stalled forks or single strand DNA abnormalities in various cancers. The topoisomerase-I (Top1) inhibitor topotecan induces DNA damage. The ATR inhibitor BAY 1895344 (elimusertib) has demonstrated cytotoxic potential in small cell lung cancer and gastrointestinal cancer xenografts when combined with Top1 inhibitors . Methods: This is phase Ia study of elimusertib combined with topotecan in adult patients with refractory advanced solid tumors for whom topotecan can be considered as part of standard care. Patients with previous topotecan exposure were excluded. The study combination was assessed starting at Topotecan 1 mg/m2 IV (D1-D5) plus elimusertib 20 mg BID (D2, D5) (Cycle=21 days). Dose escalation utilized a 3+3 design. Primary objectives were to assess safety and tolerability and estimate the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D) of the combination. Secondary objectives included estimating pharmacokinetic (PK) profiles and assessing anti-tumor activity of the combinations. Results: Eight patients were treated in dose escalation. Participants were a median of 63 years old and had received 2 median lines of previous therapy. The initial two patients enrolled into dose level (DL) 1 had dose-limiting toxicities with one of patient experiencing respiratory failure and cardiac arrest in setting of pancytopenia related to study drug. Six patients were subsequently enrolled in and received DL-1 (elimusertib decreased from 20 mg BID to 20 mg Daily) and no DLTs were observed. Notable grade 3+ treatment-related adverse events and summary best response are summarized in Table. Disease control rate was 43% among evaluation patient including one unconfirmed partial response. Median progression-free survival in the RP2D cohort was 3.45 months. PK studies are in process and results will be presented at time of meeting. Conclusions: RP2D and MTD was established for elimusertib in combination with Topotecan: Topotecan 1 mg/m2 IV [D1-D5] plus elimusertib 20 mg Daily [D2, D5] every 3 weeks. Dose escalation was notably limited by myelotoxicity. Due to sponsor decision, the study was halted prior to planned expansions cohorts but the concept of ATR + topo I inhibition remains relevant. Clinical trial information: NCT04514497 . [Table: see text]

3053 Background: Recently, early studies have identified circulating stromal cells (CStCs), i.e. Cancer Associated Macrophage-Like cells (CAMLs), in patients (pts) with newly diagnosed invasive cancers, which are phagocytic myeloid immune cells emanating from primary tumors. However, no study has evaluated CAMLs as a pan solid tumor screening tool nor their clinical impact on pt outcomes. We analyzed the blood of untreated newly diagnosed cancer pts (n=441), or in non-malignant conditions (i.e. pancreatic cysts, n=77), or healthy controls (n=100). We found that CAMLs are prevalent (82%) in cancer pt blood, absent in healthy controls (0%) and less common in non-malignant conditions (36%), with correlations to worse clinical outcomes. Methods: Anonymized peripheral blood was taken from n=441 pts before or after confirmation of invasive malignancy [stage I (n=105), stage II (n=125), stage III (n=114), stage IV (n=97) with pathologically confirmed lung (n=84), pancreas (n=61), breast (n=73), prostate (n=65), esophageal (n=34), Renal Cell (n=29), Sarcoma (n=27), or Other (n=68). In addition, anonymized blood was taken from pts with untreated non-malignant conditions including benign breast masses (n=19), Lupus (n=11), liver Cirrhosis (n=6), rising PSA (n=24), or other benign mass (n=17); and from healthy control volunteers (n=100). CAMLs were isolated by CellSieve microfiltration, defined as enlarged polyploid cells with cytokeratin+ and/or CD45/CD14+. Pts were monitored for 0-8 years (median=2.6) for progression free survival (PFS) and overall survival (OS). Results: CAMLs were found in 82% of all cancer pts averaging 5.4 CAMLs, specifically, in 66% of Stage I, 85% Stage II, 84% Stage III, and 92% Stage IV. No CAMLs were found in any healthy controls, but were in 36% of non-malignant pts. CAML sensitivity in cancer vs healthy was 82% (CI95% 78-85%), specificity=100% (CI95% 96-100%), PPV=100% (CI95% 99-100%), NPV=55% (CI95% 50-60%). CAML sensitivity in cancer vs benign was 82% (CI95% 78-85%), specificity=64% (CI95% 32-44%), PPV=93% (CI95% 90-95%), NPV=38% (CI95% 32-44%). CAML presence was significantly associated with worse PFS (HR=2.0, 95%CI 1.4-2.9, p<0.0001) & OS (HR=2.2, 95%CI 1.4-3.3, p=0.0004), with engorged phagocytic CAMLs (>50um), highly significant for worse PFS (HR=3.3, 95%CI 2.5-4.5, p<0.0001) & OS (HR=3.0, 95%CI 2.1-4.3, p<0.0001). Further, in benign pts positive for CAMLs, 2 pts were in situ, 16 had histologies with increased cancer risk (i.e. IPMN, atypical hyperplasia), and 5 pts died within 3 years. Conclusions: CAMLs appear to be a highly sensitive blood based biomarker that can identify invasive carcinoma in all stages of cancer regardless of subtype, but are not found in healthy controls & rare in non-malignant conditions. Further, enlarged phagocytic CAMLs appeared to correlate with shorter PFS and OS prior to treatment induction.

Abstract Graft-versus-host disease (GVHD) is a major cause of nonrelapse mortality (NRM) after allogeneic hematopoietic cell transplantation. Algorithms containing either the gastrointestinal (GI) GVHD biomarker amphiregulin (AREG) or a combination of 2 GI GVHD biomarkers (suppressor of tumorigenicity-2 [ST2] + regenerating family member 3 alpha [REG3α]) when measured at GVHD diagnosis are validated predictors of NRM risk but have never been assessed in the same patients using identical statistical methods. We measured the serum concentrations of ST2, REG3α, and AREG by enzyme-linked immunosorbent assay at the time of GVHD diagnosis in 715 patients divided by the date of transplantation into training (2004-2015) and validation (2015-2017) cohorts. The training cohort (n = 341) was used to develop algorithms for predicting the probability of 12-month NRM that contained all possible combinations of 1 to 3 biomarkers and a threshold corresponding to the concordance probability was used to stratify patients for the risk of NRM. Algorithms were compared with each other based on several metrics, including the area under the receiver operating characteristics curve, proportion of patients correctly classified, sensitivity, and specificity using only the validation cohort (n = 374). All algorithms were strong discriminators of 12-month NRM, whether or not patients were systemically treated (n = 321). An algorithm containing only ST2 + REG3α had the highest area under the receiver operating characteristics curve (0.757), correctly classified the most patients (75%), and more accurately risk-stratified those who developed Minnesota standard-risk GVHD and for patients who received posttransplant cyclophosphamide-based prophylaxis. An algorithm containing only AREG more accurately risk-stratified patients with Minnesota high-risk GVHD. Combining ST2, REG3α, and AREG into a single algorithm did not improve performance.

Context.— Computational pathology combines clinical pathology with computational analysis, aiming to enhance diagnostic capabilities and improve clinical productivity. However, communication barriers between pathologists and developers often hinder the full realization of this potential. Objective.— To propose a standardized framework that improves mutual understanding of clinical objectives and computational methodologies. The goal is to enhance the development and application of computer-aided diagnostic (CAD) tools. Design.— This article suggests pivotal roles for pathologists and computer scientists in the CAD development process. It calls for increased understanding of computational terminologies, processes, and limitations among pathologists. Similarly, it argues that computer scientists should better comprehend the true use cases of the developed algorithms to avoid clinically meaningless metrics. Results.— CAD tools improve pathology practice significantly. Some tools have even received US Food and Drug Administration approval. However, improved understanding of machine learning models among pathologists is essential to prevent misuse and misinterpretation. There is also a need for a more accurate representation of the algorithms’ performance compared to that of pathologists. Conclusions.— A comprehensive understanding of computational and clinical paradigms is crucial for overcoming the translational gap in computational pathology. This mutual comprehension will improve patient care through more accurate and efficient disease diagnosis.

Objective: To investigate fecal incontinence and defecatory, urinary, and sexual functional outcomes after transanal total mesorectal excision (taTME). Background: Proctectomy for rectal cancer may result in alterations in defecatory, urinary, and sexual function that persist beyond 12 months. The recent multicenter phase II taTME trial demonstrated the safety of taTME in patients with stage I to III tumors. Methods: Prospectively registered self-reported questionnaires were collected from 100 taTME patients. Fecal continence [Fecal Incontinence Quality of Life (FIQL), Wexner], defecatory function [Colorectal Functional Outcome (COREFO)], urinary function (International Prostate Symptom Score), and sexual function (Female Sexual Function Index-female, International Index of Erectile Function-male) were assessed preoperatively (PQ), 3 to 4 months postileostomy closure (FQ1), and 12 to 18 months post-taTME [postoperative questionnaire 2 (FQ2)]. Results: Among 83 patients who responded at all 3 time points, FIQL, Wexner, and COREFO significantly worsened postileostomy closure. Between FQ1 and FQ2, FIQL lifestyle and coping, Wexner, and COREFO incontinence, social impact, frequency, and need for medication significantly improved, while FIQL depression and embarrassment did not change. International Prostate Symptom Score did not change relative to preoperative scores. For females, Female Sexual Function Index declined for desire, orgasm, and satisfaction between PQ and FQ1, and did not improve between FQ1 and FQ2. In males, International Index of Erectile Function declined with no change between FQ1 and FQ2. Conclusions: Although taTME resulted in initial decline in defecatory function and fecal continence, most functional domains improved by 12 months after ileostomy closure, without returning to preoperative status. Urinary function was preserved while sexual function declined without improvement by 18 months post-taTME. Our results address patient expectations and inform shared decision-making regarding taTME.

Abstract Background: Pancreatic cancer is a leading cause of cancer-related death globally. Risk factors for pancreatic cancer include common genetic variants and potentially heavy alcohol consumption. We assessed if genetic variants modify the association between heavy alcohol consumption and pancreatic cancer risk. Methods: We conducted a genome-wide interaction analysis of single-nucleotide polymorphisms (SNP) by heavy alcohol consumption (more than three drinks per day) for pancreatic cancer in European ancestry populations from genome-wide association studies. Our analysis included 3,707 cases and 4,167 controls from case–control studies and 1,098 cases and 1,162 controls from cohort studies. Fixed-effect meta-analyses were conducted. Results: A potential novel region of association on 10p11.22, lead SNP rs7898449 (interaction P value (Pinteraction) = 5.1 × 10−8 in the meta-analysis; Pinteraction = 2.1 × 10−9 in the case–control studies; Pinteraction = 0.91 in the cohort studies), was identified. An SNP correlated with this lead SNP is an expression quantitative trait locus for the neuropilin 1 gene. Of the 17 genomic regions with genome-wide significant evidence of association with pancreatic cancer in prior studies, we observed suggestive evidence that heavy alcohol consumption modified the association for one SNP near LINC00673, rs11655237 on 17q25.1 (Pinteraction = 0.004). Conclusions: We identified a novel genomic region that may be associated with pancreatic cancer risk in conjunction with heavy alcohol consumption located near an expression quantitative trait locus for neuropilin 1, a protein that plays an important role in the development and progression of pancreatic cancer. Impact: This work can provide insights into the etiology of pancreatic cancer, particularly in heavy drinkers.

11558 Background: Nirogacestat (niro) is a targeted and selective gamma secretase inhibitor approved in the US for adults with progressing desmoid tumors (DT). In the phase 3 DeFi study, niro demonstrated significant improvement vs placebo (pbo) in progression-free survival (PFS: HR, 0.29 [95% CI: 0.15-0.55]; P<.001), objective response rate (ORR: 41% vs 8%; P<.001); and patient-reported outcomes (PROs) of pain, DT-specific symptom burden, physical and role functioning, and overall quality of life ( P≤.01, all). DT are driven by Wnt/β-catenin signaling pathway alterations and about 10-20% of DT are associated with mutations in the APC tumor suppressor gene, which may confer more aggressive DT behavior. Because patients with APC mutations may do worse, regardless of specific therapy, a post hoc analysis was conducted to assess effects of niro in patients with progressing DT and APC mutations. Methods: DeFi was a global, double-blind study that evaluated the efficacy, safety, and tolerability of niro in adults with progressing DT. Patients were randomized to oral niro (150 mg) or pbo twice-daily in continuous 28-day cycles. Descriptive post hoc analyses were conducted to assess effects of niro in patients with somatic and/or germline APC mutations. Results: Among 29 patients in DeFi with APC mutations (niro=13; pbo=16), 19 (66%) were female, 16 (55%) were aged ≤30 years, and 22 (76%) were refractory to prior treatment (with a median of 3 prior lines of treatment). In patients with APC mutation, PFS was improved with niro vs pbo (HR, 0.21 [95% CI: 0.05-1.00], P=.016). Confirmed ORR was 38% (5/13) for niro vs 13% (2/16) for pbo. Niro-treated patients also had greater reduction in median best percent change from baseline compared with pbo-treated patients in target tumor size (-29.5 vs +2.2), volumetric MRI (-71.0 vs +5.4), and T2 hyperintensity (-74.1 vs -21.0). Across all PROs assessed — Brief Pain Inventory, GODDESS DT Symptom Scale and DT Impact Scale, and European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire-Core 30 — patients treated with niro had numerically greater improvement from baseline at cycle 10 than pbo. Analyses were limited due to the small sample size. Adverse events in >50% of niro-treated patients with APC mutation were diarrhea, nausea, rash maculopapular, and fatigue; ovarian toxicity occurred in 9 of 10 of females of reproductive potential (6 resolved, 2 lost to follow-up, 1 ongoing and receiving niro). Conclusions: Improvement in PFS, ORR, tumor imaging characteristics and PROs was observed with niro compared to pbo in patients with DT harboring APC mutations. Efficacy and safety of niro in patients with APC mutations were generally consistent with findings for the overall DeFi population, suggesting that niro can provide clinically meaningful benefit to patients with progressing DT and APCmutations. Clinical trial information: NCT03785964 .

11533 Background: After initial response to first line therapy with imatinib, GISTs commonly progress due to secondary resistance mutations in KIT. As the KIT mutation targeting profiles of bezuclastinib (type I TKI) and sunitinib are distinct, when combined they inhibit a broad spectrum of secondary KIT mutations. Herein we report extended experience of patients treated with 2nd line combination bezuclastinib and sunitinib, including response assessment and safety. Methods: Peak (NCT05208047), a global randomized Phase 3, open-label study, aims to evaluate efficacy and safety of bezuclastinib + sunitinib vs sunitinib in GIST pts with imatinib intolerance or resistance. In Part 1a of the 3-part study, the dose of an optimized formulation of bezuclastinib was escalated in serial cohorts to achieve a target exposure comparable to that achieved at the RP2D established in the prior Phase 1b/2a study. Part 1b evaluated the interaction between bezuclastinib + sunitinib. Key inclusion: adult with locally advanced, metastatic and/or unresectable GIST, ≥1 measurable lesion according to modified RECIST v1.1, and ECOG PS 0 to 2. Part 1 completed enrollment in Apr 2023. Based upon PK and safety, a dose of bezuclastinib 600 mg QD + sunitinib 37.5 mg QD was selected for Part 2. All Part 1 data reported herein are as of Aug 2023; updated safety and efficacy will be presented. Results: Part 1 has completed enrollment with 19 pts in Part 1a and 23 in 1b. In Part 1a, Cohort 1 included 5 pts starting at bezuclastinib 300 mg QD + sunitinib 37.5 mg QD; Cohort 2 included 14 pts at bezuclastinib 600 mg QD + sunitinib 37.5 mg QD. Pt characteristics in Part 1a+1b: median age - 60 yrs (range: 33-77); 81% men; 98% ECOG PS 0-1; 98% metastatic and 2% locally advanced. The majority of TEAEs were low grade and reversible with low rate (38%) of Grade 3+ events. There were limited (24%) dose reductions and infrequent (n=2) discontinuations due to TEAEs. Three pts experienced serious AEs possibly associated with study medications. In pts evaluable for response (received ≥1 cycle of study treatment and had assessments at baseline and post-baseline [n=40]), the objective response rate (ORR) was 20% (6 confirmed PRs, 2 unconfirmed PRs). Data remain immature to estimate median PFS for Part 1 pts. In a subset of pts with prior imatinib only (n=6), the closest approximation for pts enrolling in Part 2, the ORR was 33% (2 confirmed PRs). The majority of 2nd-line pts remain on treatment past 12 months. Conclusions: Data from Peak Part 1 show an encouraging safety and tolerability profile generally consistent with published sunitinib monotherapy experience. ORR in evaluable pts from Part 1 was 20%; ORR in 2nd line pts was 33%. Part 2 of the Peak study is actively enrolling pts globally at the selected dose of bezuclastinib 600 mg QD + sunitinib 37.5 mg QD versus sunitinib 37.5 mg QD. Clinical trial information: NCT05208047 .

11521 Background: Osteosarcomas (OS) comprise the majority of new primary bone tumors in the US and affect a bimodal distribution of young adults (2nd-3rd decades) and older adults >65 yrs. Most large collaborative studies demonstrating the efficacy of HDMTX-containing chemotherapy regimens in OS limited enrollment to patients <40 yrs. Our study aims to fill the gap of reported clinical outcomes in adult OS patients ≥ 40 yrs by describing the feasibility and tolerability of HDMTX in these patients at Mayo Clinic. Methods: We conducted a retrospective chart review of patients ≥18 yrs with OS seen at our institution between 1/1/1980-9/30/2019 and who received ≥1 dose of HDMTX (12 g/m2, max 20 g). Extraosseous OS were excluded. Survival analyses were run for both the entire study population and the subset of patients age ≥40. Patient demographics, disease characteristics, and clinical outcomes were collected. The primary outcome evaluated was 5-year overall survival (5-yr OS). Results: We identified 94 patients whose demographic data are summarized (Table). Twenty-three of 94 (24%) were ≥40 yrs. Both the median number of HDMTX doses received and number of patients who received ≥50% recommended doses were significantly less among patients ≥40 yrs. However, HDMTX-related AKI and median number of hospital days did not differ significantly between the age groups. Among all patients, 5-yr OS was significantly improved (p=0.0025) at 45% (95% CI 35%-58%) for those who received ≥50% doses HDMTX compared to 5-yr OS of 25% (95% CI 12%-53%) for those who did not. Among patients ≥40 yrs, 5-yr OS was significantly improved (p=0.017) at 86% (95% CI 63%-100%) for those who received ≥50% doses HDMTX compared to 5-yr OS of 31% (95% CI 14%-68%) for those who did not. Conclusions: In our cohort, 5-yr OS was superior in those patients who received at least 50% of the planned doses of HDMTX. Older adults were significantly less likely to receive the majority of planned doses, which may be due to clinician bias regarding anticipated toxicity. However, we show that common HDMTX-associated toxicities did not vary significantly by age. If feasible, we recommend referring older patients with osteosarcoma to centers equipped to handle the staffing and supportive care needs of HDMTX administration. [Table: see text]