Oberstein, Paul E.

LBA5 Background: Available 2L therapies offer limited clinical benefit in mPDAC with reported mPFS of 3–4 mo and mOS of 6–7 mo. Aberrant RAS pathway activation is the key driver of PDAC, with oncogenic RAS mutations (mut) identified in >90% of cases, most commonly at codon G12. Daraxonrasib is an oral, RAS(ON) multi-selective, tri-complex inhibitor of the active, GTP-bound state of mutant and wild type RAS. Methods: RASolute 302 (NCT06625320) is a global, randomized, open-label, Ph 3 study in pts with 2L mPDAC and ECOG PS 0-1. Pts were randomized 1:1 to receive daraxonrasib 300 mg PO QD or investigator’s choice of SOC cytotoxic chemo. Dual primary endpoints were OS and PFS by BICR in the RAS G12 mutant (RAS G12) population. Key secondary endpoints included OS and PFS by BICR in the overall population, ORR by BICR in RAS G12 and overall populations. Results: 248 pts were randomized to daraxonrasib and 252 to chemo. Baseline characteristics were balanced between arms. At data cutoff (Feb 10, 2026; mFU: 8.5 mo), all primary and key secondary endpoints were met. Statistically significant, clinically meaningful improvements in OS and PFS were observed with daraxonrasib vs chemo in the RAS G12 and overall populations (Table). Gr ≥3 TRAEs occurred in 43.6% of pts receiving daraxonrasib vs 57.5% receiving chemo. The most common (≥10%) Gr ≥3 TRAEs were rash (13.7%) and stomatitis (12.0%) for daraxonrasib; neutrophil decrease (18.2%) and anemia (16.4%) for chemo. TRSAEs occurred in 10.8% of pts receiving daraxonrasib vs 18.7% receiving chemo. Discontinuation due to TRAEs occurred in 1.2% of pts for daraxonrasib vs 11.2% for chemo. Median/mean daraxonrasib dose intensity was 93.1%/84.7%. Conclusions: Daraxonrasib demonstrated unprecedented improvements in OS and PFS vs chemo in pts with 2L mPDAC with or without an identified tumor RAS mut. Daraxonrasib was generally well tolerated, with a manageable safety profile and with no new safety signals. Results support daraxonrasib as the new SOC for 2L mPDAC. Clinical trial information: NCT06625320 . RAS G12 Overall b Daraxonrasibn=228 Chemo n=231 Daraxonrasib n=248 Chemo n=252 OS Median; mos(95% CI) 13.2(10.0–NE) 6.6(5.4–8.2) 13.2(10.0–NE) 6.7(5.8–8.0) HR(95% CI)P-value 0.40(0.30-0.54)<0.0001 0.40(0.30-0.53)<0.0001 PFS a Median; mos(95% CI) 7.3(6.3–8.1) 3.5(2.9–3.8) 7.2(5.7–7.5) 3.6(2.9–4.2) HR(95% CI)P-value 0.45(0.34-0.59)<0.0001 0.49(0.38-0.64)<0.0001 ORR a %(95% CI) 33.2(27.0–39.9) 11.8(7.8–16.8) 31.6(25.8–38.0) 11.2(7.5–15.9) a By BICR. b RAS G12, G13 or Q61 mut or no RAS mut identified.

Abstract Background Surgical resection without visible or residual microscopic disease (R0 resection) is known as the optimal path to cure localized pancreatic cancer (PDAC). Neoadjuvant therapy (NAT) is used to improve R0 resection rates; however, the optimal regimen is unclear. We assessed the safety and efficacy of peri-operative gemcitabine/nab-paclitaxel (GEM/NAB) and pre-operative stereotactic body radiotherapy (SBRT) in patients with resectable (R-PDAC) and borderline resectable PDAC (BR-PDAC). Patients and Methods This was a prospective, multicenter single arm phase 2 study in patients with R-PDAC and BR-PDAC. Patients received three cycles of GEM/NAB prior to SBRT followed by surgery and three cycles of adjuvant GEM/NAB. Primary endpoint was R0 surgical resection rate in each cohort. Secondary endpoints included safety and overall survival (OS). Results Eighty-six patients consented and following radiologic screening, 49 were enrolled into two cohorts: R-PDAC (n = 20) and BR-PDAC (n = 29) between June 2016 and April 2021. Seventy percent of R-PDAC (14/20) and 55.2% of BR-PDAC patients (16/29) completed all NAT. Eleven R-PDAC (55.0%) and 11 BR-PDAC patients (37.9%) underwent surgical resection. Nine R-PDAC (45.0%) and 9 BR-PDAC patients (31.0%) had R0 resections. The median OS for R-PDAC and BR-PDAC patients with R0 resections was 22 months (95% CI: 17.7 months-NA) and 39 months (95%CI: 13.21 months-NA), respectively. Conclusion While the trial failed to meet one of its primary objectives as only 45% of R-PDAC patients had an R0 resection, the objective of 30% R0 resection for the BR-PDAC group was met. NAT should be part of current therapeutic strategies for BR-PDAC; however, our trial does not answer what is the best NAT for BR-PDAC. Trial Registration NCT02723331

4175 Background: Patients (pts) with pancreatic adenocarcinoma (PDAC) who are candidates for surgery are anatomically segregated into two groups: those with resectable tumors (R-PDAC), and those with borderline resectable tumors (BR-PDAC). For each group, complete surgical resection with no visible or microscopic disease left behind (R0 resection) is generally accepted as the path to cure. Neoadjuvant therapy (NAT) has been used to improve the R0 resection rate. However, the optimal role and type of NAT that will improve R0 resection rate and overall survival (OS) remains controversial. The Academic Gastrointestinal Cancer Consortium (AGICC) evaluated a perioperative strategy with combination chemotherapy and preoperative stereotactic radiation therapy (SBRT) to improve the R0 resection rate. Methods: This prospective, multicenter open label, single arm phase 2 clinical trial conducted among 5 member AGICC institutions enrolled pts with R-PDAC and BR-PDAC. Treatment included 3 cycles of gemcitabine (1000mg/m2) and nab-paclitaxel (125 mg/m2) (GEM/NAB) on days 1, 8 and 15 of a 28-day cycle prior to SBRT (33Gy: 6.6Gy daily x 5) followed by surgery and 3 cycles of adjuvant GEM/NAB. Accrual goal was 20 R-PDAC and 30 BR-PDAC pts selected by central radiology review. Primary objective was to estimate the R0 resection rate for each cohort. Secondary objectives included safety and tolerability of neoadjuvant treatment and OS. Results: Eighty-six pts signed consent and after radiologic screening, 20 R-PDAC patients and 29 BR-PDAC patients were found eligible to begin treatment. One R-PDAC and two BR-PDAC pts did not initiate therapy. 14 (70%) and 19 (66%) R-PDAC and BR-PDAC pts, respectively, completed all neoadjuvant chemotherapy.14 R-PDAC (70%) and 17 BR-PDAC (59%) pts completed SBRT. 11 R-PDAC pts (55%) and 11 (38%) BR-PDAC, underwent surgery. 8 R-PDAC pts (40%) had an R0 resection. One R-PDAC pt had a complete pathologic response (pCR). 8 BR-PDAC pts (28%) had an R0 resection. 19% (3/16) pts undergoing an R0 resection are alive (47-73+ mos). 16 pts (32%) had at least one grade ≥ 3 non-hematologic adverse event (AE); 25 patients (51%) had at least one grade ≥ 3 hematologic AE. 8 pts, 4 R-PDAC and 4 BR-PDAC were hospitalized prior to surgery. One pt (2%) died during NAT. There were no deaths due to surgery. Conclusions: R0 resection rates and survival in R-PDAC and BR-PDAC were low despite a perioperative approach of systemic therapy and SBRT. The lack of survival benefit of GEM/NAB as an adjuvant regimen, as well as SBRT pre-operatively (both shown in studies subsequent to this one) may explain the disappointing results. While an R0 resection for localized PDAC is recognized as essential, our results demonstrate that an R0 resection is not sufficient to cure the majority of PDAC pts who receive NAT with GEM/NAB + SBRT. Future NAT therapy trials should aim to markedly improve the pCR rates associated with R0 resection. Clinical trial information: NCT02723331 .

209 Background: Metastatic colorectal (CRC), pancreatic (PANC), and gastroesophageal cancers are the leading causes of GI cancer–related mortality (5-y survival: 15%, 3%, and 5%-6%, respectively) (ACS 2022). HLA LOH is a recurrent mechanism of immune escape observed in 15%-20% of GI cancers (Hecht R., ASCO GI 2022). The Tmod platform is a logic-gated chimeric antigen receptor (CAR) T-cell modular system, comprising a carcinoembryonic antigen (CEA)- or mesothelin (MSLN)-targeting CAR activator and a separate HLA-A*02-targeting blocker receptor. Both in vitro/in vivo, Tmod CAR T therapy kills cells with HLA-A*02 LOH (tumor) without harming cells with retained HLA-A*02 expression (normal). However, HLA-A*02 LOH can only be therapeutically exploited if patients are identifiable through a feasible and timely clinical workflow. Methods: We established a biobanking protocol (BASECAMP-1, NCT04981119) to determine whether HLA-A*02 LOH patients can be prospectively identified. Patients with CRC, PANC, or non-small cell lung cancer (NSCLC), and a high risk for incurable relapse, were screened first using a standard HLA assay. Heterozygous HLA-A*02 positive tumor samples were then assessed for LOH using a bioinformatic algorithm applied via the Tempus xT platform. Results: As of Sep 1, 2022, 83 patients were consented at 4 institutions. HLA status was obtained from 70 patients and 28 were identified as HLA-A*02:01 heterozygous (40%; expected frequency based on USA NMDP data, 27.6%). LOH results were available for 16 patients; 4 LOH-positive patients were identified (25%, 2 PANC, 2 NSCLC). The LOH assay sensitivity declines below a tumor purity of 40% (Hecht R., ASCO GI 2022). Six patients had a tumor purity of 20% (all with PANC, a tumor known for high stromal content), limiting possible LOH detection. The impact of tumor purity on LOH sensitivity was highlighted in a patient with a low initial sample tumor purity (30%) that resulted in a 41% probability of HLA-A*02:01 LOH (below positive threshold). A second sample with a higher tumor purity (70%), obtained from formalin-fixed, paraffin-embedded sections, resulted in a 92% probability of HLA-A*02:01 LOH (positive). Conclusions: BASECAMP-1 prospective identification of HLA-A*02 LOH is feasible in the real-world setting. The frequencies of the HLA-A*02 allele and of HLA-A*02 LOH in this cohort mirrored expected population frequencies. LOH results can be obtained within a clinically feasible workflow and timeframe, although samples with a < 40% tumor purity have a reduced sensitivity for LOH detection, an issue recurrently observed in patients with PANC. The BASECAMP-1 strategy enables prospective identification of appropriate patients for future therapeutic clinical trials using Tmod CEA and MSLN logic-gated CAR T cells. Clinical trial information: NCT04981119 .

PURPOSE This randomized, open-label trial compared the efficacy and safety of adjuvant nab-paclitaxel + gemcitabine with those of gemcitabine for resected pancreatic ductal adenocarcinoma (ClinicalTrials.gov identifier: NCT01964430 ). METHODS We assigned 866 treatment-naive patients with pancreatic ductal adenocarcinoma to nab-paclitaxel (125 mg/m 2 ) + gemcitabine (1,000 mg/m 2 ) or gemcitabine alone to one 30-40 infusion on days 1, 8, and 15 of six 28-day cycles. The primary end point was independently assessed disease-free survival (DFS). Additional end points included investigator-assessed DFS, overall survival (OS), and safety. RESULTS Two hundred eighty-seven of 432 patients and 310 of 434 patients completed nab-paclitaxel + gemcitabine and gemcitabine treatment, respectively. At primary data cutoff (December 31, 2018; median follow-up, 38.5 [interquartile range [IQR], 33.8-43 months), the median independently assessed DFS was 19.4 ( nab-paclitaxel + gemcitabine) versus 18.8 months (gemcitabine; hazard ratio [HR], 0.88; 95% CI, 0.729 to 1.063; P = .18). The median investigator-assessed DFS was 16.6 (IQR, 8.4-47.0) and 13.7 (IQR, 8.3-44.1) months, respectively (HR, 0.82; 95% CI, 0.694 to 0.965; P = .02). The median OS (427 events; 68% mature) was 40.5 (IQR, 20.7 to not reached) and 36.2 (IQR, 17.7-53.3) months, respectively (HR, 0.82; 95% CI, 0.680 to 0.996; P = .045). At a 16-month follow-up (cutoff, April 3, 2020; median follow-up, 51.4 months [IQR, 47.0-57.0]), the median OS (511 events; 81% mature) was 41.8 ( nab-paclitaxel + gemcitabine) versus 37.7 months (gemcitabine; HR, 0.82; 95% CI, 0.687 to 0.973; P = .0232). At the 5-year follow-up (cutoff, April 9, 2021; median follow-up, 63.2 months [IQR, 60.1-68.7]), the median OS (555 events; 88% mature) was 41.8 versus 37.7 months, respectively (HR, 0.80; 95% CI, 0.678 to 0.947; P = .0091). Eighty-six percent ( nab-paclitaxel + gemcitabine) and 68% (gemcitabine) of patients experienced grade ≥ 3 treatment-emergent adverse events. Two patients per study arm died of treatment-emergent adverse events. CONCLUSION The primary end point (independently assessed DFS) was not met despite favorable OS seen with nab-paclitaxel + gemcitabine.

4023 Background: Metastatic pancreatic cancer (mPC) remains a deadly disease with very limited treatment options. FFX is a standard first-line therapy for mPC with a median overall survival (mOS) of 11.1 months. CPI-613 is a stable intermediate of a lipoate analog that inhibits pyruvate dehydrogenase and α-ketoglutarate dehydrogenase enzymes of the tricarboxylic cycle preferentially within the mitochondria of cancer cells. In a phase I study, CPI-613+mFFX was safe and exhibited promising signal of efficacy. Methods: A global, randomized phase 3 trial was conducted across 73 sites to investigate the efficacy and safety of CPI-613 in combination with mFFX compared to standard dose FFX in treatment-naïve patients with mPC. Treatment was administered in 2-weekly cycles until progression or intolerable toxicity. In the experimental arm, CPI-613 at 500 mg/m2 was given intravenously on days 1 and 3. The doses of irinotecan, oxaliplatin, and 5-fluorouracil in the experimental arm were 65 mg/m2, 140 mg/m2, and 2,400 mg/2, respectively. Primary endpoint was OS. Secondary endpoints were progression-free survival (PFS), overall response rate (ORR), duration of response, pharmacokinetics, patient reported outcomes and safety. Results: 528 patients were randomly assigned (266 in test and 262 in control arm). There were 362 deaths, with a mOS of 11.1 months for CPI-613+mFFX vs. 11.7 months for FFX [hazard ratio (HR), 0.95; 95% CI, 0.77 to 1.18; P = 0.655]; mPFS was 7.8 months vs. 8.0 months respectively [HR, 0.99; 95% CI, 0.76 to 1.29; P = 0.94]; ORR was 39% in the test arm vs. 34% in the control arm [ORR ratio, 1.23 (95% CI, 0.86 to 1.75)]. Grade ≥ 3 treatment-emergent adverse events with ≥ 10% frequency in CPI-613 plus mFFX vs. FFX arm were diarrhea (11.2% vs. 19.6%), hypokalemia (13.1% vs. 14.9%), anemia (13.9% vs. 13.6%), neutropenia (11.2% vs. 14.0%), thrombocytopenia (11.6% vs. 13.6%) and fatigue (10.8% vs. 11.5%). Conclusions: The addition of CPI-613 to mFFX failed to show significant improvements of ORR, PFS or OS. The mFFX in the test arm that had the lowest prospectively tested doses of FFX was without compromise on PFS or OS and may be considered as a reference for future FFX administration. Clinical trial information: NCT03504423.