NRG-GI004/SWOG-S1610: Colorectal Cancer Metastatic dMMR Immuno-Therapy (COMMIT) study—A randomized phase III study of atezolizumab (atezo) monotherapy versus mFOLFOX6/bevacizumab/atezo in the first-line treatment of patients (pts) with deficient DNA mismatch repair (dMMR) or microsatellite instability high (MSI-H) metastatic colorectal cancer (mCRC)

TPS258

Background: Despite the superiority in progression-free survival (PFS) of inhibition of programmed cell death-1 (PD-1) pathway in dMMR/MSI-H as compared to chemotherapy with either anti-vascular endothelial growth factor receptor (VEGFr) or anti-epithelial growth factor receptor (EGFr) antibodies in mCRC, more pts had progressive disease as the best response in the anti-PD1 monotherapy arm (29.4% v 12.3%) with mean PFS of 13.7 mos, with ~45% of pts in the immunotherapy arm progressed at 12 mos (KEYNOTE 177). We hypothesize that dMMR/MSI-H mCRC pts may be more effectively treated with the combination of PD-1 pathway blockade and mFOLFOX6/bevacizumab (bev) rather than with anti-PD-1 therapy (atezo) alone. Preclinical work demonstrated synergistic effects between anti-PD-1/anti-VEGF and between oxaliplatin/anti-PD-1 in murine CRC models and phase II data, which showed activity of anti-PD-1/anti-VEGF in chemotherapy refractory colon cancer. A recent randomized trial subgroup analysis of 8 pts with dMMR metastatic colon cancer treated with FOLFOXIRI+bev+atezo, with the first patient having progression ~16 mos (AtezoTRIBE). Additionally, in other solid tumor malignancies, anti-PD1 plus anti-VEGFr (i.e., HCC and RCC) as well as anti-PD1 plus chemotherapy (i.e., gastric and esophageal cancers) combinations are standard first-line treatments. Methods: The redesigned COMMIT study was reactivated on 1/29/2021 as a two-arm prospective phase III open-label trial randomizing (1:1) mCRC dMMR/MSI-H to atezo monotherapy v mFOLFOX6/bev+atezo combination. Assuming our control arm, atezo monotherapy (48% PFS at 24 mos as assessed by site investigator), we have 80% power to detect a hazard ratio of 0.6 (equivalent to 64.4% PFS at 24 mos) with alpha 0.025 one-sided. Stratification factors include BRAFV600E status, metastatic site, and prior adjuvant CRC therapy. Secondary endpoints include OS, objective response rate, safety profile, disease control rate, and duration of response. Health-related quality of life is an exploratory objective. Archived tumor tissue and blood samples will be collected for correlative studies. Key inclusion criteria are: mCRC without prior chemotherapy for advanced disease; dMMR tumor determined by local CLIA-certified IHC assay (MLH1/MSH2/MSH6/PMS2) or MSI-H by local CLIA-certified PCR or NGS panel; and measurable disease per RECIST. Enrollment actively continues to the target accrual of 211 patients randomized between the two immunotherapy arms. Clinical trial: NCT02997228. Support: U10CA180868, -180822, -180888, UG1CA189867, U24CA196067; Genentech, Inc. Clinical trial information: NCT05080673 .

NSABP FC-12: A single-arm, phase II study to evaluate treatment with gevokizumab in patients with stage II/III colon cancer who remain ctDNA+ after curative surgery and adjuvant chemotherapy

TPS3642

Background: Detection of circulating tumor DNA (ctDNA) in patients (pts) following surgery is indicative of presence of minimal/molecular residual disease (MRD) and confers a near-certain risk of disease recurrence. Therapeutic strategies to treat MRD following standard curative therapies are needed because the risk of recurrence is high and therapeutic intervention may provide clinical benefit to patients. Gevokizumab is a recombinant humanized monoclonal antibody targeting interleukin-1β (IL-1β), which is involved in all phases of the malignant process (tumorigenesis, invasion, metastasis, angiogenesis, progression, and the modulation of anti-tumor immunity). Gevokizumab has been validated in pre-clinical colon cancer (CC) models and safety established in the advanced-stage clinical setting. In this trial in progress, we aim to test the efficacy of gevokizumab in pts with early-stage CC with MRD (ctDNA-positivity) following definitive treatment. Methods: NSABP FC-12 is a single-arm, multi-centered phase II study that will include pts with stage II/III CC who test MRD+ within 6 wks following completion of curative surgery and ≥3 mos of adjuvant chemotherapy. MRD will be assessed using a personalized and tumor-informed ctDNA assay (Signatera bespoke assay). Gevokizumab will be given at a flat dose of 120 mg IV every 28 days for 13 cycles. The primary endpoint is relapse-free survival (RFS) following initiation of study therapy through one year of follow-up. Secondary endpoints are rate of ctDNA clearance at 8 wks from start of study therapy, as well as safety, toxicity, pharmacokinetics, and immunogenicity of gevokizumab. Exploratory and correlative endpoints will include outcomes associated with ctDNA clearance kinetics, tumor mutations, tumor mutational burden, circulating methylated DNA, tumor immune microenvironment profile, peripheral blood immune profile, and stool microbiome analyses. The enrollment period will be ̃12 mos. Pts will be followed for 18 mos following enrollment with ctDNA analysis at prespecified timepoints until imaging is positive for recurrence of disease or death. CT scans will be at 6-mo intervals. RFS will be determined in pts who clear ctDNA at 8 wks compared to those who do not. A single-stage design to test the null hypothesis that the 12-mo RFS is P≥0.20 versus the alternative (HA) that P≥0.35 has a sample size of 31 (alpha=0.151; power 0.811). If ≥9 of 31 pts (29%) are alive and recurrence-free at 12 mos, then gevokizumab will be considered promising for further study. Enrollment continues towards the primary endpoint. Clinical trial information: 05178576.

Colorectal cancer metastatic dMMR immuno-therapy (COMMIT) study: A randomized phase III study of atezolizumab (atezo) monotherapy versus mFOLFOX6/bevacizumab/atezo in the first-line treatment of patients (pts) with deficient DNA mismatch repair (dMMR) or microsatellite instability high (MSI-H) metastatic colorectal cancer (mCRC)—NRG-GI004/SWOG-S1610

TPS3647

Background: Despite the superiority in progression-free survival (PFS) of inhibition of programmed cell death-1 (PD-1) pathway in dMMR/MSI-H as compared to chemotherapy with either anti-vascular endothelial growth factor receptor (VEGFr) or anti-epithelial growth factor receptor (EGFr) antibodies in mCRC, more pts had progressive disease as the best response in the anti-PD1 monotherapy arm (29.4% v 12.3%) with mean PFS of 13.7 mos, with ̃45% of pts in the IO arm progressed at 12 mos ( N Engl J Med 2020; 383:2207). We hypothesize that the dMMR/MSI-H mCRC pts may be more effectively treated with the combination of PD-1 pathway blockade and mFOLFOX6/bevacizumab (bev) rather than with anti-PD-1 therapy (atezo) alone. Preclinical work demonstrated synergistic effects between anti-PD-1/anti-VEGF and between oxaliplatin/anti-PD-1 in murine CRC models and phase II data, which showed activity of anti-PD-1/anti-VEGF in chemotherapy refractory colon cancer. A recent randomized trial subgroup analyses of 8 pts with dMMR metastatic colon cancer treated with FOLFOXIRI+bev+atezo, with the first patient having progression ̃16 mos ( ESMO 2021, Abstt LBA20). Additionally, in other solid tumor malignancies, anti-PD1 plus anti-VEGFr (i.e., HCC and RCC) as well as anti-PD1 plus chemotherapy (i.e., gastric and esophageal cancers) combinations are standard first-line treatments. Methods: The redesigned COMMIT study was reactivated on 1/29/2021 as a two-arm prospective phase III open-label trial randomizing (1:1) mCRC dMMR/MSI-H to atezo monotherapy v mFOLFOX6/bev+atezo combination. Assuming our control arm, atezo monotherapy (48% PFS at 24 mos as assessed by site investigator), we have 80% power to detect a hazard ratio of 0.6 (equivalent to 64.4% PFS at 24 mos) with alpha 0.025 one-sided. Stratification factors include BRAFV600E status, metastatic site, and prior adjuvant CRC therapy. Secondary endpoints include OS, objective response rate, safety profile, disease control rate, and duration of response. Health-related quality of life is an exploratory objective. Archived tumor tissue and blood samples will be collected for correlative studies. Key inclusion criteria are: mCRC without prior chemotherapy for advanced disease; dMMR tumor determined by local CLIA-certified IHC assay (MLH1/MSH2/MSH6/PMS2) or MSI-H by local CLIA-certified PCR or NGS panel; and measurable disease per RECIST. Enrollment actively continues to the target accrual of 211 patients randomized between the two immunotherapy arms. Support: U10CA180868, -180822, -180888, UG1CA189867, U24CA196067. Clinical trial information: NCT02997228.

Phase 3, multicenter, randomized study of CPI-613 with modified FOLFIRINOX (mFFX) versus FOLFIRINOX (FFX) as first-line therapy for patients with metastatic adenocarcinoma of the pancreas (AVENGER500)

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.

Phase II study of durvalumab following neoadjuvant chemoRT in operable rectal cancer: NSABP FR-2

99

Background: Although immunotherapy shows no benefit in microsatellite stable (MSS) colorectal cancer, preclinical models suggest that radiotherapy (RT) can enhance neoantigen presentation, modulate the microenvironment, and improve the likelihood of anti-tumor activity with checkpoint inhibitor use. Using a “window-of-opportunity” study design, this prospective phase II trial will determine the safety and activity of this approach with the anti-PD-L1 agent durvalumab (MEDI4736). Methods: Stage II/III patients (pts) with MSS rectal cancer undergoing standard NCCN guideline-compliant neoadjuvant chemoradiotherapy (CRT) followed by definitive surgery were eligible. Treatment included durvalumab (750mg IV infusion once every 2 wks) for 4 total doses beginning within 3-7 days after CRT completion followed by surgery within 8-12 wks of the final CRT dose. Primary end point (EP): Improvement in modified neoadjuvant rectal cancer (mNAR) score (goal 10.6) compared to historical controls (15.6) targeting a 20% DFS RR reduction and 3-4% absolute OS improvement. Secondary EPs: toxicity, pCR, cCR, therapy completion, negative surgical margins, sphincter preservation, and exploratory assessments of tumor-infiltrating lymphocytes, tumor Immunoscore, circulating immunologic profiles, and molecular predictors of response. We test H0: mNAR ≥15.6 vs HA: mNAR <15.6 at alpha 0.10 one-sided with statistical significance defined as p<0.1. Results: From May 2018 to October 2020, 45 pts were enrolled with 40 pts evaluable for mNAR. Mean mNAR was 12.03 (80% CI: 9.29-14.97) (p=0.06 one-sided). pCR=22.2%; cCR=31.1%; R0 resection=81.0%, and sphincter preservation=71.4%. Side effects were consistent with both CRT and durvalumab safety profile. Most common grade 3 AEs included diarrhea, lymphopenia, and back pain. There was one grade 4 AE (elevated amylase/lipase) and no grade 5 AEs. Remaining secondary and correlative immunologic end points are still being assessed. Conclusions: Durvalumab immediately following CRT prior to surgery for definitive management of rectal cancer was safe and without unexpected short-term toxicities. The primary end point of mean mNAR score was significantly less than our historical control, warranting further investigation. Correlative analyses for immunologic markers of response including PD-(L)1 expression and Immunoscore are ongoing. NCT 03102047. Support: AstraZeneca-Medimmune, NSABP Foundation. Clinical trial information: NCT03102047.

NRG-GI004/SWOG-S1610: Colorectal cancer metastatic dMMR immuno-therapy (COMMIT) study—A randomized phase III study of atezolizumab (atezo) monotherapy versus mFOLFOX6/bevacizumab/atezo in the first-line treatment of patients (pts) with deficient DNA mismatch repair (dMMR) or microsatellite instability high (MSI-H) metastatic colorectal cancer (mCRC)

TPS232

Background: Despite the superiority in progression-free survival (PFS) of inhibition of programmed cell death-1 (PD-1) pathway in dMMR/MSI-H as compared to chemotherapy with either anti-vascular endothelial growth factor receptor (VEGFr) or anti-epithelial growth factor receptor (EGFr) antibodies in mCRC, more pts had progressive disease as the best response in the anti-PD1 monotherapy arm (29.4% vs. 12.3%) with mean PFS of 13.7 months ( N Engl J Med 2020; 383:2207). We hypothesize that the dMMR/MSI-H mCRC pts may be more effectively treated by the combination of PD-1 pathway blockade and mFOLFOX6/bevacizumab (bev) rather than with anti-PD-1 therapy (atezo) alone. Preclinical work demonstrated synergistic effects between anti-PD-1/anti-VEGF and between oxaliplatin/anti-PD-1 in murine CRC models and phase II data showed activity of anti-PD-1/anti-VEGF in chemotherapy refractory colon cancer. Additionally, in other solid tumor malignancies, anti-PD1 plus anti-VEGFr (i.e., HCC and RCC) as well as anti-PD1 plus chemotherapy (i.e., gastric and esophageal cancers) combinations are standard first-line treatments. Methods: The redesigned COMMIT study was reactivated on 1/29/2021 as a two-arm prospective phase III open-label trial randomizing (1:1) mCRC dMMR/MSI-H (211 pts) to atezo monotherapy versus mFOLFOX6/bev+atezo combination. Assuming our control arm, atezo monotherapy, 48% PFS at 24 months, as assessed by site investigator, we have 80% power to detect a hazard ratio of 0.6 (equivalent to 64.4% PFS at 24 months) with alpha 0.025 one-sided. Stratification factors include BRAFV600E status, metastatic site, and prior adjuvant CRC therapy. Secondary endpoints include OS, objective response rate, safety profile, disease control rate, duration of response, and centrally-reviewed PFS. Health-related quality of life is an exploratory objective. Archived tumor tissue and blood samples will be collected for correlative studies. Key inclusion criteria are: mCRC without prior chemotherapy for advanced disease; dMMR tumor determined by local CLIA-certified IHC assay (MLH1/MSH2/MSH6/PMS2) or MSI-H by local CLIA-certified PCR or NGS panel; and measurable disease per RECIST. Enrollment actively continues to the target accrual of 211 patients randomized between the two immunotherapy arms. Support: U10CA180868, -180822, -180888, UG1CA189867, U24CA196067; Genentech, Inc. Clinical trial information: NCT02997228.

Colorectal Cancer Metastatic dMMR Immuno-Therapy (COMMIT) Study: A randomized phase III study of atezolizumab (atezo) monotherapy versus mFOLFOX6/bevacizumab/atezo in the first-line treatment of patients (pts) with deficient DNA mismatch repair (dMMR) or microsatellite instability high (MSI-H) metastatic colorectal cancer (mCRC)—NRG-GI004/SWOG-S1610

TPS3618

Background: The superiority of inhibition of programmed cell death-1 (PD-1) pathway in dMMR/MSI-H over chemotherapy with either anti-vascular endothelial growth factor receptor (VEGFr) or anti- epithelial growth factor receptor (EGFr) antibodies in mCRC has been demonstrated in a phase III trial (N Engl J Med 2020; 383:2207). However, more patients had progressive disease as the best response in the anti-PD1 monotherapy arm (29.4% vs. 12.3%) with mean progression-free survival (PFS) of 13.7 months. Preclinical models have demonstrated synergistic interactions between FOLFOX, anti-VEGF, and anti-PD-1. We hypothesize that the dMMR/MSI-H mCRC patients may be more effectively treated by the combination of PD-1 pathway blockade and mFOLFOX6/bevacizumab (bev) rather than with anti-PD-L1 therapy (atezo) alone. Methods: Initially a three-arm study, the mFOLFOX6/bev arm was closed to new enrollment on 6-4-20 due to emerging data; the redesigned COMMIT trial was reactivated on 1/29/2021 as a prospective phase III open-label trial that randomizes (1:1) mCRC dMMR/MSI-H pts (N=211) to either atezo monotherapy or mFOLFOX6/bev+atezo combination. Stratification factors include BRAFV600E status, metastatic site, and prior adjuvant CRC therapy. Primary endpoint is PFS as assessed by site investigator. Secondary endpoints include overall survival (OS), objective response rate (RECIST v1.1), safety profile, disease control rate, duration of response, and centrally-reviewed PFS. Health-related quality of life is an exploratory objective. Archived tumor tissue and blood samples will be collected for correlative studies. Key inclusion criteria are: mCRC without prior chemotherapy for advanced disease; dMMR tumor determined by local CLIA-certified IHC assay (MLH1/MSH2/MSH6/PMS2) or MSI-H by local CLIA-certified PCR or NGS panel; and measurable disease per RECIST. Clinical trial: NCT02997228. Support: U10CA180868, -180822, -180888, -180819, UG1CA189867, U24CA196067; Genentech, Inc. Clinical trial information: NCT02997228.

NRG-GI004/SWOG-S1610: Colorectal Cancer Metastatic dMMR Immuno-Therapy (COMMIT) Study—A randomized phase III study of atezolizumab (atezo) monotherapy versus mFOLFOX6/bevacizumab/atezo in the first-line treatment of patients (pts) with deficient DNA mismatch repair (dMMR) or microsatellite instability high (MSI-H) metastatic colorectal cancer (mCRC)

TPS158

Background: Despite activity of programmed cell death-1 (PD-1) pathway inhibition in dMMR/MSI-H mCRC, approximately one-third of patients demonstrate progressive disease as best response to anti-PD1 monotherapy. Preclinical models have demonstrated synergistic interactions between FOLFOX, anti-VEGF, and anti-PD-1. We hypothesize that the dMMR/MSI-H mCRC subset may be more effectively targeted by the combination of PD-1 pathway blockade and mFOLFOX6/bevacizumab (bev) rather than with anti-PD-1 therapy (atezo) alone. Methods: Initially a three-arm study, the mFOLFOX6/bev arm was closed to new enrollment on 6-4-20 due to emerging data; the redesigned COMMIT is a prospective phase III open-label trial that will randomize (1:1) mCRC dMMR/MSI-H pts (N=211) to either atezo monotherapy or mFOLFOX6/bev+atezo combination. Stratification factors include BRAFV600E status, metastatic site, and prior adjuvant CRC therapy. Primary endpoint is progression-free survival (PFS) as assessed by site investigator. Secondary endpoints include OS, objective response rate, safety profile, disease control rate, duration of response, and centrally-reviewed PFS. Health-related quality of life is an exploratory objective. Archived tumor tissue and blood samples will be collected for correlative studies. Key inclusion criteria are: mCRC without prior chemotherapy for advanced disease; dMMR tumor determined by local CLIA-certified IHC assay (MLH1/MSH2/MSH6/PMS2) or MSI-H by local CLIA-certified PCR or NGS panel; and measurable disease per RECIST. Support: U10CA180868, -180822, -180888, -180819, UG1CA189867, U24CA196067; Genentech, Inc. Clinical trial information: NCT02997228.

Trial in progress: A phase I study of AMG 199, a half-life extended bispecific T-cell engager (HLE BiTE) immune therapy, targeting MUC17 in patients with gastric and gastroesophageal junction (G/GEJ) cancer

TPS4649

Background: Prognosis for advanced G/GEJ cancer is poor and new treatment modalities are urgently needed. MUC17 is a transmembrane protein overexpressed and differentially localized on the cell membrane of G/GEJ cancer cells; expression and localization in normal cells is much more limited. AMG 199 is an HLE BiTE immune therapy designed to engage CD3-positive T cells to MUC17-positive G/GEJ cancer cells, mediate redirected tumor cell lysis, and induce T cell activation and proliferation. A clinical trial is being conducted for this novel and targeted immune therapy agent in patients with MUC17-positive G/GEJ cancer. Methods: This is a first-in-human phase 1, open-label, dose escalating study (NCT04117958) evaluating AMG 199 in patients with MUC17-positive G/GEJ cancer. Key eligibility criteria include metastatic or locally advanced unresectable MUC17-positive (as determined by IHC using a central laboratory assay) gastric adenocarcinoma or gastroesophageal junction adenocarcinoma ineligible for curative surgery and relapsed or treatment-refractory following ≥2 lines including a platinum, a fluoropyrimidine, taxane or irinotecan, and an approved vascular endothelial growth factor receptor antibody or tyrosine kinase inhibitor. Patients eligible for human epidermal growth factor receptor 2 (HER2) directed therapy should have received an approved HER2 targeting antibody. Primary endpoints include: dose-limiting toxicities, treatment-emergent or -related adverse events, vital signs, electrocardiogram (ECG), and laboratory changes. Secondary endpoints include: pharmacokinetics of AMG 199, objective response, duration of response, time to progression, 6-month and 1-year progression-free survival, and 1-year and 2-year overall survival. The dose exploration (n = 30) will estimate the maximum tolerated dose and/or recommended phase 2 dose; this will be followed by a dose expansion (n = 40) and evaluation of the benefit/risk profile of AMG 199. The study began enrolling patients in January 2020 and is ongoing. This is the first clinical trial to investigate MUC17 as a potential anti-tumor target. For more information, please contact Amgen Medical Information: medinfo@amgen.com . Clinical trial information: NCT04117958 .

Expectations of overall survival for patients with metastatic pancreatic cancer (mPC)

e16788

Background: Pancreatic cancer is the 4th leading cause of cancer-related death in the U.S. Metastatic pancreatic cancer has typically had a poor prognosis. However, the use of combination chemotherapy with novel agents have improved outcomes. First line therapy with either FOLFIRINOX (2011) or gemcitabine (gem)/nab-paclitaxel (2013) improved response rates (RR), progression-free survival (PFS) and OS versus (vs) gem alone. In 2015, second-line therapy with nanoliposomal irinotecan and fluorouracil (5FU) also improved RR, PFS, and OS vs 5FU. Since 2017, several newer agents have been approved for targeted patient populations – pembrolizumab for MSI-H/dMMR tumors, larotrectinib and entrectinib for NTRK gene fusion positive pts, and olaparib for germline BRCA-mutated pts. As more treatment (Tx) options become available, pts are more likely to receive Tx in later lines. A population-based study found that of mPC pts who completed 1st-line (1L) chemotherapy prior to December 31, 2014, 49% went on to receive 2nd-line (2L) Tx and 17% received 3rd-line (3L) Tx6. Methods: Prescribing patterns of 569 U.S.-based oncologists were studied using a validated, proprietary, case-based market research tool (Challenging Cases). Data were acquired using blinded, audience-response iPad technology at 8 live events during 2018-2019. Results: Estimate of mPC patients treated with 2L and 3L Tx in 2019 Estimates for mPC pts treated with 2L therapy rose from 2018 to 2019, with 46% treating > 60% of mPC patients with 2L in 2018 compared to 54% in 2019. Oncologists estimated median survivals to be 7.4 months (mos) from the regimens they prescribe in 1L, 4.3 mos in 2L, and 2.3 mos in 3L. Conclusions: With the addition of new and more effective treatments for mPC, more patients are treated in the 2L and 3L settings. However, oncologists may underestimate the survival expectation with novel agents or regimens, particularly in later lines of therapy. [Table: see text]

SGN228-001: A phase I open-label dose-escalation, and expansion study of SGN-CD228A in select advanced solid tumors

TPS3652

Background: SGN-CD228A is an investigational antibody-drug conjugate (ADC) that targets CD228, a cell-surface oncofetal protein with prevalent expression in several types of cancer and limited expression on normal tissues. SGN-CD228A consists of a humanized IgG1 anti-CD228 monoclonal antibody conjugated to an average of 8 molecules of monomethyl auristatin E (MMAE) via a PEGylated β-glucuronidase cleavable linker. MMAE is a well-studied and highly active chemotype with an established safety profile. The proposed mechanism of action involves binding CD228 on cell surfaces, ADC internalization, and trafficking to lysosomes. MMAE is then released through β-glucuronidase cleavage of the glucuronide MMAE linker. MMAE then binds tubulin, which disrupts microtubule networks and causes cell cycle arrest and apoptosis. Methods: SGN228-001 (NCT04042480) is a phase 1, open label, multicenter, dose escalation, and expansion study enrolling up to 240 subjects to evaluate the safety, tolerability, PK, and antitumor activity of SGN-CD228A in select advanced solid tumors. Eligible subjects are ≥18 years of age and have metastatic cutaneous melanoma, malignant pleural mesothelioma, human epidermal growth factor receptor 2-negative metastatic breast cancer, advanced non-small cell lung cancer, metastatic colorectal cancer, or advanced pancreatic ductal adenocarcinoma. Subjects must have relapsed, refractory, or progressive disease, and should have no appropriate standard therapy available. Measurable disease per Response Evaluation Criteria in Solid Tumors Version 1.1 (RECIST v1.1), Eastern Cooperative Oncology Group (ECOG) performance status score of ≤1, and adequate renal, hepatic, and hematologic function are required. The study includes dose escalation and dose expansion, with multiple disease-specific dose expansion cohorts and a biology cohort. Dose escalation will be conducted using the modified toxicity probability interval method (Ji 2010) to evaluate the safety and identify the maximum tolerated dose of SGN-CD228A. Following dose escalation, disease-specific expansion cohorts and a biology cohort (to evaluate exploratory biomarkers) are planned. Response assessments will be conducted every 6 weeks per RECIST v1.1 and all subjects will be followed for safety. Pharmacokinetics and markers of pharmacodynamics will be assessed regularly. Key efficacy endpoints include objective response rate, progression-free survival, and duration of objective response. Enrollment is ongoing in the US and planned in Europe. Clinical trial information: NCT04042480 .

A randomized phase III study of mFOLFOX6/bevacizumab combination chemotherapy with or without atezolizumab or atezolizumab monotherapy in the first-line treatment of patients (pts) with deficient DNA mismatch repair (dMMR) metastatic colorectal cancer (mCRC): Colorectal Cancer Metastatic dMMR Immuno-Therapy (COMMIT) study (NRG-GI004/SWOG-S1610)

TPS260

Background: Deficient DNA mismatch repair (dMMR) colorectal cancer (CRC) is highly immunogenic. Preclinical data showed synergistic interactions among FOLFOX, anti-VEGF, and programmed cell death-1 (PD-1) pathway blockade. Prior phase I study of mFOLFOX6/ bevacizumab (bev) + atezolizumab (atezo) was well tolerated and enhanced intratumoral infiltration of CD8+ T cells. We hypothesize that the dMMR subset of CRC may be effectively targeted with combination of PD-1 pathway blockade and mFOLFOX6/bev. Methods: This is a prospective randomized phase III open-label trial. Pts (N=347) with mCRC dMMR will be randomized to three trial arms (1:1:1): mFOLFOX6/bev; atezo monotherapy; or mFOLFOX6/bev + atezo. Stratification factors include BRAFV600E status, metastatic site, and prior adjuvant CRC therapy. Primary endpoint is progression-free survival (PFS) assessed by study investigator of mFOLFOX6/bev/atezo and atezo monotherapy compared to mFOLFOX6/bev. Secondary endpoints include OS, objective response rate, safety profile, disease control rate, duration of response, and PFS by retrospective central review. Health-related quality of life is an exploratory objective. Archived tumor tissue and blood samples will be collected for correlative studies. Key inclusion criteria are: mCRC without prior chemotherapy for advanced disease; dMMR tumor determined by local CLIA-certified IHC assay (MLH1/MSH2/MSH6/PMS2); availability of archived tumor tissue for central confirmation of dMMR status; and measurable disease per RECIST. Activated 11-7-17. As of 9-11-19, enrollment continues with 44/347 pts enrolled. Clinical trial: NCT02997228. Support:U10CA180868, -180822, -180888, -180819, UG1CA189867, U24CA196067; Genentech, Inc. Clinical trial information: NCT02997228.

DNA-damage repair deficiency (dDDR) and response to nanoliposomal irinotecan (nal-IRI) in metastatic pancreatic ductal adenocarcinoma (mPDAC)

731

Background: Chemotherapy is the standard of care for patients with mPDAC but there are no biomarkers to aid in treatment selection. Nal-IRI with 5-fluorouracil/folinic acid (FUFA) improves survival over FUFA in the second-line treatment of mPDAC. Nal-IRI is a topoisomerase inhibitor and its action produces DNA damage leading to cell death. We hypothesize that tumors with dDDR, a process that is altered in a subset of patients with PDAC, may be more sensitive to the effects of nal-IRI. Methods: Utilizing the IRB-approved pancreas cancer databases at the University of Miami and Wake Forest University, we identified patients with mPDAC treated with nal-IRI and FUFA who had germline and/or somatic mutation testing. We conducted a retrospective chart review to extract demographic and clinical characteristics including treatments received, response, and survival. Results: Among 31 patients identified, the median age was 66y and 47% were female. Nine patients had a DDR mutation; 6 germline and 3 somatic. Median progression-free survival (PFS) in patients with any germline or somatic DDR mutation was 3.2m vs 3.9m for those without (log-rank p = 0.7). When restricted to germline DDR mutations only, the median PFS was not reached with germline dDDR vs 4m for those without (log-rank p = 0.22). Presence of dDDR was associated with a higher clinical benefit rate (CBR = partial response + stable disease); a DDR mutation was present in 36% of patients who showed clinical benefit vs 15% in those without clinical benefit (p = 0.21). Conclusions: DDR mutations appear to define a subset of patients with mPDAC who may be more sensitive to nal-IRI and FUFA. The PFS and CBR were numerically but not statistically superior, especially in patients with germline DDR mutations. Larger data sets and longer follow-up are needed to confirm this trend.

A phase I clinical trial of fluorouracil (5-FU) + devimistat (CPI-613) combination in previously treated patients (pts) with metastatic colorectal cancer (MCR)

e15054

Background: MCR that failed standard lines of therapy have a poor outcome. Inhibition of glutamine metabolism potentially can synergize with chemotherapy and reverse resistance. Devimistat is a novel anti-mitochondrial agent that alters energy metabolism and redox processes, leading to apoptosis, necrosis, and autophagy. Methods: Phase Ib dose escalation (3+3 design) to determine the MTD of devimistat, when used in combination with fixed doses of bolus and infusional 5-FU, in non-resectable MCR, ECOG PS 0-3, and good organ function who have failed, or could not tolerate, prior standard therapies. A cycle was 2 weeks. Escalating doses of devimistat were given IV over 2 hrs via central line on days 1-4. On Day 2 when both devimistat and bolus 5-FU were given, devimistat was given first, followed by 5-FU bolus (400 mg/m2) followed by infusional 5-FU over 46 hrs (2,400 mg/m2) on Days 2-4. Plasma samples to measure devimistat and metabolites were collected before and after the first and last dose of devimistat on cycle 1. Results: 19 pts enrolled from 1/20/2015 to 1/16/2019. One was never treated with devimistat and was excluded from analyses. Median age was 63 (range 32-83). 10 males and 8 females. Median devimistat cycles were 4 (range 1-8). Dose levels of devimistat: 1 pt treated at 2,000 mg/m2, 1 pt treated at 2,250 mg/m2, 7 pts treated at 2,500 mg/m2, then dose was de-escalated for an additional 9 pts treated at 2,250 mg/m2. Two of 7 pts had a DLT at the devimistat 2,500 mg/m2 dose level; a grade 3 and a grade 4 creatinine level. The dose of devimistat was de-escalated to 2,250 mg/m2 with a total of 10 pts being treated without DLTs observed (2 still on treatment). Other G1-2 non-hematologic and G1-3 hematologic toxicities were observed but related to 5FU except for two episodes of G1 intravascular hemolysis. No radiologic responses were observed. Four pts had SD and two pts at 2,250 mg/m2 of devimistat continue on therapy. Median PFS and OS are currently 2.73 and 5.75 months respectively. Conclusions: Devimistat and 5FU combination demonstrated a tolerable safety profile in heavily pretreated MCR pts. Durable SDs observed at the MTD suggest antitumor activity at the 2,250 mg/m2 devimistat dose level. Clinical trial information: NCT02232152.

Deleterious alterations in DNA-damage repair (daDDR) genes as a predictive biomarker for platinum-based chemotherapy in metastatic pancreatic ductal adenocarcinoma (mPDAC)

266

Background: Germline genetic testing and somatic genomic profiling using commercial multigene panels are now routine in mPDAC. A subset of these patients have deleterious alterations in genes involved with DDR. Herein we investigate the role of daDDR as a predictive biomarker for response to first-line platinum-based chemotherapy. Methods: Utilizing the IRB-approved pancreas cancer and genetics clinic databases at the University of Miami, we identified all patients with mPDAC who had germline and/or somatic mutation testing. We performed a retrospective chart review to extract demographic and clinical characteristics including treatments received, response and survival. Results: Between 2012 and 2018, 116 patients with mPDAC underwent germline (using Invitae, Ambry Counsyl or Myriad) and/or somatic testing (using FoundationOne CDx). Among these, 40 received first-line therapy with FOLFIRINOX (95%) or gemcitabine/cisplatin (5%). The median age was 59 years and 15 (38%) were female. The majority (70%) were Hispanic and 63% had de-novo mPDAC (treatment-naïve). Germline testing revealed daDDR in 5 patients and somatic NGS found an additional 4 patients with daDDR (total of 9 (23%), including 5 with BRCA2, one each with BRCA1, RAD51C, ATM and MUTYH). The median progression-free survival (PFS) was significantly longer in patients with daDDR than without (17.3 vs 7.8 months, log-rank p = 0.01). The median overall survival (OS) was not statistically different between the two groups. Three patients with daDDR had complete or near-complete radiological and tumor marker responses to FOLFIRINOX and were treated with olaparib (a PARP inhibitor) as maintenance and remain progression-free after 7, 12.4 and 13.6 months respectively. Conclusions: daDDR appears to define a subset of patients with mPDAC who may be more sensitive to platinum agents. There are currently no biomarkers for selection of first-line therapy in patients with mPDAC and we demonstrate that this composite biomarker which is easily done via commercially available assays may be able to inform treatment selection.

Avenger 500, a phase III open-label randomized trial of the combination of CPI-613 with modified FOLFIRINOX (mFFX) versus FOLFIRINOX (FFX) in patients with metastatic adenocarcinoma of the pancreas

TPS479

Background: Metastatic pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers. Current treatments using FOLFIRINOX and gemcitabine plus nab-paclitaxel, provide median survivals of 11.1 and 8.5 months, respectively. PDAC cells have altered metabolism. CPI-613 is a novel TCA cycle inhibitor that targets cancer cells. In a phase I study mFFX plus CPI-613 resulted in a 61% objective response rate with 3 of 18 patients achieving a complete response. Methods: Avenger 500 (NCT03504423) is an open-label randomized trial of CPI-613 plus mFFX versus FFX in untreated patients with metastatic PDAC. 500 patients will be randomized 1:1 between arms. The experimental arm comprises CPI-613 500 mg/m2 on day 1 and 3 of a 14-day cycle. The mFFX regimen is the standard dose and schedule of 5-Fluorouracil but reduced doses of oxaliplatin (65 mg/m²) and irinotecan (140 mg/m²). The control arm is standard dose FFX. There are two co-primary endpoints: Overall Response Rate (ORR, Complete Response + Partial Response). Best response within the first 12 cycles will be used for this determination, to be confirmed by independent, blinded, central review. Progression-Free Survival (PFS), is the second co-primary endpoint. Secondary endpoints are overall survival, duration of response and safety. Patient reported outcomes will be compared using the NCCN-FACT FHSI-18. An interim analysis will be done after 167 patients are evaluable for response. The difference in ORR will be tested using a Lan-DeMets Pocock type boundary for futility and efficacy. Futility will be declared if the difference in ORR between the arms is smaller than 5%, while efficacy will be declared if it is larger than 20%. The PFS hazard ratio will be tested using a Lan-DeMets O’Brien-Fleming type boundary. Efficacy will be declared if the hazard ratio is less than 0.48. The final analysis will be done with 500 patients randomized, when ~375 PFS events are available. Significance will be reached if the PFS hazard ratio is less than 0.80, or the difference in ORR is at least 11%. If the trial reaches significance for either primary endpoint, overall survival will be tested. Clinical trial information: NCT03504423.