A shared neoantigen vaccine combined with immune checkpoint blockade for advanced metastatic solid tumors: phase 1 trial interim results

Therapeutic vaccines that elicit cytotoxic T cell responses targeting tumor-specific neoantigens hold promise for providing long-term clinical benefit to patients with cancer. Here we evaluated safety and tolerability of a therapeutic vaccine encoding 20 shared neoantigens derived from selected common oncogenic driver mutations as primary endpoints in an ongoing phase 1/2 study in patients with advanced/metastatic solid tumors. Secondary endpoints included immunogenicity, overall response rate, progression-free survival and overall survival. Eligible patients were selected if their tumors expressed one of the human leukocyte antigen-matched tumor mutations included in the vaccine, with the majority of patients (18/19) harboring a mutation in KRAS. The vaccine regimen, consisting of a chimp adenovirus (ChAd68) and self-amplifying mRNA (samRNA) in combination with the immune checkpoint inhibitors ipilimumab and nivolumab, was shown to be well tolerated, with observed treatment-related adverse events consistent with acute inflammation expected with viral vector-based vaccines and immune checkpoint blockade, the majority grade 1/2. Two patients experienced grade 3/4 serious treatment-related adverse events that were also dose-limiting toxicities. The overall response rate was 0%, and median progression-free survival and overall survival were 1.9 months and 7.9 months, respectively. T cell responses were biased toward human leukocyte antigen-matched TP53 neoantigens encoded in the vaccine relative to KRAS neoantigens expressed by the patients' tumors, indicating a previously unknown hierarchy of neoantigen immunodominance that may impact the therapeutic efficacy of multiepitope shared neoantigen vaccines. These data led to the development of an optimized vaccine exclusively targeting KRAS-derived neoantigens that is being evaluated in a subset of patients in phase 2 of the clinical study. ClinicalTrials.gov registration: NCT03953235 .

Radiation Therapy Quality Assurance Analysis of Alliance A021501: Preoperative mFOLFIRINOX or mFOLFIRINOX Plus Hypofractionated Radiation Therapy for Borderline Resectable Adenocarcinoma of the Pancreas

PURPOSE

Alliance A021501 is the first randomized trial to evaluate stereotactic body radiation therapy (SBRT) for borderline resectable pancreatic ductal adenocarcinoma (PDAC) after neoadjuvant chemotherapy. In this post hoc study, we reviewed the quality of radiation therapy (RT) delivered.

METHODS AND MATERIALS

SBRT (6.6 Gy × 5) was intended but hypofractionated RT (5 Gy × 5) was permitted if SBRT specifications could not be met. Institutional credentialing through the National Cancer Institute-funded Imaging and Radiation Oncology Core (IROC) was required. Rigorous RT quality assurance (RT QA) was mandated, including pretreatment review by a radiation oncologist. Revisions were required for unacceptable deviations. Additionally, we performed a post hoc RT QA analysis in which contours and plans were reviewed by 3 radiation oncologists and assigned a score (1, 2, or 3) based on adequacy. A score of 1 indicated no deviation, 2 indicated minor deviation, and 3 indicated a major deviation that could be clinically significant. Clinical outcomes were compared by treatment modality and by case score.

RESULTS

Forty patients were registered to receive RT (1 planned but not treated) at 27 centers (18 academic and 9 community). Twenty-three centers were appropriately credentialed for moving lung/liver targets and 4 for static head and neck only. Thirty-two of 39 patients (82.1%) were treated with SBRT and 7 (17.9%) with hypofractionated RT. Five cases (13%) required revision before treatment. On post hoc review, 23 patients (59.0%) were noted to have suboptimal contours or plan coverage, 12 (30.8%) were scored a 2, and 11 (28.2%) were scored a 3. There were no apparent differences in failure patterns or surgical outcomes based on treatment technique or post hoc case score. Details related to on-treatment imaging were not recorded.

CONCLUSIONS

Despite rigorous QA, we encountered variability in simulation, contouring, plan coverage, and dose on trial. Although clinical outcomes did not appear to have been affected, findings from this analysis serve to inform subsequent PDAC SBRT trial designs and QA requirements.

Alliance for clinical trials in Oncology (Alliance) trial A022101/NRG-GI009: a pragmatic randomized phase III trial evaluating total ablative therapy for patients with limited metastatic colorectal cancer: evaluating radiation, ablation, and surgery (ERASur)

BACKGROUND

For patients with liver-confined metastatic colorectal cancer (mCRC), local therapy of isolated metastases has been associated with long-term progression-free and overall survival (OS). However, for patients with more advanced mCRC, including those with extrahepatic disease, the efficacy of local therapy is less clear although increasingly being used in clinical practice. Prospective studies to clarify the role of metastatic-directed therapies in patients with mCRC are needed.

METHODS

The Evaluating Radiation, Ablation, and Surgery (ERASur) A022101/NRG-GI009 trial is a randomized, National Cancer Institute-sponsored phase III study evaluating if the addition of metastatic-directed therapy to standard of care systemic therapy improves OS in patients with newly diagnosed limited mCRC. Eligible patients require a pathologic diagnosis of CRC, have BRAF wild-type and microsatellite stable disease, and have 4 or fewer sites of metastatic disease identified on baseline imaging. Liver-only metastatic disease is not permitted. All metastatic lesions must be amenable to total ablative therapy (TAT), which includes surgical resection, microwave ablation, and/or stereotactic ablative body radiotherapy (SABR) with SABR required for at least one lesion. Patients without overt disease progression after 16-26 weeks of first-line systemic therapy will be randomized 1:1 to continuation of systemic therapy with or without TAT. The trial activated through the Cancer Trials Support Unit on January 10, 2023. The primary endpoint is OS. Secondary endpoints include event-free survival, adverse events profile, and time to local recurrence with exploratory biomarker analyses. This study requires a total of 346 evaluable patients to provide 80% power with a one-sided alpha of 0.05 to detect an improvement in OS from a median of 26 months in the control arm to 37 months in the experimental arm with a hazard ratio of 0.7. The trial uses a group sequential design with two interim analyses for futility.

DISCUSSION

The ERASur trial employs a pragmatic interventional design to test the efficacy and safety of adding multimodality TAT to standard of care systemic therapy in patients with limited mCRC.

TRIAL REGISTRATION

ClinicalTrials.gov: NCT05673148, registered December 21, 2022.

Utility of Circulating Tumor DNA Assessment in Characterizing Recurrence Sites after Optimal Resection for Metastatic Colorectal Cancer

INTRODUCTION

Plasma ctDNA is a promising biomarker for metastatic colorectal cancer (mCRC); however, its role in characterizing recurrence sites after mCRC resection remains poorly understood. This single-institution study investigated the timing of ctDNA detection and its levels in the context of recurrence at different sites following mCRC resection.

METHODS

Patients who underwent optimal resection of CRC metastases involving the peritoneum, distant lymph nodes, or liver, with serial postoperative tumor-informed ctDNA assessments (Signatera) were included. Recurrence sites, as defined by surveillance imaging or laparoscopy, were categorized as peritoneal-only and other distant sites (liver, lung, lymph nodes, or body wall).

RESULTS

Among the 31 included patients, ctDNA was detected in all 26 (83.4%) patients with postoperative recurrence and was persistently undetectable in five patients who did not experience recurrence. At three months post-surgery, ctDNA was detected in 2/8 (25.0%) patients with peritoneal-only recurrence and 17/18 (94.4%) patients with distant recurrence (p < 0.001). Beyond three months, ctDNA was detected in the remaining six patients with peritoneal-only disease and one patient with distant disease. ctDNA detection preceded the clinical diagnosis of recurrence by a median of nine weeks in both groups. At recurrence, peritoneal-only recurrent cases exhibited lower ctDNA levels (median 0.4 MTM/ml, IQR 0.1-0.8) compared to distant recurrence (median 5.5 MTM/ml, IQR 0.8-33.3, p = 0.004).

CONCLUSION

Peritoneal-only recurrence was associated with delayed ctDNA detection and low levels of ctDNA after optimal resection for mCRC. ctDNA testing may effectively characterize recurrence sites and may help guide subsequent treatments specific to the disease sites involved.

Fragmentation of Care in Patients with Peritoneal Metastases Undergoing Cytoreductive Surgery

BACKGROUND

The delivery of multimodal treatment at a high-volume center is known to optimize the outcomes of gastrointestinal malignancies. However, patients undergoing cytoreductive surgery (CRS) for peritoneal metastases often must 'fragment' their surgical and systemic therapeutic care between different institutions. We hypothesized that this adversely affects outcomes.

PATIENTS AND METHODS

Adults undergoing CRS for colorectal or appendiceal adenocarcinoma at our institution between 2016 and 2022 were identified retrospectively and grouped by care network: 'coordinated care' patients received exclusively in-network systemic therapy, while 'fragmented care' patients received some systemic therapy from outside-network providers. Factors associated with fragmented care were also ascertained. Overall survival (OS) from CRS and systemic therapy-related serious adverse events (SAEs) were compared across the groups.

RESULTS

Among 85 (80%) patients, 47 (55%) had colorectal primaries and 51 (60%) received fragmented care. Greater travel distance [OR 1.01 (CI 1.00-1.02), p = 0.02] and educational status [OR 1.04 (CI 1.01-1.07), p = 0.01] were associated with receiving fragmented care. OS was comparable between patients who received fragmented and coordinated care in the colorectal [32.5 months versus 40.8 months, HR 0.95 (CI 0.43-2.10), p = 0.89] and appendiceal [31.0 months versus 27.4 months, HR 1.17 (CI 0.37-3.74), p = 0.55] subgroups. The frequency of SAEs (7.8% versus 17.6%, p = 0.19) was also similar.

CONCLUSIONS

There were no significant differences in survival or SAEs based on the networks of systemic therapy delivery. This suggests that patients undergoing CRS at a high-volume center may safely receive systemic therapy at outside-network facilities with comparable outcomes.

Alliance for Clinical Trials in Oncology (Alliance) trial A022101/NRG-GI009: A pragmatic randomized phase III trial evaluating total ablative therapy for patients with limited metastatic colorectal cancer: evaluating radiation, ablation, and surgery (ERASur)

Background

For patients with liver-confined metastatic colorectal cancer (mCRC), local therapy of isolated metastases has been associated with long-term progression-free and overall survival (OS). However, for patients with more advanced mCRC, including those with extrahepatic disease, the efficacy of local therapy is less clear although increasingly being used in clinical practice. Prospective studies to clarify the role of metastatic-directed therapies in patients with mCRC are needed.

Methods

The Evaluating Radiation, Ablation, and Surgery (ERASur) A022101/NRG-GI009 trial is a randomized, National Cancer Institute-sponsored phase III study evaluating if the addition of metastatic-directed therapy to standard of care systemic therapy improves OS in patients with newly diagnosed limited mCRC. Eligible patients require a pathologic diagnosis of CRC, have BRAF wild-type and microsatellite stable disease, and have 4 or fewer sites of metastatic disease identified on baseline imaging. Liver-only metastatic disease is not permitted. All metastatic lesions must be amenable to total ablative therapy (TAT), which includes surgical resection, microwave ablation, and/or stereotactic ablative body radiotherapy (SABR) with SABR required for at least one lesion. Patients without overt disease progression after 16-26 weeks of first-line systemic therapy will be randomized 1:1 to continuation of systemic therapy with or without TAT. The trial activated through the Cancer Trials Support Unit on January 10, 2023. The primary endpoint is OS. Secondary endpoints include event-free survival, adverse events profile, and time to local recurrence with exploratory biomarker analyses. This study requires a total of 346 evaluable patients to provide 80% power with a one-sided alpha of 0.05 to detect an improvement in OS from a median of 26 months in the control arm to 37 months in the experimental arm with a hazard ratio of 0.7. The trial uses a group sequential design with two interim analyses for futility.

Discussion

The ERASur trial employs a pragmatic interventional design to test the efficacy and safety of adding multimodality TAT to standard of care systemic therapy in patients with limited mCRC.

Role of Tumor-informed Personalized Circulating Tumor DNA Assay in Informing Recurrence in Patients With Peritoneal Metastases From Colorectal and High-grade Appendix Cancer Undergoing Curative-intent Surgery

OBJECTIVE

To investigate the role of a personalized, tumor-informed circulating tumor DNA (ctDNA) assay in informing recurrence in patients with peritoneal metastases (PM) from colorectal (CRC) and high-grade appendix (HGA) cancer after curative cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS-HIPEC).

BACKGROUND

Over 50% of patients with CRC/HGA-PM recur after optimal CRS-HIPEC. The limited sensitivity of axial imaging and diagnostic biomarkers is a significant cause of delay in the detection of recurrence and initiation of further therapies. Plasma ctDNA has a promising role in monitoring response to treatment and/or recurrence after primary cancer resection.

METHODS

Patients with CRC/HGA-PM who underwent curative CRS-HIPEC and serial postresection ctDNA assessments were included. Patients with rising postoperative ctDNA levels were compared with those with stable, undetectable ctDNA levels. Primary outcomes were the percentage of patients with recurrence and disease-free survival (DFS). Secondary outcomes were overall survival, ctDNA sensitivity, lead time, and performance of ctDNA compared with carcinoembryonic antigen.

RESULTS

One hundred thirty serial postresection ctDNA assessments [median 4, interquartile range (IQR), 3 to 5] were performed in 33 patients (n = 13 CRC, n = 20 HGA) who underwent completeness of cytoreduction-0/1 CRS with a median follow-up of 13 months. Of the 19 patients with rising ctDNA levels, 90% recurred versus 21% in the stable ctDNA group (n = 14, < 0.001). Median DFS in the rising ctDNA cohort was 11 months (IQR, 6 to 12) and not reached in the stable ( P = 0.01). A rising ctDNA level was the most significant factor associated with DFS (hazard ratio: 3.67, 95% CI: 1.06-12.66, P = 0.03). The sensitivity and specificity of rising ctDNA levels in predicting recurrence were 85% and 84.6%, respectively. The median ctDNA lead time was 3 months (IQR, 1 to 4). Carcinoembryonic antigen was less sensitive (50%) than ctDNA.

CONCLUSIONS

This study supports the clinical validity of serial ctDNA assessment as a strong prognostic biomarker in informing recurrence in patients with CRC/HGA-PM undergoing curative resection. It also holds promises for informing future clinical trial designs and further research.

Early Integrated Palliative Care Within a Surgical Oncology Clinic

Importance

Advance directive (AD) designation is an important component of advance care planning (ACP) that helps align care with patient goals. However, it is underutilized in high-risk surgical patients with cancer, and multiple barriers contribute to the low AD designation rates in this population.

Objective

To assess the association of early palliative care integration with changes in AD designation among patients with cancer who underwent surgery.

Design, Setting, and Participants

This cohort study was a retrospective analysis of a prospectively maintained registry of adult patients who underwent elective surgery for advanced abdominal and soft tissue malignant tumors at a surgical oncology clinic in a comprehensive cancer center with expertise in regional therapeutics between June 2016 and May 2022, with a median (IQR) postoperative follow-up duration of 27 (15-43) months. Data analysis was conducted from December 2022 to April 2023.

Exposure

Integration of ACP recommendations and early palliative care consultations into the surgical workflow in 2020 using electronic health records (EHR), preoperative checklists, and resident education.

Main Outcomes and Measures

The primary outcomes were AD designation and documentation. Multivariable logistic regression was performed to assess factors associated with AD designation and documentation.

Results

Among the 326 patients (median [IQR] age 59 [51-67] years; 189 female patients [58.0%]; 243 non-Hispanic White patients [77.9%]) who underwent surgery, 254 patients (77.9%) designated ADs. The designation rate increased from 72.0% (131 of 182 patients) before workflow integration to 85.4% (123 of 144 patients) after workflow integration in 2020 (P = .004). The AD documentation rate did not increase significantly after workflow integration in 2020 (48.9% [89 of 182] ADs documented vs 56.3% [81 of 144] ADs documented; P = .19). AD designation was associated with palliative care consultation (odds ratio [OR], 41.48; 95% CI, 9.59-179.43; P < .001), palliative-intent treatment (OR, 5.12; 95% CI, 1.32-19.89; P = .02), highest age quartile (OR, 3.79; 95% CI, 1.32-10.89; P = .01), and workflow integration (OR, 2.05; 95% CI, 1.01-4.18; P = .048). Patients who self-identified as a race or ethnicity other than non-Hispanic White were less likely to have designated ADs (OR, 0.36; 95% CI, 0.17-0.76; P = .008). AD documentation was associated with palliative care consulation (OR, 4.17; 95% CI, 2.57- 6.77; P < .001) and the highest age quartile (OR, 2.41; 95% CI, 1.21-4.79; P = .01).

Conclusions and Relevance

An integrated ACP initiative was associated with increased AD designation rates among patients with advanced cancer who underwent surgery. These findings demonstrate the feasibility and importance of modifying clinical pathways, integrating EHR-based interventions, and cohabiting palliative care physicians in the surgical workflow for patients with advanced care.

Alliance A022101: A Pragmatic Randomized Phase III Trial Evaluating Total Ablative Therapy for Patients with Limited Metastatic Colorectal Cancer - Evaluating Radiation, Ablation and Surgery (ERASur)

PURPOSE/OBJECTIVE(S)

For patients with oligometastatic colorectal cancer (CRC), aggressive local therapy of isolated metastases, particularly in the liver, has been associated with long-term progression-free survival and overall survival (OS) primarily based on retrospective evidence. However, in patients with limited metastatic CRC that is deemed inoperable or those with additional disease outside of the liver or lungs, the role of local ablative therapies, including microwave ablation (MWA) and stereotactic body radiation therapy (SBRT), to render patients disease free is less clear. Further, despite the long history of treating oligometastatic CRC with local therapy, which is provider biased and not evidence based, questions remain regarding the benefit of extending the paradigm of metastatic directed therapy to patients with more extensive disease. This trial seeks to use a pragmatic multimodality approach that mirrors the current clinical dilemma. This study is designed to evaluate the safety and efficacy of adding total ablative therapy (TAT) of all sites of disease to standard of care systemic treatment in those with limited metastatic CRC.

MATERIALS/METHODS

A022101 is a National Clinical Trials Network randomized phase III study planned to enroll 364 patients with newly diagnosed metastatic CRC (BRAF wild-type, microsatellite stable) with 4 or fewer sites of metastatic disease on baseline imaging. Liver-only metastatic disease is not permitted, and lesions must be amenable to any combination of surgical resection, MWA, and/or SBRT with SBRT required for at least one lesion. Patients receive first-line systemic therapy for 4-6 months and are then randomized 1:1, stratified by number of metastatic organ sites (1-2 vs. 3-4), timing of metastatic disease diagnosis (de novo vs. secondary), and presence of metastatic disease outside the liver and lungs in at least one site. Patients in Arm 1 will receive TAT which consists of treatment of all metastatic sites with SBRT ± MWA ± surgical resection followed by standard of care systemic therapy. Patients in Arm 2 will continue with standard of care systemic therapy alone. The primary endpoint is OS. Secondary endpoints include event-free survival, treatment-related toxicities, and local recurrence with exploratory biomarker analyses. The study needs 346 evaluable patients combined in the 2 arms to demonstrate an improvement in OS with a hazard ratio of 0.7 to provide 80% power with a one-sided alpha of 5%. The trial utilizes a group sequential design with two interim analyses (25% and 50% of events) for futility.

RESULTS

The trial activated in January 2023.

CONCLUSION

Recruitment is ongoing.

Pan-Cancer Prevalence of Microsatellite Instability-High (MSI-H) Identified by Circulating Tumor DNA and Associated Real-World Clinical Outcomes

PURPOSE

Immune checkpoint inhibitors are approved for advanced solid tumors with microsatellite instability-high (MSI-H). Although several technologies can assess MSI-H status, detection and outcomes with circulating tumor DNA (ctDNA)-detected MSI-H are lacking. As such, we examined pan-cancer MSI-H prevalence across 21 cancers and outcomes after ctDNA-detected MSI-H.

METHODS

Patients with advanced cancer who had ctDNA testing (Guardant360) from October 1, 2018, to June 30, 2022, were retrospectively assessed for prevalence. GuardantINFORM, which includes anonymized genomic and structured payer claims data, was queried to assess outcomes. Patients who initiated new treatment within 90 days of MSI-H detection were sorted into immunotherapy included in treatment (IO) or no immunotherapy included (non-IO) groups. Real-world time to treatment discontinuation (rwTTD) and real-world time to next treatment (rwTTNT) were assessed in months as proxies of progression-free survival (PFS); real-world overall survival (rwOS) was assessed in months. Cox regression tests analyzed differences. Colorectal cancer, non-small-cell lung cancer (NSCLC), prostate cancer, gastroesophageal cancer, and uterine cancer (UC) were assessed independently; all other cancers were grouped.

RESULTS

In total, 1.4% of 171,881 patients had MSI-H detected. Of 770 patients with outcomes available, rwTTD and rwTTNT were significantly longer for patients who received IO compared with non-IO for all cancers (P ≤ .05; hazard ratio [HR] range, 0.31-0.52 and 0.25-0.54, respectively) except NSCLC. rwOS had limited follow-up for all cohorts except UC (IO 39 v non-IO 23 months; HR, 0.18; P = .004); however, there was a consistent trend toward prolonged OS in IO-treated patients.

CONCLUSION

These data support use of a well-validated ctDNA assay to detect MSI-H across solid tumors and suggest prolonged PFS in patients treated with IO-containing regimens after detection. Tumor-agnostic, ctDNA-based MSI testing may be reliable for rapid decision making.

Preoperative Treatment of Locally Advanced Rectal Cancer

BACKGROUND

Pelvic radiation plus sensitizing chemotherapy with a fluoropyrimidine (chemoradiotherapy) before surgery is standard care for locally advanced rectal cancer in North America. Whether neoadjuvant chemotherapy with fluorouracil, leucovorin, and oxaliplatin (FOLFOX) can be used in lieu of chemoradiotherapy is uncertain.

METHODS

We conducted a multicenter, unblinded, noninferiority, randomized trial of neoadjuvant FOLFOX (with chemoradiotherapy given only if the primary tumor decreased in size by <20% or if FOLFOX was discontinued because of side effects) as compared with chemoradiotherapy. Adults with rectal cancer that had been clinically staged as T2 node-positive, T3 node-negative, or T3 node-positive who were candidates for sphincter-sparing surgery were eligible to participate. The primary end point was disease-free survival. Noninferiority would be claimed if the upper limit of the two-sided 90.2% confidence interval of the hazard ratio for disease recurrence or death did not exceed 1.29. Secondary end points included overall survival, local recurrence (in a time-to-event analysis), complete pathological resection, complete response, and toxic effects.

RESULTS

From June 2012 through December 2018, a total of 1194 patients underwent randomization and 1128 started treatment; among those who started treatment, 585 were in the FOLFOX group and 543 in the chemoradiotherapy group. At a median follow-up of 58 months, FOLFOX was noninferior to chemoradiotherapy for disease-free survival (hazard ratio for disease recurrence or death, 0.92; 90.2% confidence interval [CI], 0.74 to 1.14; P = 0.005 for noninferiority). Five-year disease-free survival was 80.8% (95% CI, 77.9 to 83.7) in the FOLFOX group and 78.6% (95% CI, 75.4 to 81.8) in the chemoradiotherapy group. The groups were similar with respect to overall survival (hazard ratio for death, 1.04; 95% CI, 0.74 to 1.44) and local recurrence (hazard ratio, 1.18; 95% CI, 0.44 to 3.16). In the FOLFOX group, 53 patients (9.1%) received preoperative chemoradiotherapy and 8 (1.4%) received postoperative chemoradiotherapy.

CONCLUSIONS

In patients with locally advanced rectal cancer who were eligible for sphincter-sparing surgery, preoperative FOLFOX was noninferior to preoperative chemoradiotherapy with respect to disease-free survival. (Funded by the National Cancer Institute; PROSPECT ClinicalTrials.gov number, NCT01515787.).

Fruquintinib versus placebo in patients with refractory metastatic colorectal cancer (FRESCO-2): an international, multicentre, randomised, double-blind, phase 3 study

BACKGROUND

There is a paucity of effective systemic therapy options for patients with advanced, chemotherapy-refractory colorectal cancer. We aimed to evaluate the efficacy and safety of fruquintinib, a highly selective and potent oral inhibitor of vascular endothelial growth factor receptors (VEGFRs) 1, 2, and 3, in patients with heavily pretreated metastatic colorectal cancer.

METHODS

We conducted an international, randomised, double-blind, placebo-controlled, phase 3 study (FRESCO-2) at 124 hospitals and cancer centres across 14 countries. We included patients aged 18 years or older (≥20 years in Japan) with histologically or cytologically documented metastatic colorectal adenocarcinoma who had received all current standard approved cytotoxic and targeted therapies and progressed on or were intolerant to trifluridine-tipiracil or regorafenib, or both. Eligible patients were randomly assigned (2:1) to receive fruquintinib (5 mg capsule) or matched placebo orally once daily on days 1-21 in 28-day cycles, plus best supportive care. Stratification factors were previous trifluridine-tipiracil or regorafenib, or both, RAS mutation status, and duration of metastatic disease. Patients, investigators, study site personnel, and sponsors, except for selected sponsor pharmacovigilance personnel, were masked to study group assignments. The primary endpoint was overall survival, defined as the time from randomisation to death from any cause. A non-binding futility analysis was done when approximately one-third of the expected overall survival events had occurred. Final analysis occurred after 480 overall survival events. This study is registered with ClinicalTrials.gov, NCT04322539, and EudraCT, 2020-000158-88, and is ongoing but not recruiting.

FINDINGS

Between Aug 12, 2020, and Dec 2, 2021, 934 patients were assessed for eligibility and 691 were enrolled and randomly assigned to receive fruquintinib (n=461) or placebo (n=230). Patients had received a median of 4 lines (IQR 3-6) of previous systemic therapy for metastatic disease, and 502 (73%) of 691 patients had received more than 3 lines. Median overall survival was 7·4 months (95% CI 6·7-8·2) in the fruquintinib group versus 4·8 months (4·0-5·8) in the placebo group (hazard ratio 0·66, 95% CI 0·55-0·80; p<0·0001). Grade 3 or worse adverse events occurred in 286 (63%) of 456 patients who received fruquintinib and 116 (50%) of 230 who received placebo; the most common grade 3 or worse adverse events in the fruquintinib group included hypertension (n=62 [14%]), asthenia (n=35 [8%]), and hand-foot syndrome (n=29 [6%]). There was one treatment-related death in each group (intestinal perforation in the fruquintinib group and cardiac arrest in the placebo group).

INTERPRETATION

Fruquintinib treatment resulted in a significant and clinically meaningful benefit in overall survival compared with placebo in patients with refractory metastatic colorectal cancer. These data support the use of fruquintinib as a global treatment option for patients with refractory metastatic colorectal cancer. Ongoing analysis of the quality of life data will further establish the clinical benefit of fruquintinib in this patient population.

FUNDING

HUTCHMED.

Mutational profiles and prognostic impact in colorectal and high-grade appendiceal adenocarcinoma with peritoneal metastases

BACKGROUND

Next-generation sequencing (NGS) personalizes cancer treatments. In this study, we analyze outcomes based on NGS testing for colorectal cancer (CRC) and high-grade appendiceal adenocarcinoma (HGA) with peritoneal metastases.

METHODS

Retrospective review of genomic analyses and outcomes in patients with CRC or HGA with peritoneal metastases at a high-volume center from 2012 to 2019.

RESULTS

Ninety-two patients (57 CRC, 35 HGA) were identified. Overall survival was longer for CRC (52.8 vs. 30.5 months, p = 0.03), though rates of cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC) were similar. Multiple genes were more frequently mutated in CRC, including KRAS (51% vs. 29%, p = 0.04), TP53 (47% vs. 20%, p < 0.01), and APC (46% vs. 6%, p < 0.01). For CRC, multivariate regression showed an increased hazard ratio (HR) with increasing peritoneal cancer index (1.06 [1.01-1.11], p = 0.02) and a decreased HR following CRS/HIPEC (0.30 [0.11-0.80], p = 0.02). PIK3CA mutation associated with significantly increased HR (3.62 [1.06-12.41], p = 0.04), though only in non-CRS/HIPEC patients. Multivariate analysis in the HGA group showed a benefit following CRS/HIPEC (0.18 [0.06-0.61], p = 0.01) and for mucinous disease (0.38 [0.15-0.96], p = 0.04), while there was an increased HR with TP53 mutation (6.89 [2.12-22.44], p < 0.01).

CONCLUSION

CRC and HGA with peritoneal spread have distinct mutational profiles. PIK3CA and TP53 mutations are associated with survival for CRC or HGA with peritoneal metastases, respectively.

PI3K Pathway Alterations in Peritoneal Metastases are Associated with Earlier Recurrence in Patients with Colorectal Cancer Undergoing Optimal Cytoreductive Surgery

BACKGROUND

Colorectal cancer with peritoneal metastasis (CRC-PM) represents a biologically heterogeneous disease; yet little is known regarding the impact of tumor biology on survival outcomes following optimal cytoreductive surgery (CRS). We analyzed the frequency of alterations in cancer signaling pathways in patients with CRC-PM and their impact on recurrence-free survival (RFS) following optimal CRS.

METHODS

Thirty-five consecutive CRC-PM patients who underwent optimal CRS/HIPEC and next generation sequencing of peritoneal metastases were included in the study. Alterations in eight cancer-related signaling pathways were analyzed: Wnt/APC, p53, RTK-RAS, PI3K, TGF-B, Notch, Myc, and cell cycle. The association of pathway alterations with RFS and OS following optimal cytoreduction was estimated using Cox proportional hazard modeling.

RESULTS

The most frequently altered pathways were Wnt/APC (63%), p53 (63%), RTK-RAS (60%), and PI3K (23%). Among optimally cytoreduced patients with CRC-PM, PI3K pathway alterations were an independent predictor of worse RFS (hazard ratio 3.2, 95% confidence interval CI 1.3-8.3, p = 0.01) with a clinically meaningful impact on median months to recurrence (5 vs. 13 months, p = 0.02). Alterations in p53, Wnt, and RTK-RAS pathways were not significantly associated with a difference in RFS following CRS. Alterations in the four pathways were not associated with differences in OS following CRS (median OS was 50 (interquartile range 23-80) months).

CONCLUSIONS

In patients with CRC-PM, PI3K pathway alterations are associated with earlier recurrence following optimal CRS, which may represent a distinct molecular subtype. This novel finding can tailor clinical trials by using PIK3CA-directed interventions to reduce risk of recurrence after optimal CRS.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

Outcomes in high-grade neuroendocrine carcinomas (HG-NEC) of the gastrointestinal (GI) tract with modern therapies

e15609

Background: HG-NEC of the GI tract are rare and aggressive neoplasms with poor prognosis. Approximately 37.5% of extra-pulmonary NEC are of the GI origin and are most commonly located in esophagus, stomach, pancreas and colon (1,2). Median survival of 7.5 months, with range of 5.7 months to 25.1 months has been reported (2). However, data regarding response to immunotherapy, as well as response to molecularly directed therapies are sparse. In this study, we conducted a retrospective review of GI tract HG-NEC with objective to assess role of modern diagnostics and therapies in clinical outcomes. Methods: We identified 14 patients with GI tract HG-NEC who received care at University of Chicago Medical Center (UCMC). Electronic medical records were reviewed for disease stage, treatments and clinical course. We reviewed available next generation sequencing (NGS) and circulating tumor DNA (ct-DNA) test results. In this cohort, UCMC’s NGS panel: Oncoplus was available and Guardant 360 results were reviewed for liquid biopsy. Results: In our initial review, site of origin included right side of colon (46%), left sided colon (46%), and anus/anorectal (15%). Median overall survival (mOS) ranged from 1.3 months to 81.3 months, and notably the median response to chemo-immunotherapy (IO) was 7.9 months (table 1). Notably one patient received maintenance therapy with immunotherapy alone with progression of disease (POD) in 3 weeks. Six patients had NGS results of which three (50%) had therapeutic targetable alterations (Table). Two patients had liquid biopsy done, of which one had targetable alterations and the other had no tumor related alterations detected. Of the two patients with targetable lesions, one patient has received targeted therapy with POD in 1.2 months and median OS 8.8 months; the other is in the process of initiating targeted therapy. Conclusions: To our knowledge, this is the first report to show a response to combination chemo-immunotherapy and targeted therapies in HG-NEC of GI tract. We are collaborating with other institutions to collate outcomes to similar therapy approaches in this patient cohort. With our study, we hope to inform future therapies and innovation in this important disease.

Phase 2 randomized trial of neoadjuvant or palliative chemotherapy with or without immunotherapy for peritoneal mesothelioma (Alliance A092001)

TPS8598

Background: Peritoneal mesothelioma is a rare and poorly studied disease with few treatment options. For patients who are not surgical candidates, treatment recommendations for systemic therapy have been extrapolated from clinical trials for pleural mesothelioma that commonly exclude patients with peritoneal mesothelioma. Recently, the combination of the PD-1 inhibitor nivolumab and the CTLA-4 inhibitor ipilimumab received FDA-approval for the frontline treatment of non-resectable pleural mesothelioma. Additionally, a prospective, non-randomized phase 2 trial demonstrated activity with combined PD-L1 (atezolizumab) and VEGF (bevacizumab) blockade in peritoneal mesothelioma. In parallel, encouraging activity with combined chemo-immunotherapy has been reported in pleural mesothelioma. Given the benefits observed with immunotherapy, and the potential to improve upon those with chemotherapy and VEGF inhibition, we seek to determine whether the addition of the PD-L1 inhibitor atezolizumab improves outcomes with chemotherapy and bevacizumab in patients with newly diagnosed peritoneal mesothelioma. Methods: A092001 is a prospective, randomized phase 2 clinical trial. All patients with newly diagnosed peritoneal mesothelioma will be randomized 1:1 using a dynamic allocation Pocock-Simon procedure to receive carboplatin, pemetrexed, and bevacizumab, with or without atezolizumab, every 21 days for four cycles. Patients who are eligible to proceed with surgery after four cycles of therapy will then do so. Patients who are not eligible to proceed with surgery may receive maintenance bevacizumab and atezolizumab, or second-line atezolizumab with bevacizumab until progression of disease or toxicity. The primary objective is to determine whether frontline treatment with carboplatin, pemetrexed, bevacizumab and atezolizumab results in a superior best response rate (RR) to carboplatin, pemetrexed and bevacizumab as determined by RECIST. With 31 eligible patients per arm (62 eligible total), this randomized design has 80% power to detect an improvement in the RR from 20% to 45%, with a 1-sided significance level of 0.10 where an interim futility analysis will be conducted after 32 patients are enrolled. As stratification factors we have included eligibility for cytoreductive surgery at diagnosis, and histologic subtype. Secondary endpoints include assessment of progression-free survival, overall survival, and adverse events. As integrated biomarkers, we will determine if soluble mesothelin-related peptides and megakaryocyte potentiating factor correlate with responses. This trial was recently approved by the National Cancer Institute Central IRB and is activating at sites across the country. Support: U10CA180821, U10CA180882. Clinical trial information: NCT05001880.

Detection of microsatellite instability-high (MSI-H) by liquid biopsy predicts robust and durable response to immunotherapy in patients with pancreatic cancer

Clinical trials reporting the robust antitumor activity of immune checkpoint inhibitors (ICIs) in microsatellite instability-high (MSI-H) solid tumors have used tissue-based testing to determine the MSI-H status. This study assessed if MSI-H detected by a plasma-based circulating tumor DNA liquid biopsy test predicts robust response to ICI in patients with pancreatic ductal adenocarcinoma (PDAC). Retrospective analysis of patients with PDAC and MSI-H identified on Guardant360 from October 2018 to April 2021 was performed; clinical outcomes were submitted by treating providers. From 52 patients with PDAC +MSI-H, outcomes were available for 10 (19%) with a median age of 68 years (range: 56-82 years); the majority were male (80%) and had metastatic disease (80%). Nine of 10 patients were treated with ICI. Eight out of nine patients received single-agent pembrolizumab (8/9), while one received ipilimumab plus nivolumab. The overall response rate by Response Evaluation Criteria in Solid Tumors was 77% (7/9). The median progression-free survival and overall survival were not reached in this cohort. The median duration of treatment with ICI was 8 months (range: 1-24), and six out of seven responders continued to show response at the time of data cut-off after a median follow-up of 21 months (range: 11-33). Tissue-based MSI results were concordant with plasma-based G360 results in five of six patients (83%) who had tissue-based test results available, with G360 identifying one more patient with MSI-H than tissue testing. These results suggest that detecting MSI-H by a well-validated liquid biopsy test could predict a robust response to ICI in patients with PDAC. The use of liquid biopsy may expand the identification of PDAC patients with MSI-H tumors and enable treatment with ICI resulting in improved outcomes.

Phase 2/3, randomized, open-label study of an individualized neoantigen vaccine (self-amplifying mRNA and adenoviral vectors) plus immune checkpoint blockade as maintenance for patients with newly diagnosed metastatic colorectal cancer (GRANITE)

TPS3635

Background: Treatment options for most patients with metastatic colorectal cancer (mCRC) are largely limited to cytotoxic chemotherapy, with little advancement in the last decade. Encouragingly, a small subset of patients deficient in mismatch repair (dMMR/MSI-hi) benefit from checkpoint inhibitors (CPI) whereas those proficient in mismatch repair (pMMR/MSS) do not. The absence of clinical benefit in patients with pMMR/MSS mCRC may relate to a lack of neoantigen-specific T cells and immune infiltration. An individualized neoantigen vaccine that induces CD8 T cells capable of tumor lysis has the potential to expand the number of patients with mCRC who may benefit from immunotherapy. Data from a Phase 1/2 study evaluating neoantigen vaccines in combination with CPIs in patients with previously treated mCRC demonstrated a 44% molecular response (MR) rate (≥50% decrease in ctDNA relative to baseline) in 4/9 patients; this correlated with improvement in OS relative to those without a MR. To further investigate neoantigen vaccines in earlier lines of treatment, a Phase 2/3 study in the1L maintenance setting in mCRC was initiated. Methods: GO-010 is a Phase 2/3, randomized, open-label, multi-center study evaluating the efficacy and safety of 2 neoantigen-containing vectors (GRT-C901-adenoviral vector plus GRT-R902-self-amplifying mRNA vector) as prime/boost in combination with CPIs as an add-on to fluoropyrimidine/bevacizumab (bev) following 1L therapy with FOLFOX/bev in patients with mCRC. During Phase 2, up to 90 patients will be randomized 1:1 to the vaccine or control arm with a primary objective of assessing efficacy by MR. During Phase 3, up to 226 patients will be randomized with a primary objective of assessing PFS per iRECIST in a blinded, independent manner. There are two stages to the study. In the vaccine production stage, while patients receive FOLFOX/bev 1L therapy, neoantigen prediction is performed using a tumor biopsy and Gritstone’s EDGE™ neoantigen prediction model. For patients in the vaccine arm the top 20 predicted neoantigens are included in the vaccine vectors. After completing oxaliplatin, patients will enter the study treatment stage. Patients in the control arm will continue with maintenance therapy whereas patients in the vaccine arm will add the vaccine regimen to maintenance therapy. The vaccine regimen consists of GRT-C901/GRT-R902 as well as SC ipilimumab (30 mg) and IV atezolizumab (1680 mg). Over the first year of treatment, 6 vaccinations will occur. Ipilimumab will be administered SC with the first doses of GRT-C901 and GRT-R902. Atezolizumab will be administered every 4 weeks for up to 2 years. Study assessments include imaging, ctDNA, safety, immunogenicity and exploratory biomarker analysis. Clinical trial information: NCT05141721.

Correlation of circulating tumor DNA (ctDNA) with clinical outcomes in appendiceal cancers (AC)

29

Background: Appendiceal Cancers are a heterogenous group of rare tumors with distinct histopathologic and genomic alterations. These often have peritoneal spread that might not be easily detected on current imaging modalities, and conventional tumor markers may not lend diagnostic support. Hence, novel diagnostic techniques are needed. Measurement of ctDNA for recurrence risk prediction, response to therapy and and early diagnosis is a promising technique. However, limited published data exist in AC to validate the role and utility of ctDNA in clinical practice. Here we present a single institution experience of ctDNA analysis in patients with AC. Methods: ctDNA measurements of 37 pts with stage II-IV AC treated between 1/1/2019 and 9/15/2021 were reviewed retrospectively. ctDNA analysis was done using Signatera bespoke mPCR NGS assay. ctDNA results were compared to crossectional imaging, CEA levels, and clinical evaluation. Results: 19/37 patients (51%) had at least one positive ctDNA test result. Of those, 8 had testing done during the surveillance setting (two with grade 3, one with grade 2, two with grade 1, and three with unknown grade). Of those, 5 pts (62.5%) had positive ctDNA detected, while 33.33% had elevated CEA level, 25% had radiographic and 42.9% had clinical evidence of recurrence (Table). 7/14 (50%) pts had high-grade pathology and positive ct-DNA, 3/6 (50%) patients had low-grade (grade 1) pathology and positive ct-DNA findings. 4 patients had longitudinal ct-DNA measurements available which correlated well with their disease course. Median duration to recurrence (radiographic or laparoscopic) was 376 days. Median duration to the first positive ctDNA test was 370 days. Median duration to positive CEA after initial treatment was 475 days. Conclusions: Measurement of ctDNA can be a useful tool to follow disease course and to guide management decision-making in patients with AC. Prospective studies with serial measurements of ctDNA are planned. [Table: see text]

Survival in total preoperative verus perioperative chemotherapy for patients with metastatic high-grade appendiceal adenocarcinoma undergoing CRS/HIPEC

90

Background: Due to the relative infrequency of high grade appendiceal adenocarcinoma with peritoneal metastases, there is limited data to guide treatment strategies. Current practices for this disease are largely extrapolated from colon cancer patients with peritoneal metastases, who typically undergo six months of systemic chemotherapy in conjunction with cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (CRS/HIPEC). The optimal timing of chemotherapy in relation to CRS/HIPEC remains unknown. In this study, we compare the efficacy of peri-operative chemotherapy to pre-operative chemotherapy alone. Methods: This is a retrospective review of patients who underwent CRS/HIPEC for high grade appendiceal cancers from a tertiary referral center from 2014-2020. Outcomes were compared between patients who underwent planned 6 months of chemotherapy followed by CRS/HIPEC (pre-operative group) versus planned 3 months of chemotherapy both pre- and post-operatively (peri-operative group). Results: 85 patients were treated for metastatic high-grade appendiceal cancers during the study period, of whom24 were eligible for inclusion. Of those included, 16 were in the peri-operative group and 8 in the pre-operative group. Most patients were white (75%), non-Hispanic (96%) and female (54%). Patients in the pre-operative group tended to be older (65 vs. 56 years, p = 0.02). For patients with specified histologic grading, poorly differentiated tumors were common (50%). Signet ring cell histology (42%) and mucinous features (67%) were frequent as well. Median overall survival was similar between the pre-operative and peri-operative groups (32.3 vs. 31.6 months, p = 0.97), although patients undergoing peri-operative treatment received fewer total cycles of chemotherapy on average (14.1 vs. 9.5 cycles, p < 0.01). Half of the patients in the peri-operative group (8/16) did not complete their chemotherapy regimen, with 75% discontinuing therapy due to chemotherapy-related toxicities. Within the peri-operative group, a non-significant decrease in median survival was observed for those who did not complete chemotherapy (27.8 vs > 53.6 months, p = 0.22). Conclusions: Peri-operative and total pre-operative chemotherapy strategies are associated with similar survival in patients with high grade appendiceal cancers undergoing CRS/HIPEC. Peri-operative administration may be limited by chemotherapy-related toxicities.

A phase 1b/2 study of VS-6766 in combination cetuximab in patients (pts) with advanced KRAS mt colorectal cancer (CRC)

TPS219

Background: KRAS mutations (mts) are present in about 45% of CRC and predict lack of response to anti-EGFR therapy like cetuximab. Limited therapy options exist for pts after prior 5-FU based regimens. Regorafenib or TAS-102 is commonly used however, the modest clinical benefit, and toxicity limit their use. Novel therapies are needed for pts at this point in their disease course. KRAS G12D and G12V mts occur in 11-12% and 9-10% of CRC, respectively, whereas G12C mts occur in 3-4% of CRCs . KRAS G12C mts occur in 3-4% of CRCs. Recently, results of phase 1/2 KRYSTAL-1 study were reported. Adagrasib (a KRAS G12C inhibitor) was used with/without cetuximab in heavily pretreated CRC pts harboring KRAS G12C mts. The objective response rate (ORR) and disease control rate (DCR) was 43% and 100% (resp.) in pts receiving cetuximab and adagrasib (28 evaluable pts), and 22% and 87%, resp., in those receiving adagrasib alone (42 evaluable pts). Phase 1b CodeBreaK101 study evaluating sotorasib ( KRAS G12C inhibitor) and panitumumab (anti-EGFR) combination in KRAS G12C mt CRC showed 15.4% confirmed ORR and 26.9% unconfirmed ORR. These data are encouraging, suggesting EGFR inhibition in combination with downstream KRAS inhibition may represent important therapeutic strategy for this disease. KRAS mts lead to constitutive activation of the MAPK pathway signaling and cell activation. VS-6766 is a novel dual RAF/MEK inhibitor which has shown activity in KRAS mutated tumors. Combination of EGFR inhibition and VS-6766 may overcome resistance of KRAS mt CRC cancers to EGFR inhibition alone. Preclinically, VS-6766 and EGFR inhibition showed synergy in KRAS mt CRC cell lines, including cell lines harboring KRAS G12D and G12V mts, and CRC PDX of KRAS G12V mt CRC showed tumor regression with this combination. These data support the development of VS-6766 with anti-EGFR therapy in KRAS mt CRC warranting this phase 1 study to evaluate safety and efficacy of this combination in clinical settings. Methods: This is an open label, single arm study evaluating VS-6766 with cetuximab in pts with KRAS mt advanced CRC. Phase 1b primary endpoints include safety and tolerability, and maximum tolerated dose and recommended phase 2 dose determination. ORR is the primary endpoint of the Phase 2 study. Secondary endpoints include OS and PFS. There will be upto 4 dose levels tested. Three de-escalation doses to find the optimal cetuximab dose, and one dose escalation of VS-6766, are planned. Eligible pts include those with metastatic CRC and progression after 5-FU, oxaliplatin, irinotecan and VEGFi therapy. Based on prior studies, dermatologic, gastrointestinal, ocular and CPK elevation have been the main toxicities noted with VS-6766. The study is funded by research grants from Verastem Oncology. Cetuximab will be supplied by Eli Lilly.

Safety and efficacy of combining genotype-guided irinotecan (Iri) with 5FU, leucovorin (LV), oxaliplatin (Ox), and docetaxel (Tax) (gFOLFOXIRITAX): The I-FLOAT phase 1 dose-escalation study for advanced upper GI cancers

316

Background: 5FU, Ox, Iri, and Tax are each active in upper GI cancers. Triplet cytotoxic therapies (txs) improved survival compared to doublets/singlets. However, combination of all 4 agents (FOLFOXIRITAX) has not been studied. UGT1A1 polymorphisms reduce UGT enzymatic activity predisposing to Iri toxicity. We sought to determine the maximum tolerated dose (MTD) in the 1st month of tx among each of the low (L), intermediate (I) and high (H) risk UGT1A1 genotype (UGT) groups. Methods: Previously untx’d advanced upper GI cancer patients (pts) with ECOG PS 0/1 received gFOLFOXIRITAX (+ trastuzumab if HER2+) with pegfilgrastim. 5FU 2400mg/m2 over 46 hrs, LV 400mg/m2, Ox 85mg/m2, and Tax 25mg/m2 were given IV Q14 days. UGT-L, I, and H risk groups received starting Iri dose levels (DL1) of 120, 105 and 45mg/m2, respectively; Iri doses were escalated in each UGT group by 15mg/m2 increments and Tax to DL2 of 37.5mg/m2 using a I3+3 novel design (Liu & Ji. J Biopharm Stat 2020). Other endpoints included overall safety (thru up to 8 cycles before maintenance 5FU +/- Iri/tras), ORR (RECIST1.1), & ctDNA response (> 50% decrease in highest MAF) by G360 (Guardant Health). Results: From 6/30/2020-8/6/2021 20 pts (8F, 12M) enrolled: median age 50 (range 21-76); 8 ECOG PS 1, UGT-L:I:H with 3:14:3 pts; 10 esophageal, 6 gastric, 2 pancreatic, 1 unknown GI primary and 1 bile duct cancer; 2 pts HER2+; 18 metastatic, 2 locally advanced unresectable. The median (range) of albumin and neutrophil-to-lymphocyte ratio (NLR) were 3.9 mg/dL (3.3-4.6) and 4.28 (1.89-27.6), respectively; 80% (16/20) of pts had a NLR > 2.88, a poor prognostic marker. Dose limiting toxicities (DLTs) were seen in 4 pts: one G3 diarrhea (UGT-H, DL1/DL1 Iri/Tax), two G3 sepsis not neutropenic (one UGT-I, DL2/DL2 Iri/Tax; and one UGT-I, DL3/DL1 Iri/Tax) and one G3 fatigue (UGT-I DL2/DL2 Iri/Tax). MTD has not been reached in any UGT TAX DL1 cohorts to date; currently enrolling UGT-H Iri/Tax DL1/DL1, UGT-I DL4/DL1, & UGT-L DL3/DL1. Any Gr tx related toxicities in ³ 10% pts thru up to 8 cycles: nausea (70%), fatigue (70%, 5% G3), diarrhea (65%, 5% G3), anorexia (50%), peripheral neuropathy (30%, 5% G3), anemia (30%), thrombocytopenia (25%), elevated LFTs (25%), hyponatremia (25%), vomiting (20%), mucositis (20%, 5% G3), hyperglycemia (20%), edema (15%), alopecia (15%), hypocalcemia (15%) and dysgeusia (10%). Of evaluable pts across all cohorts, PR/CR was seen in 13/16 (81%) patients, with 2 (12.5%) SD and 1 (6.25%) PD for a disease control rate of 94%. Of evaluable pts, best ctDNA response was seen in 12/13 (92%). Conclusions: gFOLFOXIRITAX demonstrated tolerability at initial dose levels of Iri/Tax, with dose escalation continuing. Efficacy is promising and could be an aggressive approach in upper GI cancers having high relapse risk in curative-intent settings. Clinical trial information: NCT04361708.

Does detection of microsatellite instability-high (MSI-H) by plasma-based testing predict tumor response to immunotherapy (IO) in patients with pancreatic cancer (PC)?

607

Background: Immunotherapy (IO) is known to have robust anti-tumor activity in patients with MSI-H solid tumors. However, clinical trials investigating IO activity have used tissue-based testing to determine MSI-H status. Pancreatic tumor biopsy often does not provide sufficient tumor tissue for MSI testing. We investigated if the MSI-H status detected by plasma-based circulating tumor DNA (ctDNA) testing predicts robust response to IO in patients with PC. Methods: Genomic results from a well-validated plasma-based ctDNA assay (Guardant360[G360]) performed as part of routine clinical care between October 1, 2018 and September 7, 2021 in patients with PC were queried to identify patients with MSI-H tumors. Patient characteristics, tumor characteristics, treatment details, and outcomes were reported by ordering clinicians where available. The data cut-off date was September 1, 2021. Results: A total of 52 patients with PC who had MSI-H tumors on G360 were identified. Clinical outcomes data were available for 10/52 (19%) patients who were included for analysis. This patient cohort had a median age of 68 years (range: 56-82); 80% were male and 80% of patients had metastatic disease. 9/10 patients received IO: 3 in the first-line, 3 in the second-line, 3 in the third-line setting; most received pembrolizumab (8/9) while 1 received ipilimumab plus nivolumab. The median duration of IO was 8 months (range: 1-24). The overall response rate was 77% (7/9) and 6 of the 7 responders continue to show response at the time of data cut-off after a median follow-up of 21 months (range:11-33). The median progression-free survival and overall survival were not reached in the IO-treated cohort. Tissue-based MSI testing results were concordant with plasma-based G360 results in 5 of 6 patients (83%) who had tissue-based test results available. The patient with the discordant result was MSI-H by G360 but had intact mismatch repair protein expression by immunohistochemistry. This patient received neoadjuvant IO followed by surgery and the resected specimen confirmed pathological complete response. Conclusions: The detection of MSI-H status by plasma-based ctDNA testing is highly concordant to tissue-based testing and predicts robust and durable response to IO in patients with PC. The use of a well-validated plasma-based ctDNA analysis may expand the identification of MSI-H tumors in patients with PC and enable treatment with IO resulting in improved outcomes.

Clinical utility of microsatellite instability (MSI-H) identified on liquid biopsy in advanced gastrointestinal cancers (aGI)

56

Background: Identification of MSI-H is clinically meaningful in patients with aGI given the associated approval of multiple immune checkpoint inhibitors. MSI-H has long been assessed via tissue analysis; and insights from plasma-based approaches are limited to small validation studies. We sought to assess prevalence of initial and acquired MSI-H status across aGI and report real-world outcomes of colorectal (CRC) patients who received ICI after MSI-H identification by a commercially available liquid biopsy (LBx) assay. Methods: Genomic results from a well-validated LBx assay (Guardant360) completed as part of usual clinical care between 10/1/2018-9/7/2021 in patients with aGI were queried to assess MSI-H prevalence and identify cases of potential acquired MSI-H. Real-world evidence (RWE) was sourced from the GuardantINFORM database comprised of aggregated payer claims and de-identified records from 11/1/2018-3/31/2021. Patients with plasma-identified MSI-H who started new therapy < 60 days after assay report date were sorted into treatment groups: chemotherapy +/- biologic therapy (“chemo”) or immunotherapy via pembrolizumab or nivolumab (“ICI”). Real-world time to discontinuation (rwTTD) and real-world time to next treatment (rwTTNT) were assessed as proxies for progression free survival. Log-rank tests were used to assess differences in rwTTD, rwTTNT and overall survival. Results: Prevalence of MSI-H was ̃2% across aGI (Table). Five cases were observed to have potential acquired MSI not attributable to tumor shed identified on serial LBx tests. Of 222 MSI-H CRC patients eligible for RWE analysis, 89(40%) started new therapy within 60 days of results: 42(48%) received ICI, 39(44%) received chemo, 8(9%) received other/mixed regimens. Patients who received ICI had significantly longer rwTTD and rwTTNT compared to patients who received chemo [median months to discontinuation = 7.5 (95% CI 3.4-12.3) vs. 2 (95% 1.4-3.3) p<0.001; median months to next treatment = 23.8 (95% 10.6-NA) vs. 4.5 (95% CI 2.9-NA) p=0.006]; no overall survival difference was observed (p=0.559). Conclusions: This LBx assay detected MSI-H at similar frequencies to published tissue cohorts and may identify acquired MSI-H following early lines of therapy. Patients who received ICI following LBx identification of MSI-H achieved responses in line with published data in previously treated aGI. Well-validated LBx is a viable tool to identify initial and acquired MSI-H in aGI and may expand the number of patients who could benefit from ICI therapy, particularly in cases where access to tissue specimens is not feasible. [Table: see text]

Phase II Prospective, Open-Label Randomized Controlled Trial Comparing Standard of Care Chemotherapy With and Without Sequential Cytoreductive Interventions for Patients with Oligometastatic Foregut Adenocarcinoma and Undetectable Circulating Tumor Deoxyribose Nucleic Acid (ctDNA) Levels

BACKGROUND

Metastatic adenocarcinomas of foregut origin are aggressive and have limited treatment options, poor quality of life, and a dismal prognosis. A subset of such patients with limited metastatic disease might have favorable outcomes with locoregional metastasis-directed therapies. This study investigates the role of sequential cytoreductive interventions in addition to the standard of care chemotherapy in patients with oligometastatic foregut adenocarcinoma.

METHODS

This is a single-center, phase II, open-label randomized clinical trial. Eligible patients include adults with synchronous or metachronous oligometastatic (metastasis limited to two sites and amenable for curative/ablative treatment) adenocarcinoma of the foregut without progression after induction chemotherapy and having undetectable ctDNA. These patients will undergo induction chemotherapy and will then be randomized (1:1) to either sequential curative intervention followed by maintenance chemotherapy versus routine continued chemotherapy. The primary endpoint is progression-free survival (PFS), and a total of 48 patients will be enrolled to detect an improvement in the median PFS in the intervention arm with a hazard ratio (HR) of 0.5 with 80% power and a one-sided alpha of 0.1. Secondary endpoints include disease-free survival (DFS) in the intervention arm, overall survival (OS), ctDNA conversion rate pre/post-induction chemotherapy, ctDNA PFS, PFS2, adverse events, quality of life, and financial toxicity.

DISCUSSION

This is the first randomized study that aims to prospectively evaluate the efficacy and safety of surgical/ablative interventions in patients with ctDNA-negative oligometastatic adenocarcinoma of foregut origin post-induction chemotherapy. The results from this study will likely develop pertinent, timely, and relevant knowledge in oncology.

Celecoxib and Myrtol: A Novel Therapy for Recurrent Appendiceal Mucinous Neoplasms With Extensive Peritoneal Dissemination

BACKGROUND

Unresectable appendiceal mucinous neoplasms (AMNs) with extensive peritoneal dissemination cause significant morbidity and have limited treatment options. We evaluated a novel combination of Celecoxib and Myrtol in treating such AMNs.

METHODS

Patients with recurrent AMNs with extensive peritoneal disease treated with a daily regimen of 200 mg Celecoxib and 1200 mg Myrtol Standardized were included. Progression-free survival (PFS) and overall survival (OS) were calculated, and carcinoembryonic antigen (CEA) trends were compared pretreatment and post-treatment in terms of percentage change.

RESULTS

Thirteen patients with extensive, recurrent disease (median peritoneal carcinomatosis index of 36) were included between 2017 and 2020. The median age was 63 years (interquartile range: 55 to 67) and 7 (54%) were male. A total of 85% had undergone prior cytoreductive surgery while 15% underwent cytoreductive surgery >2 times. 54% had received multiple cycles of systemic chemotherapy before starting Celecoxib-Myrtol. After a median follow-up of 8 months, median PFS and OS were 16 months (interquartile range: 5 to 17) and 27 months, respectively. Nine (69.2%) showed improvement in CEA values 3 months after treatment compared with 3-month pretreatment CEA trends. None had adverse events attributable to Celecoxib-Myrtol.

CONCLUSIONS

Our feasibility study suggests that a regimen of Celecoxib-Myrtol is well tolerated and may prolong PFS and OS in patients with recurrent AMNs with peritoneal spread.

Circulating tumor-tissue modified HPV DNA analysis for molecular disease monitoring after chemoradiation for anal squamous cell carcinoma: a case report

Squamous cell carcinoma (SCC) of the anus typically arises after human papillomavirus (HPV) infection. We report on the use of molecular disease monitoring using a novel blood test measuring circulating tumor-tissue -modified HPV DNA in two patients with anal cancer. Two patients with anal SCC received concurrent chemotherapy and radiation therapy (chemoRT) with curative intent, one with a T2N0 anal margin squamous cell carcinoma with a history of AIDS, and one with a T3N0 anal squamous cell carcinoma and a history of concurrent prostate cancer. HPV genotyping at diagnosis confirmed the presence of HPV16 DNA in both cases. Circulating, tumor-tissue-modified HPV DNA (TTMV-HPV DNA) was measured in the peripheral blood utilizing digital PCR at baseline and in follow-up. Disease burden was assessed post-treatment with standard anoscopy, biopsy, and PET/CT. Plasma TTMV-HPV DNA levels were elevated at diagnosis, and decreased during and after chemoRT completion in both cases. During post treatment surveillance, TTMV-HPV DNA levels correlated with disease status including one case with progressive local recurrence within 2 months, and one case with 12 months of local control both confirmed by biopsy. These case studies present the first use of circulating tumor-tissue-modified HPV DNA as a biomarker for anal cancer. Further study of this blood test an adjunct to standard treatment and monitoring is warranted in HPV-positive anal cancer.

DNA Double-strand Break Signaling Is a Therapeutic Target in Head and Neck Cancer

BACKGROUND

Head and neck cancer (HNC) is common worldwide. Given poor outcomes for patients with HNC, research into targeted therapies is needed. Ataxia telangiectasia mutated (ATM) is a DNA damage kinase which is activated by double-strand DNA breaks. We tested the effects of a novel ATM inhibitor on HNC cell lines and xenografts.

MATERIALS AND METHODS

p53-Binding protein 1 and phosphorylated ATM were localized in cultured cells by immunofluorescence microscopy. Protein expression was determined by western blot. Tumor xenografts were established by injecting HNC lines into immunocompromised mice. Tumor sections were characterized by immunohistochemistry. Apoptotic cells were determined by terminal transferase-mediated dUTP nick-end labeling assay.

RESULTS

ATM inhibition increased double-strand DNA breaks at replication foci in HNC cell lines. ATM inhibition affected cell-cycle regulatory protein expression, blocked cell-cycle progression at the G2/M phase and resulted in apoptosis.

CONCLUSION

ATM inhibition may be therapeutically useful in treating HNC.

Supportive care services (SCS) during curative-intent treatment with chemoradiation for patients with locally advanced head and neck cancer (HNC)

e18041

Background: SCS assist in managing symptoms and outcomes for patients in palliative care settings. But impact of services in curative intent settings is not well defined. Here we evaluate this for head and neck cancer patients. Methods: Following IRB approval, we retrospectively reviewed charts of patients with HNC treated from 2014-2017 at the University of Illinois Hospital. Of 260 patient charts reviewed, 67 patients fit the study criteria, which included completing treatment with curative intent at University of Illinois Hospitals, not living at a skilled nursing facility, and follow-up of at least 3 months. Demographic data and treatment course data were collected. SCS included opioid use, tracheostomy use, G-tube use, prophylaxis for mucositis, speech and swallow f/u, nutritionist visits, social worker visits, and anti-emetic prophylaxis. Outcomes included number of hydration visits, number of ER visits, and number of days in the hospital. We tested the significance of correlations between continuous variables using Pearson correlation and the significance of difference in a continuous variable between two groups using the Wilcoxon ranked sum test. We used Cox proportional hazards model for analyses of overall survival (OS). Analyses were univariable. Results: 20 patients had oropharyngeal cancer. 47 had non-oropharyngeal disease. 57 patients received cisplatin and 10 patients received cetuximab, concurrently with radiation therapy. Median weight loss was 6.0kg during treatment. Highest potency opioid at end of treatment was not associated with outcomes. Among the full cohort, having a G-tube was associated with increased number of ER visits (median 1.5 vs. 0.0, p < 0.01), hospitalizations (median 2.0 vs. 0.0, p < 0.01), and number of days in the hospital (median 7.0 vs. 0.0, p < 0.01). Increased hydration appointments, meanwhile, did not predict outcomes. In subgroup analysis of patients who received G-tubes, ER visits before or after G-tube placement did not predict OS (HR 0.64, p = 0.56 for ER visits before G-tube placement, HR 1.06, p = 0.75 for ER visits after G-tube placement). Number of hydration visits after starting treatment for cetuximab vs cisplatin was significant (median 8 for cisplatin and 2 for cetuximab, p = 0.02). Conclusions: G-tube placement, even after placement, was associated with medical care needs during treatment, suggesting an unmet need for this patient population. Further studies are needed to determine how to best provide support for this vulnerable patient population.

Randomized phase II study of sorafenib with or without everolimus in patients with radioactive iodine refractory Hürthle cell thyroid cancer (HCC) (Alliance A091302/ ITOG 1706)

6076

Background: HCC is a rare subtype of follicular cell thyroid cancer that has been poorly studied in the past. Recent genomic studies have shown the PI3K/Akt/mTOR pathway is frequently altered in HCC. In addition, a phase II study of sorafenib (S) and everolimus (E) showed promising data in HCC. A study to evaluate this was initiated through Alliance and the International Thyroid Oncology Group. Methods: Patients (pts) were randomized to either sorafenib and everolimus (SE) vs. sorafenib alone (S). Inclusion criteria included; (1) diagnosis of HCC (confirmed through central review), no prior S or E, refractory to radioactive iodine, progressive disease by RECIST over prior 14 months. Primary endpoint was a comparison of progression-free survival (PFS) between SE and S using a stratified 1-sided log-rank test with 0.20 significance level and a power of 80%. 28 events were needed at final analysis. Secondary endpoints consisted of overall survival (OS), confirmed response rate (RR), and adverse events. Results: 35 pts were randomized from 10/2014 to 9/2019, 34 of which were evaluable for analysis (17-SE; 17-S) because 1 patient cancelled prior to receiving treatment. Median age was 66.5 years and 74% were male. ECOG performance status (PS) was 0 (47%) and PS 1 (53%). 41% had prior systemic treatment for HCC. No significant differences in baseline characteristics were observed between treatment arms. Median follow-up in 22 alive patients was 39.2 months (range: 15.1-64.9). Seven (21%) patients remain on treatment. PFS was significantly improved in the SE arm as compared to the S arm (HR=0.65 (95% CI: 0.26, 1.57); median PFS: SE=24.7 months (95% CI: 6.1-no upper), S=10.9 months (95% CI: 5.5-no upper); stratified 1-sided p=0.1662). OS was similar between the arms (2-sided p=0.4138). Confirmed response rate was similar between arms as well (SE: 18% (3 partial response (PR) vs. S: 24% (3 PR, 1 complete response)); Fisher’s exact p=1.00). Grade 3 adverse event (AE) rates (regardless of attribution) were similar between arms (SE: 77% vs. S: 77%; p=1.00). Each arm had 1 patient with at least one grade 4 AE (SE patient: cardiac arrest, tracheal obstruction, encephalopathy; S patient: mucositis oral) and no grade 5 AEs. Conclusions: PFS was improved with the addition of E to S in this small randomized multi-institutional phase II study done. Accrual was difficult, but these promising results suggest that this combination should be further studied. Support: U10CA180821, U10CA180882, U24CA196171; https://acknowledgments.alliancefound.org ; Novartis/GSK; ClinicalTrials.gov Identifier: NCT02143726. Clinical trial information: NCT02143726.

Guide to Enhanced Recovery for Cancer Patients Undergoing Surgery: ERAS for Patients Undergoing Cytoreductive Surgery with or Without HIPEC

ERAS protocols may reduce length of stay and return to full functional recovery after cytoreductive surgery and HIPEC. Prehabilitation programs and post-operative goal directed pathways, along with other essential components of ERAS are discussed with supporting evidence.

PDIGREE: An adaptive phase III trial of PD-inhibitor nivolumab and ipilimumab (IPI-NIVO) with VEGF TKI cabozantinib (CABO) in metastatic untreated renal cell cancer (Alliance A031704)

TPS366

Background: First-line treatment of mRCC has rapidly changed to include IPI-NIVO or CABO, with clinical benefit of each based on the Checkmate 214 and CABOSUN (A031203) trials. Combination immunotherapy with VEGF therapies has shown benefit over sunitinib in the JAVELIN 101 and KEYNOTE 426 trials. It is yet unclear which patients (pts) benefit most from combination immunotherapy-VEGF inhibitors, and the optimal sequence of drugs. Methods: In an adaptive, randomized, multicenter phase III trial (Alliance A031704, PDIGREE), pts start treatment with induction IPI 1 mg/kg and NIVO 3 mg/kg intravenously (IV) once every 3 weeks. Key inclusion criteria include clear cell mRCC, International Metastatic RCC Database Consortium (IMDC) intermediate or poor risk, Karnofsky performance status >70, and no prior treatments for mRCC. Based on 3-month radiographic assessment (after completing IPI-NIVO combination), pts with complete responses (CR) undergo maintenance NIVO 480 mg IV every 4 weeks; pts with progression of disease (PD) switch to CABO 60 mg oral daily; pts with non-CR/non-PD are randomized to NIVO 480 mg IV every 4 weeks versus NIVO 480 mg IV every 4 weeks with CABO 40 mg oral daily. Randomization is stratified by IMDC risk criteria and presence of bone metastases. The primary endpoint of the study is overall survival (OS). We hypothesize that 3-year OS will improve to 70% for NIVO-CABO compared to 60% for NIVO alone; to achieve 85% power with a two-sided alpha of 0.05 and exponential distribution, 696 patients will be randomized. Accounting for 30% patients with either CR or PD, and 5% dropout from toxicity, up to 1046 pts will be enrolled. Key secondary endpoints include progression-free survival, 12-month CR rate, overall response rate based on RECIST 1.1 and iRECIST criteria, and toxicity profiles. Quality of life will be assessed based on the FKSI-19, PROMIS-fatigue, and EQ5D-5L questionnaires. Biomarkers associated with CR, tissue-based and plasma-based biomarkers will be assessed. Updated enrollment through January 2021 will be presented. Clinical trial information: NCT03793166 .

Novel Application of Iterative Hyperthermic Intraperitoneal Chemotherapy for Unresectable Peritoneal Metastases from High-Grade Appendiceal Ex-Goblet Adenocarcinoma

BACKGROUND

Peritoneal metastases (PMs) from appendiceal ex-goblet adenocarcinoma (AEGA) are associated with a poor prognosis. While cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has been shown to prolong survival, the majority of patients are ineligible for complete cytoreduction. We describe a novel approach to the management of such patients with iterative HIPEC (IHIPEC).

METHODS

Patients with signet ring/poorly differentiated AEGA with high Peritoneal Cancer Index (PCI) and extensive bowel involvement underwent IHIPEC with mitomycin C at 6-week intervals for a total of three cycles. Survival outcomes for these patients were compared with patients with high-grade appendiceal tumors matched for tumor burden who were treated with other conventional approaches, i.e. systemic chemotherapy only (SCO) or complete CRS + HIPEC.

RESULTS

Between 2016 and 2019, seven AEGA patients with high PCI (median 32.5 [range 21-36]) underwent 18 IHIPEC cycles (median cycles per patient 3 [2-3]) in combination with systemic chemotherapy (median 2 lines [1-3], 12 cycles [10-28]). IHIPEC was delivered laparoscopically in 14/18 cases. Postoperatively, the median length of stay was 1 day (1-8 days), no procedure-related complications were reported, and five (28%) 90-day readmissions for bowel obstruction were documented. Median overall survival after IHIPEC was better compared with a matched group of patients (n = 16) receiving SCO (24.6 vs. 7.9 months; p = 0.005), and similar to those (n = 7) who underwent CRS + HIPEC (24.6 vs. 16.5 months; p = 0.62).

CONCLUSIONS

IHIPEC in combination with systemic chemotherapy is tolerable, safe, and may be associated with encouraging survival outcomes compared with SCO in selected patients with high-grade, high-burden AEGA PM.

A multi-institutional comparison of mitoxantrone, etoposide, and cytarabine vs high-dose cytarabine and mitoxantrone therapy for patients with relapsed or refractory acute myeloid leukemia

Relapsed or refractory acute myeloid leukemia (R/R AML) has a poor prognosis and is best treated with salvage chemotherapy as a bridge to allogeneic stem cell transplant (alloSCT). However, the optimal salvage therapy remains unknown. Here we compared two salvage regimens; mitoxantrone, etoposide, and cytarabine (MEC) and mitoxantrone and high-dose Ara-C (Ara-C couplets). We analyzed 155 patients treated at three academic institutions between 1998 and 2017; 87 patients received MEC and 68 received Ara-C couplets. The primary endpoint was overall response (OR). Secondary endpoints included progression-free survival (PFS), overall survival (OS), duration of hospitalization, hematologic and nonhematologic toxicities, and success in proceeding to alloSCT. Baseline characteristics of the cohorts were well matched, though patients receiving Ara-C couplets had more co-morbidities (48.5% vs 33%; P = .07). OR was achieved in 43.7% of MEC and 54.4% of Ara-C couplets patients (P = .10). Ara-C couplets patients also trended towards a longer OS and PFS, more frequently proceeded to alloSCT (31% vs 54.4%; P = .003), and experienced less febrile neutropenia (94% vs 72%; P < .001) and grade 3/4 gastrointestinal toxicities (17.2% vs 2.94%; P = .005). No significant differences in other toxicities or median duration of hospitalization were noted. This is the first multi-institutional study directly comparing these regimens in a racially diverse population of R/R AML patients. Although these regimens have equivalent efficacy in terms of achieving OR, Ara-C couplets use is associated with significant reductions in toxicities, suggesting it should be used more frequently in these patients.

PDIGREE: An adaptive phase III trial of PD-inhibitor nivolumab and ipilimumab (IPI-NIVO) with VEGF TKI cabozantinib (CABO) in metastatic untreated renal cell cancer (Alliance A031704)

TPS5100

Background: First-line treatment of mRCC has rapidly changed to include IPI-NIVO or CABO, with clinical benefit of each based on the Checkmate 214 and CABOSUN (A031203) trials. Combination immunotherapy with VEGF therapies has shown benefit over sunitinib in the JAVELIN 101 and KEYNOTE 426 trials. It is yet unclear which patients (pts) benefit most from combination immunotherapy-VEGF inhibitors, and the optimal sequence of drugs. Methods: In an adaptive, randomized, multicenter phase 3 trial (Alliance A031704, PDIGREE), pts start treatment with induction IPI 1 mg/kg and NIVO 3 mg/kg intravenously (IV) once every 3 weeks. Key inclusion criteria include clear cell mRCC, International Metastatic RCC Database Consortium (IMDC) intermediate or poor risk, Karnofsky performance status > 70, and no prior treatments for mRCC. Based on 3-month radiographic assessment (after completing IPI-NIVO combination), pts with complete responses (CR) undergo maintenance NIVO 480 mg IV every 4 weeks; pts with progression of disease (PD) switch to CABO 60 mg oral daily; pts with non-CR/non-PD are randomized to NIVO 480 mg IV every 4 weeks versus NIVO 480 mg IV every 4 weeks with CABO 40 mg oral daily. Randomization is stratified by IMDC risk criteria and presence of bone metastases. The primary endpoint of the study is overall survival (OS). We hypothesize that 3-year OS will improve to 70% for NIVO-CABO compared to 60% for NIVO alone; to achieve 85% power with a two-sided alpha of 0.05 and exponential distribution, 696 patients will be randomized. Accounting for 30% patients with either CR or PD, and 5% dropout from toxicity, up to 1046 pts will be enrolled. Key secondary endpoints include progression-free survival, 12-month CR rate, overall response rate based on RECIST 1.1 and irRECIST criteria, and toxicity profiles. Quality of life will be assessed based on the FKSI-19, PROMIS-fatigue, and EQ5D-5L questionnaires. Biomarkers associated with CR, tissue-based and plasma-based biomarkers will be assessed. Updated enrollment through May 2020 will be presented. Clinical trial information: NCT03793166 .

A randomized phase II study of MLN0128 (M) versus pazopanib (P) in patients (pt) with advanced sarcoma (Alliance A091304)

11562

Background: Soft tissue sarcoma (STS) is a heterogeneous malignancy of connective tissue. Although mTOR is implicated in STS pathogenesis, clinical activity from mTORC1 inhibitors is modest. M, a potent selective mTORC1/mTORC2 inhibitor, was more effective in STS preclinical models than inhibitors of mTORC1, IGF1R and mTORC1+IGF1R, owing to more complete suppression of PI3K/AKT/mTOR and abrogation of feedback AKT activation. P, an oral multikinase inhibitor, is approved for non-adipocytic STS and often used after progression (PD) on chemotherapy. In phase 1, the RP2D of M was 30 mg weekly. A091304 was to evaluate M as a novel targeted therapy for STS. Methods: In A091304, pts were randomized 1:1 to M 30 mg weekly or P 800 mg daily. Eligibility required Eastern Cooperative Oncology Group PS ≤ 1, progression on ≥ 1 prior chemotherapy and specific STS subtypes (cohort 1: UPS; 2: LMS; 3: MPNST, SS). Crossover to M was allowed after PD on P. 1° endpoint was progression-free survival (PFS). Assuming median PFS of P was 4.6 months (mo), 98 pts yielded 80% power to detect a hazard ratio of 0.66 favoring M [1-sided test, alpha = 0.15] and including 1 planned futility analysis. 2° endpoints were response rate, clinical benefit rate (CBR) at 4 mo and safety. After 4 of the first 12 pts randomized to P experienced ≥ grade (gr) 3 toxicity, the study was amended to begin at P 400 mg, allowing titration to 800 per investigator discretion. Results: After protocol amendment, 114 pt underwent randomization (M: 56, P: 58), and 111 initiated treatment. Median PFS was 2 mo for M and 2.1 mo for P (HR = 1.47; 1-sided 85% upper confidence boundary = 1.85), with 2 partial responses in each arm. CBR was 5.4% for M and 13.8% for P. Median OS was 10.7 mo for M and 13.9 mo for P (HR = 1.41; 95% CI 0.80-2.49). 26/43 pt with PD on P crossed over to M. Median PFS after crossover was 1.8 mo (95% CI 1.5-3.5). Gr 3 drug-related adverse events (AEs) occurred in 36% on M and 41% on P; gr 4 toxicity was rare. AEs were consistent with known effects of M and P. Conclusions: P at 400 mg daily (allowing escalation to 800 mg per investigator discretion) demonstrated a shorter PFS as compared prior randomized studies with P. Despite this, M failed to demonstrate superior clinical activity as compared to P at the interim analysis. Further work will examine activity within histology-specific cohorts and evaluate available tissue samples for evidence of pharmacodynamic activity. Support: U10CA180821, U10CA180882, U10CA180888, UG1CA233324 (SWOG); https://acknowledgments.alliancefound.org . Clinical trial information: NCT02601209 .

A large subtype of squamous cell carcinoma enriched for TrkB-T1 mRNA

e14751

Background: A large subtype of squamous cell carcinoma enriched for TrkB-T1 mRNA. Background The NTRK2 genetic locus encodes neurotrophin membrane receptors that play an important role in normal neural tissue plasticity, growth, and survival. One NTRK2-encoded protein is TrkB-FL, which can regulate multiple pathways relevant to cancer. A second NTRK2 gene mRNA isoform encodes TrkB-T1, a receptor that has a different cytoplasmic domain and is encoded in a mRNA with a unique 3’ terminal exon. Methods: Tumors from The Cancer Genome Atlas (TCGA) and other studies were classified according to the expression of a single form of NTRK2 mRNA that of TrkB-T1. Analysis of differentially expressed genes in TrkB-T1 high expressers was done to determine if tumors enriched for TrkB-T1 were a uniform group independent of anatomic site. Results: The mRNA for TrkB-T1 is the most abundant NTRK2 gene mRNA in all squamous cell carcinomas (SCCs). Comparison of oral SCC (OSCC) high TrkB-T1 RNA expressers to low expressers (n = 284) revealed gene expression differences consistent with the high TrkB-T1 tumors being more neural-like. The upregulated genes in the TrkB-T1 RNA high expressers also showed enrichment of pathways involved in retinol metabolism, hedgehog signaling, and the Nfe2l2 response, among other pathways. An examination of larynx, esophagus, and lung SCCs (n = 100, 100, 540) showed induction of the same pathways among the tumors that expressed high levels of TrkB-T1 mRNA.. Surprisingly, the relationship of high level TrkB-T1 expression to patient outcomes was SCC anatomic site specific. High TrkB-T1 mRNA levels in laryngeal SCC correlated with poor survival, but the opposite was true for lung SCC. This may be because pathways enriched in the TrkB high expressers, like those regulated by Nfe2l2, Pik3ca, and Sox2, are known to have SCC anatomic site-specific effects on progression. Conclusions: High level TrkB-T1 mRNA serves as a marker of a distinct SCC subtype. These tumors share the enrichment of at least 3 pathways relevant to tumor progression, Nfe2l2 response, retinol metabolism, and hedgehog signaling.

Personalized antibodies for gastroesophageal adenocarcinoma (PANGEA): A phase II precision medicine trial (NCT02213289)

TPS198

Background: Targeted therapies (tx) in GEA have had limited efficacy despite recognition of numerous ‘targetable’ molecular events. This may be due to the molecular heterogeneity (MH) that exists between patients (pts), within the primary tumor (PT), between PT and synchronous metastatic lesions (MLs), and in lesions over time. Current biomarker profiling (BP) is performed on one site, usually the PT, yet this fails to capture the MH of GEA, with likely major clinical implications. Classic trial designs are challenged by MH, low frequency oncogenic drivers, and scarcity of tissue. There is need for novel trial designs and BP technologies that address these concerns, provide tx algorithms for pts with multiple aberrations, and have access to several txs. Methods: This phase IIa, open-label, non-randomized ‘platform trial’ enrolls pts with newly diagnosed metastatic GEA or recurrent disease after curative-intent surgery. Baseline tumor BP is performed on PT/ML along with circulating free (cf)DNA. Pts receive first line (1L) mFOLFOX6 + biologic tx based on BP of the ML using a prioritized tx algorithm (HER2+: trastuzumab; MET+: none; FGFR2+: none; EGFR+: ABT806; MSI-H: nivolumab; ‘RAS-like’: ramucirumab). MET/FGFR2 arms (~10% of all pts) are tx’d with cytotoxics only and followed for natural outcome until/if tx becomes available on study. At first progression (PD1), pts undergo biopsy of growing ML and change to 2L FOLFIRI + biologic agent as assigned in 1L tx. Upon results of PD1 biopsy, pts change to a new biologic tx if the molecular category evolves. At PD2, pts change to 3L FOLTAX + biologic as determined after PD1, and switch biologic tx from PD2 biopsy result. All PD1/PD2 tumor/cfDNA samples undergo BP to assess evolution and resistance mechanisms. Co-primary endpoints: safety, feasibility, and overall survival (OS) of this personalized treatment strategy (excluding MET/FGFR2) compared to historical controls (HR 0.66). Secondary endpoints include rate of baseline MH between PT and ML leading to new treatment assignment; utility of cfDNA; overall progression-free survival (PFS)/response rate (RR); OS/PFS/RR in each targetable group. Since 8/2015, 38 of 68 planned pts have been accrued. Clinical trial information: NCT02213289.