Randomized phase II trial of encorafenib and cetuximab with or without nivolumab for patients with previously treated, microsatellite stable, BRAFV600E metastatic and/or unresectable colorectal cancer: SWOG S2107

TPS265

Background: Patients with microsatellite stable (MSS), BRAFV600E metastatic colorectal cancer (mCRC) experience poor survival outcomes. Treatment with the BRAF inhibitor encorafenib (E) and anti-EGFR antibody cetuximab (C) is an approved treatment combination, with a reported overall response rate (ORR) of 20% and median progression-free survival (PFS) of 4.1 months. Anti-PD-1 antibodies like nivolumab (N) are ineffective as monotherapy for patients with MSS, BRAFV600E mCRC. In preclinical models of MSS, BRAFV600E CRC, inhibition of BRAF and EGFR induces a loss of expression of mismatch repair genes and promotes a microsatellite instability-high phenotype, which may prime these tumors for response to immunotherapy. In support of these findings, a single-institution clinical trial of E + C + N for 26 patients with MSS, BRAFV600E mCRC reported an ORR of 50% and median PFS of 7.2 months. We hypothesize that the addition of N to E + C will improve median PFS for patients with MSS, BRAFV600E mCRC. Methods: In this prospective phase II clinical trial (N = 75), patients with previously treated MSS, BRAFV600E mCRC will be randomized 2:1 into 2 arms, respectively: experimental treatment (E + C + N) or standard treatment (E + C). No prior BRAF, EGFR, or immunotherapy agents are allowed. All patients will receive E (300 mg PO daily) and C (500 mg/m2 IV every 14 days), and patients in the experimental arm will receive N (480 mg IV every 28 days). The primary endpoint is PFS. Secondary endpoints include overall survival, best overall response, duration of response, and safety/tolerability. Using a one-sided α = .10 and power 80%, we target an improvement in median PFS from 4.2 to 7.3 months and a hazard ratio of 0.57. Additional patient specimens will be collected for exploratory correlative research. The study activated across the United States in June 2022 and as of September 2022 has enrolled 2 of 75 planned participants. Funding: NIH/National Cancer Institute grants U10CA180888, U10CA180819, U10CA180820, U10CA180821, U10CA180868; and in part by The Hope Foundation for Cancer Research STrS award. Clinical trial information: NCT05308446 .

The Brown University Oncology Group Experience With FOLFOX + Nab-paclitaxel [FOLFOX-A] for Metastatic and Locally Advanced Pancreatic, BrUOG-292 and BrUOG-318

OBJECTIVES

To evaluate response rate, toxicity, and efficacy of the novel combination of nab-paclitaxel, oxaliplatin, 5-fluorouracil, and leucovorin [FOLFOX-A] in patients with advanced pancreatic ductal adenocarcinoma [PDAC].

METHODS

BrUOG-292 and BrUOG-318 were two concurrently run, prospective, single-arm phase II studies evaluating FOLFOX-A as first-line therapy in patients with metastatic and locally advanced/borderline resectable PDAC respectively. The FOLFOX-A regimen consisted of 5-fluorouracil, 1200 mg/m 2 /d as a continuous intravenous (IV) infusion over 46 hours, leucovorin 400 mg/m 2 IV, oxaliplatin 85 mg/m 2 IV, and nab-paclitaxel 150 mg/m 2 IV on day 1 every 14 days up to a maximum of 12 cycles. Patients with locally advanced or borderline resectable disease were permitted to stop treatment after 6 cycles and receive radiation therapy and/or surgical exploration if feasible. The primary end point was overall response rate [ORR]. Secondary end points were median progression-free survival [PFS], median overall survival [OS], and safety.

RESULTS

Seventy-eight patients with previously untreated PDAC were enrolled between June 2014 and November 2019; 76 patients were evaluable. The median follow-up was 40 months and 32 months, respectively. overall response rate was 34%. Among the patients enrolled on BrUOG-292 [48 patients], the PFS was 5 months and OS was 11 months, respectively. For those enrolled on BrUOG 318 [28 patients], the PFS was 11 months and OS was 22 months. Treatment-related toxicities included grade 3 fatigue [40%], diarrhea [14%], and neuropathy [2%].

CONCLUSIONS

The combination of FOLFOX-A has promising activity in PDAC and may represent an alternative to FOLFIRINOX when reduction of gastrointestinal toxicity is required.

Comparison of tumor registry reporting and gastrointestinal oncologist determination of intrahepatic cholangiocarcinomas: A quality review analysis

e16113

Background: Diagnosing cholangiocarcinoma (CCA) can be challenging and these tumors are often misclassified as adenocarcinomas of unknown primary (AUP). Accurate identification is critically important to determine the true incidence and to understand the epidemiology of these cancers. Methods: As a quality assessment, gastrointestinal oncologists at our institution reviewed the tumor registry records of all patients diagnosed with intrahepatic CCA, extrahepatic CCA, hepatocellular carcinoma, adenocarcinoma of unknown primary, and adenocarcinoma not otherwise specified. Mixed hepatocellular/cholangiocarcinoma was excluded. Results: Initially the tumor registry reported 37 cases of intrahepatic CCA at the Lifespan Cancer Institute/Rhode Island Hospital between 2017-2020. However, review of the registry records by gastrointestinal oncologists revealed 10 additional cases of intrahepatic cholangiocarcinoma. These cases had been entered into the tumor registry with diagnosis codes of liver adenocarcinoma NOS (n = 8), liver cancer (n = 1) and liver NOS (n = 1). Following review, a total of 47 cases of intrahepatic CCA and 59 cases of extrahepatic CCA were identified at our institution between 2017-2020. The mean age of intrahepatic CCA was 58 and 48% were women. The mean age of extrahepatic CCA was 73 and 42% were women. The updated numbers were reported to the state tumor registry. Conclusions: Difficulties in diagnosis of cholangiocarcinoma may underestimate the true incidence of this disease in the United States. Careful review of tumor registry data across the United States would likely reveal large discrepancies between actual and reported incidence of this disease and further study is warranted.

Colon cancer and immunotherapy-can we go beyond microsatellite instability?

Immune checkpoint blockade (ICB) has changed the landscape of cancer therapy in multiple tumor types since the first agent, Ipilimumab, was first FDA approved for the treatment of metastatic melanoma in 2011. Its role in GI Cancers, particularly in colon cancers, has not been as robust as in other tumor types but select patients with DNA mismatch repair defects, even those who has progressed on multiple standard chemotherapeutic regimens have demonstrated significant, almost unprecedented, responses in this multidrug refractory population. Unfortunately, these cases represent only a small percentage of colon cancer patients with little efficacy in the 95% of metastatic colon cancers who have proficient DNA mismatch repair. Multiple strategies have been, and are currently being, evaluated to determine the potential benefits of this drug class to microsatellite stable (MSS) patients.

Complete neoadjuvant treatment for rectal cancer: A single institution experience

148

Background: Full dose adjuvant chemotherapy following preoperative chemoradiation and surgery is poorly tolerated in stage II and III rectal cancer. We reviewed our institution’s experience with complete neoadjuvant treatment for rectal cancer since publication of the BrUOG R-224 trial results. Methods: After obtaining IRB approval, Data on patients with stage II and III rectal cancer who underwent complete neoadjuvant therapy were collected.. Patients who were planned to receive 8 cycles of modified FOLFOX6, chemoradiation with capecitabine 825 mg/m2 twice daily and 50.4 Gy intensity-modulated radiation therapy, then surgery were included. Results: Thirty-five patients were treated with complete neoadjuvant therapy between January 2014 and December 2017. Median age was 58 years (27 to 75 y); 1 patient (3%) was clinical stage II and 34 (97%) stage III. Twenty-seven patients (77%) received all 8 cycles of mFOLFOX6, of whom 24 completed subsequent chemoradiation. Therefore 69% of patients completed therapy according to the BrUOG R-224 protocol. Pathologic complete response (ypT0N0) was observed in 9 patients (26%). Treatment related toxicities resulted in dose reductions or treatment interruption in 57% and 29% of patients receiving chemotherapy and chemoradiation respectively. Conclusions: Complete neoadjuvant therapy for clinical stage II to III rectal cancer is well-tolerated in routine practice and offers an alternative to preoperative chemoradiation, surgery, then adjuvant full dose chemotherapy.

Adjuvant FOLFOX + nab-paclitaxel (FOLFOX-A)for pancreatic cancer, BrUOG 278: A Brown University oncology research group phase II study

e15733

Background: Adjuvant FOLFIRINOX increases survival in pancreatic cancer but is associated with significant toxicity. The Brown University Oncology Research Group (BrUOG) developed the FOLFOX-A regimen in a phase I study in advanced pancreatic cancer (Am J Clin Oncol, 2016). Phase II studies (BrUOG 292 and BrUOG 318) have shown substantial activity in patients with metastatic and locally advanced disease. Highly active regimens have the potential to improve survival in the adjuvant setting. The primary objective of BrUOG 295 was to determine the feasibility of administering 10 cycles of FOLFOX-A. Secondary objectives were toxicity and disease free survival. Methods: Patients received oxaliplatin, 85mg/m2 day 1, nab-paclitaxel, 150mg/m2 and leucovorin 400mg/m2 day 1 and fluorouracil 2400mg/m2 by continuous IV infusion over 46 hours. Myeloid growth factor support was optional. Cycles were repeated every 14 days for up to 10. Oxaliplatin was dose reduced to 68mg/m2 for grade 2 neurotoxicity. CTCAE version 4 toxicity scales were utilized. Results: The study reached its initial accrual goal of 25 patients. The median age was 60 (43-69). Twenty-one patients were node +. Twelve of the first 20 patients have received 10 cycles of FOLFOX-A and 17 of the first 20 patients received > 8 cycles. The most common grade >3 toxicities were neutropenia grade 3 (N = 3), grade 4 (N = 3) and fatigue grade 3 (n = 13). One patient had grade 3 neuropathy. Conclusions: Adjuvant FOLFOX-A is well tolerated with low incidences of grade 3 neuropathy and gastrointestinal toxicity. Toxicity, feasibility and disease free survival will be updated at the May 2019 BrUOG DSMB meeting. Clinical trial information: NCT02022033.

Toxicity of FOLFOX-abraxane (FOLFOX-A) on phase II Brown University Oncology Group (BrUOG) trials

354

Background: FOLFIRINOX increases survival in pancreatic cancer. The Brown University Oncology Group developed the FOLFOX-A regimen in a phase I study. (Am J Clin Oncol, 2016). We subsequently opened phase II studies of FOLFOX-A in patients with metastatic pancreatic cancer (BrUOG 292), locally advanced/borderline pancreatic cancer (BrUOG 318) and adjuvant disease following resection (BrUOG 295). The BrUOG Data Safety Monitoring Committee met on May 22, 2018. Toxicity of FOLFOX-A reviewed at the May meeting aligned with data lock in April on phase II FOLFOX-A studies and is summarized. Methods: Patients received oxaliplatin, 85mg/m2 day 1, nab-paclitaxel, 150mg/m2 and leucovorin 400mg/m2 day 1 and fluorouracil 2400mg/m2 by continuous IV infusion over 46 hours. Myeloid growth factor support was optional. Cycles were repeated every 14 days for up to 10-12 cycles. Oxaliplatin was dose reduced to 68mg/m2 for grade 2 neurotoxicity. CTCAE version 4 toxicity scales were utilized. Results: A total of 81 patients were accrued, (22 adjuvant, 36 metastatic, 23 locally advanced disease). Cumulative fatigue was the most common toxicity and required dose reduction in 50% of patients. The incidences of grade 2, 3 and 4 neutropenia were 26%, 17% and 6%, respectively. Grade 2,3 and 4 diarrhea were 9%, 15% and 0%. The rates of grade 2,3 and 4 neuropathy were 29%, 2% and 0%. Conclusions: FOLFOX-A is well tolerated with low incidences of grade 3 neuropathy and gastrointestinal toxicity. Toxicities were less frequent in patients treated in the adjuvant setting. Clinical trial information: NCT02080221, NCT02022033, NCT02578732.

Adjuvant FOLFOX-Nab-paclitaxel (FOLFOX-A) for pancreatic cancer: A phase II Brown University Oncology Research Group (BrUOG) trial

TPS550

Background: The FOLFOX-A regimen was developed by BrUOG, in response to the activity of nab-paclitaxel (nP) in metastatic pancreatic cancer (mPC), by substituting nP for irinotecan in FOLFIRINOX. In a phase I/II study of FOLFOX-A in mPC, median overall survival (OS) was 15 months (Safran H, et al. Am J Clin Oncol, 2016 Dec;39(6):619-622), which motivated evaluation of the tolerability and efficacy of this aggressive regimen in the adjuvant setting. Therefore, a phase II study of FOLFOX-A was initiated for patients with resected pancreatic cancer. Methods: Eligibility criteria included potentially curative resection of pancreatic adenocarcinoma (positive margins allowed if all gross tumor was removed), pathologic stages T1-3/N0-1/M0, interval between surgery and registration of 21-70 days and post resection serum CA19-9 ≤ 180 units/mL. All patients received nab-paclitaxel 150mg/m2, oxaliplatin 85mg/m2 and leucovorin 400mg/m2, followed by fluorouracil 2400mg/m2 infused over 46 hours. Cycles were repeated every 2 weeks. The primary objective is to assess the feasibility of administering at least 10 of 12 planned cycles of FOLFOX-A without unacceptable toxicity in 25 patients. Secondary endpoints include progression-free survival and OS. Results: Between June 2014-August 2017, 19 patients have been enrolled, 8 male and 11 female. Median age is 63 (43-68). Fifteen patients had positive lymph nodes on pathology with stages T1N0(n = 2), T3N0(n = 2), T1N1(n = 1), T3N1(n = 14) [AJCC Cancer Staging Manual, 7th Edition (2010)]. Conclusions: This study is testing the tolerability of administering adjuvant FOLFOX-A to patients with resected pancreatic cancer. Accrual is expected to be complete by January 2018. Clinical trial information: NCT02022033.