Real world outcomes in patients with neuroendocrine tumor receiving peptide receptor radionucleotide therapy

Aim

¹⁷⁷Lu-Dotatate (Lu-177), a form of peptide receptor radionuclide therapy (PRRT), was approved by Food and Drug Administration (FDA) for the treatment of somatostatin-receptor-positive neuroendocrine tumors (NETs) in 2018. Clinical trials prior to the FDA approval of Lu-177 showed favorable outcomes but there is limited published real world outcomes data. This study aims to describe and analyze real world outcomes of patients with NET who received Lu-177.

Methods

After obtaining institutional review board approval, retrospective evaluation was performed to analyze the efficacy of Lu-177 for somatostatin receptor-positive gastro-entero-pancreatic NETs (GEP-NETs) patients at the University of Kansas Cancer Center between June 2018 and September 2021. This study aims to determine the response rate to the treatment of the entire cohort and subgroups.

Results

A total of 65 patients received Lu-177 of which 58 completed treatment. The 58 patients had a median age of 61.5 years, 24 females and 34 males, 86% Caucasian and 12% black. The origins of NETs were primarily small bowel (n = 24) and pancreatic (n = 14). Pathology showed grades 1 (n = 21), 2 (n = 25), and 3 (n = 4) and were primarily well-differentiated tumors (n = 4). Among the cohort, 52 patients had imaging to assess response with 14 (26.9%) patients with partial response (PR), 31 (59.6%) with stable disease (SD), and 7 (13.5%) with progressive disease (PD). In a subset analysis, patients with non-functional disease (n = 29) had higher rates of PR 42.3% (compared to 11.5%, P = 0.0147) and higher disease control rate of 96% (compared to 78%, P = 0.042) than patients with functional disease (n = 29). Patients with non-functional disease had a lower PD of 3.85% (compared to 23%, P = 0.0147) than those with functional disease.

Conclusions

This real world outcomes analysis of NETs treated with Lu-177 shows improved PR when compared to the initial clinical trials and is promising for patients. In addition, patients with non-functional tumors were found to have a statistically significant improved response rate which has not been described in the literature before. If these study findings are validated in a larger cohort they may guide patient selection for Lu-177 therapy in the future.

Equitable Access to Clinical Trials: How Do We Achieve It?

The mismatch between the study populations participating in oncology clinical trials and the composition of the targeted cancer population requires urgent amelioration. Regulatory requirements can mandate that trial sponsors enroll diverse study populations and ensure that regulatory revue prioritizes equity and inclusivity. A variety of projects directed at increasing accrual of underserved populations to oncology clinical trials emphasize best practices: broadened eligibility requirements for trials, simplification of trial procedures, community outreach through patient navigators, decentralization of clinical trial procedures and institution of telehealth, and funding to offset costs of travel and lodging. Substantial improvement will require major changes in culture in the educational and professional practice, research, and regulatory communities and will require major increases in public, corporate, and philanthropic funding.

A multicenter, open-label, phase I/II study of FN-1501 in patients with advanced solid tumors and acute myeloid leukemia

e15083

Background: FN-1501, a potent inhibitor of receptor FMS-like tyrosine kinase 3 (FLT3) and CDK4/6, KIT, PDGFR, VEGFR2, ALK and RET tyrosine kinase proteins, has demonstrated significant in vivo anti-tumor activity in a broad range of solid tumor and leukemia xenograft models. FLT3 mutations have an established role as a therapeutic target in Acute Myeloid Leukemia (AML), where the gene plays a critical role in the growth, differentiation, and survival of hematopoietic cells. An open-label, Phase I/II study ( NCT03690154 ) is evaluating the safety and PK profile of FN-1501 as monotherapy in patients (pts) with advanced solid tumors and relapsed, refractory (R/R) AML. Methods: Pts received FN-1501 IV thrice weekly for 2 weeks followed by 1 week off treatment in 21-day cycles. Dose escalation follows a 3+3 design. Primary objectives include determination of maximum tolerated dose (MTD), safety, and recommended phase 2 dose (RP2D). Secondary objectives include pharmacokinetics (PK) and preliminary anti-tumor activity. Exploratory objectives include the relationship between pharmacogenetic mutations (e.g., FLT3, TP53, KRAS, NRAS), safety, efficacy and pharmacodynamic effects of FN-1501. Dose expansion at RP2D was designed to further explore safety and efficacy. Results: As of Dec 3, 2021 data cut-off (DCO), 47 pts with advanced solid tumors (N = 46) or AML (N = 1) were enrolled at doses ranging from 2.5 to 226 mg. The median age was 65 (range 30-92) with 57% female and 43% male. The median prior lines of treatment were 5 (range 1-12). Forty pts with median exposure of 9.5 cycles (range 1-18 cycles) were evaluable for dose limiting toxicity (DLT). Treatment-related adverse events (TRAEs) were reported in 64% of pts. The most common treatment-emergent adverse events (TEAEs) defined as those occurring in ≥ 20% of patients primarily consisted of reversible grade 1-2 fatigue (34%), nausea (32%) and diarrhea (26%). The most common grade ≥ 3 events occurring in ≥ 5% of pts consisted of diarrhea and hyponatremia. Dose escalation was discontinued due to DLTs of grade 3 thrombocytopenia (N = 1) and grade 3 infusion related reaction (N = 1) in 2 pts in the 226 mg dose group (2nd DLT reported after DCO). At the time of DCO, 33 pts were evaluable for disease response showing 1 with partial response (PR) (47% target lesion shrinkage), 15 with stable disease (SD) and 17 with progression of disease (PD). The PR lasted > 4 months (mts) in a patient with endometrial carcinoma (ca) at the 40 mg dose level. The longest treatment exposures were recorded in 6 pts with SD of 2.6 to > 12 mts (thymoma [1]; ovarian ca [2]; renal cell ca [1]; laryngeal ca [1] and intestinal adeno ca [1]) at doses ranging from 15 mg to 170 mg. Conclusions: FN-1501 IV has shown reasonable safety, tolerability, and preliminary activity against solid tumors up to 170 mg. Dose escalation was terminated based on 2 DLTs occurring at the 226 mg dose level. Clinical trial information: NCT03690154.

A phase II study of perioperative mFOLFOX plus pembrolizumab combination in patients with potentially resectable adenocarcinoma of the esophageal, gastroesophageal junction (GEJ) and stomach

4047

Background: Surgical rection is the only potentially curative intervention for locally advanced adenocarcinoma of esophagus, GEJ and stomach. Results from various studies have demonstrated the benefits of perioperative treatment including neoadjuvant and adjuvant chemotherapy or chemoradiation, however, there is lack of universally accepted standard. Recent data demonstrated the benefit of immune checkpoint inhibitor in adjuvant setting in patients who had pre-operative chemoradiation. This single arm phase 2 trial is aimed to evaluate efficacy and safety of pembrolizumab, an immune checkpoint inhibitor, in combination with mFOLFOX in patients with potentially resectable adenocarcinoma of distal esophagus, GEJ and stomach. The primary objective is pathological response rate (ypRR with tumor regression score, TRS ≤ 2). Methods: Newly diagnosed locally advanced (T1N1-3M0 or T2-3NanyM0), potentially resectable adenocarcinoma of distal esophagus, GEJ and stomach by PET, EUS, CT C/A/P and staging laparoscopy were treated with pre-operative mFOLFOX6 (oxaliplatin 85mg/m2, Leucovorin 400mg/m2, 5-FU bolus 400mg/m2, and 5-FU 2400mg/m2 infusion every 2 weeks) for 4 cycles and pembrolizumab (200 mg IV q3week) for 3 cycles. Patients with no evidence of metastatic disease by PET and CT C/A/P who are eligible for resection underwent surgery. Post-operative treatment consisted of 4 cycles of mFOLFOX and 13 cycles of pembrolizumab 4-8 weeks postoperatively. Results: Up to 2/10/2021, all 37 patients eligible for the study finished preoperative treatment. 27 had curative intended operations, and all had R0 resection. 5 of 27 (19%) achieved ypCR and 6/27 (22 %) with regression score of 0 in the primary cancer. All except 2 patients (25/27, 93%) had shown pathologic response to the treatment with TRS ≤ 2. 21 patients completed all planned treatment with an average follow-up of 27 months. 2 patients had recurrence/metastatic disease (at 9 and 10 months from the enrollment) with 1 died at 23 months, and the other is still alive at 20 month. The rest patients (19/21) are all free of disease. G3/4 toxicities were reported in 21 of all 37 treated patients. There were no unexpected toxicities. Conclusions: The combination of mFOLFOX and pembrolizumab as peri-operative (pre- and post-operative) therapy in patients with locally advanced adenocarcinoma of distal esophagus, GEJ and stomach is safe. The preliminary benefit data are very encouraging with ypRR of 93%, ypCR of 19 %, and the long-time survival. The data support the combination of chemotherapy and Immune checkpoint inhibitor at perioperative setting. In addition, the data supports the staging laparoscopy for peritoneal disease assessment as the standard in resctacbility evaluation. Clinical trial information: NCT03488667.

Phase I study of epacadostat in combination with sirolimus in advanced malignancy

2575

Background: Epacadostat (E) is an inhibitor of Indoleamine 2,3 dioxygenase-1 (IDO1) which is a rate-limiting enzyme in the catabolism of tryptophan to kynurenine. The inhibition of IDO1 leads to increase tryptophan and reversal of immunosuppression by increasing the proliferation of T cells, suppression of regulatory T cells (Tregs) and activation of mTOR which suppresses autophagy. Sirolimus (S) can reverse the mTOR activation induced by E, suppress the expression of PD-L1 and function of Tregs. We initiated a phase I trial to test the safety and tolerability of SE combination in patients with advanced solid tumors, with plans for an expansion phase II study in patients with advanced recurrent lung cancer once maximum tolerated dose (MTD) was defined. Methods: The phase I trial portion of the study used a modified 3+3 design in which the dose transition rule was similar to standard 3+3 design with the modification based on sirolimus PK data. S had a lead-in of 3mg/day(d) at day -7 followed by 1mg/d with E added on day 1 of Cycle 1 starting at 300mg bid in a 28d cycle at dose level 1; then S is escalated to 6mg/d followed by 2mg/d maintenance with E at 300mg bid at level 2. An additional level 3 was added with S at 6mg/d followed by 2mg/day with E at 400 bid based on results of E at 400-600 mg bid in combination with a checkpoint inhibitor with improved control of peripheral kynurenine and intra-tumoral kynurenine reductions. Enrollment continued until Dose limiting toxicity (DLT) which was defined as grade 3 hematologic toxicities or grade 3 or 4 non-hematologic toxicities up to Cycle 2 day 1. MTD was defined as DLT not exceeding 33% of subjects. Results: The phase I study enrolled 15 patients, with 9 patients evaluable. The types of cancers were non-small cell lung ca (1), colorectal (5), esophagus (1), gallbladder (1) and sarcoma (1). DLT was not observed up to level 3. Adverse events attributed to SE were Grade 1 Diarrhea (2), stomach pain (1); elevated liver enzymes (ELE) (1), decreased white blood cell (1), anorexia (1), hypokalemia (1), dizziness (1), skin rash (1); Grade 2 ELE (1), Anemia (1), Vertigo (1), Constipation (1), Nausea (2); Grade 3: Diarrhea (1), serotonin syndrome (1), dyspnea (1). The best response observed was stable disease in 3 patients, 5 patients had disease progression and 1 patient was not assessable for response due treatment discontinuation related to side effect of serotonin syndrome. The Expansion Cohort (Part 2) did not proceed since the sponsor decided to discontinue further development of E. Conclusions: The combination of SE is feasible, tolerable with mostly grade 1 and 2 toxicities. There were few grades 3 toxicities. SE produced stable disease as best response in 33% of patients. Research using the combination of SE as an immunomodulatory therapy in patients with lung cancer resistant to checkpoint inhibitor is worth additional exploration. Clinical trial information: NCT03217669.

Phase Ib/IIa trial of CEND‐1 in combination with neoadjuvant FOLFIRINOX-based therapies in pancreatic, colorectal, and appendiceal cancers (CENDIFOX)

TPS4195

Background: The efficacy of chemotherapy is often compromised due to poor penetration of drugs in solid tumors. The tumor microenvironment, which is characterized by dense extracellular matrix‐rich stroma that creates a physical barrier to penetration of anti‐cancer drugs, is especially pronounced in Pancreatic Ductal Adenocarcinoma (PDAC) and in peritoneal metastases from Colorectal/Appendiceal Adenocarcinoma. CEND‐1 is a tumor‐penetrating peptide (scientifically also known as iRGD) that has preclinically demonstrated to enhance the tumor penetration of chemotherapy agents through binding and activation of alphav-integrins and neuropilin‐1 (NRP-1). The 2-step mechanism leads to a higher delivery and concentration of chemotherapeutics selectively in the tumor, while sparing normal tissue. Hence CEND-1 therapy has the potential to improve the efficacy of anti‐cancer therapies and reduce side effects through increased tumor access, specificity, and sensitivity. We hypothesize that CEND‐1 may become a powerful adjuvant that safely enhances standard anti‐neoplastic therapy in the neoadjuvant setting for the above populations. Methods: A safety lead-in 6-9 patients (Phase Ib) will be followed by an open label, single arm, parallel (3 cohorts) Phase IIa study. A total of 50 patients (20 PDAC, 15 colorectal/appendiceal with peritoneal metastases, 15 oligometastatic colorectal) will be enrolled. A starting CEND-1 dose of 3.2 mg/kg in combination with the standard doses of FOLFIRINOX (+/- Panitumumab if RAS/RAF wild type) will be used for the safety lead-in. CEND-1 dose will be lowered for Phase IIa if > 1/6 patients experienced DLTs. Participants enrolled will receive standard doses of FOLFIRINOX q2w +/- Panitumumab q2w 6mg/kg IV q2w (14-day cycles) for Cycles 1-3. After a subsequent research biopsy, the CEND-1 + chemotherapy combo will be continued at RP2D q2w for cycles 4-6, followed by CEND-1 +/- Panitumumab ̃72h prior to resection. Assessment of tumor response using RECIST v1.1 will be done every 3 cycles. Up to 10 patients may receive Panitumumab. Eligible Pts are untreated, newly diagnosed, resectable/borderline resectable PDAC or colorectal/appendiceal adenocarcinoma with peritoneal metastases or oligometastases eligible for cytoreductive surgery, as determined by multidisciplinary evaluation. Inclusion criteria also include ECOG PS 0-1, adequate organ function, measurable or evaluable disease. Primary objectives are safety and biological activity of CEND‐1. Secondary objectives include ORR, R0 resection rate, DFS, OS. Exploratory objectives include pathologic response, tissue immune response, EGFR expression, tumor tissue-to-plasma concentration of Panitumumab pre and post CEND-1 treatment. Enrollment to the CENDIFOX trial is currently ongoing. Clinical trial information: NCT05121038.

Bringing experimental therapeutics clinical trials network (ETCTN) to underrepresented population

6542

Background: Access to health care including clinical trials (CT) leading to paradigm-changing cancer treatments are critical for high quality cancer care and equity in society. In this report, we highlight methods in accruing to ETCTN wherein underrepresented rural, low-income, and racial minorities comprise >50% of enrollment. Methods: University of Kansas Cancer Center (KUCC) is one of eight National Cancer Institute (NCI) designated cancer centers awarded CATCH-UP.2020 (CATCH-UP), a congressionally mandated P30 supplement to enhance access for minority/underserved populations to ETCTN precision medicine CT. KUCC catchment area is 23% rural by Rural Urban Continuum Codes (RUCC); almost 90 % of counties are designated primary care HPSA’s (Health Professional Shortage Areas). KUCC Early Phase and Masonic Cancer Alliance (rural outreach network) partnered to operationalize CATCH-UP. We engaged disease-focused champion investigators in disease working groups and MCA physicians who selected scientifically sound CT that fit catchment area needs. Patient and Investigator Voices Organizing Together, a patient research advocacy group provided practical feedback. MCA navigator coordinated recruitment. Telehealth was used for rural patients that would have a significant distance to travel just to be screened. Results: CATCH-UP was initiated in September 2020. Twenty-eight CT were activated, many in community sites. Average activation time was 81 days. Delays were mainly from CT amendments. KUCC enrolled the first patient in the CATCH-UP program. In 6 months, we met accrual requirements (24/year, 50% minorities). During first year, we enrolled 47 (>50% minorities), an increase of 680% from our average accrual of 6/year (>50% minorities) in ETCTN through Early Drug Development Opportunity Program (2016-2020). To date, we have enrolled 61, 54% from rural, HPSA, race and other minorities. Although the proportion of minorities did not change but remained high, this funding allowed us to substantially increase the number of patients from a catchment area with high proportion of geographically and socioeconomically underserved minorities given access to early phase CT through ETCTN. Conclusions: Amid COVID-19 pandemic, the NCI CATCH-UP program and methods we used allowed access to novel therapies for rural, medically underserved, and other minority groups. Funded by NIH: 3P30CA168524-09S2.

Association of pathologic response and survival after peri-operative therapy in resected pancreatic adenocarcinoma: KU cancer center experience

e16254

Background: Neo-adjuvant therapy (NAT) and associated pathologic complete response (pCR) rates have correlated with improved survival in resected pancreatic ductal adenocarcinoma (PDAC). In this study, we explored the relationship between pathologic response, peri-operative therapy, and survival, especially the impact of change in adjuvant therapy in patients with no/poor path response to NAT. Methods: Retrospectively reviewed 66 PDAC patients who received NAT ± radiation and underwent resection at KU Cancer Center between 2011-2022. We compared DFS and OS between Path Responders vs Non-Responders based on standard Tumor Regression Scores from pathology reports. A subanalysis was performed in path non-responders based on switch in adjuvant therapy (AT) versus not. Results: Patient characteristics are summarized in the table. Among 66 PDAC patients, 50 (75.8%) achieved a path response (G0-G2), 16 (24.2%) experienced no/poor path response (G3). Of the 50 pts who achieved a path response, 4 (8.0%) had a complete path response (pCR; G0), 5 (10%) marked response (G1), 41 (82%) moderate response (G2). Median DFS (mDFS) was 17.3 months (95% CI: 12.7-22.4) in Path Responders vs 15.9m (95% CI: 9.6-35.8) in Non-Responders [p=0.59]. Median OS (mOS) was 32.9m (95% CI: 23.4-41.5) vs 27.7m (95% CI: 15.2-38.2), respectively [p=0.39). A sub-analysis in the Non-Responders (n=16) based on switch in AT (n=8) vs not (n=3), revealed mDFS 16.4m (95% CI: 9.6-41.8) when AT was switched vs mDFS 11.3m (95% CI: 5.9-16.6) when AT was not switched [p=0.24]; and mOS 30.6m (95% CI: 15.7-60.3) vs 17.2 months (95% CI: 6.7-27.7), respectively [p=0.18]. Conclusions: Our study found no statistical difference in DFS and OS between Pathologic Responders and Non-Responders to neo-adjuvant therapy. However, a sub-analysis within Pathologic Non-Responders revealed a longer DFS and OS after switching adjuvant therapy without reaching statistical significance, likely due to small sample size. Our findings warrant validation in a larger cohort as switch in adjuvant therapy could potentially change the treatment landscape for Pathologic Non-Responders.[Table: see text]

A phase II study of perioperative mFOLFOX chemotherapy plus pembrolizumab combination in patients with potentially resectable adenocarcinoma of the esophageal, gastroesophageal junction (GEJ), and stomach

329

Background: Surgical rection is the only potentially curative intervention for locally advanced adenocarcinoma of esophagus, GEJ and stomach. Results from various studies have demonstrated the benefits of perioperative treatment including neoadjuvant and adjuvant chemotherapy or chemoradiation, however, there is lack of universally accepted standard. Recent data demonstrated the benefit of immune checkpoint inhibitor in adjuvant setting in patients who had pre-operative chemoradiation. This single arm phase 2 trial is aimed to evaluate efficacy and safety of pembrolizumab, an immune checkpoint inhibitor, in combination with mFOLFOX in patients with potentially resectable adenocarcinoma of distal esophagus, GEJ and stomach with the primary objectives of pathological response rate (ypRR with tumor regression score, TRS ≤ 2). We are reporting the preliminary analyses while the study nears completion. Methods: Patients with newly diagnosed locally advanced (T1N1-3M0 or T2-3NanyM0), potentially resectable adenocarcinoma of distal esophagus, GEJ and stomach by PET, EUS, CT C/A/P and staging laparoscopy were treated with pre-operative mFOLFOX6 (oxaliplatin 85mg/m2, Leucovorin 400mg/m2, 5-FU bolus 400mg/m2, and 5-FU 2400mg/m2 infusion every 2 weeks) for 4 cycles and pembrolizumab (200 mg IV q3week) for 3 cycles. Patients with no evidence of metastatic disease by PET and CT C/A/P who are eligible for resection underwent surgery. Post-operative treatment consisted of 4 cycles of mFOLFOX and 13 cycles of pembrolizumab 4-8 weeks postoperatively. Results: Of 35 patients enrolled (age range 44-86, mean of 65 years; with male:female of 28:7), 33 finished preoperative treatment, 26 had curative intended operations with R0 resection for all, 1 is pending for surgery, and 2 are still on pre-operative treatment. 5 of 26 pts achieved ypCR (19% regression score of 0). All except 2 patients (24/26, 92%) had shown pathologic response to the treatment with TRS ≤ 2. 23/26 (88%) finished post-operative treatment. 20 patients completed all planned treatment with an average follow-up of 22.7 months. Amount them, 2 patients had recurrence/ metastatic disease (at 9 and 10 months, respectively) with 1 died 23.3 months from enrollment, and the rest are all free of disease. G3/4 toxicities were reported in 19 of all 35 treated patients. There were no unexpected toxicities. Conclusions: The combination of FOLFOX and pembrolizumab as peri-operative (pre- and post-operative) therapy in patients with locally advanced adenocarcinoma of distal esophagus, GEJ and stomach is safe and preliminary benefit data are very encouraging with ypRR of 92% and ypCR of 19% and supporting the combination of chemotherapy and Immune checkpoint inhibitor at perioperative setting. Clinical trial information: NCT03488667.

Phase II trial of moderate dose omega-3 acid ethyl esters for colorectal cancer prevention in patients with lynch syndrome (COLYNE)

TPS209

Background: Lynch syndrome (LS) is the most common inherited colorectal cancer (CRC) syndrome and is responsible for about 3% of newly diagnosed CRC. It is caused by germline mutations in one of the DNA mismatch repair (MMR) genes, and patients with LS carry a lifetime risk of CRC ranging between 10% and 70%. The role of inflammation in driving this malignant transformation is now well established and retrospective studies have revealed a potential chemo-preventative role for omega-3 (ω-3) polyunsaturated fatty acids (PUFAs), possibly via inhibition of inflammatory pathways associated with the development of defective MMR CRC tumors. While patients with LS have the highest risk of developing CRC, the majority of chemoprevention trials are focused on sporadic CRC. Effective interventions to reduce the risk of developing CRC in this population are limited to close surveillance and surgical prophylaxis. There is an unmet need for safe, effective, and non-invasive chemo-preventive interventions in patients with LS. Methods: This pilot study is a single-arm, open-label, phase 2 clinical trial of omega-3 acid ethyl esters (generic Lovasa; 2 grams orally once daily) for adult patients (≥ 18 years of age) with confirmed LS (based on germline testing of the MMR genes panel: MLH1, MSH2, MSHS6, PMS2 or deletion in EPCAM gene). Patients who are not candidate for elective endoscopy and/or with prior history of right sided or pan-colectomy are excluded. Thirty-four patients are expected to enroll, with a primary objective to determine the feasibility (defined as 80% retention rate) of 12 months of treatment with 2 grams capsules of omega-3 acid ethyl esters daily. Secondary endpoints include safety and tolerability of the intervention. Correlative aims include pre and post treatment assessment of colon mucosal tissue proliferation (right sided colon specimens will be evaluated for markers of proliferation (Ki-67) and apoptosis (Caspase-3)), the effect of omega-3 acid ethyl esters on inflammatory markers in serum, urine and feces (PGE-2, COX-2, β-catenin levels, and EPA:AA ratios), and gene expression related to proliferation, apoptosis and cell survival in colon tissue (NF-κB/Wnt pathways). The impact of omega-3 acid ethyl esters on intestinal microbiota will also be assessed (16S rRNA-based profiling). Correlative Colon tissue, serum, urine and feces samples are collected at baseline and at 12 months. The study is actively enrolling with 20 patients enrolled at the time of submission. Clinical trial information: NCT03831698.

CA209-8YD: A phase I/II trial of rucaparib in combination with ramucirumab with or without nivolumab in previously treated advanced gastroesophageal adenocarcinoma (GEA) (RiME)

TPS377

Background: GEA is one of the leading causes of cancer-related deaths worldwide and in the US. In chemo refractory GEA, therapeutic options are limited with modest efficacy. About 35% of GC have DNA damage response (DDR) gene alterations and PARP inhibitors have shown to induce synthetic lethality and reduce tumor burden in in vitro and in vivo models of GEA. DDR deficient tumors have increased tumor mutational load, tumor infiltrating lymphocytes, and increased chemokines and PD-L1 expression in the tumor microenvironment. PARP inhibitors like rucaparib enhance antigen presentation, induce pro-inflammatory cytokines, influence PD-1/PD-L1 expression, and modulate T- and B- cell activity. Furthermore, results from multiple GEA early phase trials have supported the immune modulatory impact of VEGF targeted agents like ramucirumab. We hypothesize that modulation of the tumor microenvironment via PARP and VEGF inhibition will enhance anti-tumor immunity and lead to clinical synergy when combined with immune checkpoint inhibitors like nivolumab in this population. Methods: A safety lead in phase of 6-9 patients will be followed by an open label, two parallel cohorts phase II study. A total of 52 patients (26 in each cohort) will be enrolled. A starting rucaparib dose of 600 mg BID in combination with the standard doses of ramucirumab and flat doses of nivolumab will be used for the safety lead in. Rucaparib dose will be lowered for phase II if > 1/6 patients experienced DLTs. Participants enrolled to cohort A will receive rucaparib at the recommended phase II dose (RP2D) PO twice daily + ramucirumab 8mg/kg IV q2w + nivolumab 480mg IV q4w (28-day cycles). Participants in cohort B will receive rucaparib at RP2D PO twice daily + ramucirumab 8mg/kg IV q2w (28-day cycles). Assessment of tumor response using modified RECIST v1.1 will be done every 2 cycles. 50% of Pts who will be enrolled in each of the 2 cohorts must have a deleterious tumor gene alteration in at least 1 gene in a screening 17-gene homologous recombination deficient (HRD) panel. Eligible Pts received ≥1 line of therapy, ECOG PS 0-1, adequate organ function, no prior PARP inhibitors, and have mismatch repair (MMR) proficient tumors with measurable disease. Primary objectives are to determine the RP2D and overall response rate (ORR) in phase I and II respectively. Secondary objectives include safety, overall benefit rate (OBR), median PFS, OS, and ORR in HRD positive and negative cohorts. Enrollment to the RiME trial is currently ongoing. The study is funded by research grants from Bristol Myers Squibb and Clovis. Clinical trial information: NCT03995017.

Phase II trial of cabozantinib (Cabo) plus durvalumab (Durva) in chemotherapy refractory patients with advanced mismatch repair proficient/microsatellite stable (pMMR/MSS) colorectal cancer (CRC): CAMILLA CRC cohort results

135

Background: Cabo is an anti-VEGFR2/MET/AXL drug with broad multi-kinase inhibitory spectrum. Preclinical and clinical studies in various solid tumors demonstrated favorable immune modulatory activity of Cabo with clinical synergy seen when combined with PD-1/ PD-L1 inhibitors like Durva. Upon completion of phase Ib gastrointestinal (GI) basket CAMILLA trial evaluating Cabo + Durva in 30 patients (pts) demonstrating favorable safety & efficacy, the trial was expanded to phase 2 multi-cohort, multi-center trial of 117 pts. Herein, we report results of the phase 2 CRC cohort, the first evaluation of cabo + IO in this population. Methods: Pts enrolled in this cohort were administered Cabo + Durva at the RP2D of 40mg QD and 1500mg IV Q4W respectively. Enrolled pts must have progressed on 2 or more lines of therapy. Primary outcome measure was investigator assessed overall response rate (ORR) and secondary outcomes were rate of treatment related adverse events (TRAE), investigator assessed disease control rate (DCR), progression free survival (PFS), and overall survival (OS). Subgroup analysis was done in pts with RAS wild type tumors. Exploratory analysis of pathogenic molecular tumor alterations using next generation sequencing (NGS) was done in pts who achieved confirmed partial response (PRc)/ stable disease (SD) > 6 months. Results: Of the 36 pts enrolled, 29 (16F, 13M) were evaluable for efficacy. Median age 57 years (27-76). 90% (26) had ECOG of 1. All had pMMR/MSS, 41% (12) had RAS wild type tumors, and 6.9% (2) had HER2 amplification. 52% (15) had received ≥ 3 lines of therapy. All had metastases at ≥ 3 sites and 79% (23) metastases in the liver. Among 36 pts evaluable for safety, treatment related serious adverse events (SAEs) occurred in 31% (11/36). Most common TRAEs were grade 1-2 fatigue (53%), nausea (42%), diarrhea (36%), anorexia (31%), hand-foot syndrome (22%), & hypertension (16%). Grade ≥ 3 immune-related adverse events (IRAE) occurred in 16.6% (6/36). Efficacy analysis revealed an ORR 27.6% (8/29); PRc 21% (6/29); DCR 86.2% (25/29); median DOR was not reached (NR); median PFS 4.4 months; 6-month PFS 28% & median OS 9.1 months. In the RAS wild type subgroup, ORR (PRc) was 50.0%; DCR 83.3%; median PFS 6.3 months and median OS was NR. Of the 7 pts who achieved PRc/SD > 6 months, one had KRAS G12V tumor mutation along with mutations in ARID1A & IDH1. Remaining pts had RAS wild type tumors & among those, the following NGS alterations were detected: 1 HER-2 amplification, 1 MET amplification, & 2 alterations in ATM. Conclusions: Cabo + Durva demonstrated promising efficacy and was fairly tolerated without new safety signals in heavily treated pMMR/MSS CRC pts. These encouraging results warrant further evaluation of this regimen in a randomized setting as salvage therapy in pMMR/MSS CRC. Clinical trial information: NCT03539822.

Real-world outcomes in patients with neuroendocrine tumor receiving peptide receptor radionucleotide therapy

504

Background: (177)Lu-Dotatate, a form of Peptide Receptor Radionuclide Therapy (PRRT), was approved by FDA for treatment of somatostatin-receptor-positive NETs in 2018. Clinical trials prior to the FDA approval of (177)Lu-Dotatate showed favorable outcomes but there is limited published real world outcomes data. Methods: After obtaining IRB approval we retrospectively evaluated the efficacy of (177)Lu-Dotatate PRRT for somatostatin receptor positive gastroenteropancreatic NET patients at University of Kansas Cancer Center between June 2018 and September 2021. Results: A total of 65 patients received PRRT of which 58 completed treatment and 7 are still undergoing therapy. The 58 patients who completed treatment had a median age of 61.5 years, included 24 females and 34 males, and were 86% Caucasian and 12% black. These patients had primarily NETs of small bowel (n=24) and pancreatic (n=14) origin. Pathology showed grades 1 (21), 2 (25), and 3 (4) with a majority of well-differentiated tumors (47). All 4 treatments of PRRT were completed by 43 patients. In the entire cohort, response assessment to PRRT revealed 14 (26.9%) partial response (PR), 31 (59.6%) with stable disease (SD) and 7 (13.5%) with progressive disease (PD). In subset analysis, we found that patients with nonfunctional disease (n=29) had a higher rate of PR 42.3% vs 11.5% (p=0.0147) and higher disease control rate 96% vs 78% (p=0.042) than functional disease (n=29). Patients with nonfunctional disease had a lower PD 3.85% vs 23% (p=0.0147) and 53% vs 65% stable disease than functional disease. The table below shows clinical characteristics of these patients. Conclusions: Our real world outcomes analysis of NET treated with PRRT shows improved PR when compared to the initial clinical trials which is promising for patients. In addition, we found that there was statistically significant improved response rate in patients with non functional tumors which has not been described in literature before. If our study findings are validated in a larger cohort then it may guide patient selection for PRRT therapy in the future.[Table: see text]

A novel outpatient regimen in management of fluoropyrimidine-induced cardiotoxicity

e15613

Background: Fluoropyrimidines, such as 5-fluorouracil (5-FU) and capecitabine, are commonly used chemotherapies for solid tumors, and essential for curative intent treatment of colorectal cancer. But sometimes, their use may be limited by cardiac toxicity limiting the possibility of cure in some patients. Cardiotoxicity could be asymptomatic (EKG changes) or manifested as chest pain, arrhythmias, acute coronary syndrome or death. Rechallenging may be daunting and it may result in interruption or even discontinuation of planned chemo. Traditionally, nitrates and/or IV/oral calcium channel blockers (CCB) have been used for management of fluoropyrimidine-induced cardiotoxicity but without much benefit. Ranolazine, an oral antianginal drug approved for chronic angina, diminishes myocardial ischemia by reducing calcium overload caused by inhibition of late sodium current and it does not affect heart rate or blood pressure. Our objective was to evaluate the efficacy of our novel approach using ranolazine with other traditional drugs. Methods: 8 patients (median age 49.5 yrs) with fluoropyrimidine induced cardiotoxicity were retrospectively analyzed. They were rechallenged with the planned fluoropyrimidine regimen with our 3 drug cardioprotective regimen (KU protocol). This included oral Ranolazine 1000mg BID and Amlodipine 2.5 mg daily to start the day before starting 5FU infusion/oral capecitabine and to continue it until the day after completion of infusion/treatment, and Nitroglycerin paste 1 inch every 6 hours starting before infusion and continue until it was completed. These meds were discontinued upon completion of chemo. Results: 8 patients were rechallenged with fluoropyrimidine utilizing KU protocol, 6 patients (75%) were able to complete previously planned fluoropyrimidine regimen. One pt (*) discontinued capecitabine due to recurrent chest pain and treatment was switched to 5FU based regimen with KU protocol, which pt was able to complete without chest pain. Another pt (**), 5FU was stopped due to severe diarrhea, not due to cardiotoxicity. All pts tolerated KU protocol well. Conclusions: In our small, single center experience, we were able to safely and effectively rechallenge pts with fluoropyrimidines and complete curative intent treatment with our KU protocol. This protocol uses FDA approved oral and transcutaneous drugs without requiring a healthcare personnel to administer an IV CCB that can cause precipitous bradycardia and/or hypotension. Our results need validation in a larger cohort. [Table: see text]

Initial results of a first-in-human, dose escalation study of a cell-based vaccine in HLA A*02+ patients (pts) with recurrent, locally advanced or metastatic HPV16+ solid tumors: SQZ-PBMC-HPV-101

2536

Background: Ineffective MHC-I presentation of tumor antigens to CD8+ T cells limits T cell activation and the efficacy of cancer vaccines. The Cell Squeeze technology drives peripheral blood mononuclear cells (PBMCs) through a microfluidic chip leading to temporary cell membrane disruption and delivery of HPV16 E6 and E7 antigens cytosolically. These antigen presenting cells (APC) were matured with CpG7909 and were not genetically modified. Preclinically, this approach showed improvement in MHC-I presentation for human and murine cells. In murine tumor studies, m-SQZ-PBMC-HPV elicited robust CD8+ T cell responses and improved anti-tumor effects when compared to other vaccine modalities. Methods: SQZ-PBMC-HPV-101 included pts with incurable HPV16+ cancers progressing after unlimited prior therapy, ECOG 0-1, adequate organ function and a biopsiable lesion. After leukapheresis at the study site, manufacturing of the cryopreserved product took < 24 hours with a vein-to-vein time of approx. 1 week. Out-patient SQZ-PBMC-HPV was given IV q 3 weeks without a conditioning regimen. Double antigen priming (DP) was introduced with Cohort 3 and occurred on Cycle 1 Days 1 and 2. Maximum treatment duration for each patient was determined by the cell batch size. Response was assessed via RECIST 1.1 and iRECIST. Investigational biomarkers were measured pre- and post-treatment. Results: 12 pts [anal (7), head and neck (3), and cervical (2)] were dosed in 3 cohorts (3 pts in 0.5 x10e6/kg, 5 pts in 2.5 x10e6/kg, and 4 pts in 2.5x 10e6/kg [DP]). Median lines of prior Tx were 4 (range 1 - 7) and all but one pt were pretreated with checkpoint inhibitors (CPI); 10 pts had liver or lung metastases. All batches of SQZ-PBMC-HPV demonstrated CD8 activation in vitro after thawing, and batch size did not limit therapy duration at dose levels tested to date. Median number of doses were 3 (3 - 10), 3 (2 - 4), and 3 (3 – 4) in the 3 cohorts, respectively. One pt (10 doses) remained on study for 42 weeks. Tx was well-tolerated and there were no DLTs, Grade (G) >3 related SAEs or related G >3 AEs. One pt in cohort 1 experienced both a G2 infusion-related reaction and cytokine release syndrome. One pt in cohort 2 was not evaluable for DLT. Four out of 10 evaluable pts had stable disease per RECIST 1.1 as the best response. Preliminary tumor analyses pre- and post-therapy indicated increased immune activity in some patients after SQZ infusion. Conclusions: SQZ-PBMC-HPV-101 demonstrated clinical feasibility of the Cell Squeeze technology and favorable tolerability of engineered APCs. The study allows for the characterization of the immunogenicity of engineered APCs in humans. Preliminary results warrant the testing in combination with CPI. Efficacy, safety, and correlative biomarker data will be presented, from pre- and post-therapy biopsies and blood samples. Clinical trial information: NCT04084951.

Efficacy of immunotherapy in hepatocholangiocarcinoma (HCC-CC): Proof of concept

e16194

Background: Hepatocholangiocarcinoma (HCC-CC) is a rare form of cancer with a poor prognosis. Of all primary liver cancers, the incidence of HCC-CC ranges from 0.4 to 14.2%. HCC-CC is a mixed carcinoma with findings of both hepatocellular carcinoma and cholangiocarcinoma. Immune checkpoint inhibitors are a potent first line treatment in hepatocellular carcinoma with multiple clinical trial showing effectiveness in cholangiocarcinoma. HCC-CC has limited proven treatment options as patients are generally excluded from clinical trials. In this study we reviewed outcomes of patients with HCC-CC who received immune checkpoint inhibitor in a single center. Methods: Records of patients who had a pathological confirmed HCC-CC by a subspecialized hepatic pathologist at the University of Kansas medical center were reviewed. We identified 6 patients with locally advanced unresectable or metastatic HCC-CC that received immune checkpoint inhibitor between February 2017 and January 2021. Baseline characteristics were obtained, as well as best response, line of therapy, and duration of response. Results: Of the six patients 4 (66%) received PD-1 inhibitor alone and 2 (34%) received combination therapy with CTLA-4 inhibitor for the treatment of HCC-CC. There were 3 (50%) females and 6 (100%) with prior hepatitis C infection. four (66%) patients had metastatic disease and 2 had locally unresectable advanced disease. Objective response rate was 83.3%. One patient achieved complete response and had a treatment holiday after receiving treatment for 2 years, and restarted immunotherapy upon relapse. Four patients had a partial response, of which two passed away after disease progression. One patient had stable disease on 2 different lines of immunotherapy then progressed. Of those who responded, one patient received immunotherapy, 3 (50%) received liver directed therapy and two received chemotherapy or Lenvatinib as first line treatment (Table). Conclusions: Immune checkpoint inhibitors demonstrate potential activity in patients with HCC-CC without unexpected side effect in this unmet need high-risk population. Larger studies are needed to confirm activity and efficacy in this setting.[Table: see text]

Safety, pharmacokinetic and pharmacodynamic results from dose escalation of SAR439459, a TGFβ inhibitor, as monotherapy or in combination with cemiplimab in a phase 1/1b study

2510

Background: SAR439459 is a human anti-TGFβ monoclonal antibody that neutralizes all isoforms of TGFβ. In preclinical models, combining SAR439459 with an anti-PD-1 showed improved anti-tumor activity compared to single agent. Here we report preliminary results of SAR439459 ± cemiplimab in a first in human study. Methods: This is an open-label study (dose escalation and expansion) of SAR439459 ± cemiplimab administered intravenously in adult patients with advanced solid tumors to determine safety and tolerability, the maximum tolerated dose (MTD) and/or maximum administered dose (MAD) of SAR439459 ± cemiplimab, pharmacokinetics (PK); pharmacodynamic (PD) and preliminary clinical benefit. In Part 1A, SAR439459 (0.05-15 mg/kg) was administered as monotherapy Q2W in an adaptive Bayesian design with overdose control. In Part 1B, SAR439459 doses cleared from monotherapy were administered in combination with fixed dose of cemiplimab (3 mg/kg Q2W or 350 mg Q3W) in a 3+3 design. Results: As of 31 January 2020, 28 (1A) and 24 (1B) patients with ECOG performance status of 0-1 with a median age of 60.5 and 63 years respectively were enrolled. In Part 1A, 25 patients (89.3%) had at least one treatment emergent adverse event (TEAE) and 15 (53.5%) experienced grade (G)≥ 3 events. In Part 1B, 22 patients (91.7%) had at least one TEAE and 14 (58.3%) experienced G ≥ 3 events. Dose-limiting toxicities (DLTs) were evaluable in 24 and 21 patients respectively. In 1A, 2 DLTs were reported in 2 of 8 evaluable patients in dose level (DL) 4: G5 brain stem hemorrhage in a patient on concomitant low molecular weight heparin treatment and G3 myocardial infarction in a patient with diabetes, chronic kidney disease, chronic obstructive pulmonary disease, and hypertension. In 1B, 1 of 6 evaluable patients in DL5 had DLTs (G3 ALT and AST increase). MTD was not reached in either part. Ten patients had best overall response of stable disease: 6 in 1A and 4 in 1B. The PK of SAR439459 was dose proportional over the dose range tested with no evidence of cemiplimab effect on SAR439459 PK, when given in combination. Treatment with SAR439459 ± cemiplimab led to rapid reduction in total plasma TGFβ level in all dose levels tested and induced CD8 & NK cells expansion and Th1 cytokines production, suggesting peripheral T cell activation. Preliminary results from paired tumor biopsies collected from patients treated with SAR439459 ± cemiplimab in expansion showed trend of TGFβ signaling pathway inhibition and conversion from excluded to inflamed tumor-immune phenotype. Conclusions: SAR439459 ± cemiplimab showed an acceptable tolerability profile overall. MTD was not reached. Peripheral and tumor target engagement and modulation of key immune cells was observed in treated patients. Dose expansion cohorts are currently enrolling selected solid tumor patients. Funding: Sanofi. Clinical trial information: NCT03192345.

Similar response rates and survival with PARPi treatments for patients harboring somatic versus germline BRCA mutations: A meta-analysis and systematic review

e16802

Background: PARP inhibitor (PARPi) has recently been approved for various cancers. However, trials have mostly recruited pts with germline BRCA (gBRCA) mutations, and it is unclear whether PARPi have similar efficacy in pts with somatic BRCA (sBRCA) mutations. We aimed to determine the efficacy of PARPi in pts with sBRCA mutations. Methods: Per PRISMA guidelines, systematic review of PubMed, Embase, Cochrane RCT, and Web of Science Collection was performed from inception thru Jan 2020 to identify studies. Our inclusion criteria were clinical trials and retrospective studies that reported use of PARPi in pts with both s and g BRCA mutations. We performed a meta-analysis comparing overall response rate and PFS with PARPi in pts with s versus g BRCA mutations. Results: After screening, 18 studies met our criteria for including both s and g BRCA mutations. Only 8 studies reported response rates for both s and g BRCA mutations (Table). In those studies, 24 out of 43 pts with sBRCA mutations (55.8%), and 69 out of 157 (43.9%) pts with gBRCA had a response to PARPi (pooled OR 1.13, p value = 0.399, I2 = 0). In all five studies that reported PFS, there was no obvious difference in outcomes between sBRCA (HR in these studies ranged 0.23 to 0.27) versus gBRCA (HR ranged 0.17 to 0.27), however a precise statistical analysis could not be done. Conclusions: Our meta-analysis and systematic review of the literature indicates similar outcomes of PARPi therapy in pts with s and g BRCA mutations. Investigation of use of PARPi therapy in a broader patient population, and the inclusion of sBRCA mutations in future clinical trials is essential. [Table: see text]

Cabozantinib (cabo) combined with durvalumab (durva) in gastroesophageal (GE) cancer and other gastrointestinal (GI) malignancies: Preliminary phase Ib CAMILLA study results

4563

Background: Cabo targets multiple tyrosine kinases, including VEGFR, MET, and AXL, and has been reported to show immunomodulatory properties that may counteract tumor-induced immunosuppression, providing a rationale for combining it with PD-L1 inhibitors like durva. We conducted a phase Ib GI basket trial to evaluate the safety & efficacy of this regimen in advanced GE adenocarcinoma (GEA), colorectal cancer (CRC), & hepatocellular carcinoma (HCC). Methods: Patients received cabo and durva in 3+3 dose escalation then expansion to determine the dose limiting toxicity (DLT), Recommended Phase 2 Dose (RP2D), ORR, PFS & OS. Cabo was dosed at 20mg QD, 40mg QD, and 60mg QD in the first, second, and third cohorts respectively. Durva was dosed at 1500mg IV Q4W in all cohorts. DLT window was 28 days. Scans were obtained every 8 wks. Treatment beyond progression was allowed. Results: 23 Pts (16 M, 7 F), median age 60 yrs (range 33-79) were currently enrolled. 12 in the dose escalation cohort with cabo 20mg (6 pts), or 40mg (3 pts), or 60mg (3 pts). 11 pts enrolled in the dose expansion cohort with cabo 60mg. 8 pts had GEA, 13 pts had CRC, and 2 pts had HCC. Median number of prior chemotherapies was 3 (range 1-3). 3 pts were not evaluable for DLT due to missing ≥30% of DLT window doses, not related to DLT. No DLTs were observed. Drug-related Grade (G) 1&2 AEs included fatigue (83%), abnormal LFTs (39%), anorexia (26%), diarrhea (26%), nausea (13%), & hand foot syndrome (13%). One pt each developed drug related G3 hypertension, hyperthyroidism, thrombocytopenia, & thromboembolic event, all occurring outside the DLT window. 19 pts were evaluable for response: 4 PR (2 GEA & 2 CRC), 12 SD, 3 PD; ORR 21%; clinical benefit rate 84%; median time to PD 16 wks (range 8-40+). Conclusions: RP2D was determined to be Cabo 60mg QD and Durva 1500mg Q4W. Enrollment to phase I dose expansion is ongoing. RP2D may be adjusted based on additional experience & long-term tolerability. Early efficacy data was encouraging. This is an investigator-initiated trial funded by Exelixis & Astrazeneca. Clinical trial information: NCT03539822 .

Niraparib in metastatic pancreatic cancer after previous chemotherapy (NIRA-PANC): A phase 2 trial

TPS4168

Background: Attempts to improve therapy for patients with pancreatic adenocarcinoma with traditional chemotherapy have largely failed to meaningfully improve survival. Therefore, there is a critical need for identification of specific molecular changes that define prognosis and potentially guide therapy decisions. Defective DNA damage response pathways in pancreatic cancer represent a targeted opportunity for treatment. PARP inhibitors exert activity in tumor cells that may not be effectively able to repair initially single-stranded and cumulatively double-stranded DNA breaks and can have a heightened susceptibility in tumor cells over normal tissue. This concept is referred to as synthetic lethality. Niraparib is an orally available, potent, highly selective PARP-1 and -2 inhibitor. We are studying the efficacy of Niraparib in pancreatic cancer patients that harbor DNA repair defects. Methods: This study is funded by a research grant from TESARO. Pre-screening of patients to find biomarker positive patients is funded by KU Cancer Center. This is a phase II open label single arm trial in metastatic pancreatic cancer patients with germline or somatic mutations, either already known, or tested after consent to pre-screening tumor tissue analysis in BRCA1/2, PALB2, ATM, NBN, ATR, BRIP1, IDH1/2, RAD51, RAD51B/C/D, RAD54L, CDK12, BARD1, FAM175A, BAP1, CHEK1/2, GEN1, MRE11A, XRCC2, SHFM1, FANCD2, FANCA, FANCC, FANCG, RPA1, ARID1A. Patients are being treated with Niraparib 300mg or 200mg by mouth daily for 28 days (1 cycle = 28 days) (200mg dose is for participants whose baseline weight is < 77 kg [169.756 lbs] or baseline platelet count is < 150,000 µL). The primary objective is to assess antitumor efficacy of niraparib using Objective Response Rate per RECIST 1.1. Secondary objectives include PFS, OS, DCR, DOR, and safety. Eligible patients received > 1 line of therapy, no prior PARP inhibitor(s), have measurable disease, and ECOG PS 0-1. Accrual target enrollment of 18 patients over a period of 24 months with a study duration of 30 months. Correlative studies include assessment of pharmacokinetics, circulating tumor cells and storing samples for future research. The trial is currently enrolling. Clinical trial information: NCT03553004.

A window of opportunity trial of atorvastatin in p53-mutant and p53 wild type malignancies

TPS3165

Background: Mutations in p53 contribute to tumor progression. A rational approach is to destabilize mutant (m) p53. The group at the University of Kansas Cancer Center screened compounds that suppress m p53 in a preclinical model. Luciferase-based reporter assay identified statins as suppressors of m p53 expression. In vitro validation assay demonstrated atorvastatin (A) suppressed m p53 level and cell growth selectively; and depletion of mevalonic acid lead to degradation of m p53. These effects were limited to mutations in the conformation of p53, while wild-type and DNA contact mutations were not as sensitive to statin-induced degradation of p53. M p53 xenograft model confirmed that A could suppress tumor growth at a concentration that can decrease LDL level. The primary objective of this trial is to determine if A decreases the level of conformational m p53. The secondary objective is to assess the effects of A on Ki-67 and caspase-3 in conformational m p53 tumors. Methods: This is an open-label, window of opportunity pilot trial to see if A given for 1 to 4 weeks at a dose of 80 mg/day is sufficient to reduce the levels of conformational m p53 in the tumor tissues. Subjects with new diagnosis of malignancy with a planned surgical therapy, and subjects with previously treated AML, in between treatment regimens, are eligible. Tissues from solid tumors, and bone marrow or peripheral blood samples from AML will be used to screen for m p53 by immunohistochemistry (IHC). Subjects will receive A at 80 mg/day po for 1 to 4 weeks. Pharmacokinetics at pre-dose and 1-hour post-dose on Day 1 and on the day of surgery will be done. Mutational analysis using exome sequencing technique will be done on m p53. Using IHC, the amount of p53 in pre-treatment and post-treatment samples will be measured and compared simultaneously. The levels of Ki67 and caspace-3 will be tested and compared between pre-treatment and post-treatment samples in subjects with conformational m p53, between conformational and non-conformational m p53, and in wild-type p53 tumors. The trial is actively enrolling subjects. The results of this trial will determine further investigations on the role of atorvastatin in tumors with p53 mutations in a placebo-controlled, randomized trial. Clinical trial information: NCT03560882.

A phase Ib trial of cabozantinib in combination with durvalumab (MEDI4736) in previously treated patients with advanced gastroesophageal cancer and other gastrointestinal (GI) malignancies (CAMILLA)

TPS56

Background: GI malignancies including Gastric (GC), esophageal (EAC), colon (CRC), and hepatocellular carcinoma (HCC) remain a significant health problem in the US & globally. The current standard upfront therapy has < 12 month median survival. Hypoxia mimetic agents such as VEGFR targeted therapy down regulate the angiogenesis pathway and sensitize tumors to chemotherapy. Cabozantinib targets multiple tyrosine kinases, including VEGFR, MET, and AXL, and has been reported to show immunomodulatory properties that may counteract tumor-induced immunosuppression, providing a rationale for combining it with PD-1 or PD-L1 inhibitors. We believe that modulating the tumor microenvironment with small molecule inhibitors like cabozantinib will have synergistic effect when combined with checkpoint based immunotherapy like durvaluamb in patients with chemo refractory GC, EAC, CRC and HCC. Methods: The study is funded by research grants from both Exelixis and AstraZeneca. A phase 1 dose escalation is followed by an open-label single arm expansion. Dose escalation will be conducted using a 3+3 design. Starting dose for cabozantinib is 20mg daily. Single agent durvalumab MTD has been used, given that a regimen with full dose durvalumab may be better accepted as a backbone for comparison in future studies. MTD of cabozantinib in combination with standard dose durvalumab will be defined as the highest safely tolerated dose where 0/6 or 1/6 patients experience a DLT and ≥ 2 patients have experienced a DLT at the next higher dose level. Primary objective is to determine the Recommended Phase 2 Dose (RP2D). Secondary objectives include safety, ORR, PFS and OS. Eligible patients received > 1 line of therapy, no prior checkpoint inhibitors, have measurable disease, & ECOG PS 0-1. Phase 1 dose escalation will enroll 9-18 patients and the expansion phase will enroll 12-21 patients. Correlative studies include assessment of tumor microenvironment, angiogenesis & immune molecular markers. The dose escalation phase is currently enrolling. Clinical trial information: NCT03539822.

Mature results from EV-101: A phase I study of enfortumab vedotin in patients with metastatic urothelial cancer (mUC)

377

Background: Enfortumab vedotin (EV) is an antibody–drug conjugate that delivers MMAE, a microtubule disrupting agent, to tumors expressing Nectin-4, a protein found on most urothelial cancers. Preliminary results of the EV-101 study (NCT02091999) suggest EV is active and tolerable. Methods: Patients with mUC treated with ≥1 prior chemotherapy, or those ineligible for cisplatin, received EV 1.25 mg/kg on Day 1, 8, and 15 every 28 day cycle. The primary objective was tolerability; antitumor activity (ORR per RECIST v1.1), assessed every 8 wk, was a secondary objective. Results: As of14 Sept 2018,112 pts with mUC received EV with a median follow up of 13.4 mo. Bladder was the primary tumor site in 86 pts (77%) and 33 (29.5%) had liver metastases (LM). Nearly all pts received prior platinum chemotherapy; 89 (79.5%) received prior anti-PD(L)1. EV was well tolerated; fatigue (53%), alopecia (46%), and decreased appetite (42%) were the most commonly reported treatment-related AEs (TRAEs). Anemia (8%), hyponatremia (7%), UTI (7%), and hyperglycemia (6%) were the grade ≥3 AEs reported in ≥5% of pts regardless of attribution; 4 fatal TRAEs were reported (respiratory failure, urinary tract obstruction, diabetic ketoacidosis, multi-organ failure). Confirmed ORR was 42% (CR, n = 5; PR, n = 42). Among responders, median duration of response was 7.7 mo (95% CI 5.6, 9.6) and 23.4% of responses were ongoing with a median follow up of 11.3 mo. Estimated median PFS and OS were 5.4 mo (95% CI 5.1, 6.3) and 12.5 mo (95% CI 9.3, 16.1), respectively; OS at 1 yr was 51.8%. Similar results were seen in pts with prior anti-PD(L)1 and with LM (Table). Conclusions: Single-agent EV was generally well tolerated and provided encouraging response and survival data in a population with an unmet medical need including pts with LM, which is associated with poor prognosis. Phase 2 and 3 monotherapy studies as well as evaluation of combination therapies are ongoing. Clinical trial information: NCT02091999. [Table: see text]

Novel prognostic biomarkers and their association with survival in pancreatic cancers

296

Background: Early detection of pancreatic cancer would allow for improved survival outcomes. Methods: We retrospectively evaluated serum protease levels and the survival of 15 pancreatic cancer patient samples (6 localized and 9 metastatic) at the KU Cancer Center. Available serum protease assays measured matrix metalloproteinases (MMPs), urokinase plasminogen activator (uPA), arginase, neutrophil elastase (NE), cathepsin B (CTSB) and cathepsin E (CTSE). The assays utilize fluorescent nanoparticle-based nanobiosensors which increase fluorescence upon posttranslational modification or enzymatic cleavage of targeted compounds and were read by a Spectral scan plate reader. Survival analysis was performed using Kaplan-Meier methods. Results: Baseline characteristics for all 15 patients are in (Table). Median OS was 18.8m in patients with high CTSB expression (mean >51968.9) vs 9.7m in low CTSB expression (p=0.04). Similarly, median OS was 20.4m in high CTSE expression (>123264.8) vs 10m in low CTSE expression (p=0.05). Whereas, median OS was 16.3m in low NE expression (mean <30293.5) vs 9.6m in high NE expression (p=0.06). MMPs, uPA, and Arginase were not associated with survival. Conclusions: Higher CTSB expression is associated with statistically significant improvement in survival. CTSB is a lysosomal protease involved in processing antigens and overexpression could aid in immunologic cancer suppression. CTSB is also involved in the development of desmoplasia which is hypothesized to be a physical barrier to metastasis. CTSE and NE expression did not meet statistically significant association with survival, likely due to sample size. Hence, we identify CTSB as a potential prognostic biomarker in pancreatic cancer. However, these findings need to be validated in a larger study. [Table: see text]

Total neoadjuvant therapy compared with standard therapy in locally advanced rectal cancer: A systematic review and meta-analysis

709

Background: Standard therapy of locally advanced rectal cancer (LARC) includes concurrent chemoradiotherapy (CRT) followed by surgery and adjuvant chemotherapy (CT). An alternative strategy known as Total Neoadjuvant Therapy (TNT) involves administration of CRT and CT prior to surgery with the goal of delivering uninterrupted systemic therapy to eradicate micrometastases. A comparison of these two approaches has not been reviewed previously. Methods: Following PRISMA guidelines, a systematic review of PubMed and Web of Science was performed from inception through September 2018 to identify studies which compared TNT with CRT in LARC. The outcomes of interest were pathologic complete response rates (PCR), sphincter-preserving surgery rates, ileostomy rates, disease-free survival (DFS) and overall survival (OS). Summary hazard ratios (HR) with 95% confidence intervals (CI) were estimated using a random effects model and heterogeneity was estimated using the inconsistency index (I2). Results: After reviewing 2,163 reports, 5 studies which compared CRT and TNT were selected for inclusion. These were reported from Europe and the United States and included a total of 1,134 patients of whom 552 received TNT. The pooled prevalence of PCR was 32.4% (range 17-28%) in the TNT group and 22.3% (range 4-21%) in the CRT group. In a meta-analysis of five studies, TNT was associated with a higher chance of achieving a pathologic complete response (OR 1.92; 95% CI 1.44- 2.57, I2= 22%). Recipients of TNT also had higher odds of receiving sphincter-sparing surgery (5 studies, OR 1.92; 95% CI 1.44- 2.57, I2= 0%) and lower odds of requiring an ileostomy (2 studies, OR 0.72; 95% CI 0.54- 0.96, I2= 0%). Only one study presented data on DFS and noted improved DFS in patients who received TNT (OR 0.72; 95% CI 0.54- 0.96). The impact of TNT relative to standard therapy on overall survival was not reported. Conclusions: Total Neoadjuvant Therapy is a promising strategy in locally advanced rectal cancer, with superior PCR rates compared to standard therapy. However, the long term impact on disease recurrence and overall survival remain unclear. These are best be studied in a prospective randomized clinical trial.

Enfortumab vedotin (EV) in patients (Pts) with metastatic urothelial carcinoma (mUC) with prior checkpoint inhibitor (CPI) failure: A prospective cohort of an ongoing phase 1 study

431

Background: EV is an ADC that selectively targets and kills cells expressing Nectin-4 by delivering a potent microtubule-disrupting agent, monomethyl auristatin E. As mUC tumors express Nectin-4 in almost all pts, the EV clinical profile was assessed in an ongoing Phase 1 study (NCT02091999) at the recommended phase 2 dose (RP2D; 1.25 mg/kg) in mUC pts with CPI failure, a population with a high unmet medical need. Methods: Pts with mUC, treated with ≥1 prior chemotherapy or who were ineligible for platinum chemotherapy, and who had disease progression after CPI therapy received an IV infusion of EV at RP2D on Days 1, 8, and 15 of each 28-day cycle. Primary endpoint was tolerability; a secondary endpoint was investigator-assessed antitumor activity per RECIST v1.1. Results: As of 2 Oct 2017, 62 pts with mUC and prior CPI failure received EV at RP2D (48 M/14 F; median age, 68 yr [range: 41–83]; ECOG 0/1 29%/71%). Primary tumor site was bladder in 73% pts; 63% pts had visceral and 27% had liver metastasis (LM). Most pts (71%) had ≥2 prior therapies in the metastatic setting, including platinum (87%) or taxanes (26%). CPI was the most recent therapy in 76% pts; time from last CPI to first EV dose was < 12 wk for 58% pts. Median treatment duration was 14.8 wk (range: 1.6–40.4); 39 pts continue treatment. Treatment-related AEs occurring in ≥30% pts were fatigue, rash, nausea, alopecia, decreased appetite and diarrhea; most grade ≤2. Grade ≥3 AE reported in ≥5% pts, regardless of attribution, was hyponatremia (6.5%). One fatal AE (respiratory failure) was possibly treatment related. Response evaluable pts (n = 54) had ≥1 post baseline scan or discontinued prior to scan. ORR (confirmed + unconfirmed) was 54% (95% CI: 39.6–67.4); 15 pts had a confirmed PR, 5 had unconfirmed PR, and 9 are pending subsequent assessment. This ORR is similar to CPI-naïve pts (59%; 95% CI: 36.4–79.3). ORR from 17 evaluable pts with LM was 41% (95% CI: 18.4–67.1). Conclusions: EV is tolerable and exhibits antitumor activity in a cohort of pts with mUC and disease progression after CPI. A phase 2 study assessing EV in this population with high unmet need has been initiated (NCT03219333; EV-201 study). Clinical trial information: NCT02091999.

The impact of guideline treatment nonadherence on survival for colorectal cancer patients: Propensity score calibration via a validation cohort

308

Background: The quality of cancer care has been the focus of ongoing concern for cancer researchers, providers, and policy makers. The objectives of this study were: 1) to evaluate nonadherence with National Comprehensive Cancer Network treatment guidelines for colorectal cancer (CRC) patients and the impact on survival, and 2) to obtain error-corrected estimates of effect by means of propensity score calibration via a validation cohort. Methods: CRC patients identified by the Georgia Comprehensive Cancer Registry for the years 2000-07 were eligible (N = 18,388). Naïve propensity score (PSn) adjustment and PS calibration (PSC) via a validation cohort were utilized to obtain hazard ratio estimates for the impact of guideline treatment nonadherence on 5-year overall survival. The validation cohort contained additional information on comorbidity and payer status which was used to obtain error-corrected estimates of effect by PSC. Results: Treatment nonadherence conferred a large increased risk of death early in the follow-up period which declined over time (Table 1). Comparison of results from the PSn and PSC models indicated moderate to large bias due to unmeasured confounding in the PSn model (data not shown). Conclusions: PSC produced attenuated estimates and had an impact on study conclusions in the latter follow-up period. For CRC patients, health services research into the quality of care received by cancer patients is necessary to continue the improving trend in CRC-related mortality. [Table: see text]

A phase II/III randomized study to compare the efficacy and safety of rigosertib plus gemcitabine versus gemcitabine alone in patients with previously untreated metastatic pancreatic cancer

BACKGROUND

Rigosertib (ON 01910.Na), a first-in-class Ras mimetic and small-molecule inhibitor of multiple signaling pathways including polo-like kinase 1 (PLK1) and phosphoinositide 3-kinase (PI3K), has shown efficacy in preclinical pancreatic cancer models. In this study, rigosertib was assessed in combination with gemcitabine in patients with treatment-naïve metastatic pancreatic adenocarcinoma.

MATERIALS AND METHODS

Patients with metastatic pancreatic adenocarcinoma were randomized in a 2:1 fashion to gemcitabine 1000 mg/m(2) weekly for 3 weeks of a 4-week cycle plus rigosertib 1800 mg/m(2) via 2-h continuous IV infusions given twice weekly for 3 weeks of a 4-week cycle (RIG + GEM) versus gemcitabine 1000 mg/m(2) weekly for 3 weeks in a 4-week cycle (GEM).

RESULTS

A total of 160 patients were enrolled globally and randomly assigned to RIG + GEM (106 patients) or GEM (54). The most common grade 3 or higher adverse events were neutropenia (8% in the RIG + GEM group versus 6% in the GEM group), hyponatremia (17% versus 4%), and anemia (8% versus 4%). The median overall survival was 6.1 months for RIG + GEM versus 6.4 months for GEM [hazard ratio (HR), 1.24; 95% confidence interval (CI) 0.85-1.81]. The median progression-free survival was 3.4 months for both groups (HR = 0.96; 95% CI 0.68-1.36). The partial response rate was 19% versus 13% for RIG + GEM versus GEM, respectively. Of 64 tumor samples sent for molecular analysis, 47 were adequate for multiplex genetic testing and 41 were positive for mutations. The majority of cases had KRAS gene mutations (40 cases). Other mutations detected included TP53 (13 cases) and PIK3CA (1 case). No correlation between mutational status and efficacy was detected.

CONCLUSIONS

The combination of RIG + GEM failed to demonstrate an improvement in survival or response compared with GEM in patients with metastatic pancreatic adenocarcinoma. Rigosertib showed a similar safety profile to that seen in previous trials using the IV formulation.

Irinotecan (Iri) and buparlisib (B) in previously treated patients (pts) with metastatic colorectal cancer (mCRC)

655

Background: The PIK3CA pathway has oncogenic role in mCRC. Buparlisib is an oral pan-class PIK3CA inhibitor. It is currently being studied in combination trials for various malignancies. The primary objective of this phase I trial was to identify the maximum tolerated dose (MTD) for Iri plus B in pts with previously treated mCRC, with or without previous Iri therapy. We also performed PK analysis of each drug alone and in combination, determined clinical response to the combination, and evaluated achieval FFPE samples for somatic mutations in a panel of cancer associated genes, including PIK3CA for clinical correlation. Methods: A 3+3 dose titration method was used. Iri was administered intravenously every 14 days (one cycle) and B orally daily. Pts received the first dose of Iri on Cycle1 Day1. B was started 24 hours after the first dose of Iri. Safety and toxicity assessments were performed every cycle. Results: Twenty patients were enrolled: 4 in cohort 0 (Iri 120 mg/m2 + B 50 mg/d), 11 in cohort 1 (Iri 150 mg/m2 + B 50 mg/d), 5 in cohort 2 (Iri 150 mg/m2 + B 80 mg/d). The most common Grades 3/4 adverse events were neutropenia and abdominal pain. The MTD was Iri 150 mg/m2 + B 50 mg/d. The DLTs include male genital mucositis, grade 3 diarrhea, and asymptomatic grade 3 hyponatremia. In cohort 1, one pt experienced grade 2 delirium and a pt in cohort 2 had grade 3 psychosis. Of the 4 pts who received 4 cycles of therapy 2 had stable and 2 had progressive disease. No objective responses were seen. There is no significant change in the PK of Iri between Cycles 1 and 2. B at 50 mg had no consistent effect on the disposition of Iri given at 120 mg/m2 and 150 mg/m2. The Cmax and AUC for B show clear dose proportionality. Using targeted re-sequencing, a 48-gene panel that included AKT1, BRAF, KRAS, and PTEN was performed. The complete analysis of the correlative study will be presented in the meeting. Conclusions: This first human trial established that Buparlisib (50 mg qd) and Iri (150 mg/m2 q14d) are tolerable in combination. However, it is too early to determine the activity of this combination in the treatment of mCRC. Clinical trial information: NCT01304602.

A phase II/III randomized study to compare the efficacy and safety of rigosertib plus gemcitabine versus gemcitabine alone in patients with previously untreated metastatic pancreatic cancer

342

Background: Rigosertib (ON 01910.Na), a dual non-ATP inhibitor of polo-like kinase 1 (Plk1) and phosphoinositide 3-kinase (PI3K) pathways, was assessed in patients with treatment-naïve metastatic pancreatic adenocarcinoma. Methods: Patients with metastatic adenocarcinoma of the pancreas were randomized in a 2:1 fashion to gemcitabine 1000 mg/m2 weekly for 3 weeks of a 4-week cycle plus rigosertib 1800mg/m2 via 2-hr CIV infusions given twice weekly for 3 weeks of a 4-week cycle versus gemcitabine 1000mg/m2 weekly for 3 weeks in a 4-week cycle. Results: A total of 160 patients were enrolled globally and randomly assigned to rigosertib plus gemcitabine (106 patients) or gemcitabine (54). The most common grade 3 or higher adverse events were neutropenia (8% in the rigosertib plus gemcitabine group vs. 6% in the gemcitabine group), hyponatremia (17% vs. 4%), and anemia (8% vs. 4%). The primary outcome of the study, median OS, was 6.1 months in the gemcitabine plus rigosertib arm versus 6.4 months with gemcitabine alone (hazard ratio (HR), 1.24; 95% confidence interval [CI], 0.85-1.81). The median PFS was 3.4 months for both groups (HR, 0.96; 95% CI, 0.68-1.36). The overall best response between arms were partial response rates of 19% versus 13% and stable disease in 50% versus 56% in the gemcitabine plus rigosertib versus gemcitabine alone, respectively. Of 64 tumor samples sent for molecular analysis, 47 were adequate for multiplex genetic testing and 41 were positive for mutations. The majority of cases had KRAS gene mutations (40/47, 85%), which included c.35G>T, p.G12V (12 cases), c.35G>A, p.G12D (21 cases), c.34G>C, p.G12R (4 cases), c.34G>T, p.G12C (1 case) and c.183C>A, p.Q61H (2 cases). Other mutations detected included TP53 (13 cases) and PIK3CA(1 case). No correlation between mutational status and efficacy was detected. Conclusions: The combination of rigosertib plus gemcitabine failed to demonstrate an improvement in survival or response compared to gemcitabine alone in metastatic pancreatic adenocarcinoma. Clinical trial information: NCT01360853.

Predictors of guideline treatment nonadherence and the impact on survival in patients with colorectal cancer

254

Background: We investigated the effect of comorbidity, age, health insurance payer status, and race on the risk of nonadherence with National Comprehensive Cancer Network (NCCN) treatment guidelines for colorectal cancer (CRC) patients. In addition, the prognostic impact of NCCN treatment nonadherence on survival was assessed. Methods: Colon and rectal cancer patients who received primary treatment at Memorial University Medical Center in Savannah, GA from 2003 to 2010 were eligible for this study (final N = 679). Modified Poisson regression was used to obtain risk ratios for the outcome of nonadherence with NCCN treatment guidelines. Hazard ratios (HRs) for the relative risk of CRC-related death were obtained by Cox regression. Results: Guideline-adherent treatment was received by 82.5% of patients. Moderate/severe comorbidity, being uninsured, having rectal cancer, older age, and increasing tumor stage were associated with increased risks of receiving nonadherent treatment. Treatment nonadherence was associated with 4.5 times the risk of CRC-related death (HR, 4.53; 95% CI, 2.56-8.00) in the first year following diagnosis and 2.0 times the risk of death (HR, 1.97; 95% CI, 1.20-3.25) in years 2 to 5. The detrimental effect of nonadherence was demonstrated across all levels of comorbidity and age. Conclusions: Although there are medically justifiable reasons to deviate from NCCN treatment guidelines in CRC patients, patients who received nonadherent treatment had much higher risks of CRC-related death, especially in the first year following diagnosis. This study’s results highlight the importance of cancer health services research to drive quality improvement efforts in cancer care for CRC patients. [Table: see text]

Final results of the UGT1A1-based dose modification of irinotecan and its impact on rates of severe neutropenia and hospitalization

461

Background: UGT1A1 7/7 genotype has been associated with a 3-fold increase in severe neutropenia for patients treated with irinotecan (IRI) (Mcleod 2010, Liu 2013). UGT1A1 determination may tailor IRI therapy and reduce toxicities. However, the impact of the FDA-recommended IRI dose modification on outcomes is unclear. Methods: UGT1A1 genotyping was done for patients with various cancers wherein IRI therapy was planned and who consented to 1 of 3 IRB-approved registries. For patients with UGT1A1 7/7, a reduction in IRI doses was recommended per FDA and toxicities monitored during the first 2 doses. Results: 323/341 patients registered had UGT1A1 determined, of which 13% (42/323) had the 7/7 or 7/8 genotypes. Notably, a significantly higher proportion of African-Americans (AA) harbor these genotypes compared to Caucasians (C) (26.32% vs 10.08%, p=0.001). Among the 251 evaluable for toxicities, the incidence of grade 3-5 ANC for patients with 7/7 was not significantly different than those with 6/6 or 6/7 (Kendall's Tau-b coefficient p=0.494) (see Table). Among the 7/7 patients, 23/33 were treated at IRI doses of 150 mg/m2 or higher. 30% of patients treated at the higher dosages still developed grade 3-5 neutropenia compared to 17-21% for those with other genotypes. 38 of 251 patients were hospitalized during their first 2 cycles of therapy. The proportion of hospitalized patients with 7/7 genotype was not significantly different than those with 6/6 or 6/7 (15% vs 17% vs 12.6%). Conclusions: UGT1A1 can be used to tailor IRI therapy and reduce toxicities. The incidence of severe neutropenia and rate of hospitalization is comparable among patients with all UGT1A1 genotypes when IRI dose is adjusted for those with UGT1A1 7/7. There is a higher incidence of UGT1A1 7/7 genotype among African-Americans comnpared to Caucasians, which warrants further evaluation. [Table: see text]

Assessment of HER2 gene amplification in adenocarcinomas of the stomach or gastroesophageal junction in the INT-0116/SWOG9008 clinical trial

BACKGROUND

Trastuzumab has been approved for patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic gastric carcinoma; however, relatively little is known about the role of HER2 in the natural history of this disease.

PATIENTS AND METHODS

Patients enrolled in the INT-0116/SWOG9008 phase III gastric cancer clinical trial with available tissue specimens were retrospectively evaluated for HER2 gene amplification by FISH and overexpression by immunohistochemistry (IHC). The original trial was designed to evaluate the benefit of postoperative chemoradiation compared with surgery alone.

RESULTS

HER2 gene amplification rate by FISH was 10.9% among 258 patients evaluated. HER2 overexpression rate by IHC was 12.2% among 148 patients evaluated, with 90% agreement between FISH and IHC. There was a significant interaction between HER2 amplification and treatment with respect to both disease-free survival (DFS) (P = 0.020) and overall survival (OS) (P = 0.034). Among patients with HER2-non-amplified cancers, treated patients had a median OS of 44 months compared with 24 months in the surgery-only arm (P = 0.003). Among patients with HER2-amplified cancers, there was no significant difference in survival based on treatment arm. HER2 status was not a prognostic marker among patients who received no postoperative chemoradiation.

CONCLUSION

Patients lacking HER2 amplification benefited from treatment as indicated by both DFS and OS.

CLINICAL TRIAL

INT-0116/SWOG9008 phase III.

Assessment of HER2 gene amplification in adenocarcinomas of the stomach or gastroesophageal junction in the INT-0116/SWOG9008 clinical trial

BACKGROUND

Trastuzumab has been approved for patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic gastric carcinoma; however, relatively little is known about the role of HER2 in the natural history of this disease.

PATIENTS AND METHODS

Patients enrolled in the INT-0116/SWOG9008 phase III gastric cancer clinical trial with available tissue specimens were retrospectively evaluated for HER2 gene amplification by FISH and overexpression by immunohistochemistry (IHC). The original trial was designed to evaluate the benefit of postoperative chemoradiation compared with surgery alone.

RESULTS

HER2 gene amplification rate by FISH was 10.9% among 258 patients evaluated. HER2 overexpression rate by IHC was 12.2% among 148 patients evaluated, with 90% agreement between FISH and IHC. There was a significant interaction between HER2 amplification and treatment with respect to both disease-free survival (DFS) (P = 0.020) and overall survival (OS) (P = 0.034). Among patients with HER2-non-amplified cancers, treated patients had a median OS of 44 months compared with 24 months in the surgery-only arm (P = 0.003). Among patients with HER2-amplified cancers, there was no significant difference in survival based on treatment arm. HER2 status was not a prognostic marker among patients who received no postoperative chemoradiation.

CONCLUSION

Patients lacking HER2 amplification benefited from treatment as indicated by both DFS and OS.

CLINICAL TRIAL

INT-0116/SWOG9008 phase III.

Assessment of HER2 gene amplification in adenocarcinomas of the stomach or gastroesophageal junction in the INT-0116/SWOG9008 clinical trial

4010

Background: Trastuzumab has been approved for treatment of patients with HER2-positive metastatic gastric carcinoma; however, relatively little is known about the role of HER2 in the natural history of this disease. Methods: Patients enrolled in the INT-0116/SWOG9008 phase III gastric cancer clinical trial (n=559) were retrospectively evaluated for HER2 gene amplification by fluorescence in situ hybridization (FISH)(n=258), overexpression by immunohistochemistry (IHC)(n=148) and HER2 amplification by silver-enhanced in situ hybridization (n=77) based on availability of tissue specimens. The purpose of the original clinical trial was to evaluate the benefit of post-operative 5-fluorouracil/leucovorin plus radiation therapy compared to surgery alone. Results: HER2 gene amplification rate by FISH was 10.9% in tumor tissue from 258 patients evaluated. HER2 status determined by FISH was 92% concordant with SISH. HER2 overexpression rate by IHC was 12.2% among 148 patients evaluated, with 90% agreement between FISH and IHC. There was a significant interaction between HER2 status by FISH and treatment with respect to both OS (p=0.034) and DFS (p=0.020). Among patients with HER2 non-amplified cancers, treated patients had a median OS of 44 months compared to 24 months for patients in the surgery only arm (34 and 17 months respectively for DFS, p=0.003). Among 28 patients with HER2 amplified cancers, the medians for OS were 16 months in the treated arm, and 22 months in the surgery arm (p=0.55) (13 and 11 months respectively for DFS, p=0.87). We were unable to detect a statistically significant treatment benefit in this small subset of patients with HER2 amplification. HER2 amplification status was not an independent prognostic marker of OS among patients who received no postoperative chemotherapy or radiation therapy (p=0.76). Conclusions: Patients lacking HER2 amplification responded significantly to treatment as indicated by both OS and DFS.