Citations

TPS3172 Background: Ulixertinib (BVD-523) is a small molecule inhibitor of extracellular signal-regulated kinases 1/2 (ERK1/2) in development as a novel anti-cancer drug. Early clinical data demonstrated anti-tumor activity, especially for patients with tumors harboring atypical BRAF or MEK1/2 alterations (Sullivan et al., Cancer Discov. 2018;8(2):184-195). Atypical BRAF (non-V600) alterations can be categorized according to characteristics of molecular signaling (Class II or III), are seen in approximately 3% of all human cancers, and there are currently no approved therapies for this indication. Similar to atypical BRAF alterations, the incidence of MEK1/2 alterations are rare in human tumors (< 1 %). Preclinical data have demonstrated activity of ulixertinib in MEK mutant models. Ulixertinib has FDA fast-track designation for patients with solid tumors, other than CRC, with specific BRAF mutations (G469A, L485W, or L597Q). Designed with intent to register, the BVD-523-ABC clinical trial will continue evaluation of ulixertinib in patients with tumors harboring any atypical BRAF or MEK1/2 alteration (NCT04488003). Methods: This multi-center, phase II study, will be conducted in two parts and assess the clinical benefit, safety, pharmacokinetics, and pharmacodynamics of ulixertinib in patients with advanced malignancies. Ulixertinib will be administered at the RP2D of 600 mg BID for 28-day treatment cycles. Eligible patients will have locally advanced or metastatic cancer which progressed following standard systemic therapies, or for which the patient is not a candidate or refused systemic therapy. Planned correlative analyses include reverse phase protein array and transcriptomics of tumor tissue. Part A is open-label and tumor agnostic, except for group 4 and 6 (CRC patients only). Patients will enroll into one of six groups based on BRAF (groups 1-4) or MEK1/2 (groups 5-6) tumor alteration (38 patients per group). Overall response rate (ORR) is the primary endpoint for Part A, with secondary endpoints including duration of response (DOR), progression-free survival (PFS), and overall survival (OS). Part B is tumor histology specific. Patients will be randomized to receive either ulixertinib or physician's choice of treatment in a 2:1 ratio. Up to three specified tumor histologies will be defined, guided by available Part A data (n = 80-100 per histology). The primary endpoint of Part B is PFS, and secondary endpoints include OS, ORR, and DOR. This study has enrolled 43 patients of the planned 228 in Part A at the time of abstract submission. Clinical trial information: NCT04488003.

PURPOSE This investigation sought to evaluate the prognostic value of pretreatment of circulating tumor DNA (ctDNA) in metastatic biliary tract cancers (BTCs) treated with platinum-based first-line chemotherapy treatment. MATERIALS AND METHODS We performed a retrospective analysis of 67 patients who underwent ctDNA testing before platinum-based chemotherapy for first-line treatment for metastatic BTC. For analysis, we considered the detected gene with highest variant allele frequency as the dominant clone allele frequency (DCAF). Results of ctDNA analysis were correlated with patients' demographics, progression-free survival (PFS), and overall survival (OS). RESULTS The median age of patients was 67 (27-90) years. Fifty-four (80.6%) of 67 patients evaluated had intrahepatic cholangiocarcinoma; seven had extrahepatic cholangiocarcinoma, and six gallbladder cancers. Forty-six (68.6%) of the patients were treated with cisplatin plus gemcitabine, and 16.4% of patients received gemcitabine and other platinum (carboplatin or oxaliplatin) combinations, whereas 15% of patients were treated on a clinical trial with gemcitabine and cisplatin plus additional agents (CX4945, PEGPH20, or nab-paclitaxel). TP53, KRAS, FGFR2, ARID1A, STK11, and IDH1 were the genes with highest frequency as DCAF. The median DCAF was 3% (0%-97%). DCAF > 3% was associated with worse OS (median OS: 10.8 v 18.8 months, P = .032). Stratifying DCAF in quartiles, DCAF > 10% was significantly related to worse PFS (median PFS: 3 months, P = .014) and worse OS (median OS: 7.0 months, P = .001). Each 1% increase in ctDNA was associated with a hazard ratio of 13.1 in OS when adjusting for subtypes, metastatic sites, size of largest tumor, age, sex, and CA19-9. CONCLUSION DCAF at diagnosis of advanced BTC can stratify patients who have worse outcomes when treated with upfront platinum-based chemotherapy. Each increase in %ctDNA decreases survival probabilities.

TPS213 Background: Regorafenib (R) is an oral multikinase inhibitor that blocks several protein kinases involved in angiogenesis and oncogenesis; it has a survival benefit in refractory metastatic colorectal cancer (mCRC). The current standard (std) treatment in patients (pts) with RAS wildtype (WT) mCRC is sequential treatment with an anti-EGFR antibody (AEA) followed by R. However, R, which is orally administered once daily, may be more convenient and thus preferable for pts than AEA. REVERCE, a Japanese trial, demonstrated a significant 5.8 month (mo.) survival benefit with regorafenib administered prior to AEA compared to the std sequence. Based off these findings, the proposed phase II trial is to confirm the observed survival benefit from regorafenib sequencing prior to anti-EGFR monoclonal antibody therapy in REVERCE in a US patient population. Methods: REVERCEII is an Academic and Community Cancer Research United (ACCRU) network-led randomized phase II study of R (dose escalation from 80mg to 160mg based on tolerance) prior to AEA (R+AEA) compared to standard sequencing (AEA+R) in pts with refractory RAS WT mCRC. Patients are randomized 1:1 to receive R (Arm A) vs. AEA (with or without irinotecan per investigator choice) (Arm B). At the time of disease progression or intolerance, patients will receive sequential treatment until disease progression. Eligibility criteria include histologically confirmed mCRC, ECOG ≤ 2, acceptable organ function, and patients must have had prior fluoropyrimidine, oxaliplatin and irinotecan, and no prior AEA nor R. The primary objective is to compare the overall survival (OS), the primary endpoint, between evaluable patients (eligible, consented, started protocol treatment) who were randomized to R+AEA (arm A) and AEA+R (arm B). With 83 OS events, we have 87% power to detect an improvement in median OS from 9 months to 14.5 mo., assuming 1-sided significance level of 0.15, and exponential distribution. The total sample size is 124 patients. Secondary endpoints include progression-free survival, objective response, and adverse events. The total study duration is expected to be 3 years. Clinical trial information: NCT04117945. Clinical trial information: 04117945.

4079 Background: Cell-free circulating tumor DNA (ctDNA) holds significant promise and is being used for clinical decision making in multiple tumors. This study aimed to evaluate the prognostic value of pre-treatment ctDNA in metastatic biliary tract cancers (BTC) treated with platinum based first-line chemotherapy treatment. Methods: We performed a retrospective analysis of 67 patients who underwent ctDNA testing before platinum-based chemotherapy for first-line treatment for metastatic BTC. For analysis we considered the detected gene with highest variant allele frequency (VAF). Results of ctDNA analysis were correlated with patients’ demographics, progression-free survival (PFS) and overall survival (OS). Results: The median age of patients was 67 y/o (27-90). 54 (80.6%) of 67 patients evaluated had intrahepatic cholangiocarcinoma; seven had extrahepatic cholangiocarcinoma and six gallbladder cancer. 46 (68.6%) of the patients were treated with cisplatin plus gemcitabine, 14 (21%) patients received gemcitabine and other platinum (carboplatin or oxaliplatin) combinations while 7 (10.4%) patients were treated on a clinical trial with gemcitabine and cisplatin plus additional targeted agents (CX4945 or PEGPH20). TP53, KRAS, APC, FGFR2 and IDH1 were the genes with highest frequency as dominant clone. The median dominant clone allele frequency (DCAF) was 3% (0-97%). DCAF >3% was associated with statistically significant worse PFS (median PFS: 4.05 vs. 7.70 months, p=0.046) and OS (median OS: 10.8 vs. 18.8 months, p=0.056). Each 1% increase in DCAF is associated with a hazard ratio of 26.21 in OS when adjusting for subtypes, age, treatment type, and CA19-9 [Table]. Conclusions: Patients with metastatic BTC with DCAF > 3% at diagnosis have worse PFS and OS compared to patients with low ctDNA when treated with upfront platinum-based chemotherapy.[Table: see text]

We report a male patient who developed eight different cancers between ages 57 and 64. BRAF p.V600E mutation was detected in Langerhans cell histiocytosis, chronic lymphocytic leukemia, histiocytic sarcoma, melanoma, and adenocarcinoma of the lung. It was not detected in multiple myeloma, basal cell carcinoma, and papillary thyroid cancer. BRAF p.V600E was not detected in normal skin tissue biopsy indicating that BRAF V600E was a somatic mutation affecting cancer cells. The presence of eight different cancers with five of them positive for BRAF p.V600E in a single patient is unprecedented. This type of BRAF p.V600E-associated poly-neoplastic syndrome has never been reported in the medical literature.

423 Background: Advanced PDAC remains a deadly disease with a 5-year survival rate of less than 10%. cfDNA - based next generation sequencing (NGS) may identify actionable alterations in patients with PDAC. In this study, we aim to determine the feasibility of utilizing serial cfDNA NGS testing and its potential relevance in predicting therapeutics outcomes. Methods: A total of 23 PDAC patients with PDAC cfDNA isolated from plasma collected at diagnosis and upon disease progression to first line SOC therapy and were analyzed on a 73-74 gene NGS panel (Guardant Health). Changes in molecular profiles from baseline to progression were analyzed for overall survival, progression free survival (PFS), and treatment response. PFS and OS were analyzed using the Kaplan-Meier method and the log-rank test was used to compare the survival of different groups of patients. All p-values were two-sided. Analyses were performed using R (version 3.5.1, R Foundation, Vienna, Austria). Results: In this retrospective study, the 1-year probability of survival was 71% (median 473 days) and the 1-year PFS was 14% (median 212 days). TP53 and KRAS were the most frequently mutated genes identified in baseline samples, with 78% prevalence for each. Patients with clearance of TP53 17% (3/18) patients and/or KRAS 33% (6/18) patients clones after first line therapy significantly increases PFS (p=0.0056 and p=0.037, with HR of 0.087 and 0.32, respectively). However, appearance of TP53 or KRAS alterations upon progression does not significantly affect overall survival or PFS. Conclusions: The preliminary results from this study suggest that cfDNA clearance of TP53 and/or KRAS alterations may predict for improved PFS in PDAC. Confirmation of these findings in larger studies is warranted.

230 Background: Inpatient mortality review is commonly used to improve patient care. Individual review of outpatient deaths is less common, yet 30-day mortality after hospital stay is an important quality metric. In this study, we sought to identify opportunities for care improvement by reviewing outpatient mortalities for cancer patients who died within 30 days of hospitalization. Methods: We identified 48 patients at Mayo Clinic Florida, with a hematologic (heme) or solid tumor (onc) cancer, who died within 30 days of an index hospital stay in 2018. We created a 32-question review survey to address quality of care around the hospital stay. The review team consisted of 1) heme or onc attendings, 2) heme/onc fellows, and 3) palliative care attendings. Each case was reviewed by one member of each of the 3 groups, split into heme or onc cases. Discrepancies in objective data points were resolved by the research team. Results: Of 143 surveys sent to 13 physicians (3 heme), 112 responses from 11 physicians (1 heme) for 47 patients were received. Twenty-one patients (45%) received cancer therapy within 30 days of death, and 23 (49%) were admitted >2 times in 2 months prior to death. For onc cases, attendings rated prognosis as discussed 83% of the time, vs 65% of fellows and 39% of palliative care; in heme cases, the attending rated prognosis as discussed 11% of the time, vs 86% of fellows and 50% of palliative care. In heme cases, the attending rated expected survival <3 months in 33% of cases vs 71% by fellows and 89% by palliative care; in onc cases, the reviews were more consistent (79% attending, 85% fellow, 93% palliative care). See Table for timing of prognosis discussions and palliative care involvement. Conclusions: The most common improvement opportunities identified by reviewing heme/onc patients who died within 30 days of a hospital stay included documented prognosis discussion and involvement of palliative care. Opportunities differed between heme and onc patients. Future directions include identifying and mitigating barriers that providers face in reaching these goals for their patients. [Table: see text]

e19088 Background: Significant disparities in the stage at diagnosis and survival outcomes exist between various groups diagnosed with hepatocellular carcinoma (HCC) based on sex, race, insurance coverage, and marital status. Previously published data shows disparities more in patients who are African-American, Asian and low income. Little data has been published on factors that influence timeliness to treatment initiation in patients diagnosed with HCC. Methods: Retrospective analysis was performed on 96,586 patients diagnosed with HCC from 2004-2014 using data in the National Cancer Database (NCDB). Time to treatment was divided into two categories: ≤40 days (early, n = 66322) and > 40 days (late, n = 30264). We carried out univariate and multivariate analyses to compare demographic, clinical, treatment, and facility-related factors influencing the timeliness of treatment initiation in HCC. Results: Univariate analysis revealed a significant difference in time to treatment initiation based on age, race, income, insurance status, type of area, geographic region, type of facility, and cancer stage (P < 0.001). Multivariate analysis showed that household income < $30,000/year, Pacific region, urban area of residence, black race, age 70-79 years old or ≥80 years old, academic centers, stage II disease and medicaid insurance were all factors with longer time to treatment initiation. Discussion: HCC is the sixth most common cancer and the second leading cause of cancer mortality worldwide. The 5-year relative survival for localized, regional, and distant stages are 32.6%, 10.8% and 2.4% respectively. In our results we noted significant disparities in time to treatment with respect to various socioeconomic factors. These results are comparable to that reported in other cancer types. Further subgroup analysis of our data shows 2581 patients who received their first treatment after 200 days. In a similar study done in Taiwan, those treated more than 181 days and 61–180 days after diagnosis had a 1.68 and a 1.39 increased risk of death respectively, which were statistically significant. Many factors contribute to delayed treatment, some of which are difficult to circumvent, however where possible efforts should be made to overcome these. Conclusions: Various socioeconomic factors were found to affect the time to treatment initiation in HCC patients. The next step would be to strategically implement policies and practices to address these factors.