Fluoropyrimidine Chemotherapy Research Articles

FDA Approval Summary: Fruquintinib for the Treatment of Refractory Metastatic Colorectal Cancer.

On November 8, 2023, the FDA approved fruquintinib, an inhibitor of vascular endothelial growth factor receptors (VEGFR)-1, -2, and -3, for the treatment of patients with metastatic colorectal cancer (mCRC) who have been previously treated with fluoropyrimidine‑, oxaliplatin‑, and irinotecan‑based chemotherapy, an anti‑VEGF therapy, and, if RAS wild‑type and medically appropriate, an anti EGFR therapy. Approval was based on Study FRESCO-2, a globally-conducted, double-blind, placebo-controlled randomized trial. The primary endpoint was overall survival (OS). The key secondary endpoint was progression-free survival (PFS). A total of 691 patients were randomized (461 and 230 into the fruquintinib and placebo arms, respectively). Fruquintinib provided a statistically significant improvement in OS with a hazard ratio (HR) of 0.66 (95% CI: 0.55, 0.80; p<0.001). The median OS was 7.4 months (95% CI: 6.7, 8.2) in the fruquintinib arm and 4.8 months (95% CI: 4.0, 5.8) for the placebo arm. Adverse events observed were generally consistent with the known safety profile associated with inhibition of the VEGFR. The results of FRESCO-2 were supported by the FRESCO study, a double-blind, single country, placebo-controlled, randomized trial in patients with refractory mCRC who have been previously treated with fluoropyrimidine‑, oxaliplatin‑, and irinotecan‑based chemotherapy. In FRESCO, the OS HR was 0.65 (95% CI: 0.51, 0.83; p<0.001). FDA concluded that the totality of the evidence from FRESCO-2 and FRESCO supported an indication for patients with mCRC with prior treatment with fluoropyrimidine, oxaliplatin-, and irinotecan-based chemotherapy, an anti-VEGF biological therapy, and if RAS wild‑type and medically appropriate, an anti-EGFR therapy.

Unveiling Discrepant and Rare Dihydropyrimidine Dehydrogenase (DPYD) Results Using an In-House Genotyping Test: A Case Series.

Fluoropyrimidine chemotherapy is a primary component of many solid tumor treatment regimens, particularly those for gastrointestinal malignancies. Approximately one-third of patients receiving fluoropyrimidine-based chemotherapies experience serious adverse effects. This risk is substantially higher in patients carrying DPYD genetic variants, which cause reduced fluoropyrimidine metabolism and inactivation (ie, dihydropyridine dehydrogenase [DPD] deficiency). Despite the known relationship between DPD deficiency and severe toxicity risk, including drug-related fatalities, pretreatment DPYD testing is not standard of care in the United States. We developed an in-house DPYD genotyping test that detects 5 clinically actionable variants associated with DPD deficiency, and genotyped 827 patients receiving fluoropyrimidines, of which 49 (6%) were identified as heterozygous carriers. We highlight 3 unique cases: (1) a patient with a false-negative result from a commercial laboratory that only tested for the c.1905 + 1G>A (*2A) variant, (2) a White patient in whom the c.557A>G variant (typically observed in people of African ancestry) was detected, and (3) a patient with the rare c.1679T>G (*13) variant. Lastly, we evaluated which DPYD variants are detected by commercial laboratories offering DPYD genotyping in the United States and found 6 of 13 (46%) did not test for all 5 variants included on our panel. We estimated that 20.4% to 81.6% of DPYD heterozygous carriers identified on our panel would have had a false-negative result if tested by 1 of these 6 laboratories. The sensitivity and negative predictive value of the diagnostic tests from these laboratories ranged from 18.4% to 79.6% and 95.1% to 98.7%, respectively. These cases underscore the importance of comprehensive DPYD genotyping to accurately identify patients with DPD deficiency who may require lower fluoropyrimidine doses to mitigate severe toxicities and hospitalizations. Clinicians should be aware of test limitations and variability in variant detection by commercial laboratories, and seek assistance by pharmacogenetic experts or available resources for test selection and result interpretation.

Assessing the Hepatotoxic Effects of Fluoropyrimidine Chemotherapy in Male Iraqi Colorectal Cancer Patients.

Colorectal cancer (CRC) is one the most frequently occurring cancer types among various populations. Fluoropyrimidine is the backbone of first-line chemotherapy, the oral capecitabine, or intravenous 5-fluorouracil (5-FU) in various combinations and schedules the chemotherapy regime in the treatment of a wide variety of gastrointestinal cancers. The enzyme dihydropyrimidine dehydrogenase (DPD) functions as the rate-limiting step in the metabolism of fluoropyrimidine chemotherapies, and patients with complete or partial DPD deficiency are at increased risk of severe and fatal toxicity during treatment with fluorouracil. This study aimed to examine thechemotoxicity of the 5-FU drug on hepatocytes in male Iraqi CRC patients. This research is a cross-sectional study conducted between November 2022 and April 2023. The study included 80 male participants who had undergone surgical intervention for stage III CRC under the care of the Misan Health Directorate, Misan Center for Tumors Treatment, located in Misan, Iraq. Based on their subsequent surgical treatment, the participants were divided into two groups. The first group, comprising 45 males aged between 41 and 71 years, experienced a relapse despite receiving adjuvant therapy, which involved a singular cycle of fluoropyrimidine-based chemotherapy (5-FU). The second group consisted of 35 male patients with CRC, aged between 40 and 57 years, who did not experience a relapse post-adjuvant therapy. Their adjuvant therapy involved a single round of fluoropyrimidine-based chemotherapy with 5-FU. Relapse in patients was determined by assessing the white blood cell count(WBC). Liver enzymes were significantly increased after 5-FU treatment, while the concentration of albumin was significantly decreased. The findings of our study clearly indicate that 5-FU induced hepatic injury, lowering the hepatocytefunction with elevated levels of hepatic enzymes and low concentration of albumin in the blood, which is an important predictive marker of chemotherapy toxicity.

Nivolumab in unresectable advanced, recurrent or metastatic esophageal squamous cell carcinoma.

Esophageal cancer (EC) is the eighth most common cancer worldwide. In view ofbiology and anatomical restrictions, multimodality treatment strategies have been developed for EC. However, the prognosis of patients with advanced EC remains especially poor. Immunotherapy, such as PD-1/PD-L1 and CTLA-4/B7 blockade, has emerged as a potent treatment for many types of cancer and has been approved in many countries. Based on the results of the ATTRACTION-3 trial, nivolumab, an anti-PD-1 monoclonal antibody, was approved by the US FDAfor patients with platinum-resistant, unresectable, recurrentor metastatic esophageal squamous cell carcinoma. The CheckMate 648 trial demonstrated that the combination of nivolumab with platinum-based fluoropyrimidine chemotherapy and combination immunotherapy with nivolumab and ipilimumab, an anti-CTLA-4 monoclonal antibody, showed a survival benefit in patients with advanced esophageal squamous cell carcinomacompared with doublet chemotherapy. This review focuses on nivolumab-containing treatments for patients with advanced esophageal squamous cell carcinoma.

DPYD testing makes fluoropyrimidine chemotherapy safer.

DPYD testing makes fluoropyrimidine chemotherapy safer.

Preoperative Strategies for Locally Advanced Colon Cancer.

Neoadjuvant chemotherapy is safe for patients with locally advanced colon cancer (LACC). The FOxTROT trial demonstrated a reduction in residual and recurrent cancer at 2 years with neoadjuvant chemotherapy for patients with cT3-4 LACC. Preoperative chemotherapy should be avoided, if possible, for patients with dMMR LACC, as over 50% of dMMR cancers have no pathologic response. Early universal testing of MMR status is critical to selecting the appropriate neoadjuvant therapy. Concerns about CT staging of LACC have limited uptake of neoadjuvant chemotherapy, as approximately 25% of patients with cT3-T4 cancer on CT have low-risk stage II disease. Development of CT criteria for malignant nodes should reduce the risk of over-staging. A multidisciplinary approach is needed to identify patients for neoadjuvant therapy. Neoadjuvant immunotherapy is safe and results in dramatic pathologic responses in patients with dMMR LACC. Longer follow-up is needed to determine if the exceptionally high pathologic response rates observed will translate into long-term remission. Remarkably, neoadjuvant immunotherapy has been found to cause major pathologic responses in a subset of patients with pMMR LACC, indicating the potential to cure more patients with this common cancer. Patients with cT4 LACC, whether stage II or III, have a substantial risk of recurrence despite adjuvant fluoropyrimidine plus oxaliplatin chemotherapy. We recommend neoadjuvant systemic therapy for all patients with cT4b LACC (dMMR and pMMR). Features of T4b disease are routinely reported by radiology. We use three cycles of FOLFOX chemotherapy for patients with cT4b pMMR LACC, due to the high rate of compliance and improvement in residual and recurrent disease. Patients with cT4b dMMR LACC should receive neoadjuvant immunotherapy, if there are no contraindications. Clinical trials of neoadjuvant therapy for LACC are of great interest and should provide training for radiologists to identify eligible patients. Results are anticipated from multiple ongoing trials of neoadjuvant chemotherapy, immunotherapy, and targeted therapy for pMMR LACC and immunotherapy for dMMR LACC.

Circulating tumor DNA analysis informing adjuvant chemotherapy in locally advanced rectal cancer: The randomized AGITG DYNAMIC-Rectal study.

12 Background: Adjuvant chemotherapy (CT) following neoadjuvant chemoradiation and surgery for locally advanced rectal cancer (LARC) is widely adopted, despite uncertain survival benefit. Circulating tumor DNA (ctDNA) detection after surgery has been shown to be a strong prognostic marker in localized colorectal cancer and potentially could inform adjuvant treatment decision making. Methods: AGITG DYNAMIC-Rectal is a multi-centre randomized controlled phase II trial. Eligible patients (pts) had LARC (cT3-4 and/or cN+) treated with neoadjuvant chemoradiation, total mesorectal excision, and were fit for adjuvant CT. Pts were randomly assigned 2:1 to ctDNA-guided management or standard management (clinician decision). A tumor-informed personalized ctDNA assay was used. For the ctDNA-guided group, a positive result at 4 and/or 7 weeks after surgery prompted 4 months of oxaliplatin-based or fluoropyrimidine CT; for ctDNA-negative patients, no chemotherapy if ypN0 or clinician’s choice if ypN+. The primary endpoint was adjuvant CT use. A key secondary endpoint was non-inferiority in RFS rate at 3 years. The target sample size of 408 would provide 80% power with 95% confidence to demonstrate non-inferiority between the two arms with a margin of at most 10%. Results: The study ceased recruitment prematurely due to COVID-19 and increasing adoption of total neoadjuvant therapy. 230 eligible pts were enrolled from Jul 2018 to Nov 2021, median follow-up was 37 months. In the 155 ctDNA-guided patients, ctDNA analysis was successful in 150 (97%) pts and 42 (28%) were ctDNA-positive. Fewer pts in the ctDNA-guided arm received adjuvant CT (71/155, 46%) compared to 58/75 (77%) pts receiving standard management (p &lt; 0.001). Overall, an oxaliplatin-based doublet was administered in 43 (28%) and 19 (25%) of ctDNA-guided compared to standard management pts (P = 0.82). 3-year recurrence-free survival for ctDNA-guided and standard management was 76% and 82% respectively (difference 6%, 95% CI: -6% to 17%). Cumulative probability of distant and locoregional recurrence at 3 years for ctDNA-positive pts treated with CT were 36% and 11% respectively; for ctDNA-negative pts without adjuvant CT were 12% and 1%. Of the 15 ctDNA-negative pts who recurred, 12 (80%) were lung only, 1 (7%) peritoneal and lung, and 2 (13%) nodal only relapse. Conclusions: A ctDNA-guided approach to adjuvant therapy for LARC post neoadjuvant chemoradiation and surgery was associated with a reduced rate of CT administration. The small sample size precludes any conclusions to be drawn about the non-inferiority of ctDNA-guided vs standard management. The recurrence rate in treated ctDNA positive pts appears low when compared to untreated historical controls. Our data confirms a lower risk of recurrence in pts with undetectable post-op ctDNA, with a notable proportion of these being in the lung. Clinical trial information: ACTRN12617001560381 .

Common dihydropyrimidinase ( DPYS ) genetic variations do not predict fluoropyrimidine-related chemotherapy toxicity in a Canadian cohort.

Known genetic variations in dihydropyrimidine dehydrogenase (gene name DPYD ) do not fully predict patients at risk for severe fluoropyrimidine-associated chemotherapy toxicity. Dihydropyrimidinase (gene name DPYS ), the second catabolic enzyme in fluoropyrimidine metabolism, has been noted as a potential determinant of variation in fluoropyrimidine metabolism and response. In this study, we genotyped for DPYS c.-1T>C (rs2959023), c.265-58T>C (rs2669429) and c.541C>T (rs36027551) in a Canadian cohort of 248 patients who were wild type for Clinical Pharmacogenetics Implementation Consortium recommended DPYD variants and had received a standard dose of fluoropyrimidine chemotherapy. None of our patients were found to carry the DPYS c.541C>T variant, while the minor allele frequencies were 63% and 54% for c.-1T>C and c.265-58T>C, respectively. There was no association between DPYS c.-1T>C wild type and heterozygote [odds ratio (OR) (95% confidence interval, CI) = 1.10 (0.51-2.40)] or homozygote variant carriers [OR (95% CI) = 1.22 (0.55-2.70)], or between DPYS c.265-58T>C wild-type patients and heterozygote [OR (95% CI) = 0.93 (0.48-1.80)] or homozygote variant carriers [OR (95% CI) = 0.76 (0.37-1.55)] in terms of fluoropyrimidine-associated toxicity. Therefore, in our cohort of mostly Caucasian Canadians, genetic variations in DPYS do not appear to be a significant contributor to severe fluoropyrimidine-associated toxicity.

Risk of Toxicity From Topical 5-Fluorouracil Treatment in Patients Carrying DPYD Variant Alleles.

Patients carrying DPYD variant alleles have increased risk of severe toxicity from systemic fluoropyrimidine chemotherapy. There is a paucity of data regarding risk of toxicity from topical 5-fluorouracil (5-FU) treatment in these patients, leading to inconsistent guideline recommendations for pretreatment testing and topical 5-FU dosing. The objective of this retrospective cohort study was to investigate whether DPYD variant allele carriers have increased risk of toxicity from topical 5-FU. Treatment and toxicity data were retrospectively abstracted from the electronic medical records. Genotypes for the five DPYD variants that are associated with increased toxicity from systemic fluoropyrimidine chemotherapy (DPYD*2A, DPYD*13, DPYD p.D949V, DPYD HapB3, and DPYD p.Y186C) were collected from a genetic data repository. Incidence of grade 3+ (primary end point) and 1+ (secondary end point) toxicity was compared between DPYD variant carriers vs. wild-type patients using Fisher's exact tests. The analysis included 201 patients, 7% (14/201) of whom carried a single DPYD variant allele. No patients carried two variant alleles or experienced grade 3+ toxicity. DPYD variant allele carriers did not have a significantly higher risk of grade 1+ toxicity (21.4% vs. 10.2%, odds ratio = 2.40, 95% confidence interval: 0.10-2.53, P = 0.19). Given the low toxicity risk in patients carrying a single DPYD variant allele, there is limited potential clinical benefit of DPYD genetic testing prior to topical 5-FU. However, the risk of severe toxicity in patients with complete DPD deficiency remains unknown and topical 5-FU treatment should be avoided in these patients.

Clinical outcomes of Epstein-Barr virus (EBV)-associated metastatic and locally advanced unresectable gastric cancers (GCs) in patients receiving first-line fluoropyrimidine and platinum (FP) doublet chemotherapy.

Epstein-Barr virus-associated gastric cancer (EBVaGC) is a distinct molecular subgroup showing excellent outcomes after surgery for localized disease. Prominent immune cell infiltration in EBVaGC reflects the immunogenicity of Epstein-Barr virus (EBV) and, as suggested by some investigators, responsiveness to immune checkpoint inhibitors in the palliative setting. However, few data are available on the prevalence, clinical characteristics, and prognosis of EBVaGC patients receiving palliative cytotoxic chemotherapy. In this retrospective study, we identified 1061 patients with metastatic, recurrent, or locally advanced unresectable gastric cancer (GC) who started first-line fluoropyrimidine/platinum (FP) doublet chemotherapy with or without trastuzumab from January 2015 to August 2018. For 766 patients with available tumor tissue, the presence of EBV in cancer cells was evaluated by EBV-encoded RNA in situ hybridization and correlated with clinical characteristics and treatment outcomes. Among the patients evaluated (n = 766), 40 (5.0%) were EBV-positive. EBVaGC was associated with male sex (p = 0.009) and lower neutrophil-lymphocyte ratio (NLR < 2.46, p = 0.03). Efficacy of first-line FP chemotherapy, in terms of response rate ad progression-free survival (PFS), did not differ between EBVaGC and EBV-negative GC (overall response rate: 53.8% vs. 51.8%, p = 0.99; median PFS: 6.4 vs. 6.7months, p = 0.90). However, overall survival tended to be better with EBVaGC than EBV-negative GC (16.4 vs. 14.0months, p = 0.07). EBVaGC accounted for 5% of metastatic/unresectable GCs. While EBVaGC was not associated with better response to or PFS following first-line cytotoxic chemotherapy, it showed a trend toward better overall survival.

Clinical Utility and Prognostic Value of Coronary Computed Tomography Angiography in Patients With Cancer

There is growing interest in the role of coronary computed tomography angiography (CTA) in cardio-oncology. However, there is a paucity of real-world experience and outcome data for patients with cancer. This study sought to determine the clinical utility and prognostic value of coronary CTA in patients with cancer. In this prospective, single-center study, we recruited patients with cancer who underwent coronary CTA. Coronary artery disease (CAD) extent was classified as normal, nonobstructive (1% to 49% stenosis), and potentially obstructive (≥50% stenosis). Patients were followed up for a median of 9months (interquartile range 3 to 30 months) for cancer-related deaths and major adverse cardiovascular events (MACEs) defined as nonfatal myocardial infarction, urgent unplanned revascularization, or cardiovascular death. The mean age of patients (n=113) was 61 ± 12years, and 68 were female (60%). The most common underlying cancers were breast (29%) and lymphoma (13%). A total of 25 patients had potentially obstructive CAD, most commonly of the left anterior descending artery. After coronary CTA, 88% statin-naive patients with potentially obstructive CAD were initiated on statin therapy. A total of 28/32 patients who were taking fluoropyrimidine chemotherapy (5-fluorouracil or capecitabine) continued therapy, of whom none had MACEs. Overall, there were no episodes of MACEs in this cohort and 11% had cancer-related deaths. Coronary CTA has an important role in the clinical decision-making in patients with cancer to detect CAD, initiate primary preventative therapy, and guide coronary revascularization. No MACEs occurred. Using this coronary CTA-guided approach, preventative therapy was initiated, and most patients continued prognostically important cancer therapy.

Nivolumab Plus Chemotherapy for Advanced Gastric, Gastroesophageal Junction, and Esophageal Adenocarcinoma: Analysis of Number Needed To Treat and Number Needed To Harm

PurposeNivolumab, a programmed cell death protein (PD)-1 inhibitor, was approved by the US Food and Drug Administration in 2021 advanced/metastatic gastric cancer, gastroesophageal junction cancer, and esophageal adenocarcinoma, in combination with fluoropyrimidine and platinum-based chemotherapy. In the present study, the number needed to treat (NNT) for overall survival (OS), progression-free survival (PFS), and objective response rate (ORR)—and the number needed to harm (NNH) for tolerability outcomes—with nivolumab + chemotherapy versus chemotherapy alone were determined. MethodsNNT and NNH were calculated as the reciprocal of the risk difference between the two treatment arms, with the 95% CIs calculated as the reciprocals of the upper and lower bounds of the 95% CI of the risk difference, using data from the CheckMate 649 study. FindingsAmong all treated patients, the NNTs for OS over 1 and 2 years were 15.15 and 12.05; for PFS, 10.87 and 19.61; and for ORR over the entire trial period, 8.95. The corresponding NNTs in the subgroup with PD-L1 CPS ≥5 were less. The NNH for grade ≥3 treatment-related adverse events (TEAEs) over 1 year among all treated patients was 7.02. ImplicationsThe small estimated NNT values in this study suggest that patients would benefit from nivolumab + chemotherapy, and while the NNH for grade ≥3 TRAEs was small, the NNH for any individual TRAE were large or negative.

Response to the FDA Decision Regarding DPYD Testing Prior to Fluoropyrimidine Chemotherapy.

Fluoropyrimidine (FP) chemotherapy is associated with severe, life-threatening toxicities, particularly among patients who carry deleterious germline variants in the DPYD gene. Pretreatment DPYD testing is standard of care throughout most of Europe; however, it has not been recommended in clinical practice guidelines in the United States. Due to increased risk of severe toxicity, a Citizen's Petition asked the US Food and Drug Administration (FDA) to update language in FP drug labels to recommend DPYD testing as part of a boxed warning and recommend FP dose reduction in patients carrying deleterious germline variants. In response, the FDA updated the capecitabine package insert to inform patients about the toxicity risk and test availability and consider DPYD testing. However, the FDA did not include a testing recommendation or requirement, or a boxed warning. Additionally, the FDA did not recommend FP dose adjustment in DPYD variant carriers. This review provides a critical assessment of the DPYD-FP pharmacogenetic association using the FDA's previously published Pharmacogenetic Pyramid, demonstrating that the evidence is compelling for recommending DPYD testing prior to FP treatment. Additionally, the FDA's stated concerns about recommending DPYD testing and DPYD-guided FP dose adjustment are addressed and discussed in the context of the FDA's other genetic testing and dose adjustment recommendations. We call on the FDA to follow our European counterparts in recommending DPYD testing and genotype-based dose adjustment to ensure patients with cancer receive safe and effective FP chemotherapy.

Cost-effectiveness of extended DPYD testing before fluoropyrimidine chemotherapy in metastatic breast cancer in the UK.

The aim of this study was to evaluate the cost-effectiveness of ToxNav©, a multivariant genetic test, to screen for DPYD followed by personalized chemotherapy dosing for metastatic breast cancer in the UK compared with no testing followed by standard dose, standard of care. In the main analysis, ToxNav© was dominant over standard of care, producing 0.19 additional quality-adjusted life yearsand savings of £78,000 per patient over a lifetime. The mean additional quality-adjusted life years per person from 1000 simulations was 0.23savings(95% CI: 0.22-0.24) at £99,000 (95% CI: £95-102,000). Varying input parameters independently by range of 20% was unlikely to change the results in the main analysis. The probabilistic sensitivity analysis showed ~97% probability of the ToxNav©strategy to be dominant.

Risk of severe toxicity from topical fluoropyrimidine treatment in patients carrying DPYD variant alleles.

12123 Background: Patients carrying variant alleles of DPYD that reduce activity of dihydropyrimidine dehydrogenase have unacceptably high risk of severe toxicity from systemic fluoropyrimidine chemotherapy. DPYD testing prior to systemic fluoropyrimidine treatment is standard of care across Europe and is increasingly used in USA. There is a published case report of fatal toxicity from topical fluoropyridine chemotherapy in a DPYD variant carrier, but the risk of severe toxicity in these patients is unknown. This information is critical to determine whether patients receiving topical fluoropyrimidine treatment should also undergo DPYD genetic testing. The objective of this retrospective cohort study was to determine whether patients carrying DPYD variant alleles have increased risk of severe toxicity from topical fluoropyrimidine treatment. Methods: Individuals who received topical fluoropyrimidine treatment at Michigan Medicine and had available DPYD genotype data, due to participation in the Michigan Genomics Initiative institutional genetic data repository, were eligible for this analysis. Clinical data for the first cycle of topical fluoropyrimidine treatment was abstracted from the electronic medical record by an investigator blinded to genetic data. Toxicities were graded based on the Common Terminology Criteria for Adverse Events (CTCAE) version 5.0. The primary endpoint was grade 3+ toxicity. The secondary endpoint was grade 1+ toxicity. Genotypes for five validated decreased- or null-activity DPYD variant alleles were included: DPYD*2A (rs3918290), DPYD*13 (rs55886062), DPYD p.D949V (rs67376798) DPYD HapB3 (rs56038477) and DPYD p.Y186C (rs115232898). Toxicity rates in DPYD variant carriers vs. wild-type were compared using Fisher’s Exact tests. Results: 201 patients receiving topical fluoropyrimidine therapy who had available DPYD genotype data were included in the analysis. Most patients were self-reported white (97%), male (71%), and received topical fluoropyrimidine for a diagnosis of actinic keratosis (79%). As expected in a US patient cohort, 7.0% (14/201) of patients carried a DPYD variant. No patients experienced grade 3+ toxicity. Patients carrying a DPYD variant allele had nominally higher risk of grade 1+ toxicity (21.4% vs. 10.2%, odds ratio = 2.40 (95% Confidence Interval: 0.10-2.53), p = 0.19). Conclusions: Patients carrying DPYD variant alleles may have increased risk of non-severe toxicity from topical fluoropyrimidines, but the risk of severe toxicity is minimal regardless of genotype. DPYD genetic testing to prevent severe and fatal fluoropyrimidine toxicity should be reserved for patients receiving systemic treatment and need not include patients receiving topical treatment, in whom risk of severe toxicity is minimal.

Confirmatory DPYD Testing in Patients Receiving Fluoropyrimidines Who are Suspected DPYD Variant Carriers Based on a Genetic Data Repository.

Using pharmacogenetics (PGx) to inform clinical decision making can benefit patients but clinical use of PGx testing has been limited. Existing genetics data obtained in the course of research could be used to identify patients who are suspected, but have not yet been confirmed, to carry clinically actionable genotypes, in whom confirmatory genetic testing could be conducted for highly efficient PGx implementation. Herein, we demonstrate that it is regulatorily and technically feasible to implement PGx by identifying suspected carriers of actionable genotypes within an institutional genetics data repository and conduct confirmatory PGx testing immediately prior to that patient receiving the PGx-relevant drug, using a case study of DPYD testing prior to fluoropyrimidine chemotherapy. In 2 years since launching this program, ~ 3,000 suspected DPYD carriers have been passively monitored and one confirmed DPYD carrier was prevented from receiving unacceptably toxic fluoropyrimidine treatment, for minimal cost and effort. Now that we have demonstrated the feasibility of this strategy, we plan to transition to PGx panel testing and expand implementation to other genes and drugs for which the evidence of clinical benefit of PGx-informed treatment is high but PGx testing is not generally conducted. This highly efficient implementation process will maximize the clinical benefits of testing and could be explored at other institutions that have research-only genetic data repositories to expand the number of patients who benefit from PGx-informed treatment while we continue to work toward wide-scale adoption of PGx testing and implementation.

Real-world tolerance and outcomes of oxaliplatin-based adjuvant chemotherapy for stage III colon cancer-Does dose intensity matter?

Fluoropyrimidine and oxaliplatin-based adjuvant chemotherapy delivered as 5-fluorouracil, leucovorin and oxaliplatin (FOLFOX), or capecitabine and oxaliplatin (CAPOX) is the standard of care for resected stage III colon cancer. Without randomized trial data, we compared real-world dose intensity, survival outcomes, and tolerability of these regimens. Records of patients treated with FOLFOX or CAPOX in the adjuvant setting for stage III colon cancer across four institutions in Sydney during 2006-2016 were reviewed. The relative dose intensity (RDI) of fluoropyrimidine and oxaliplatin of each regimen, disease-free survival (DFS), overall survival (OS), and incidence of grade ≥2 toxicities were compared. Characteristics of patients receiving FOLFOX (n=195) and CAPOX (n=62) were evenly matched. FOLFOX patients had a higher mean RDI for both fluoropyrimidine (85% vs. 78%, p<0.01) and oxaliplatin (72% vs. 66%, p=0.06). In spite of a lower RDI, CAPOX patients trended toward a better 5-year DFS (84% vs. 78%, HR=0.53, p=0.068) and similar OS (89% vs. 89%, HR=0.53, p=0.21) compared to the FOLFOX group. This difference was most pronounced in the high-risk (T4 or N2) group where 5-year DFS was 78% versus 67% (HR=0.41, p=0.042). Patients receiving CAPOX experienced more grade ≥2 diarrhea (p=0.017) and hand-foot syndrome (p<0.001) but not peripheral neuropathy or myelosuppression. In a real-world setting, patients who received CAPOX had similar OS rates when compared to those receiving FOLFOX in the adjuvant setting in spite of lower RDI. In the high-risk population, CAPOX appears to demonstrate a superior 5-year DFS over FOLFOX.

Phase 2 study of preoperative chemotherapy with nab-paclitaxel and gemcitabine followed by chemoradiation for borderline resectable or node-positive pancreatic ductal adenocarcinoma.

Neoadjuvant treatment with nab-paclitaxel and gemcitabine for potentially operable pancreatic adenocarcinoma has not been well studied in a prospective interventional trial and could down-stage tumors to achieve negative surgical margins. A single-arm, open-label phase 2 trial (NCT02427841) enrolled patients with pancreatic adenocarcinoma deemed to be borderline resectable or clinically node-positive from March 17, 2016 to October 5, 2019. Patients received preoperative gemcitabine 1000 mg/m2 and nab-paclitaxel 125 mg/m2 on Days 1, 8, 15, every 28 days for two cycles followed by chemoradiation with 50.4 Gy intensity-modulated radiation over 28 fractions with concurrent fluoropyrimidine chemotherapy. After definitive resection, patients received four additional cycles of gemcitabine and nab-paclitaxel. The primary endpoint was R0 resection rate. Other endpoints included treatment completion rate, resection rate, radiographic response rate, survival, and adverse events. Nineteen patients were enrolled, with the majority having head of pancreas primary tumors, both arterial and venous vasculature involvement, and clinically positive nodes on imaging. Among them, 11 (58%) underwent definitive resection and eight of 19 (42%) achieved R0 resection. Disease progression and functional decline were primary reasons for deferring surgical resection after neoadjuvant treatment. Pathologic near-complete response was observed in two of 11 (18%) resection specimens. Among the 19 patients, the 12-month progression-free survival was 58%, and 12-month overall survival was 79%. Common adverse events were alopecia, nausea, vomiting, fatigue, myalgia, peripheral neuropathy, rash, and neutropenia. Gemcitabine and nab-paclitaxel followed by long-course chemoradiation represents a feasible neoadjuvant treatment strategy for borderline resectable or node-positive pancreatic cancer.

Impact of pharmacogenomic DPYD variant guided dosing on toxicity in patients receiving fluoropyrimidines for gastrointestinal cancers in a high-volume tertiary centre

BackgroundDihydropyrimidine dehydrogenase (DPD) is a key enzyme in the metabolism of fluoropyrimidines. Variations in the encoding DPYD gene are associated with severe fluoropyrimidine toxicity and up-front dose reductions are recommended. We conducted a retrospective study to evaluate the impact of implementing DPYD variant testing for patients with gastrointestinal cancers in routine clinical practice in a high volume cancer centre in London, United Kingdom.MethodsPatients receiving fluoropyrimidine chemotherapy for gastrointestinal cancer prior to, and following the implementation of DPYD testing were identified retrospectively. After November 2018, patients were tested for DPYD variants c.1905+1G>A (DPYD*2A), c.2846A>T (DPYD rs67376798), c.1679T>G (DPYD*13), c.1236G>A (DPYD rs56038477), c.1601G>A (DPYD*4) prior to commencing fluoropyrimidines alone or in combination with other cytotoxics and/or radiotherapy. Patients with a DPYD heterozygous variant received an initial dose reduction of 25–50%. Toxicity by CTCAE v4.03 criteria was compared between DPYD heterozygous variant and wild type carriers.ResultsBetween 1st December 2018 and 31st July 2019, 370 patients who were fluoropyrimidine naïve underwent a DPYD genotyping test prior to receiving a capecitabine (n = 236, 63.8%) or 5FU (n = 134, 36.2%) containing chemotherapy regimen. 33 patients (8.8%) were heterozygous DPYD variant carriers and 337 (91.2%) were wild type. The most prevalent variants were c.1601G > A (n = 16) and c.1236G > A (n = 9). Mean relative dose intensity for the first dose was 54.2% (range 37.5–75%) for DPYD heterozygous carriers and 93.2% (42.9–100%) for DPYD wild type carriers. Overall grade 3 or worse toxicity was similar in DPYD variant carriers (4/33, 12.1%) as compared to wild-type carriers (89/337, 25.7%; P = 0.0924).ConclusionsOur study demonstrates successful routine DPYD mutation testing prior to the initiation of fluoropyrimidine chemotherapy with high uptake. In patients with DPYD heterozygous variants with pre-emptive dose reductions, high incidence of severe toxicity was not observed. Our data supports routine DPYD genotype testing prior to commencement of fluoropyrimidine chemotherapy.

The success of anti-PD-1 with chemotherapy for esophageal squamous cell carcinoma

In the ASTRUM-007 randomized double-blind phase III study, Song etal.1 showed that the combination of PD-1 inhibitors with first-line fluoropyrimidine and platinum-based chemotherapy improves outcomes in PD-L1-overexpressing esophageal squamous cell carcinomas.