Citations

ABSTRACT Enzalutamide and abiraterone are hormonal treatments that improve survival in metastatic castration‐resistant prostate cancer. Identifying genetic variants associated with the clearance of these drugs may aid in improved dosing and outcomes. We performed genetic association studies of enzalutamide and abiraterone oral clearance in the Alliance A031201 clinical trial. Genome‐wide genotyping was performed with the primary analysis limited to European‐descent participants. Pharmacogene metabolic phenotypes were estimated using PyPGx and Stargazer. Associations of metabolic activity groups for CYP3A4 , CYP3A5 , CYP2C19 and SLCO1B1 with enzalutamide clearance ( N = 706) and CYP3A4 , SLCO2B1 and UGT1A4 with abiraterone clearance ( N = 323) were tested by linear regression. Targeted SNP associations were assessed for abiraterone clearance at loci proximal to major metabolizing genes. Full genome‐wide association studies were performed for both sets of clearance values. No significant associations were identified between metabolic phenotypes and enzalutamide or abiraterone oral clearance SNPs in the SULT2A1 5′ flanking region were significantly associated with lower abiraterone clearance, (rs296373, minor allele frequency = 0.15, β = −0.457, p = 3.2E‐06). Liver protein and liver and adrenal gland gene expression QTL databases indicated significantly lower SULT2A1 expression patterns for individuals carrying associated alleles, likely explaining the lower abiraterone oral clearance. CYP2C8*3 was associated with higher enzalutamide clearance ( p = 0.012), but this was not significant after correction for multiple testing. This study is the first to identify the genetic association of SULT2A1, known to be involved in the metabolism of steroids in the liver and adrenal glands, with abiraterone clearance. Genetic variation in SULT2A1 may be useful to inform personalized dosing of abiraterone. ClinicalTrials.gov Identifier: NCT01949337

Barriers to incorporating pharmacogenetics into routine clinical practice in the United States are well documented. Initial surveys by the Clinical Pharmacogenetics Implementation Consortium (CPIC) in 2009 and 2010 identified barriers across four key domains that have hindered the widespread adoption of clinical pharmacogenetic testing. These are presented verbatim as: (i) absence of a definition of the processes required to interpret genotype information and to translate genetic information into clinical actions; (ii) need for recommended drug/gene pairs to implement clinically now; (iii) clinician resistance to consider pharmacogenetic information at the bedside; and (iv) concerns about test costs and reimbursement. Over time, many of these challenges have been overcome, and clinical pharmacogenetic testing has subsequently reached broader implementation. Despite this progress, several barriers remain that block further adoption. This narrative review used authors' expertise and experience to identify and describe current barriers to pharmacogenetic implementation across seven domains in the United States: equity and inclusion; guidelines and supporting evidence; regulatory agency oversight; payer coverage and insurance; availability of quality pharmacogenetic tests; electronic health records; and provider and patient education. Within each domain, it revisits past successes and challenges and explores remaining barriers. We also propose solutions to address ongoing challenges across these domains, including further expansion of recommendations beyond pharmacogenetic‐specific guidelines, standards for designing clinical decision support tools, and broader pharmacogenetics education. Addressing these remaining obstacles directs work to enable broader adoption of clinical pharmacogenetic implementation to ultimately improve patient outcomes.

Abstract Purpose: Chemotherapy-induced peripheral neuropathy (CIPN) is a debilitating toxicity of many drugs used in cancer treatment. There are numerous available strategies for preventing or treating CIPN, but few are guideline-recommended, due to limited evidence of their effectiveness. The primary objective of this survey was to understand what strategies patients used to prevent or treat CIPN, and to understand their perceptions around CIPN prevention and treatment. Methods: The Multinational Association of Supportive Care in Cancer (MASCC) Neurological Complications Study Group created a cross-sectional online survey to recruit individuals who are currently or had previously received neurotoxic chemotherapy treatment and self-reported peripheral neuropathy. Descriptive statistics were reported. Results: Most of the 447 survey participants did not use any CIPN prevention strategy (71%), though given options of any strategy the plurality preferred a prescribed medication or supplement (30%). The most common treatment strategy used was exercise (47%), with some patients trying prescription medications including non-guideline recommended gabapentin (33%) or guideline-recommended duloxetine (8%) options. Nearly half of participants (49%) used at least one non-prescribed medication for treating CIPN. Patient’s often followed suggestions of their medical oncology clinical team, but sometimes relied on the internet or other patients to recommend non-prescription strategies. Conclusion: In the absence of many guideline-recommended strategies for CIPN prevention and treatment, some patients use options with minimal evidence of effectiveness. Additional research is needed to determine which strategies are effective for prevention and treatment so these can be implemented in practice to improve treatment outcomes in patients with cancer.

Abstract Purpose Clinical practice guidelines recommend altering neurotoxic chemotherapy treatment in patients experiencing intolerable chemotherapy-induced peripheral neuropathy (CIPN). The primary objective of this survey was to understand patient’s perspectives on altering neurotoxic chemotherapy treatment, including their perceptions of the benefits of preventing irreversible CIPN and the risks of reducing treatment efficacy.Methods A cross-sectional online survey was distributed via social networks to patients who were currently receiving or had previously received neurotoxic chemotherapy for cancer. Survey results were analyzed using descriptive statistics and qualitative analysis.Results Following data cleaning, 447 participants were included in the analysis. The median age was 57 years, 93% were white, and most were from the United Kingdom (53%) or United States of America (38%). Most participants who were currently or recently treated expected some CIPN symptom resolution (86%), but 45% of those who had completed treatment more than a year ago reported experiencing no symptom resolution. Participants reported that they would discontinue chemotherapy treatment for less severe CIPN if they knew their symptoms would be permanent than if symptoms would disappear after treatment. Most patients stated that the decision to alter chemotherapy or not was usually made collaboratively between the patient and their treating clinician (61%). The most common reason participants were reluctant to talk with their clinician about CIPN was fear that treatment would be altered. Participants noted a need for improved understanding of CIPN symptoms and their permanence, better patient education relating to CIPN prior to and after treatment, and greater clinician understanding and empathy around CIPN.Conclusions This survey highlights the importance of shared decision-making, including a consideration of both the long-term benefits and risks of altering neurotoxic chemotherapy treatment due to CIPN. Additional work is needed to develop decision aids and other communication tools that can be used to improve shared decision making and help patients with cancer achieve their treatment goals.

12090 Background: Clinical guidelines recommend altering chemotherapy treatment by decreasing, delaying, or discontinuing dosing in patients (pts) experiencing chemotherapy-induced peripheral neuropathy (CIPN). There are few data available on clinical use of treatment alteration including the severity of CIPN at the time of alteration. Our objective was to investigate the incidence of oxaliplatin treatment alterations and CIPN severity at that time. Methods: This was a retrospective analysis of pts with colon cancer scheduled to receive oxaliplatin-containing combination chemotherapy on the N08CB trial of intravenous calcium and magnesium for prevention of CIPN. Dose alterations were not mandated by the N08CB protocol. Clinicians assessed CIPN using NCI-CTCAE V.4.0; pts used the sensory subscale of the EORTC-QLQ Chemotherapy-Induced Peripheral Neuropathy 20 (CIPN8). Pts were classified as 1) completed oxaliplatin treatment without alteration, 2) dose reduction or delay due to CIPN, 3) discontinuation due to CIPN, 4) discontinuation due to other AE, or 5) discontinuation for another reason. Comparisons focused primarily on pts with alteration due to CIPN (groups 2 and/or 3) compared with pts completing treatment without alteration (group 1) using chi-squared and Kruskal-Wallis tests. Results: In this analysis of 350 N08CB pts, 135 (39%) completed oxaliplatin without treatment alteration, 70 (20%) had a dose reduction (n=66) or delay (n=4) due to CIPN and 35 (10%) discontinued early due to CIPN. Pts who experienced alterations due to CIPN were younger (p=0.0249) and more likely to be female (p=0.008). Clinician-assessed CIPN severity was greater in pts at the time of dose reduction or delay compared with CIPN severity at the end of treatment in pts with no alteration (p<0.0001). Pt-assessed CIPN severity was not different in pts who completed treatment without alteration compared to pts who had a dose reduction or delay (p=0.88) or a discontinuation (p=0.37). CIPN8 scores at cycle 4 were higher (worse) in pts who eventually had any alteration (i.e., reduction, delay, or discontinuation) compared to pts who completed treatment without any alteration (median CIPN8 11.5 vs. 7.7, p=0.023). Conclusions: Treatment alterations due to CIPN are relatively common in pts receiving adjuvant oxaliplatin for colon cancer and are associated with clinician-assessed but not pt-reported CIPN severity. Rapid CIPN8 increases early in treatment are indicative of increased likelihood of a future oxaliplatin treatment alteration, indicating a potential use of early monitoring and intervention. Support: UG1CA189823; https://acknowledgments.alliancefound.org. Clinical trial information: NCT01099449 (NCCTG N08CB).

Abstract Background: Clinical guidelines recommend altering chemotherapy treatment by decreasing, delaying, or discontinuing dosing in patients who are experiencing chemotherapy-induced peripheral neuropathy. There are few data available on the clinical use of treatment alteration including the severity of CIPN at the time of treatment alteration. Methods: This was a retrospective analysis of patients receiving oxaliplatin on the NCCTG N08CB trial. Neuropathy severity was assessed at each cycle by clinicians and patients. Patients were classified as 1) completed treatment without alteration, 2) dose reduction or delay due to neuropathy, 3) discontinuation due to neuropathy, or discontinuation for other toxicity (4), or another reason (5). Comparisons focused primarily on patients with alteration due to neuropathy (groups 2 and/or 3) compared with patients who completed treatment without alteration (group 1). Results: In 350 participants, 135 (39%) completed treatment without alteration, 70 (20%) had a dose reduction or delay due to neuropathy, and 35 (10%) discontinued early due to neuropathy. Clinician-assessed neuropathy severity was greater in patients at the time of dose reduction or delay compared with severity at the end of treatment in patients without alteration (p<0.0001). Patient-reported neuropathy severity at cycle 4 was worse in patients who had an alteration as compared with patients who completed treatment without alteration (p=0.017). Conclusions: Treatment alterations due to neuropathy are common in patients receiving oxaliplatin for colon cancer and are associated with clinician-assessed neuropathy severity. Rapid increases in patient-reported neuropathy severity indicate a potential need for monitoring and intervention.

PURPOSE To update the ASCO guideline on the recommended prevention and treatment approaches in the management of chemotherapy-induced peripheral neuropathy (CIPN) in adult cancer survivors. METHODS An Expert Panel conducted targeted systematic literature reviews to identify new studies. RESULTS The search strategy identified 257 new references, which led to a full-text review of 87 manuscripts. A total of 3 systematic reviews, 2 with meta-analyses, and 28 primary trials for prevention of CIPN in addition to 14 primary trials related to treatment of established CIPN, are included in this update. RECOMMENDATIONS The identified data reconfirmed that no agents are recommended for the prevention of CIPN. The use of acetyl-l-carnitine for the prevention of CIPN in patients with cancer should be discouraged. Furthermore, clinicians should assess the appropriateness of dose delaying, dose reduction, substitutions, or stopping chemotherapy in patients who develop intolerable neuropathy and/or functional impairment. Duloxetine is the only agent that has appropriate evidence to support its use for patients with established painful CIPN. Nonetheless, the amount of benefit from duloxetine is limited. Additional information is available at www.asco.org/survivorship-guidelines .

e13535 Background: Pediatric patients (pts) receiving long-term vincristine treatment for acute lymphoblastic leukemia (ALL) who carry two variant alleles of CEP72 rs924607 experience more severe peripheral neuropathy (PN) at lower cumulative vincristine doses. The objective of this retrospective pharmacogenetic analysis was to determine if pts homozygous for rs924607 have increased PN risk when receiving short-term vincristine treatment for diffuse large B-cell lymphoma (DLBCL). Methods: Caucasian pts with DLBCL randomized to either of two vincristine-containing regimens (R-CHOP or DA-EPOCH-R) on the CALGB 50303 (Alliance) trial were genotyped for germline rs924607 via TaqMan. Vincristine was administered intravenously 1.4 mg/m2 (2 mg cap) on day 1 of each R-CHOP cycle (1.4 mg/m2/cycle) or 0.4 mg/m2/day (no cap) on days 1-4 of each DA-EPOCH-R cycle (1.6 mg/m2/cycle). Dosing was repeated every 21 days for 6 treatment cycles, for a maximum cumulative vincristine dose of 8.4 (R-CHOP) or 9.6 (DA-EPOCH-R) mg/m2 over 18 weeks. The primary analysis compared risk of NCI CTCAE grade 3 or higher PN in rs924607 homozygous variant pts versus wild-type allele carriers using multivariable Cox proportional hazards regression adjusted for treatment received (R-CHOP vs. DA-EPOCH-R), age (continuous), and sex (male vs. female). A secondary analysis was conducted only in pts assigned to the DA-EPOCH-R arm. Results: Of 307 pts included in the analysis, 32 (10.4%) experienced grade 3+ PN. PN occurrence was nominally lower in homozygous pts (5/59 = 8.5%) than wild-type carriers (27/248 = 10.9%). In the primary analysis, homozygous pts did not experience PN earlier in treatment (Hazard ratio (HR) = 1.04, (95% confidence interval: 0.39-2.75), one-sided p-value = 0.47). There was no significant difference between groups in dose-at-PN occurrence (homozygous (n = 5): 8.81 mg/m2 vs. wild-type carrier (n = 27):6.74 mg/m2, p > 0.05). The secondary analysis in pts on the DA-EPOCH-R arm (n = 147), in which the majority of PN events occurred (n = 27/32 = 84%), homozygous pts (n = 26) did not have significantly increased PN risk (HR = 1.30, p = 0.56). Conclusions: This retrospective analysis of the prospective CALGB 50303 trial did not find that pts homozygous for CEP72 rs924607 had increased PN risk during short-term vincristine treatment for DLBCL. Support: U10CA180821, U10CA180882, U24CA196171; https://acknowledgments.alliancefound.org . ClinicalTrials.gov Id: NCT00118209.