Schmerold, Luke

AbstractBackgroundThe relationship between CINV duration and recurrence in subsequent cycles is largely unstudied. Our objective was to determine if patients experiencing CINV in their first cycle of chemotherapy (C1) would face increased risk of CINV in later cycles and whether the duration of the CINV would predict increased risk of recurrence.Patients and MethodsUsing data from a previously reported phase III trial, we assessed patients’ recurrence of breakthrough CINV after antiemetic prophylaxis for anthracycline+cyclophosphamide (AC) for breast cancer, comparing C1 short CINV vs. extended CINV as a secondary analysis. Complete response (CR) and CINV duration were primary and secondary endpoints, respectively. CR was considered prophylaxis success; lack of CR was considered treatment failure (TF).ResultsAmong 402 female patients, 99 (24.6%) had TF in C1 (TF1). The remaining 303 patients (CR1) had ≥93% CR rates in each subsequent cycle, while the 99 patients with TF1 had TF rates of 49.8% for cycles 2-4 (P < .001). The 51 patients with extended TF (≥3 days) in C1 had recurrent TF in 73/105 later cycles (69.5%, P < .001), while the 48 patients with short TF (1-2 days) in C1 had recurrent TF in 33/108 later cycles (30.6%). The relative risk of recurrence after C1 extended TF was 2.28 (CI 1.67-3.11; P < .001) compared to short TF.ConclusionsProphylaxis success in C1 led to >90% repeat success across cycles of AC-based chemotherapy. For patients with breakthrough CINV, extended duration strongly predicted recurrent CINV. The duration of CINV should be closely monitored, and augmenting antiemetic prophylaxis considered for future cycles when extended CINV occurs.

Abstract Background: CINV remains a challenging chemotherapy toxicity, particularly for anthracyclines + cyclophosphamide (AC) for breast cancer. Complete response (CR), defined as no vomiting or use of rescue medication over 5 days after chemotherapy, has been the standard endpoint for successful antiemetic prophylaxis, yet duration of prophylaxis treatment failure (i.e., breakthrough CINV) is rarely assessed. Previous work demonstrated that initial cycle breakthrough CINV is associated with at least one subsequent cycle with CINV (Schwartzberg 2011), and that longer duration CINV is associated with more lost work time and impaired activity (Schwartzberg ASCO 2020). We sought to evaluate the duration of breakthrough CINV in cycle one and its association with individual patients’ repeat breakthrough CINV in subsequent cycles. Methods: Days of CINV was a prespecified endpoint in a prospective, 4-cycle CINV prophylaxis trial of combination netupitant/palonosetron (NEPA) + dexamethasone (Dex) for patients with breast cancer receiving AC; the primary endpoint was CR. Patients without CR were classified as prophylaxis treatment failure (TF) and categorized as short TF (sTF, 1-2 days) or extended TF (xTF, ≥3 days), consistent with work by Ballatori [2006] and Roeland [2019]. We analyzed patients’ sequences of CR, sTF, and xTF for cycles 1-4 and assessed likelihood of CR for cycles 2-4 based on cycle 1 TF duration, using chi-square statistics. Results: Of 402 patients in cycle 1, 303 had CR and 99 (24.6%) had TF. Duration of TF in cycle 1 was sTF for 48 patients while 51 patients had xTF. Patients with sTF in cycle 1 often experienced CR in cycle 2 (32/46 remaining patients; 69.6%) while patients with xTF in cycle 1 often had TF in cycle 2 (38/49; 77.6%). Patients had >84% likelihood of repeating their cycle 2 outcome (CR or TF) in cycles 3 and 4. Over all cycles, those with sTF in cycle 1 had CR in 75/108 later cycles (69.4%) while xTF in cycle 1 led to CR in 32/105 later cycles (29.0%), p<0.001) (see Table). Duration of later-cycle TF was typically consistent with initial cycle TF duration (p=0.046). As a predictor of later cycle TF, xTF had a positive predictive value of 0.695, with sensitivity of 0.689 and specificity of 0.701. Those with xTF in cycle 1 had 2.28 times the relative risk of later TF (CI 1.67-3.11; p<0.001) vs those with sTF. The absolute increase in risk from xTF was 40.4%. Conclusions: Although the majority of patients receiving NEPA + Dex as prophylaxis for AC in breast cancer successfully avoided breakthrough CINV, for patients with prophylaxis treatment failure, CINV duration in cycle 1 strongly predicted their future likelihood of CINV. Patients with extended (≥3 days) breakthrough CINV in cycle 1 had CINV again in over 2/3 of later cycles; conversely those with short breakthrough CINV in cycle 1 avoided CINV entirely in over 2/3 of later cycles. The markedly higher risk faced by patients with initial-cycle extended CINV is both statistically significant and clinically meaningful, due not only to its longer duration and risk-prediction but also to previously demonstrated worsening of work loss and impaired activity. Clinicians should monitor breakthrough CINV duration, seek to avoid extended CINV, and consider changing antiemetic prophylaxis when extended CINV does occur. Further study is needed to confirm this finding in other chemotherapy regimens and with other triple prophylaxis regimens. Impact of Extended CINV in Cycle 1 on CINV in Later CyclesTF1P valueInitial Cycle Result (n/total initial cycles)Total TF1 (99/402)Short TF1 (48/99)Extended TF1 (51/99)Short vs Extended TF1Later CR cycles (n, % of total later cycles)107 (50.2%)75 (69.4%)32 (29.0%)<0.0001Later TF (n, % of total later cycles)106 (49.8%)33 (30.6%)73 (71.0%)Duration of Later TF (n, % of all later TF)Later sTFLater xTFLater sTFLater xTF0.04620 (60.6%)13 (39.4%)29 (39.7%)44 (60.3%)Total later cycles (n, %)213 (100%)108 (100%)105 (100%)TF: prophylaxis Treatment Failure; TF1: TF in cycle 1; CR: Complete Response (0 days TF); CR1: CR in cycle 1; sTF: Short (1-2 days) TF; xTF: Extended (≥3 days) TF Citation Format: Rudolph M. Navari, Gary Binder, Eric J. Roeland, Alexander Molassiotis, Kathryn J. Ruddy, Thomas W. LeBlanc, Dwight D. Kloth, Silvia Sebastiani, Marco Turini, Luke M. Schmerold, Xing Liu, Lee Schwartzberg. Duration of chemotherapy-induced nausea and vomiting (CINV) as a predictor of later-cycle CINV [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS13-27.

Abstract Background: Although many studies have demonstrated consistent levels of effectiveness of CINV prophylaxis for the entire study population across multiple chemotherapy cycles, rarely have studies reported how each patient’s risk of subsequent CINV differs based on prior cycle breakthrough CINV with the same prophylaxis. We lack data on whether prophylaxis continues to fail in the same group of patients each cycle, or whether failure is random with each subsequent cycle. We sought to evaluate individual patients’ risk of repeat CINV in each subsequent chemotherapy cycle. Methods: In a prospective, 4-cycle CINV prophylaxis trial of oral or intravenous combination netupitant/palonosetron (NEPA) + dexamethasone (day 1) for patients with breast cancer receiving anthracycline + cyclophosphamide (AC), we defined CINV as vomiting or use of rescue medication during days 1-5 after chemotherapy. Patients without CINV were classified as complete response (CR); the rest as treatment failure (TF). We analyzed patients’ sequences of CR and TF, and compared CR or TF for cycles 2-4 based on cycle 1 outcomes, using chi-square statistics. To provide context, we performed a post-hoc similar analysis of results reported by Herrstedt et al [2005] from a clinical trial of ondansetron + aprepitant (APR) for patients with breast cancer receiving 4 cycles of AC. Results: The 402 female patients in the NEPA trial received a total of 1,299 cycles. In cycle 1, 99 (24.6%) patients experienced TF (TF1); over all 4 cycles, TF occurred 253 times (19.5%). Patients with CR in cycle 1 (CR1) had a ≥92% rate of CR in cycle 2; their rates of repeat CR were similar in each subsequent cycle. Patients with TF1 had nearly equal risk of CR or TF in cycle 2 (45:55); thereafter 85% of this TF1 subgroup repeated their cycle 2 outcome (CR or TF) in cycles 3 and 4. Over all cycles of NEPA, patients with CR1 subsequently had CR in >90% of cycles 2-4; those with TF1 subsequently had TF in 49.8% of cycles 2-4 (p<0.0001) (see Table). We separately examined Herrstedt’s evaluation of 433 patients across 1537 cycles with APR. In cycle 1, TF was seen 213 times (49.2%), with TF reported in 46.7% of cycles 1-4. We found that patients with CR1 had an 80.5% rate of CR in cycle 2 and repeat CR rates were higher in subsequent cycles. Patients with TF1 had TF in cycle 2 (TF2) at a rate of 78.4%, with 76.6% TF3 and 72.7% TF4. For APR, CR1 resulted in subsequent CR in 78.6% of cycles 2-4 while patients with TF1 again had TF in 74.8% of cycles 2-4 (p<0.0001). Patients with TF1 were more likely to later drop from the study (see Table). Notably, among those with CR1 after APR, the few patients who later had TF in any cycle, had a subsequent repeat failure rate similar to those with TF1. Conclusions: When patients receiving guideline-recommended triple antiemetic prophylaxis successfully avoided CINV in their first cycle of HEC, they had 80-95% likelihood of repeating that success in later cycles. After NEPA, those whose prophylaxis failed in cycle 1 did not face a similar high risk of repeat failure in cycle 2. The pattern of repeat failure after aprepitant was different, with a high repeat failure risk starting in cycle 2. These findings strongly suggest that consistent population average CR rates reported across cycles may mask a higher repeat failure rate for individual patients that experience cycle 1 CINV, particularly for aprepitant. Further study of this phenomenon is needed for other HEC regimens, and to confirm the lack of high repeat failure seen in cycle 2 for NEPA. Repeat CINV in Later Cycles, Based on Cycle 1 ResultsNEPAAprepitant + OndansetronInitial Cycle Result (n/total initial cycles)CR1 (303/402)TF1 (99/402)CR1 vs TF1 (P value)CR1 (220/433)TF1 (213/433)CR1 vs TF1 (P value)Subsequent CR cycles (n, % of total subseq. cycles)636 (93.0%)107 (50.2%)<0.0001464 (78.6%)124 (25.2%)<0.0001Subsequent TF cycles (n, % of total subseq. cycles)48 (7.0%)106 (49.8%)126 (21.4%)370 (74.8%)Total subsequent cycles (n, % of total subseq. cycles)684 (100%)213 (100%)590 (100%)494 (100%)Dropped vs ITT* (n, % ITT cycles)225 (24.8%)84 (28.3%)0.226370 (10.6%)145 (22.7%)<0.0001* The NEPA trial was closed when the last patient completed the first cycle, resulting in an artificially high proportion of patients that did not complete 4 cycles. Citation Format: Rudolph M Navari, Gary Binder, Alexander Molassiotis, Eric Roeland, Kathryn J. Ruddy, Thomas W. LeBlanc, Dwight D. Kloth, Silvia Sebastiani, Lina Y. Dimberg, Luke M. Schmerold, Xing Liu, Lee Schwartzberg. Chemotherapy-induced nausea and vomiting (CINV) risk after prior breakthrough CINV: Unmasking the false average [abstract]. In: Proceedings of the 2020 San Antonio Breast Cancer Virtual Symposium; 2020 Dec 8-11; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2021;81(4 Suppl):Abstract nr PS13-09.

Abstract Purpose Chemotherapy-induced nausea and vomiting (CINV) contributes to avoidable acute care, a metric now tracked in Medicare's oncology outcome measure. CINV is preventable, yet guidelines are often not followed. We sought to quantify acute care involving CINV and other avoidable toxicities after highly emetogenic chemotherapy (HEC) to identify excess risk and assess clinician adherence to antiemesis guidelines for HEC. Materials and Methods We retrospectively evaluated U.S. electronic health records (2012-2018) using Medicare's OP-35 outcome measure to identify avoidable acute care involving any of 10 toxicities, including CINV, after HEC regimens relative to non-HEC. Antiemetic guideline adherence was defined as use ofneurokinin-1 (NKl) receptor antagonists Q5 (RAs) plus 5-hydroxytryptamine type 3 RA+ dexamethasone at HEC initiation. Results Among 17,609 patients receiving HEC, acute care rates associated with HEC chemotherapy included 32% cisplatin, 31% carboplatin, and 21% anthracycline/cyclosphospharnide (AC), with 76% meeting the criteria as avoidable events. Oxaliplatin rates were 29%. Avoidable acute care occurred 1.83 times (95% confidence interval, 1.76-1.91, p < .0001) as often after HEC versus non-HEC excluding oxaliplatin; CINV-related acute care occurred 2.29 times as often. Nonadherence to antiemesis guidelines occurred in 34% and 24% of cisplatin and AC courses, respectively, because of omission of a NKl RA. Conclusions Patients treated with HEC regimens experienced high avoidable acute care use, 1.8 times the risk seen for other chemotherapy. Nonadherence to guideline-directed antiemetic prophylaxis highlights the need to ensure adherence to antiemetic guidelines, including the use of NKl RA in HEC. Implications for Practice After survival, perhaps the most important goal in oncology is limiting avoidable acute care, a goal now used by Medicare to impact cancer reimbursement. This study found that patients treated with highly emetogenic chemotherapy (HEC) regimens had high rates of avoidable acute care use, 1.8 times the risk seen for other chemotherapy. A substantial proportion of the avoidable acute care involved chemotherapy-induced nausea and vomiting. Results showed that incomplete adherence to national antiemetic guidelines for HEC regimens primarily driven by omission of upfront neurokinin-1 receptor antagonist use, suggesting that improved adherence can meaningfully resolve this gap in quality and cost of care.

Background: Clinician adherence to antiemetic guidelines for preventing chemotherapy-induced nausea and vomiting (CINV) caused by highly emetogenic chemotherapy (HEC) remains poorly characterized. The primary aim of this study was to evaluate individual clinician adherence to HEC antiemetic guidelines. Patients and Methods: A retrospective analysis of patients receiving HEC was conducted using the IBM Watson Explorys Electronic Health Record Database (2012–2018). HEC antiemetic guideline adherence was defined as prescription of triple prophylaxis (neurokinin-1 receptor antagonist [NK1 RA], serotonin type-3 receptor antagonist, dexamethasone) at initiation of cisplatin or anthracycline + cyclophosphamide (AC). Clinicians who prescribed ≥5 HEC courses were included and individual guideline adherence was assessed, noting the number of prescribing clinicians with >90% adherence. Results: A total of 217 clinicians were identified who prescribed 2,543 cisplatin and 1,490 AC courses. Patients (N=4,033) were primarily women (63.3%) and chemotherapy-naïve (92%) with a mean age of 58.6 years. Breast (36%) and thoracic (19%) cancers were the most common tumor types. Guideline adherence rates of >90% were achieved by 35% and 58% of clinicians using cisplatin or AC, respectively. Omission of an NK1 RA was the most common practice of nonadherence. Variation in prophylaxis guideline adherence was considerable for cisplatin (mean, 71%; SD, 29%; coefficient of variation [CV], 0.40) and AC (mean, 84%; SD, 26%; CV, 0.31). Conclusions: Findings showed substantial gaps in clinician adherence to HEC CINV guidelines, including a high variability across clinicians. Clinicians should review their individual clinical practices and ensure adherence to evidence-based CINV guidelines to optimize patient care.

e24133 Background: The impact of chemotherapy-induced nausea and vomiting (CINV) on work loss and activity impairment is important to patients yet not well described in literature. We sought to evaluate CINV-related work loss and activity impairment and their associations with CINV duration. Methods: In a prospective CINV prophylaxis trial of oral or intravenous netupitant/palonestron (NEPA) + dexamethasone (DEX) (12mg day 1 only) for patients with breast cancer receiving anthracycline + cyclophosphamide (AC), we defined CINV as vomiting or use of rescue medication during days 1-5 after AC. Pre-specified endpoints included CINV duration (0-5 days), patient reported CINV-associated work loss (Work Productivity and Activity Impairment survey), and CINV-related impaired activity [0 (none) - (worst) Likert scale] for chemotherapy cycles 1 and 2. CINV-related work loss and activity impairment could involve nausea with or without vomiting or rescue medication use. We categorized CINV duration as 1-2 days (d) or ≥3 d, and compared results using the chi-squared test. We report here on the first 2 cycles. Results: Survey data was captured for 792 cycles in 402 female patients including 132 (32.8%) employed patients. Mean age was 55.4. CINV was observed in 173 (21.8%) of total cycles. CINV-related work loss was reported in 26 (3.3% of all cycles, 15.0% of cycles with CINV, 38.2% of employed patient cycles with CINV) while 142 had related activity impairment. When we categorized cycles by CINV duration, CINV-related work loss was seen in 25.9% of 81 cycles with ≥3 d CINV duration vs. 5.4% for 92 cycles of 1-2 d of CINV (p < 0.001); mean scores of CINV-related impaired activity were 5.0 for ≥3 d CINV vs 3.0 for 1-2 d CINV (p < 0.001). Conclusions: Despite guideline recommended prophylaxis, CINV occurred in > 20% of AC cycles. In cycles with CINV, CINV-related work loss occurred in 38.2% for employed patients while activity impairment occurred in 82.1% for all patient cycles. The majority of CINV lasted 1-2 d. Notably, ≥3 d of CINV was associated with considerably higher levels of work loss and activity impairment suggesting that duration may be a meaningful measure of CINV impact. Clinical trial information: NCT03403712 . [Table: see text]

Abstract Background: Anthracycline and cyclophosphamide (AC) is a highly emetogenic chemotherapy (HEC) regimen. Combination netupitant/palonosetron (NEPA) + dexamethasone (DEX) is guideline-recommended for prophylaxis of chemotherapy-induced nausea and vomiting (CINV) in HEC and moderately emetogenic chemotherapy. CMS’ OP-35 measure deems 30-day post-chemotherapy acute care as avoidable if involving nausea and emesis (NV) or any of 8 other toxicities. Results will be publicly reported and impact Medicare reimbursement. CMS (2017) found that 10% of &gt;58,000 patients with avoidable acute care after chemotherapy involved NV. Because NEPA is new, insufficient real world data exist to assess its CINV resource use. CINV-related acute-care after NEPA prophylaxis in AC has been reported in a prospective clinical trial. Our aim was to compare these rates to those seen after prophylaxis with other antiemetics for AC outside of a clinical trial. Methods: Pre-specified endpoints in a prospective trial of oral or IV NEPA + DEX in AC included acute-care use (emergency [ED] visits or inpatient admissions [IP]) involving CINV, defined as emesis or rescue drug use ≤5 days after AC, and concomitant ED/IP in the same period. We also evaluated CINV-related acute care after non-NEPA prophylaxis for AC in breast cancer from 10/2012-8/2018 in IBM Explorys electronic health records. We age-matched patients 3:1 to the NEPA trial. We further adjusted the event rate to address under-reporting of a) CINV rates (vs. 49.2% for aprepitant in AC in a clinical trial [Warr 2005]) and b) acute-care use, projected at 17-50% at sites external to the dataset. To compare the resulting adjusted event rate to the NEPA study, we conducted 10,000 Monte Carlo simulations, using random probabilities from 5.2-8.7% for Explorys patients, and from 0-2% for NEPA patients to address potential reporting variability, despite the trial including daily patient diaries. Analysis of data was limited to the first two cycles, the median duration in the NEPA trial. Results: In the NEPA trial, 402 patients received ≥1 cycle; 391 completed two cycles. Nine patients had IP admissions; none involved CINV. Five patients had 6 total ED visits; one met criteria for involving CINV; the resulting rate of acute care rate involving CINV was 0.25 per 100 patients. For other antiemetics, 2598 patients received AC (excluding NEPA prophylaxis). Among 1206 age-matched to the NEPA trial, 15 patients had acute-care events in the first 2 cycles, (1.24 per 100 patients), an odds ratio of 1:5.1 (CI 0.7-38.5) in favor of NEPA. After adjusting via the simulation, the odds ratio was 1:8.3 (CI: 2.43-24.21) in favor of NEPA. Conclusions: Comparing CINV-related acute care seen in a large prospective trial relative to real-world evidence in patients with breast cancer treated with AC, &lt;1% of patients receiving NEPA prophylaxis required acute care for CINV; the CINV-related acute-care risks seen with other antiemetic prophylaxis were 5 times (unadjusted) to 8 times (adjusted) the levels for NEPA. A similar comparison using only real world data should be conducted as data permit. Citation Format: Lee Schwartzberg, Kathryn J Ruddy, Rudolph M Navari, Thomas W LeBlanc, Rebecca Clark-Snow, Rita Wickham, Gary Binder, William L. Bailey, Ravi Potluri, Luke M Schmerold, Eros Papademetriou, Eric J Roeland. Avoidable acute care involving chemotherapy-induced nausea and vomiting (CINV) among patients with breast cancer receiving anthracycline + cyclophosphamide (AC) with NEPA prophylaxis relative to other antiemetics: An external control arm analysis [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P5-14-07.

11595 Background: In 2017, NCCN (2/2017) and ASCO (8/2017) each amended antiemetic guidelines to classify carboplatin AUC ≥4 as highly emetogenic chemotherapy (HEC), recommending upfront triple prophylaxis with an NK1 receptor antagonist (RA) + 5HT3 RA + dexamethasone. Physician concordance with the new recommendations, and the consequences for avoidable post-chemotherapy acute care, merit study. Methods: In a large electronic health record database (IBM Explorys), we identified carboplatin courses of therapy (≥14-day cycles as a proxy for AUC ≥4) and courses with ≥7-day cycles of other HEC and non-HEC therapy from 4Q 2012 through August 2018. Guideline concordance, defined as triple prophylaxis at HEC initiation, was evaluated. We also assessed 30-day post-chemotherapy acute care (inpatient or emergency department) associated with nausea or vomiting (NV) or eight other toxicities deemed avoidable in the US Centers for Medicare & Medicaid’s new oncology outcome measure OP-35. Results: 11,554 carboplatin courses were identified. Before the guideline change, rates of upfront triple prophylaxis grew from 14% in 2013 to 16% in mid-2017. Rates then rose to 26% by 1Q 2018 before dropping to 21% by 3Q 2018; quarterly rates averaged 20% (range 15%-26%) following the guideline change. In 31% of carboplatin courses we noted 30-day acute care use, of which 75% involved ≥1 of the ten OP-35 toxicities. NV (with or without acute care use) was reported in 24% of courses, and 27% of total OP-35 acute care events involved NV. Rates for NV, and for OP-35-related and NV-related acute care after carboplatin, were similar to rates after other HEC chemotherapy, and higher than rates after other non-HEC IV chemotherapy or oral HEC/MEC agents. Conclusions: Use of upfront triple antiemetic prophylaxis has increased only marginally for carboplatin AUC ≥ 4 since its 2017 re-classification as HEC in national guidelines, perhaps due to low awareness of the change. Patients receiving carboplatin had similar rates of NV and related 30-day acute care events as seen for other HEC, confirming that the new HEC definition fits clinical experience. More triple prophylaxis use is needed to reduce NV and NV-related avoidable acute care seen with carboplatin AUC ≥ 4.

PURPOSE: After ASCO and National Comprehensive Cancer Network guideline recommendations for triple antiemetic prophylaxis for carboplatin area under the curve (AUC) ≥ 4, and the publication of studies documenting avoidable acute care after chemotherapy involving nausea and vomiting (NV) and other toxicities, we studied clinician adherence to the guideline change and assessed avoidable acute-care use. METHODS: Using a large electronic health record database, we evaluated antiemetic prophylaxis as recommended in the guidelines and post-chemotherapy avoidable acute-care use (defined as involving any of NV or 8 other toxicities) for patients initiating carboplatin or other chemotherapy from October 2012 to August 2018. RESULTS: We identified 11,554 carboplatin courses. After the guideline change adding neurokinin-1 receptor antagonists (RAs) for carboplatin AUC ≥ 4, its use rose to 20% of courses from the prior average of 16%; virtually all courses also included a 5-HT3 RA plus dexamethasone. We found avoidable acute care in 23% of courses; one quarter of these events were associated with NV. Acute care rates after carboplatin mirrored those after other highly emetogenic chemotherapy or oxaliplatin and exceeded those after other chemotherapy regimens. The > 80% shortfall in adherence may have been caused by low awareness or acceptance of the guideline change and/or by poor awareness of avoidable acute-care use after carboplatin. CONCLUSION: Neurokinin-1 RA prophylaxis for carboplatin AUC ≥ 4 remains low and largely unchanged despite National Comprehensive Cancer Network and ASCO 2017 recommendations for inclusion. NV and avoidable acute care involving NV seen after carboplatin were consistent with other highly emetogenic chemotherapy. Clinician action is required to remediate incomplete prophylaxis and to no longer place patient outcomes, resources for cancer treatment, and clinician reimbursement at risk.

e23108 Background: ASCO antiemetic guidelines recommend upfront triple prophylaxis (NK1 receptor antagonist (RA) + 5HT3 RA + dexamethasone) for patients receiving highly emetogenic chemotherapy (HEC). Physicians exhibit high variation in HEC guideline adherence, principally involving inclusion of NK1 RA. Whether adherence is associated with selection of the specific 5HT3 RA agent remains inadequately studied. Methods: In the IBM Explorys electronic health record database, we used procedure and diagnosis codes to identify HEC courses and related nausea/vomiting (NV) from 2012 to 2018. We defined HEC guideline adherence as triple prophylaxis at chemotherapy initiation. We assigned HEC courses for ≥ 7 day cycles of cisplatin or anthracycline + cyclophosphamide (AC), or carboplatin (≥ 14 day cycles as a proxy for AUC ≥ 4) to prescribing oncologists based on encounter frequency. We categorized 5HT3 RA use of each physician treating ≥ 5 HEC courses based on their most commonly used 5HT3 and performed descriptive statistics. Results: Of 12,262 HEC courses, 57% involved physicians having greater use of ondansetron (OND) (mean OND to palonosetron (PALO) ratio of 3.9:1). These courses had lower guideline adherence (due to NK1 RA omission) and higher rates of NV for combined HEC, AC, and carboplatin. NV rates for cisplatin did not vary by 5HT3 agent used. Courses involving physicians with greater PALO use (mean OND:PALO ratio of 0.2:1) had superior adherence and NV rates, despite involving a slightly higher risk population (younger and/or female). Conclusions: According to HEC antiemetic guidelines, NK1 RA use should occur independent of 5HT3 RA agent selection. However, we observed less NK1 RA use where OND was preferred, which may have caused the observed higher rates of NV with OND. Further evaluation should assess whether pharmacy cost minimization is a driver of both OND preference and NK1 omission in HEC. [Table: see text]