Treatment Dose Reductions Research Articles

CTNI-11. A PHASE 1 OPEN-LABEL STUDY OF BRAF INHIBITOR ABM-1310 IN PATIENTS (PTS) WITH RECURRENT BRAF V600-MUTATED PRIMARY CNS TUMORS

Abstract BACKGROUND ABM-1310 is a blood-brain barrier penetrant BRAF inhibitor. Here we report interim results from our phase 1 study of ABM-1310. METHODS This is a dose-escalation plus expansions trial for adult pts with BRAF V600-mutated primary CNS tumors. In the dose-escalation, ABM-1310 is given at 150 or 200 mg twice a day (bid). In the expansion, ABM-1310 150 mg bid is administered. Study objectives include patient safety, maximum tolerated dose (MTD), preliminary efficacy and pharmacokinetics (PK). Clinical trial information: NCT05892653. RESULTS By May 6, 2024, 15 pts (7 male; median age 39 years old) have been treated. In the dose escalation: 4 pts received ABM-1310 150 mg bid, and another 7-pts received ABM-1310 200 mg bid. In the expansion, all 4 pts were given ABM-1310 at 150 mg bid. Among 14 efficacy evaluable pts, 3 had partial response (PR) (including one each of glioblastoma, WHO grade 2 and 3 pleomorphic xanthoastrocytoma) and 9 pts had stable disease as their best responses. Two pts have PR response for > 8 months and continue study treatment. All pts experienced treatment-related AEs. Common AEs were asymptomatic QT prolongation (n=11) and rash (n=10). Seven pts had grade 3 QT prolongation. There was no drug-related SAE. There was no ABM-1310 related dose limiting toxicity although a few pts had study treatment interruption or dose reduction. One patient discontinued prematurely due to asymptomatic Grade 3 QT prolongation. There were no drug-related deaths. The MTD for ABM-1310 was 200 mg bid, the recommended dose was 150 mg bid. In PK assessment, ABM-1310 drug exposure vs. dosage showed a linear proportional relationship. This trial is ongoing. CONCLUSIONS ABM-1310 was generally safe and tolerated. There were no new safety signals. Preliminary efficacy data demonstrate favorable anti-cancer activity in patients with recurrent BRAF V600-mutated primary CNS tumors.

CTNI-73. ASSESSMENT OF MOLECULAR ALTERATIONS IN NEWLY DIAGNOSED GBM MGMT-UNMETHYLATED PATIENTS TREATED WITH VAL-083

Abstract Glioblastoma (GBM) commonly features molecular alterations in the TERT, EGFR, PTEN, and TP53 genes, which contributes to uncontrolled cell growth, evasion of apoptosis, and enhanced tumor cell survival. VAL-083 is a bi-functional DNA-targeting agent which rapidly induces inter-strand DNA cross-links at N7 and O6-guanine inducing double-strand breaks causing cell death independently of MGMT DNA repair and DNA mismatch repair deficiency. VAL-083 was evaluated in an open-label, biomarker-driven, phase 2 trial in MGMT-unmethylated, bevacizumab-naïve GBM patients. The molecular profile of tumors from a newly diagnosed GBM patient subgroup who received VAL-083 alone after chemo-radiation with concurrent TMZ, was determined in order to correlate with clinical outcomes. Thirty-four (34/36, 94.4%) patients who received 30 mg/m2 VAL-083 (days 1-3 of 21-day cycle) had available next-generation sequencing data on their primary tissue. Patient median age was 54.8 years (5-95pth: 29.8-66.0), median KPS was 90 (5-95pth: 80-100) and 58.8% were males. The median number of cycles of VAL-083 was 7.5 (5-95pth: 1-12). There were 5 dose reductions due to toxicity. The median time to progression (PFS) and overall survival (OS) were 9.2 mo (95%CI: 7.6-10.2) and 16.5 mo (95%CI: 13.3-19.0), respectively. The mean number of molecular alterations was 3.9 (5-95pth 1-8). Six (17.6%) patients had gene fusions. The most common molecular alterations were TERT promoter (91.2%), EGFR amplification (amp) (52.9%), PTEN (50.0%), EGFR (20.6%), and TP53 (20.6%). Additional alterations (in ≥2 patients; 6%) included EGFR-EGFR (EGFRvIII), BRCA2, CDKN2A/B, CDK4/6 amp, MDM2/4 amp, NF1, NOTCH1, PIK3R1 and RB1. While TP53 mutations showed a trend as predictors for time to progression (P 0.027), this was not observed with OS. None of the molecular alterations were predictors of number of treatment cycles or dose reductions. No specific molecular alterations were identified that predicted either improved or poorer patient outcome, during treatment with VAL-083. Clinicaltrials.gov identifier: NCT02717962.

Avatrombopag for the treatment of patients with chemotherapy-induced thrombocytopenia: A case series.

Management of chemotherapy-induced thrombocytopenia (CIT) is challenging, often resulting in chemotherapy treatment delays, dose reduction, and treatment interruption. Randomized trials support the potential efficacy and safety of thrombopoietin receptor agonists in CIT management. A phase III trial of avatrombopag (AVA) demonstrated increased platelet counts (PC) in patients with solid tumours experiencing CIT. To complement those findings, this case series of six patients with solid tumours and CIT is presented. Results from these cases support the clinical benefit of AVA in improving PC and reducing the impact of CIT on tumour treatment, allowing continued therapy without dose reduction or treatment interruption.

Identifying risk factors of dose reduction or treatment discontinuation due to fatigue or gastrointestinal symptoms in patients receiving lenvatinib treatment for hepatocellular carcinoma

Introduction Lenvatinib (LEN) is the standard treatment for hepatocellular carcinoma (HCC). In clinical practice, gastrointestinal (GI) symptoms such as fatigue and loss of appetite often lead to dose reduction or treatment discontinuation. This study aimed to identify the predictors of patients who will experience dose reduction or treatment discontinuation owing to fatigue or GI symptoms during LEN treatment for HCC. Methods We retrospectively identified 99 patients who received LEN at the Ogaki Municipal Hospital (Ogaki, Japan) between April 2018 and December 2023. To investigate the risk factors for treatment discontinuation or dose reduction due to fatigue or GI symptoms during LEN administration, patients were divided into two groups based on whether treatment discontinuation or dose reduction occurred due to fatigue or GI symptoms during LEN administration (37 patients) or not (62 patients). We compared baseline characteristics between the two groups. Results Multivariate analysis revealed that body weight (odds ratio 4.310, 95% confidence interval 1.380–13.500; P = 0.002) was an independent risk factor that significantly contributed to treatment discontinuation or dose reduction owing to fatigue or GI symptoms during LEN administration. The cut-off value calculated using the body weight curve was 55.0 kg. Using this cutoff value, the sensitivity and specificity of body weight to detect treatment discontinuation or dose reduction due to fatigue or GI symptoms during LEN administration were 83.9% and 56.8%, respectively. Conclusion In clinical practice, patients weighing less than 55 kg who start with a full dose will likely experience weight loss or discontinuation during treatment.

292. CHEMOTHERAPY AND CHEMORADIOTHERAPY FOR ADENOCARCINOMA OF THE OESOPHAGUS AND JUNCTION WITH OLIGOMETASTASES: RESULTS OF THE TNT-OES-1 TRIAL

Abstract Background Chemotherapy (FLOT) and chemoradiotherapy (CROSS) are both effective as neoadjuvant regimens for esophageal and junctional cancer. Total Neoadjuvant Therapy (TNT) aims to increase efficacy by combining chemotherapy with chemoradiotherapy. Although TNT is increasingly used in rectal cancer, there are no data on combining e.g. FLOT and CROSS in esophageal cancer. This phase-II study aimed to evaluate the feasibility and safety of the TNT FLOT-CROSS combination in esophageal and junctional adenocarcinoma patients with oligometastatic disease. Methods Patients with oligometastatic (defined as a maximum of four lesions in up to two organs, excluding lymph nodes) esophageal adenocarcinoma were treated with four biweekly cycles of FLOT followed by response evaluation (CT-scan). Patients without disease progression (RECIST v1.1) proceed to CROSS. Afterwards, response was assessed by CT-scan, endoscopy with biopsies and endoscopic ultrasonography with fine-needle aspiration on indication. The multidisciplinary tumor board discussed whether patients could proceed to four additional cycles of FLOT or local therapy of metastases and/or esophagectomy. Primary endpoint was tolerability of TNT FLOT-CROSS, defined as the proportion completing four cycles of FLOT and five cycles of chemoradiotherapy. Secondary endpoints included progression-free survival (PFS), disease control rate (DCR), toxicity and the proportion proceeding to local therapy of metastases and/or esophagectomy. Results Twenty patients (85% males, median age 62.5 years (interquartile range 58.3-66) were included of whom 16 (80%) had a single metastatic lesion. Eighteen patients (90%) successfully completed FLOT and fifteen (75%) completed TNT FLOT-CROSS (Figure 1). Toxicity mainly consisted of grade 1-2 leukopenia/neutropenia during FLOT, leading to treatment delay in twelve patients and dose-limiting of oxaliplatin in one patient. One patient had malaise grade 2. No grade 3-5 toxicities occurred during CROSS. Following TNT FLOT-CROSS, ten patients underwent four additional cycles of FLOT and toxicity resulted in treatment delay and dose reduction in seven patients and hospitalization in two patients. Six patients underwent esophagectomy of whom two underwent local treatment of metastases. The 1- and 2-year PFS was 56% and 48%. Three months after TNT FLOT-CROSS completion, DCR was 73%. Conclusion(s) This study showed that sequencing TNT FLOT-CROSS in patients with oligometastatic esophageal adenocarcinoma is feasible and comes with manageable toxicity and promising efficacy. In follow-up to this study, the TNT-OES-2 study will assess the efficacy and feasibility of TNT FLOT-CROSS and TNT CROSS-FLOT in patients with resectable nodal-positive adenocarcinoma of the esophagus or esophagogastric junction.

Comparative Efficacy and Safety of Lorlatinib Versus Alectinib and Lorlatinib Versus Brigatinib for ALK-Positive Advanced/Metastatic NSCLC: Matching-Adjusted Indirect Comparisons

IntroductionThe comparative efficacy and safety of lorlatinib, a third-generation anaplastic lymphoma kinase (ALK) tyrosine kinase inhibitor (TKI), versus second-generation ALK TKIs as a first-line treatment for ALK+ advanced/metastatic nonsmall cell lung cancer (NSCLC) remains uncertain as there are no head-to-head clinical trials. MethodsMatching-adjusted indirect comparisons (MAICs) were conducted using phase III trial data demonstrating superior efficacy over crizotinib, a first-generation ALK TKI. MAICs were conducted to compare lorlatinib (CROWN) versus alectinib (ALEX and ALESIA) and brigatinib (ALTA-1L) with matching based on prespecified effect modifiers. Efficacy outcomes included progression-free survival (PFS), objective response (OR), and time to progression in the central nervous system (TTP-CNS). Safety outcomes included Grade ≥3 adverse events (AEs) and AEs leading to treatment discontinuation, dose reduction, or dose interruption. ResultsLorlatinib was estimated to improve PFS compared to alectinib (ALEX) (HR: 0.54 [95% CI: 0.33, 0.88]) and brigatinib (ALTA-1L) (HR: 0.51 [95% CI: 0.31, 0.82]). Lorlatinib was estimated to improve TTP-CNS compared with brigatinib (HR: 0.19 [95% CI: 0.05, 0.71]). The estimated Grade ≥3 AE rate was higher with lorlatinib than with alectinib (RR: 1.48 [95% CI: 1.13, 1.94]); however, no differences were observed in other safety endpoints (ie, AEs leading to discontinuation, dose reduction, or interruption) or compared to brigatinib. ConclusionLorlatinib was estimated to have superior efficacy over first- and second-generation ALK-TKIs, but a higher rate of Grade ≥3 AEs compared to alectinib. These data support the use of lorlatinib as a first-line treatment for ALK+ advanced/metastatic NSCLC.

Chidamide plus R-GDP for relapsed/refractory diffuse large B-cell lymphoma in patients ineligible for autologous transplantation: A prospective, single-arm, phase II study.

In relapsed/refractory (R/R) diffuse large B-cell lymphoma (DLBCL), a negative prognosis is frequently linked to heightened epigenetic heterogeneity. Chidamide, a selective histone deacetylase inhibitor, shows promise as a targeted therapy for R/R DLBCL by targeting abnormal epigenetic changes associated with poor prognosis. A cohort of 27 ineligible patients with R/R DLBCL participated in an open - label, single - arm study. Chidamide was administered orally at a dose of 30 mg twice weekly for one week during the induction monotherapy phase. The subsequent combination therapy phase involved oral chidamide at a dose of 20 mg twice weekly for two weeks, followed by a one-week discontinuation period, in conjunction with intravenous R-GDP every 21 days. Among the cohort of 31 patients who underwent screening (median age: 67 years), 27 were ultimately included in the study, with 14 individuals successfully completing six cycles of C-R-GDP treatment. The overall best objective response rate was determined to be 79.1% (95% CI: 75.1%-83.3%), comprising a complete response rate of 45.8% (95% CI: 41.6%-49.9%) and a partial response rate of 33.3% (95% CI: 29.3%-37.4%). Within the subgroup of 14 patients who completed the full treatment regimen, the best objective response rate reached 100%, with 71.4% achieving complete response (n = 10) and 28.6% achieving partial response (n = 4). The median follow-up period for these patients was 17.0 months, ranging from 3.5 to 55 months. Progression-free survival was 5.9 months and overall survival was 48.3 months. Anemia was the most common adverse event, affecting all patients. Thrombocytopenia led to treatment interruption or dose reduction in 13 patients. Other common adverse events included hypocalcemia, hyponatremia, and hypokalemia. Three patients experienced grade 3 pneumonitis and one had grade 3 skin rash. Chidamide combined with R-GDP is a safe and effective treatment option for patients with R/R DLBCL who are not eligible for autologous stem cell transplantation.

Association between body composition phenotypes and treatment toxicity in women with cervical cancer undergoing chemoradiotherapy

ObjectiveTo identify whether there is an association between body composition phenotypes and toxicity to chemoradiotherapy in women with cervical cancer. MethodsThis is a prospective cohort study that included 330 adult patients with cervical cancer treated with chemoradiotherapy. Computed tomography images were used to assess skeletal muscle index (SMI) and radiodensity (SMD), total adipose tissue index, and visceral adipose tissue index. Chemoradiotherapy toxicity was assessed weekly, and toxicity-induced modification of treatment (TIMT) was considered as any severe adverse event resulting in treatment interruption, delay, or dose reduction. ResultsApproximately 45% of the patients presented at least one unfavorable body composition parameter (lower SMI, lower SMD, higher total adipose tissue index, or higher visceral adipose tissue index), 23% had two conditions, and 3% had three conditions. The incidence of toxicity ≥ grade 3 and TIMT was 55% and 30%, respectively. For adverse events ≥ grade 3, lower SMI was the determining factor for worse outcomes when evaluated alone or combined with lower SMD and normal adiposity. All body composition phenotypes were associated with TIMT, increasing the risk when both conditions were present. ConclusionsLower SMI was an independent factor for the higher number of adverse events, as it remained a risk factor when analyzed in isolation or in association with adipose tissue. Women with excess adipose tissue associated with lower muscle mass had a risk approximately 4 times higher of delaying or interrupting chemoradiotherapy. Furthermore, for the sum of unfavorable conditions, there was a progressive increase in the risk of TIMT.

Evaluation of the Tolerability of Hedgehog Pathway Inhibitors in the Treatment of Advanced Basal Cell Carcinoma: A Narrative Review of Treatment Strategies.

Hedgehog pathway inhibitors (HHIs) have broadened the treatment options available for patients with advanced basal cell carcinoma (BCC) for whom traditional therapeutic approaches are not feasible or effective. Sonidegib and vismodegib are oral HHIs that were approved for treatment of patients with advanced BCC after demonstrating promising efficacy in the pivotal Phase II BOLT (NCT01327053) and ERIVANCE (NCT00833417) trials, respectively. However, the incidence and types of treatment-emergent adverse events (AEs) observed with these agents may limit continuous use of HHIs and ultimately impact clinical outcomes. In this review, we summarize the safety and tolerability profiles of sonidegib and vismodegib and discuss potential management strategies for HHI class-effect AEs, including muscle spasms, creatine phosphokinase increase, alopecia, and dysgeusia. These AEs primarily occur early in treatment and can lead to treatment discontinuation. Differences in the pharmacokinetic profiles of sonidegib and vismodegib may contribute to the variability noted in times to onset and resolution of these and other AEs. Evidence suggests that protocol modifications, such as treatment interruptions and dose reductions, are effective ways to manage AEs while maintaining disease control. Nonpharmacologic and pharmacologic interventions may also be considered as part of an AE management strategy. Overall, healthcare providers and patients with advanced BCC should be aware of the HHI class-effect AEs and plan effective management strategies to avoid treatment discontinuation and optimize therapeutic response.

Symptom management through electronic patient-reported outcome (ePRO)-based intervention in patients with breast cancer treated with abemaciclib: Primary results from the LIBRA study, a phase II randomized controlled trial.

11110 Background: We have developed a system using LINE, a widely-used social network service in Japan, for rapid collection of ePROs based on the PRO-CTCAE criteria. To evaluate the effectiveness of intervention through this system in reducing diarrhea frequency and enhancing quality of life (QOL) in patients treated with abemaciclib, we conducted a randomized controlled trial. Methods: Patients with hormone receptor-positive advanced breast cancer scheduled to begin abemaciclib treatment were randomized to the intervention and control arms with 1:1 ratio. The LINE-ePRO system was used to monitor symptoms daily in both arms. In the intervention arm, expert medical staffs contacted patients via phone when symptoms met certain criteria, whereas patients in the control arm received standard care. The primary endpoint was the increase in the number of defecations from baseline during 28 days. The secondary endpoints included the increase in the number of defecations from baseline during 56 days, other symptoms monitored via the LINE-ePRO system, QOL evaluated by EORTC QLQ C-30 and EQ-5D-5L, relative dose intensity (RDI), treatment interruption rate, progression-free survival (PFS), and overall survival (OS). This study (LIBRA, UMIN000045432) is funded by Eli Lilly. Results: Between Jan 2022 and Apr 2023, 60 women were enrolled and 58 (29 in each arm) were analyzed in this study. Median age was 57.5 years (range 43-80), 93% of patients were post-menopausal, 71% received abemaciclib as first-line treatment, and 74% were treated in combination with aromatase inhibitors. The increase in the number of defecations from baseline was significantly lower in the intervention arm compared to the control arm both during 28 days (0.64 vs. 1.21 per day, p=0.003) and during 56 days (0.55 vs. 1.18 per day, p=0.0004). No significant difference was observed in other symptoms between the arms. In the EORTC QLQ C-30 scales, global health status/QOL (mean score change from baseline to after one cycle of abemaciclib treatment: 0 vs. -13.5, p=0.038) and diarrhea (20.7 vs. 32.2, p=0.049) were better in the intervention arm. The treatment interruption and dose reduction rates were 41.4 and 31.0% in the intervention arm, and 31.0 and 27.6% in the control arm, respectively. The mean RDI of abemaciclib was numerically lower in the intervention arm (73.5% vs. 84.8%). Conclusions: This study is the first randomized trial to demonstrate that the intervention based on daily ePROs reduces the frequency of diarrhea in patients with advanced breast cancer treated with abemaciclib. Clinical trial information: UMIN000045432.

First-in-human phase 1 trial of the safety, tolerability, pharmacokinetics of BY101298: Initial report from dose escalation cohort.

e15132 Background: Radiotherapy (RT) is a cornerstone of cancer treatment, leveraging the effect of ionizing radiation to induce DNA damage, primarily through DNA double-strand breaks (DSBs). Non-homologous end joining (NHEJ) stands as the predominant pathway for repairing DSBs, with DNA-dependent protein kinases (DNA-PK) playing a pivotal role in NHEJ pathway. DNA damage repair can compromise tumor cells sensitivity to RT, potentially leading to the development of radiation resistance. BY101298, an innovative and highly selective DNA-PK inhibitor, works to diminish DSBs repair. In synergy with RT or chemotherapy, BY101298 enhances tumor cells eradication, preventing local recurrence and metastasis, thereby improving clinical benefits for cancer patients. Methods: This phase Ⅰa multicenter, open-label, dose-escalation study assessed the safety, tolerability, and clinical efficacy of BY101298. Oral doses ranged from (50 mg to 400 mg once/day [QD]) in continuous 28-day cycles. Primary outcome was safety and tolerability; secondary outcome was PK; exploratory outcome was DNA-PK phosphorylation (PD). Adverse events (AEs) were monitored per the Common Terminology Criteria for Adverse Events (CTCAE version5.0). Responses were assessed every other cycle using Response Evaluation Criteria in Solid Tumors (RECIST version 1.1). Results: Data from 9 pts with advanced solid tumors (cutoff: 26 December 2023; 2 men, 7 women; median age 58.0) revealed a linear increase in BY101298 AUC exposure and Cmax with dose escalation. Daily dosing for 15 consecutive days showed no AUC increase. Serum drug concentration correlated significantly with DNA-PK phosphorylation. All pts, previously systemic treated, received doses of 50 mg QD (n = 2), 100 mg QD (n = 3), and 200 mg QD (n = 4). Median treatment duration was 30 days (range: 1-57), with one patient (11.1%) continuing. Median relative dose intensity was 100%. Common treatment-related AEs (≥25%), primarily grade 1, included hypoalbuminemia (n = 5, 55.56%); anemia (n = 4, 44.44%); nausea (n = 3, 33.33%); weight decreased (n = 3, 33.33%). No pts experienced ≥Gr3 AEs. Two pts experienced serious AEs (none of which were considered treatment-related). No treatment discontinuations, dose reductions, or deaths attributed to treatment-related. The final dose group, representing the fourth cohort, is scheduled to commence shortly and is expected to conclude in April as per our estimation. Conclusions: In pts with advanced solid tumors, BY101298 exhibits a favorable safety profile and manageable toxicity. Vomiting was noted as a potential risk associated with BY101298. Further studies are imperative to elucidate the efficacy of BY101298 in combination with radiotherapy among pts with advanced solid tumors. Research Sponsor: This study received support from Chengdu Baiyu Pharmaceutical Co., Ltd. Clinical trial information: CTR20230997.

Adverse events of patients treated with antibody-drug conjugates in phase 1 clinical trials at the Royal Marsden Drug Development Unit from 2014 to 2024.

e15020 Background: Antibody-drug conjugates (ADCs) are designed to improve therapeutic indices of cytotoxic agents. Nevertheless, they may induce unexpected toxicities not observed with parent payloads. This study aimed to characterize the adverse events (AEs) seen in patients treated with ADCs in Phase 1 trials at The Royal Marsden Drug Development Unit (DDU). Methods: This is a retrospective cohort analysis of consecutive patients who received at least one dose of an ADC in a phase I trial from January 2014 to January 2024 at The Royal Marsden DDU. Descriptive statistics of patient characteristics, ADCs, and treatment-related AEs were performed. Univariate and multivariate logistic regression will be utilized to assess correlations among patient and ADC characteristics and adverse events. P values of < 0.05 will be considered significant. Results: A total of 131 patients who participated in twelve ADC trials were included. The median age of participants was 63 years (range: 31-84) and 61% were females. Patients received a median of three prior lines of systemic treatment. The most common type of ADC target, antibody, linker and payload were receptor tyrosine kinase (51%), humanized IgG monoclonal antibody (69%), valine-citrulline (VC) cleavable linker (85%), and a tubulin-binding payload (59%), respectively. Most patients received an ADC dose of 1-3 mg/kg (76%) with each cycle given once every 3 weeks (64%). The median number of cycles was 3 with an average treatment duration of 63 days. Within the cohort, 89% of patients developed any grade AE and 17% experienced grade 3 or higher AEs. The major treatment-related AEs were fatigue (48%), nausea/vomiting (27%), ocular toxicity (26%), neuropathy (26%), skin rash (20%) and pneumonitis (8%). The median time to first onset of treatment-related adverse events were 37 days for ocular toxicity, 46 days for pneumonitis, and 54 days for neuropathy. ADC-related AEs led to treatment interruptions (51%), dose reductions (13%), and treatment discontinuations (28%). Two treatment-related grade 5 events occurred. The objective response rate was 18%, with 1 complete response and 22 partial responses. Conclusions: Despite being designed to minimize side effects, ADCs were associated with significant toxicities, including unexpected adverse events unrelated to target, antibodies or the payloads, limiting their therapeutic indices. Further analysis of the relationship between different components of the wide range of ADCs and AEs are warranted to better understand the potential mechanisms of ADC toxicity.

Hematologic Toxicity and Bone Marrow-Sparing Strategies in Chemoradiation for Locally Advanced Cervical Cancer: A Systematic Review.

The standard treatment for locally advanced cervical cancer typically includes concomitant chemoradiation, a regimen known to induce severe hematologic toxicity (HT). Particularly, pelvic bone marrow dose exposure has been identified as a contributing factor to this hematologic toxicity. Chemotherapy further increases bone marrow suppression, often necessitating treatment interruptions or dose reductions. A systematic search for original articles published between 1 January 2006 and 7 January 2024 that reported on chemoradiotherapy for locally advanced cervical cancer and hematologic toxicities was conducted. Twenty-four articles comprising 1539 patients were included in the final analysis. HT of grade 2 and higher was observed across all studies and frequently exceeded 50%. When correlating active pelvic bone marrow and HT, significant correlations were found for volumes between 10 and 45 Gy and HT of grade 3 and higher. Several dose recommendations for pelvic bone and pelvic bone marrow sparing to reduce HT were established, including V10 < 90-95%, V20 < 65-86.6% and V40 < 22.8-40%. Applying dose constraints to the pelvic bone/bone marrow is a promising approach for reducing HT, and thus reliable implementation of therapy. However, prospective randomized controlled trials are needed to define precise dose constraints and optimize clinical strategies.

Abstract PO5-17-04: Tolerability of pertuzumab in older adults with HER2 positive breast cancer: A single institution experience

Abstract Background: Tumor HER2 over-expression occurs in 10 to 15% of older adults with breast cancer (BC). Combination HER2-directed therapy (pertuzumab and trastuzumab) with chemotherapy (CT) is the standard treatment for early and advanced HER2-positive bc. However, a study of more than 1,300 Medicare beneficiaries showed that about half of patients (pts) aged 65 or older with stage I to III HER2 positive bc did not receive trastuzumab-based therapy. This is likely due to concern for tolerability as older women remain underrepresented in clinical trials of breast cancer making it difficult to extrapolate tolerability of these agents in these patients. In the Neosphere and TRYPHAENA studies, the mean age of pts were 49.8 and 50.6 years, respectively. We examined the real-world tolerability of pertuzumab in combination with trastuzumab and systemic ct in women over the age of 65 with HER2 positive bc. Methods: An IRB approved retrospective review of medical records was conducted evaluating pts over the age of 65 with early or advanced HER2 positive bc treated at The Ohio State University Comprehensive Cancer center from January 1, 2015 to May,1 2020. Descriptive statistics (means, standard deviations, medians and ranges for continuous variables and frequencies and percents for categorical variables) were used to summarize disease and patient characteristics for pts enrolled in this study and treated with pertuzumab. The total number of planned and completed cycles of treatment as well as the number of treatment delays and dose reductions were also summarized using frequencies and percentages. The same descriptive statistics were used to summarize the number of grade II or IV toxicities and pathologic complete response (pCR) in the neoadjuvant setting. Results: A total of 71 pts met inclusion criteria. Mean age was 76 years (SD 4.1). Of these pts, 62 had stage I-III disease and 9 had metastatic disease. Additionally, 68% (48/71) had estrogen positive (ER) disease whereas 32% (23/71) had ER negative disease. Neoadjuvant systemic therapy was provided to 81% (50/62) of non-metastatic pts and 19% (12/62) received adjuvant therapy. The median number of completed neoadjuvant cycles (ct plus trastuzumab and pertuzumab) was 5.4 (SD 1.5). Among those who received pertuzumab with systemic ct in the neoadjuvant setting, 46% (23/50) of pts achieved a pCR (56% for ER negative disease and 41% for ER positive disease) The median number of completed adjuvant cycles (ct plus trastuzumab and pertuzumab) was 4.9 (SD 2.0). Pts with stage I to III disease completed a mean of 8.6 (SD 5.0) targeted therapy cycles (pertuzumab/trastuzumab). Pts with metastatic disease had a median of 5.7 (SD 1.0) cycles of ct plus trastuzumab and pertuzumab and received a mean of 34.4 (SD 36.0) cycles of maintenance pertuzumab. Treatment delay by 7 or more days occurred in 11% (8/71) of pts whereas 25% (18/71) of pts discontinued pertuzumab early. Pertuzumab termination occurred due to toxicity in 44% (8/18), metastasis in 11% (2/18), and other causes in 44% (8/18) of cases. For toxicities, 2% (1/51) of patients reported grade 3 pain, 25% (2/8) reported grade 3 fatigue, and 12% reported grade 4 diarrhea (1/8) (Table 1). Conclusions: Our study showed that pertuzumab was well tolerated in older pts with bc in the real-world setting. However, 25 % of pts still discontinued pertuzumab early which illustrates the importance of identifying pts who are at higher risk for toxicities prior to starting treatment. Table 1 Reported adverse events in patients age 65 and older receiving pertuzumab Citation Format: Nicole Williams, Austin Warmbier, Dureti Doto, Marilly Palettas, Julie Stephens, Dionisia Quiroga, Kai Johnson, Ashley Pariser, Mathew Cherian, Sagar Sardesai, Daniel Stover, Margaret Gatti-Mays, Robert Wesolowski, Bhuvana Ramaswamy. Tolerability of pertuzumab in older adults with HER2 positive breast cancer: A single institution experience [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-17-04.

Abstract PO4-12-10: Sacituzumab Govitecan Toxicity Outcomes In Arab Patients with Metastatic Breast Cancer

Abstract Background: The Arab population is often underrepresented in clinical trials, which limits our knowledge of drug safety and efficacy in this population due to genetic variability that can affect drug metabolism and adverse events (AEs). Sacituzumab govitecan (SG) is approved for metastatic triple negative breast cancer (mTNBC), and recently hormone receptor positive metastatic breast cancer (HR+ MBC). Here we report toxicity outcomes and RDI in Arab population. Methods: A multi-center retrospective study of patients with mTNBC and HR+ MBC treated with SG from January 2021 until May 2023 was conducted. Demographics and clinical variables including site of metastases, prior lines of therapy, relative dose intensity (RDI), adverse events (AEs) were collected. For continuous variables, Mann-U Whitney and Kruskal Wallis tests were used to compare mean, median, standard deviation, and range. For categorical variables, Fisher's exact tests and Pearson Chi-square tests were used. SAS v9.4 was used to perform statistical analysis at a significance level of 0.05. Results: A total of 35 patients was enrolled. The median age at diagnosis of metastatic breast cancer was 39 years interquartile range (IQR) (35, 44). The median age at starting SG was 44.5 years IQR (38,50). The majority of patients (65%) had an Eastern Cooperative Oncology Group performance status (ECOG PS) of 1, (21%) of the patients had an ECOG PS of 0, and (15%) had an ECOG PS of 2. 48.6% received 3 or more lines of prior therapy in the metastatic setting while 51.4% received less than 3 lines of prior therapy in the metastatic setting. 77.1% of patients had 3 or &amp;gt; organs involved with metastatic disease, while 22.9% of patients had &amp;lt; 3 organ involved. The most common metastatic sites were the lung (54.3%), liver (62.9%), bone (68.6%), and brain (45.7%). The median RDI of SG was 100% for a sample of 34 individuals, with one missing value IQR (94%,100%). The rate of overall AEs was (77.1%), with the most common AEs being; neutropenia (44.4%), diarrhea (37.0%), anemia (22.2%), thrombocytopenia (22.2%), nausea (14.8%), and vomiting (7.4%). Garde 3 AEs rate was 34.3%. The most common grade 3 adverse events were diarrhea (11.4%), fatigue (5.7%), and alopecia (2.9%). The rate of treatment interruption and dose reduction due to AEs was 31.4%. Only one patient (2.9%) had to discontinue SG treatment due to adverse events. Conclusion: The study suggests that SG is safe and well-tolerated in young Arab patient population. The sample consisted of relatively young patients, which may reflect a reluctance to prescribe SG to older Arab patients. Caution should be exercised when generalizing the findings due to limitations of the study. Further studies with larger sample sizes are needed to validate these findings and to explore the efficacy of SG in Arab patients with mTNBC and HR+ MBC. Citation Format: Maymouna Altarturi, Kausar Suleman, Adhar AlSayed, Humaid Al-Shamsi, Aydah Alawadhi, Bassam Basuliamn, Sabah Alaklabi. Sacituzumab Govitecan Toxicity Outcomes In Arab Patients with Metastatic Breast Cancer [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-12-10.

Abstract PO4-17-12: Early adherence to adjuvant abemaciclib: Data from the Belgian Medical Need Program

Abstract Patient adherence profiles for adjuvant hormonal therapy combined with abemaciclib in HR+/HER2- High Risk EBC based on real world evidence (RWE) from a Medical Need Program in Belgium Background Following results of MonarchE, demonstrating clinically meaningful improvement in invasive disease-free survival (IDFS) and distant relapse-free survival (DRFS), a 2-year treatment with abemaciclib has been reimbursed in Belgium since May 1st, 2023 for the adjuvant treatment of HR+, HER2–, lymph node-positive (&amp;gt;3 or 1-3 if pT3 or grade 3) early breast cancer (EBC). In this trial, adverse event related treatment discontinuation was reported in 18,5% (8.9% after dose reduction) of which 10.1% in the first 5 months after starting this CDK 4/6 inhibitor. Prior to reimbursement, an early access program was initiated in Belgium on June 28 2022. We studied the proportion of patients estimated to be eligible for the program nationwide who effectively started adjuvant abemaciclib, as well as early treatment discontinuation and dose reductions. Methods The number of eligible patients for the adjuvant abemaciclib Medical Need Program (MNP) was estimated by the Belgian Cancer Registry based on the above mentioned reimbursement criteria for patients registered during the incidence year 2018. The MNP was active in Belgium from June 28 2022 until May 1 2023. Discontinuation rate and proportion with dose reductions were calculated using a nationwide prospective managed monthly updated register of participating patients including information on age at diagnosis, time since therapy start, delivered doses and patient reported adverse events (AE). They all signed an informed consent and agreed to share their registered data after anonymization. Data analysis was retrospective. Descriptive statistics were used. Results In this 10-month period, 840 patients were estimated to be eligible to receive adjuvant abemaciclib in Belgium. A total of 311 patients (309 women, 2 men) were included in the program, 37% of the estimated number of patients. Median age at initiation was 57 y. Median time on treatment was 4.5 months (156 patients &amp;gt;4.5 months on treatment). 21/311 (6.7%) patients discontinued (all causes). 2 patients never started. 10 patients (3.2%) discontinued their therapy without dose reduction. 12/311 (3.8%) had a starting dose of 2 × 100 mg/d. 128/311 (41.1%) had a dose reduction, 96/128 (75%) before 3 months of therapy. In the subgroup of 156 patients starting treatment &amp;gt;4.5 months ago, 16/156 (10.2%) discontinued treatment, 13 patients have not yet been reported. 79/156 (50.6%) required a dose reduction, of which 7 (4.5%) discontinued after dose reduction. The reasons for discontinuation reported: 8/21 (38%) gastro-intestinal intolerance, 3/21 (14.2%) real deterioration in renal function, 8/21 quality of life issues (not specified), 1/21 anal burning sensation and anal fistula, 3/21 asthenia and fatigue. Conclusion Of the estimated eligible patients in Belgium 37 % started with adjuvant abemaciclib. These results illustrate that there is a need to further improve implementation of adjuvant abemaciclib. Early results show that 89.8% of patients receiving adjuvant abemaciclib therapy in Belgium continued their treatment after 4.5 months and 50% of patients needed a dose reduction. Longer follow-up will be needed. Understanding the reasons of discontinuation and early dose adjustments can enable better patient support on adherence. This is a critical capability to ensure optimal patient compliance. Citation Format: Maxime Van Houdt, Marc Michaux, Sevilay Altintas, Ahmad Awada, Jean-Luc Canon, Hannelore Denys, François Duhoux, Guy Jerusalem, Jeroen Mebis, Rosanne Janssens, Isabelle Huys, Barbier Liese, Charlotte Verbeke, Sileny Han, Hans Wildiers, Patrick Neven. Early adherence to adjuvant abemaciclib: Data from the Belgian Medical Need Program [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO4-17-12.

Use of romiplostim for antineoplastic therapy-induced thrombocytopenia in gynecologic and breast cancers

ObjectiveRomiplostim is used to treat chemotherapy-induced thrombocytopenia in a variety of tumor types; however, few studies have examined its use in breast and gynecologic cancers. We evaluated platelet response and durability of response to romiplostim in patients with gynecologic or breast cancer complicated by chemotherapy-induced thrombocytopenia. MethodsWe retrospectively identified 33 patients with gynecologic or breast cancer who received romiplostim between 07/1/2021–07/31/2022 at an academic cancer center. ResultsThirty-three patients met inclusion criteria; 26 (79 %) had breast cancer, 4 (12 %) had ovarian cancer, and 3 (9 %) had endometrial cancer. Twenty patients (61 %) experienced treatment delays and 12 (36 %) required dose reductions prior to starting romiplostim for chemotherapy-induced thrombocytopenia, with some patients experiencing both. Eleven patients (33 %) did not undergo a dose reduction or delay prior to initiation of romiplostim. Median platelet count prior to romiplostim therapy was 53 k/mcL (range, 40.5–78.8). Median platelet count within 3 weeks following initiation of romiplostim was 147 k/mcL (range, 31–562). Twenty-one patients (64 %) achieved platelet correction within 3 weeks, of whom 10 (48 %) resumed anticancer therapy and maintained platelet levels above 100 k/mcL at 8 weeks. Twelve patients did not achieve platelet correction within 3 weeks of romiplostim initiation; 4 (33 %) required a treatment change secondary to persistent thrombocytopenia, 3 (25 %) required a treatment dose reduction, 3 (25 %) were deemed too ill to continue therapy, and 2 (17 %) required a treatment delay. ConclusionsRomiplostim facilitated the resumption of anticancer therapy in 64 % of patients with gynecologic or breast cancer complicated by chemotherapy-induced thrombocytopenia.

Pharmacist's role in the management of drug-drug interactions caused by nirmatrelvir/ritonavir in COVID-19 oncohematology patients.

New drugs developed for SARS-CoV-2 infection, such as nirmatrelvir/ritonavir (NMV/r), represent a potential for oncohematology patients, but also pose a challenge in managing the potential clinically relevant drug-drug interactions (pDDIs) that may arise. The aim of this study is to assess the frequency, severity, and pharmacist detection of pDDIs. This prospective, observational, study spanned 8 months, involving 42 oncohematology patients prescribed NMV/r in a tertiary-level hospital. A Board Certified oncology pharmacist assessed pDDIs using three databases and made recommendations to prescribing physicians. Linear and logistic regression analyses were employed to explore the relationship between prescribed drugs and pDDIs. Clinically relevant pDDIs were detected in 76.2% of patients, with 18.1% of all medications involved in drug-drug interactions (DDIs). The most common drugs implicated were atorvastatin and imatinib. Micromedex® identified 63.3% of interactions as major severity, while Lexicomp® and University of Liverpool classifications were less restrictive. Pharmacists prevented most DDIs from reaching patients through different interventions, including treatment monitoring (44.2%), discontinuation (36.5%), and dose reduction (17.3%). This study highlights the high prevalence of clinically significant pDDIs in oncohematology patients receiving NMV/r for COVID-19. Pharmacists, as integral members of the healthcare team, played a crucial role in detecting, categorizing, and mitigating these interactions. The results underscore the need for comprehensive studies to evaluate the impact of pharmacist-led interventions in optimizing drug therapy and enhancing patient safety in this vulnerable population.

Real‐world implementation of DPYD and UGT1A1 pharmacogenetic testing in a community‐based cancer center

AbstractWe set out to demonstrate the feasibility of pharmacogenetic testing of DPYD and UGT1A1 and explore the clinical benefits in a community‐based cancer center. We conducted a retrospective review of 280 patients who underwent pharmacogenetic testing between November 2020 and May 2023. The primary end points included the percentage of patients with results prior to chemotherapy initiation, percentage of DPYD‐ and UGT1A1‐guided interventions implemented before chemotherapy initiation, and the turnaround time (TAT) for the pharmacogenetics results. Exploratory end points included a comparison of unplanned hospitalizations and treatment interruptions among (1) DPD phenotypes in patients who received fluoropyrimidines and (2) UGT1A1 phenotypes in patients who received irinotecan ± fluoropyrimidines. We evaluated cancer progression among patients who received DPYD‐guided dose reductions in the curative setting. More than 75% of patients had results prior to initiation of chemotherapy and 61.5% of the actionable interventions were implemented before chemotherapy, with a median TAT of 7 calendar days (IQR 5–8 calendar days). A non‐significant higher percentage of unplanned hospitalizations and treatment interruptions occurred among patients with normal DPYD compared with patients with DPYD‐guided dose reductions. A non‐significant higher frequency of treatment interruptions and dose reductions were observed in UGT1A1 intermediate metabolizer (IM) compared with UGT1A1 normal metabolizer (NM). None of the patients who received DPYD‐guided dose reductions in the curative setting experienced progression after a median follow‐up of 342 days. The real‐world evidence generated from this study demonstrates the feasibility of pre‐chemotherapy pharmacogenetic testing of DPYD and UGT1A1 in a community‐based cancer center.

Effect of food on selumetinib pharmacokinetics and gastrointestinal tolerability in adolescents with neurofibromatosis type 1-related plexiform neurofibromas.

Selumetinib is approved for the treatment of pediatric patients with neurofibromatosis type 1 (NF1) who have symptomatic, inoperable plexiform neurofibromas (PN) in multiple countries, including the USA (≥ 2 years). Until recently, individuals had to take selumetinib twice daily (BID) in a fasted state. This study evaluated the effect of a low-fat meal on selumetinib PK parameters and gastrointestinal (GI) tolerability in adolescent participants with NF1-PN. Eligible participants aged ≥ 12 to< 18 years took 25mg/m2 selumetinib BID with a low-fat meal (T1) for 28 days, followed by a 7-day washout, and then administration in a fasted state (T2) for another 28 days. Primary objectives were to evaluate the effect of a low-fat meal on AUC0-12,ss and GI tolerability after multiple selumetinib doses in T1 versus T2. Key secondary objectives were additional PK parameters and adverse events (AEs). At primary data cut-off, all 24 participants completed T1, and 23 participants completed T2. There were no significant differences in AUC0-12,ss between T1 and T2. In T1 and T2, 29.2% and 33.3% participants, respectively, reported ≥ 1 GI AE. No GI AEs Grade ≥ 3, or serious AEs, or GI AEs resulting in treatment interruptions, discontinuation, or dose reductions were reported in T1 and T2. Dosing selumetinib with a low-fat meal had no clinically relevant impact on selumetinib AUC0-12,ss nor GI tolerability in adolescents with NF1-PN. NCT05101148.