Drug-related Treatment-emergent Adverse Events Research Articles

Interim analysis of the multinational, post-authorization safety study (NISSO) to assess the long-term safety of sonidegib in patients with locally advanced basal cell carcinoma.

Following the pivotal phase II trial BOLT, the Hedgehog (Hh) inhibitor sonidegib was approved in the EU to treat locally advanced basal cell carcinoma (laBCC) in patients not amenable to surgery or radiotherapy. We report safety data from the interim analysis of the real-world NISSO study. NISSO is an ongoing non-interventional, multinational, post-authorization safety study (NCT04066504). Patients with laBCC are treated with sonidegib 200mg orally once daily and followed for 3years. Dose modifications were allowed according to the local prescribing information. Between May 6, 2019, and March 15, 2022, 321 patients with laBCC were enrolled at 46 European sites (data cut-off: June 22, 2023). Treatment was discontinued in 241 (75.1%) patients, with the main reasons being the patient/guardian decision (n = 69, 28.6%), treatment success (n = 40, 16.6%) and the physician decision (n = 35, 14.5%). The median duration of sonidegib exposure was 8.8months (4.4-13.7months). Overall, 284 (88.5%) patients had ≥ one treatment-emergent adverse event (TEAE). Most TEAEs were ≤ grade 2 and the most common were muscle spasms (n = 141; 43.9%), dysgeusia (n = 119; 37.1%), and alopecia (n = 97; 30.2%). After 3months of treatment, the cumulative rates of muscle spasms, dysgeusia, and alopecia were 21.8%, 16.2%, and 3.7%, respectively. TEAEs led to treatment discontinuation in 59 (18.4%) patients, while 149 (46.4%) patients had at least one TEAE leading to dose reduction or interruption. Serious drug-related TEAEs were reported in 13 (4.1%) patients. These results confirm the safety profile previously observed. Most patients experienced the onset of common TEAEs after 3months of treatment, and the cumulative incidence of most common TEAEs was 10-20% lower compared to the BOLT study, except for dysgeusia and fatigue that had a similar incidence. The percentage of patients experiencing TEAEs requiring interruption or dose reduction was similar to the BOLT study, while the proportion of patients with TEAE leading to discontinuation of sonidegib was lower. This study demonstrates that the tolerability of sonidegib is manageable in routine clinical practice. NCT04066504.

Safety, outcomes, and pharmacokinetics of isavuconazole as a treatment for invasive fungal diseases in pediatric patients: a non-comparative phase 2 trial.

Invasive aspergillosis (IA) and mucormycosis (IM) cause significant morbidity and mortality in immunocompromised and/or hospitalized patients. Isavuconazonium sulfate, a prodrug of the antifungal triazole isavuconazole, has been approved for treatment of IA and IM in adults; and was recently approved in children. This study describes the outcomes, safety, and pharmacokinetics of isavuconazole for the treatment of proven, probable, or possible IA or IM in children. In this phase 2, open-label, non-comparative study, patients aged 1 to <18 years with at least possible invasive mold disease were enrolled across 10 centers in the US, Spain, and Belgium from 2019 to 2022. Patients received 10 mg/kg isavuconazonium sulfate daily (maximum 372 mg; equivalent to 5.4 mg/kg or 200 mg isavuconazole) for up to 84 (IA) or 180 days (IM). Outcomes included rates of all-cause case fatality, overall response, treatment-emergent adverse events (TEAEs), and pharmacokinetics. Of 31 patients enrolled, 61.3% were 1-<12 years old; 58.1% had underlying hematologic malignancies. The successful overall response rate at the end of treatment was 54.8%. Day 42 all-cause case fatality was 6.5%; 93.5% experienced TEAEs, and two patients discontinued treatment due to drug-related TEAEs. Dosing at 10 mg/kg (maximum dose: 372 mg) met the pre-defined exposure threshold of above the 25th percentile for the area under the concentration-time curve (≥60 mg·h/L). Simulated doses of 15 mg/kg improved drug exposures in patients aged 1-<3 years. Isavuconazole was well tolerated in children, with exposure consistent with adult studies. Successful response was documented in 54.8% of patients.CLINICAL TRIALSThis study is registered at ClinicalTrials.gov as NCT03816176.

Abstract 4134320: Integrated safety and tolerability of mavacamten treatment over 5 years in patients with obstructive hypertrophic cardiomyopathy

Background: Mavacamten, a cardiac myosin inhibitor, is approved across 5 continents for the treatment of obstructive hypertrophic cardiomyopathy (HCM). Long-term data of mavacamten are available from multiple studies, providing the opportunity to further understand mavacamten long term safety, including adverse events (AEs) of clinical interest. Aim: To present integrated safety data of patients who received mavacamten treatment for obstructive HCM across 5 studies. Methods: The pooled population included all patients who received ≥1 dose of mavacamten in PIONEER-HCM, PIONEER-Open Label Extension (data cut-off: May 31, 2022), EXPLORER-HCM, MAVA-Long-Term Extension (EXPLORER cohort; data cut-off: August 31, 2023) and VALOR-HCM including long-term extension (data cut-off: November 11, 2022). Results: The population consisted of 368 patients (mean [SD] age: 59.4 [12.2] years; male: 57.1%; White: 90.8%), including 350 patients who continued onto an extension study after completing a parent study. The majority of patients (57.6%) had a cumulative time on study of ≥3 years. Forty (10.9%) patients permanently discontinued treatment (13 due to AEs). In total, 20.7% of patients had a treatment emergent AE (TEAE) of Grade ≥3 and 14.7% had a TEAE leading to drug interruption. Overall, 4.3% of patients had drug-related serious TEAEs and 1.6% had a TEAE leading to death. The cumulative exposure adjusted incidence rates (EAIR) of all TEAEs, including AEs of clinical interest (atrial fibrillation [AF], ejection fraction [EF] decreased and heart failure [HF]), decreased as exposure increased over time, from 347.1/100 patient-years (P-Y) at Week 60 (~year 1) to 271.8/100 P-Y at Week 252 (~year 5). The EAIR of AF decreased over time from 13.3/100 P-Y at Week 60 (~year 1) to 6.2/100 P-Y at Week 252 (~year 5) ( Figure ). The EAIR for EF decreased and HF also decreased over time ( Figure ). Conclusions: This integrated analysis of all patients with obstructive HCM treated with mavacamten across the 5 clinical studies over 5 years demonstrated that mavacamten treatment is generally well tolerated and that the EAIRs of selected TEAEs of clinical interest (AF, EF decreased and HF) decreased as exposure increased over time.

Early sedation using ciprofol for intensive care unit patients requiring mechanical ventilation: a pooled post-hoc analysis of data from phase 2 and phase 3 trials

BackgroundCiprofol was approved for use in intensive care unit (ICU) patients requiring sedation during mechanical ventilation in July 2022. A pooled post-hoc analysis of phase 2 and phase 3 trials was conducted primarily to explore hypotension-free outcome in ICU patients who required mechanical ventilation and achieved the target light sedation goal at an early stage after being sedated with ciprofol or propofol.MethodsAll eligible ICU patients who were expected to require sedation for 6–24 h were randomly assigned in a 2:1 ratio to either a ciprofol or propofol group. Ciprofol or propofol was initially infused at loading doses of 0.5 or 1.0 mg/kg followed by maintenance doses of 0.3 or 1.5 mg/kg/h. Ciprofol or propofol dosages were adjusted up or down at rates of 0.05–0.10 mg/kg/h or 0.25–0.50 mg/kg/h, respectively, to achieve the target light sedation (a Richmond Agitation-Sedation Scale of -2 to + 1). The primary post-hoc outcome was the hypotension-free rate in patients who had achieved the target sedation goal after 30-min administration of ciprofol or propofol.ResultsIn total, 174 patients were enrolled for pooled post-hoc analysis, of whom 116 and 58 were assigned to the ciprofol and propofol groups, respectively. The hypotension-free rate was significantly higher in patients who achieved the target sedation goal after 30-min administration of ciprofol (93.0% vs. 81.0%, P = 0.018), and especially in the subgroups of males and patients aged < 65 years. Multivariable analysis revealed that ciprofol treatment, a younger age and lower baseline body mass index were independent favorable predictors for a higher hypotension-free rate in patients who achieved the target sedation goal after 30-min of drug administration. Moreover, hypotension-free patients who reached the target sedation level after 30 min had a more favorable short-term prognosis including a lower incidence of drug-related treatment-emergent adverse events, shorter time to extubation and fewer dose adjustments of ciprofol or propofol (all P < 0.05).ConclusionICU patients undergoing mechanical ventilation and sedated with ciprofol had significantly lower rate of hypotension during the early phase of achieving light sedation during a 6–24 h period, leading to a more favorable short-term prognosis (within 24 h).Trial registrationPhase 2 trial (clinicaltrials.gov, NCT04147416. Registered November 1, 2019, https://classic.clinicaltrials.gov/ct2/show/NCT04147416) and phase 3 trial (clinicaltrials.gov, NCT04620031. Registered November 6, 2020, https://classic.clinicaltrials.gov/ct2/show/NCT04620031).

A Phase3, Open-Label, Single-Arm Trial of the Efficacy and Safety of Triptorelin 6-Month Formulation in Chinese Children with Central Precocious Puberty.

This phase3 study assessed the efficacy, safety, and pharmacokinetics of the 6-month prolonged release (PR) formulation in Chinese children with central precocious puberty (CPP). In this open-label study (NCT05029622), Chinese children (girls < 9years, boys < 10years) received two doses of triptorelin pamoate 22.5mg (day1 and month6). Primary endpoint was the proportion at month6 with luteinizing hormone (LH) suppression (stimulated peak LH ≤ 5IU/L after gonadotropin-releasing hormone stimulation). Secondary endpoints included safety assessments, hormone level changes, and clinical parameters from baseline. Overall, 66 children completed the study (93.9% girls; median age 8.0 [range 5-9] years). At month6, all patients had LH suppression; this was maintained at month12 in 98.5% of patients. Mean basal and peak LH and follicle-stimulating hormone levels were suppressed throughout follow-up. All patients at months3 to 12had sex hormone suppression to prepubertal levels. Stable or reduced breast development was seen for 98.4% and 93.5% of girls at month6 and 12, respectively; all boys had regression or stable genital development until month12. Compared with baseline (9.82cm/year), mean growth velocity was 5.88cm/year at month6 and 5.17cm/year at month12. Mean bone age/chronological age ratio decreased from 1.27 at baseline to 1.23 and 1.21 at month6 and 12, respectively. In girls, 64.5% showed decreased uterine length at month6 and 12 versus baseline, while 75.0% of boys showed stable testicular volume versus baseline. Thirteen patients (19.7%) had 22 drug-related treatment emergent adverse events (TEAEs); no grade ≥ 3 TEAEs were reported. The efficacy and safety profile of triptorelin 6-month PR in Chinese children with CPP was consistent with data previously reported in non-Chinese children with CPP, supporting this as a viable treatment option for Chinese children with CPP. Trial registration:ClinicalTrials.gov identifier, NCT05029622.

Phase 1b study of the anti-CD38 antibody mezagitamab in patients with relapsed/refractory multiple myeloma

AbstractThis phase 1b trial aimed to determine the safety, tolerability, and preliminary efficacy of mezagitamab, a subcutaneously administered anti-CD38 monoclonal antibody, in patients with relapsed/refractory multiple myeloma (RRMM). Eligible patients had received ≥3 prior lines of treatment, including an immunomodulatory drug (IMiD), a proteasome inhibitor (PI), and a steroid, or ≥2 prior lines in which 1 included a PI + IMiD, and were refractory or intolerant to ≥1 IMiD and ≥1 PI. Fifty patients were enrolled: 44 received mezagitamab monotherapy (dose-escalating cohorts at 45-1200 mg) and 6 received mezagitamab 300 mg in combination with pomalidomide plus dexamethasone. Patients received mezagitamab weekly for 8 doses, every other week for 8 doses, and monthly thereafter. No dose-limiting toxicities were reported with single-agent mezagitamab, and the recommended phase 2 dose was determined as 600 mg. The most common drug-related treatment-emergent adverse events (TEAEs) were fatigue in the monotherapy cohort (9/44 patients) and neutropenia in the combination cohort (4/6 patients); neutropenia was the only drug-related grade ≥3 TEAE to occur in >1 patient. No infusion reactions occurred, and 4 injection-site reactions were reported. Three patients discontinued treatment due to TEAEs. Among the 22 patients receiving 600 mg mezagitamab, the overall response rate was 47%, and the median duration of response was 22.1 months. Mezagitamab had a manageable safety profile and activity in patients with RRMM, with comparable outcomes to those reported with other anti-CD38 therapies in patients with advanced RRMM. Further development of mezagitamab in myeloma is not planned, but given its encouraging safety, studies are underway in autoimmune conditions with underlying abnormal autoantibodies. This trial was registered at www.ClinicalTrials.gov as #NCT03439280.

Trastuzumab deruxtecan in patients with HER2-positive advanced colorectal cancer (DESTINY-CRC02): primary results from a multicentre, randomised, phase 2 trial

Trastuzumab deruxtecan has shown encouraging activity in patients with treatment-refractory HER2-positive, RAS wild-type and BRAF wild-type metastatic colorectal cancer. Dose optimisation and further antitumour assessments in patients with RAS mutations and those with previous anti-HER2 therapy are warranted. We aimed to evaluate two doses of trastuzumab deruxtecan (5·4 mg/kg and 6·4 mg/kg) to establish the recommended dose in patients with pretreated HER2-positive, RAS wild-type or mutant metastatic colorectal cancer. DESTINY-CRC02 was a multicentre, randomised, two-stage, two-arm, phase 2 study done in 53 research hospitals and medical centres in Australia, Belgium, France, Italy, Japan, South Korea, Spain, Taiwan, the UK, and the USA. Eligible patients were aged 18 years and older or 20 years and older (depending on region) with pretreated pathologically documented, unresectable, recurrent, or metastatic HER2-positive, and RAS wild-type or mutant colorectal cancer. Patients were required to have an Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1 and have received previous chemotherapy, and anti-EGFR, anti-VEGF, or anti-PD-L1 therapy, if clinically indicated. In stage 1, patients were randomly assigned (1:1), via a secure interactive response technology system, to receive 5·4 mg/kg or 6·4 mg/kg trastuzumab deruxtecan administered intravenously every 21 days. Stratification factors were ECOG performance status, HER2 status, and RAS status. In stage 2, patients were assigned into the 5·4 mg/kg treatment group only. The primary endpoint was confirmed objective response rate by blinded independent central review, assessed in all patients for whom treatment was assigned (full analysis set). Safety was assessed in all patients who received at least one dose of study drug. This trial is registered with ClinicalTrials.gov, NCT04744831, and is ongoing (not recruiting). Between March 5, 2021, and March 29, 2022, 135 patients were centrally screened, 122 of whom were enrolled. In stage 1, 40 patients each were randomly assigned to receive trastuzumab deruxtecan 5·4 mg/kg and 6·4 mg/kg. In stage 2, an additional 42 patients were enrolled in the 5·4 mg/kg group. 64 (52%) participants were male and 58 (48%) were female. The median duration of follow-up was 8·9 months (IQR 6·7-10·5) in the 5·4 mg/kg group and 10·3 months (5·9-12·7) in the 6·4 mg/kg group. The confirmed objective response rate by blinded independent central review was 37·8% (31/82 [95% CI 27·3-49·2]) in the 5·4 mg/kg group and 27·5% (11/40 [14·6-43·9]) in the 6·4 mg/kg group. 34 (41%) of 83 patients in the 5·4 mg/kg group and 19 (49%) of 39 in the 6·4 mg/kg group had grade 3 or worse drug-related treatment-emergent adverse events. The most common grade 3 or worse drug-related treatment-emergent adverse events were neutrophil count decreased (13 [16%] of 83 patients), anaemia (six [7%]), nausea (six [7%]), and white blood cell count decreased (five [6%]) in the 5·4 mg/kg group; and were neutrophil count decreased (10 [26%] of 39 patients), anaemia (eight [21%]), platelet count decreased (four [10%]), and white blood cell count decreased (four [10%]) in the 6·4 mg/kg group. Drug-related serious adverse events occurred in 11 (13%) of 83 patients in the 5·4 mg/kg group and six (15%) of 39 patients in the 6·4 mg/kg group; the most common in the 5·4 mg/kg group was nausea (three [4%] patients) and the most common in the 6·4 mg/kg group were fatigue (two [5%] patients), neutropenia (two [5%]), and thrombocytopenia (two [5%]). A drug-related treatment-emergent adverse event related to death occurred in one (1%) patient in the 5·4 mg/kg group (due to hepatic failure). Adjudicated drug-related interstitial lung disease or pneumonitis events were observed in seven (8%) patients in the 5·4 mg/kg group (all grade 1 or 2) and in five (13%) patients in the 6·4 mg/kg group (four grade 1 or 2; one grade 5). The promising antitumour activity and favourable safety profile support trastuzumab deruxtecan 5·4 mg/kg as the optimal single-agent dose for patients with pretreated HER2-positive metastatic colorectal cancer, including those with RAS mutations, previous anti-HER2 therapy, or both. Daiichi Sankyo and AstraZeneca.

ISIS 449884 Injection Add-On to Metformin in Patients with Type 2 Diabetes: A Randomized, Double-Blind, Placebo-Controlled, Phase II Clinical Study.

ISIS 449884, a 2'-O-methoxyethyl antisense oligonucleotide that targets the glucagon receptor (GCGR), has demonstrated an ability to reduce hepatic glucose output and lower the blood glucose level. The primary objective of this study was to investigate the safety and efficacy of ISIS 449884 as an add-on to metformin in a population of Chinese patients with type 2 diabetes mellitus (T2DM). This was a multicenter, placebo-controlled (2:1), randomized, double-blind, parallel-enrollment, multiple-dose phase II study in Chinese patients with T2DM. A total of 90 patients who were uncontrolled by stable metformin monotherapy were randomized into three cohorts. Thirty subjects were enrolled in each cohort and received injections of ISIS 449884 (50mg or 60mg weekly or 100mg every other week) or a corresponding volume of placebo (0.25mL and 0.3mL weekly or 0.5mL every other week) subcutaneously in a 2:1 ratio for 16weeks. The primary efficacy endpoint was analyzed in 88 subjects (ISIS 449884, n = 59; placebo, n = 29). The corrected LS mean change from baseline in glycated hemoglobin (HbA1c) at week 17 in the pooled ISIS 449884 treatment group was -1.31% (95% CI -1.66%, -0.96%), and that in the pooled placebo group was 0.15% (95% CI -0.37%, 0.66%). The LS mean difference between the two groups was -1.46% (95% CI -1.92%, -1.00%, P < 0.001). Treatment-emergent adverse events (TEAEs) occurred in 53/60 subjects (88.3%) and 25/30 subjects (83.3%) in the pooled ISIS 449884 treatment group and the pooled placebo group, respectively, with similar incidences. Drug-related TEAEs occurred in 41/60 subjects (68.3%) and 9/30 subjects (30.0%), respectively. TEAEs of grade 3 or higher occurred in 5/60 (8.3%) subjects and 2/30 (6.7%) subjects, respectively, and none of them were drug related. The ISIS 449884 injection add-on to metformin significantly reduced HbA1c in patients with T2DM uncontrolled by stable metformin monotherapy and showed an acceptable benefit/risk profile. www.chinadrugtrials.org.cn , CTR20191096.

Trastuzumab deruxtecan versus trastuzumab emtansine in Asian patients with HER2-positive metastatic breast cancer.

The global phase 3 DESTINY-Breast03 study (ClinicalTrials.gov; NCT03529110) showed statistically significant and clinically meaningful improvements in progression-free survival (PFS) and overall survival (OS) with trastuzumab deruxtecan (T-DXd) over trastuzumab emtansine (T-DM1) in patients with human epidermal growth factor receptor 2 (HER2)-positive metastatic breast cancer (mBC) previously treated with trastuzumab and a taxane. Here, we report a subgroup analysis of Asian patients enrolled in DESTINY-Breast03. In total, 309 patients (149 in the T-DXd arm and 160 in the T-DM1 arm) from Asian countries and regions were randomized. At data cutoff (July 25, 2022), the median duration of follow-up in the Asian subpopulation was 29.0 months with T-DXd and 26.0 months with T-DM1. The PFS (determined by blinded independent central review) hazard ratio was 0.30 (95% confidence interval 0.22-0.41) favoring T-DXd over T-DM1 (median PFS 25.1 vs. 5.4 months). Median OS was not reached in the T-DXd arm and was 37.7 months in the T-DM1 arm. The median treatment duration was 15.4 months with T-DXd and 5.5 months with T-DM1. The incidence of grade ≥3 drug-related treatment-emergent adverse events was similar between both treatment arms (49.0% vs. 46.5%) and was consistent with the overall DESTINY-Breast03 population. Adjudicated drug-related interstitial lung disease or pneumonitis occurred in 12.9% of patients treated with T-DXd and 2.5% treated with T-DM1, with a higher incidence in Japanese patients; none of these were grade ≥4 events. These efficacy and safety data reinforce the favorable benefit-risk profile of T-DXd in HER2-positive mBC, including in the Asian subgroup.

Trastuzumab deruxtecan versus treatment of physician’s choice in previously treated Asian patients with HER2-low unresectable/metastatic breast cancer: subgroup analysis of the DESTINY-Breast04 study

BackgroundIn the global phase 3 DESTINY-Breast04 study (NCT03734029), the anti-human epidermal growth factor 2 (HER2) antibody–drug conjugate trastuzumab deruxtecan (T-DXd) demonstrated a statistically significant improvement in progression-free survival (PFS) and overall survival (OS), with manageable safety compared with treatment of physician’s choice (TPC) in patients with HER2-low metastatic breast cancer (mBC) who had received 1–2 prior lines of chemotherapy.MethodsThis subgroup analysis examined the efficacy and safety of T-DXd versus TPC in 213 patients from Asian countries and regions who were enrolled in the DESTINY-Breast04 trial and randomized to T-DXd (n = 147) or TPC (n = 66).ResultsMedian PFS with T-DXd and TPC was 10.9 and 5.3 months, respectively, in Asian patients with hormone receptor-positive mBC, and 10.9 and 4.6 months, respectively, in the overall Asian population. In both populations, median OS was not reached with T-DXd and was 19.9 months with TPC. The objective response rate was higher with T-DXd versus TPC in all Asian patients. Median treatment duration was 8.4 months with T-DXd and 3.5 months with TPC. The most common grade ≥ 3 drug-related treatment-emergent adverse events in Asian patients treated with T-DXd were neutropenia (16.3%), anemia (12.9%), and leukopenia (11.6%); the incidences of neutropenia and leukopenia were higher with TPC versus T-DXd. Adjudicated drug-related interstitial lung disease or pneumonitis with T-DXd was 14.3%; the majority of events were grade 1–2.ConclusionsT-DXd demonstrated clinically meaningful survival benefits versus TPC in Asian HER2-low mBC patients, regardless of hormone receptor status, with no new safety signals.Clinical trial registration numberClinicalTrials.gov, NCT03734029.

International, open-label phase 2 study of regorafenib plus pembrolizumab in patients with advanced hepatocellular carcinoma (HCC) previously treated with immune checkpoint inhibitors (ICI).

4007 Background: The optimal second-line treatment for HCC after ICI is not established. Regorafenib is approved for treatment of advanced HCC after sorafenib. The primary aim of this study was to evaluate the activity of regorafenib plus pembrolizumab in patients with advanced HCC who progressed on only one prior ICI regimen. Methods: Patients aged ≥18 years, CP Class A, BCLC stage B or C, and ECOG PS of 0 or 1 received oral regorafenib 90 mg once daily 3 weeks (wk) on/1 wk off plus i.v. pembrolizumab 400 mg every 6 wk. The daily regorafenib dose could be escalated to 120 mg after the first 4-wk cycle of regorafenib if tolerated. Pembrolizumab dose reductions were not allowed. Cohorts were defined by prior treatment: Cohort 1 = atezolizumab + bevacizumab; Cohort 2 = any other ICI regimen (alone or combination). Primary endpoint was overall response rate (ORR) by independent central review (RECIST 1.1). Results: 95 patients were treated in 8 countries; Cohort 2 appeared to have more favorable disease characteristics (Table). Most common prior ICIs in Cohort 2 were durvalumab (30%), nivolumab (30%), ipilimumab (22%), and pembrolizumab (19%). Overall, median follow up was 7.1 months (mo). Median duration of regorafenib/pembrolizumab treatment (including interruptions, delays) was shorter in Cohort 1 vs Cohort 2 (11.0/9.4 wk vs 21.4/24.1 wk). ORR was 5.9% in Cohort 1 and 11.1% in Cohort 2; stable disease rates were 48.5% and 63.0%, respectively. Median PFS was 2.8 mo in Cohort 1 and 4.2 mo in Cohort 2. Overall, treatment-emergent adverse events (TEAE) were grade 3 in 56% of patients and grade 4 in 5%; drug-related grade 3 and 4 TEAE occurred in 37% and 3%, respectively. One patient (Cohort 1) had a grade 5 drug-related TEAE (cardiac arrest). Most common drug-related TEAE were palmar-plantar erythrodysesthesia syndrome (39%), asthenia (33%), decreased appetite (32%), diarrhea (28%), and hypertension (20%). Biomarkers assessed in paired biopsies (baseline and wk 6/day 1) showed on-treatment reductions in macrophages and angiogenesis RNA signatures. Conclusions: To our knowledge, this is the first prospective evaluation of a kinase inhibitor plus an ICI following first-line ICI therapy for HCC. Regorafenib plus pembrolizumab had modest activity in second line after first-line ICI regimens. The safety profile of the combination was consistent with those of either drug. Optimal treatment for patients with advanced HCC who progress after an ICI regimen remains an unmet need. Biomarker findings will be detailed in presentation. Clinical trial information: NCT04696055 . [Table: see text]

Efficacy and safety of MCLA-129, an EGFR/c-MET bispecific antibody, in advanced non-small cell lung cancer (NSCLC).

8604 Background: MCLA-129 is a common light chain, Biclonics, bispecific antibody targeting EGFR and c-MET with enhanced antibody-dependent cellular cytotoxicity. Here we describe the ongoing first-in-human phase 1/2 study of MCLA-129 in patients with NSCLC, including patients with MET exon 14 skipping (METex14) mutation (cohort A), EGFR exon 20 insertion (exon20ins)-mutated (cohort B) and sensitized EGFR-mutated disease (cohort C). Methods: Patients received MCLA-129 (100–2000 mg) IV biweekly or 1000-1500 mg IV weekly in a 28-day cycle in dose escalation. Doses at 1500 and 2000 mg IV biweekly are being explored in dose expansion. The primary endpoint was safety and tolerability. Objective response rate by investigator assessment per RECIST v1.1 of patients with NSCLC treated at 1500 and 2000 mg IV biweekly in three cohorts is reported. Results: As of 26 May 2023, 217 enrolled patients received MCLA-129 in China. The data cut-off was 24 Nov 2023. The most common treatment-emergent adverse events (TEAEs) were infusion related reaction (71.9%), hypoalbuminemia (54.8%), decreased neutrophil count (46.1%), and decreased white blood cell count (40.1%). TEAEs mostly were grade 1-2. Grade ≥3 TEAEs and drug-related TEAEs were reported in 51.6% and 39.2% of patients, respectively. 176 of the 215 NSCLC patients were evaluable. The confirmed objective response rates (ORR) in Cohort A, B and C were 43.5%, 28.6% and 21.8%, respectively. Especially, for patients in Cohort A receive prior MET TKI, the ORR was 37.5% and disease control rate (DCR) was 93.8%. Overall efficacy is shown (Table). Conclusions: MCLA-129 demonstrates robust and durable antitumor activity in patients with NSCLC harboring METex14, EGFR exon20ins and sensitized EGFR mutations, with a manageable safety profile; enrollment in dose expansion is ongoing. Clinical trial information: NCT04930432 . [Table: see text]

Pooled analysis by best confirmed response to trastuzumab deruxtecan (T-DXd) in patients (pts) with HER2+ metastatic breast cancer (mBC) from DESTINY-Breast-01, -02, and -03.

1023 Background: DESTINY-Breast (DB)-01, -02, and -03 evaluated T-DXd in pts with HER2+ mBC who received ≥1 prior line of therapy. These studies showed confirmed objective response rates by independent central review (ICR; blinded for DB-02 and -03) of 62%, 70%, and 79% and complete response (CR) rates of 7%, 14%, and 21%, respectively, with T-DXd. We report a pooled analysis according to pts’ best confirmed response in DB-01, -02, or -03. Methods: Endpoints included best confirmed response per (blinded) ICR ([B]ICR) based on RECIST v1.1, duration of response (DoR), progression-free survival (PFS) by (B)ICR, overall survival (OS), and safety. Results: The median (range) duration of T-DXd treatment for pts with a CR, partial response (PR), or stable disease (SD)/progressive disease (PD) was 27.4 (4.5-45.1) mo, 14.0 (2.1-39.3) mo, or 6.2 (0.7-40.1) mo, respectively. Of 834 evaluable pts assigned to T-DXd in DB-01, -02, or -03, 125 (15.0%) had a CR, 477 (57.2%) had a PR, and 232 (27.8%) had SD/PD. Pts with CR had a median of 2 prior regimens (range, 1-11) in the metastatic setting, whereas pts with PR or SD/PD had a median of 3 prior regimens. As shown in the Table, pts with CR had more favorable PFS and OS outcomes vs pts with PR or SD/PD. The proportion of pts with drug-related, serious treatment-emergent adverse events (TEAEs) was numerically lower in pts with CR (8.0%) than those with PR (12.4%) or SD/PD (15.5%). Pts with CR also had numerically lower rates of drug-related TEAEs associated with T-DXd discontinuation (14.4% vs 17.8% or 16.8%) and adjudicated drug-related interstitial lung disease (ILD)/pneumonitis (8.8% [0 fatal] vs 15.1% [2 fatal] or 11.6% [5 fatal]) and longer median time to first ILD onset (461 days vs 211 or 125 days) vs pts with PR or SD/PD. Conclusions: Pts treated with T-DXd benefited from durable responses resulting in prolonged PFS and OS, especially those with a CR. Despite longer treatment duration in responders, safety remained generally manageable and did not result in a higher percentage of pts with TEAEs over time. These results further support the use of T-DXd across broad pt groups with HER2+ mBC. Clinical trial information: NCT03248492 , NCT03523585 , NCT03529110 . [Table: see text]

#437 A multicenter, single-arm study of roxadustat in Chinese patients with chronic kidney disease-associated anemia receiving peritoneal dialysis

Abstract Background and Aims Anemia increases morbidity and mortality in patients with chronic kidney disease (CKD). Phase 3 studies have demonstrated the efficacy of roxadustat for anemia treatment in patients with CKD undergoing dialysis; however, data from Chinese patients undergoing peritoneal dialysis (PD) are limited. We evaluated the efficacy and safety of roxadustat in Chinese patients with CKD-anemia undergoing PD. Method In this phase 4, single-arm, multicenter study, we planned to enroll at least 150 Chinese patients with CKD-anemia undergoing PD (either erythropoiesis-stimulating agent [ESA]-treated or ESA-naïve at enrollment), including at least 50 patients with type 2 diabetes mellitus (T2DM) and 50 patients without diabetes mellitus (DM). Study visits occurred every 2 weeks until Week 8 and then every 4 weeks. All patients received oral roxadustat treatment three times per week for 24 weeks according to the approved product package insert. The primary efficacy endpoint was the proportion of patients with a mean hemoglobin (Hb) ≥100 g/L at Weeks 20–24. The secondary efficacy endpoints were subgroup analyses (T2DM vs. non-DM). The exploratory endpoints were the dose required to maintain Hb at ≥100 g/L over Weeks 20–24, the proportion of time when Hb was 100–130 g/L, changes in residual renal function (RRF), urea clearance index (Kt/V), and creatinine clearance (Ccr), amongst others. For the safety analyses, adverse events (AEs) were assessed during treatment and at 4 weeks after completion. Results Overall, 195 patients (116 male [59.5%]) with a mean (standard deviation [SD]) age of 46.3 (12.3) years were enrolled from 22 centers, and 172 (88.2%) completed the study (main reasons for discontinuation: withdrawal, 7 [3.6%]; AE, 5 [2.6%]; switched from PD to hemodialysis, 5 [2.6%]). Overall, 189 patients (96.9%) were ESA-treated and 43 (22.1%) had T2DM. The median (interquartile range) dialysis duration was 16.1 (5.2–43.2) months. The mean (SD) baseline Hb was 98.1 (10.7) g/L, and the ferritin level and transferrin saturation were 320.9 (287.5) μg/L and 35.5% (17.0%), respectively. The mean (SD) treatment duration was 154.3 (35.6) days, and the mean (SD) weekly dose was 244.9 (88.7) mg. The intention-to-treat (ITT) set and safety analysis set (SAF) included all 195 patients. In the ITT set, 85.1% (95% confidence interval [CI] 79.8%–90.5%) of patients had Hb ≥100 g/L over Weeks 20–24. According to the subgroup analysis, 89.2% (95% CI 78.5%–99.9%) of T2DM patients and 84.0% (95% CI 77.8%–90.1%) of non-DM patients had Hb ≥100 g/L over Weeks 20–24 (Fig. 1). The mean (SD) weekly dose required to maintain Hb at ≥100 g/L at Weeks 20–24 was 215.9 (100.0) mg, and the proportion of time that Hb was 100–130 g/L was 76.4% (23.2%). There was a slight decrease in RRF and Ccr. Table 1 shows the RRF, Kt/V, and Ccr results. Of the 195 SAF patients, 158 (81.0%) had ≥1 treatment-emergent AE (TEAE), 20 (10.3%) had drug-related TEAEs, 40 (20.5%) had treatment-emergent serious AEs, and 1 (0.5%) had a TEAE that led to death. The top three TEAEs were upper respiratory tract infection (25 [12.8%]), hypokalemia (17 [8.7%]), and hypoalbuminemia (15 [7.7%]). Conclusion Treatment with roxadustat for 24 weeks effectively corrected anemia in Chinese CKD patients undergoing PD and maintained Hb at ≥100 g/L in the majority of patients, irrespective of baseline T2DM. The AEs were consistent with the characteristics of patients with CKD undergoing PD and with the known safety profile of roxadustat.

Trastuzumab deruxtecan in patients with solid tumours harbouring specific activating HER2 mutations (DESTINY-PanTumor01): an international, phase 2 study

Trastuzumab deruxtecan is a HER2-directed antibody-drug conjugate approved by the US Food and Drug Administration and the European Medicines Agency for HER2-mutant non-small-cell lung cancer. Few treatment options exist for patients with HER2-mutant solid tumours beyond lung cancers. We investigated trastuzumab deruxtecan in metastatic solid tumours with specific activating HER2 mutations. In this open-label, phase 2, basket study done in 29 centres in Asia, Europe, and North America, we investigated trastuzumab deruxtecan (5·4 mg/kg every 3 weeks by intravenous infusion) in patients aged 18 years or older with unresectable or metastatic solid tumours with specific activating HER2 mutations, an Eastern Cooperative Oncology Group performance status of 0 or 1, and disease progression following previous treatment (previous HER2-targeted therapy was permitted) or with no satisfactory alternative treatment options. The primary endpoint was confirmed objective response rate by independent central review. Anti-tumour activity and safety were analysed in all patients who received at least one dose of trastuzumab deruxtecan. This trial is registered with ClinicalTrials.gov, NCT04639219, and is active but no longer recruiting. Between Dec 30, 2020, and Jan 25, 2023, 102 patients (62 [61%] female and 40 [39%] male; median age 66·5 years [IQR 58-72]; 51 [50%] White, two [2%] Black or African American, 38 [37%] Asian, and 11 [11%] did not have race information reported) with solid tumours with activating HER2 mutations received trastuzumab deruxtecan and were included in the anti-tumour activity and safety analyses sets. Patients had a median of three (IQR 2-4) previous treatment regimens. The median duration of follow-up was 8·61 months (IQR 3·71-12·68). The objective response rate by independent central review was 29·4% (95% CI 20·8-39·3; 30 of 102 patients). 52 (51%) patients had a treatment-emergent adverse event of grade 3 or worse; the most common events (in ≥5% of patients) were anaemia (16 [16%]) and neutrophil count decreased (eight [8%]). Drug-related treatment-emergent serious adverse events occurred in ten (10%) patients. Adjudicated drug-related interstitial lung disease or pneumonitis of any grade occurred in 11 patients (11%; three grade 1, five grade 2, one grade 3, and two grade 5); there were two (2%) cases of fatal adjudicated drug-related interstitial lung disease or pneumonitis. Trastuzumab deruxtecan showed anti-tumour activity and durable responses in heavily pretreated patients across multiple tumour types with activating HER2 mutations, with no new safety signals. Prespecified HER2 mutations might be targeted by HER2-directed antibody-drug conjugates and our findings support further investigation of trastuzumab deruxtecan in the pan-tumour setting. AstraZeneca and Daiichi Sankyo.

Rimegepant orally disintegrating tablet 75 mg for acute treatment of migraine in adults from China: a subgroup analysis of a double-blind, randomized, placebo-controlled, phase 3 clinical trial

Background Rimegepant orally disintegrating tablet (ODT), an oral small-molecule calcitonin gene-related peptide receptor antagonist, is indicated for acute and preventive treatment of migraine in the United States and other countries. Previously, a large clinical trial assessed the efficacy and safety of rimegepant ODT 75 mg for the acute treatment of migraine in adults living in China or South Korea. A post hoc subgroup analysis of this trial was performed to evaluate the efficacy and safety of rimegepant for acute treatment of migraine in adults living in China.Methods Eligible participants were ≥ 18 years of age and had a ≥ 1-year history of migraine, with 2 to 8 attacks of moderate or severe pain intensity per month and < 15 headache days per month during the 3 months before screening. Participants self-administered rimegepant ODT 75 mg or matching placebo to treat a single migraine attack of moderate or severe pain intensity. The co-primary endpoints were pain freedom and freedom from the most bothersome symptom (MBS) at 2 h post-dose. Key secondary endpoints included pain relief at 2 h post-dose, ability to function normally at 2 h post-dose, use of rescue medication within 24 h post-dose, and sustained pain freedom from 2 to 24 h and 2 to 48 h post-dose. All p values were nominal. Safety was assessed via treatment-emergent adverse events (TEAEs), electrocardiograms, vital signs, and routine laboratory tests.ResultsOverall, 1075 participants (rimegepant, n = 538; placebo, n = 537) were included in the subgroup analysis. Rimegepant was more effective than placebo for the co-primary endpoints of pain freedom (18.2% vs. 10.6%, p = 0.0004) and freedom from the MBS (48.0% vs. 31.8%, p < 0.0001), as well as all key secondary endpoints. The incidence of TEAEs was comparable between the rimegepant (15.2%) and placebo (16.4%) groups. No signal of drug-induced liver injury was observed, and no study drug-related serious TEAEs were reported in the rimegepant group.ConclusionsA single dose of rimegepant 75 mg rimegepant was effective for the acute treatment of migraine in adults living in China, with safety and tolerability similar to placebo.Trial registration Clinicaltrials.gov NCT04574362 Date registered: 2020-10-05.Graphical

Efficacy, safety, and tolerability of adjunctive brivaracetam in adult Asian patients with uncontrolled focal-onset seizures: A phase III randomized, double-blind, placebo-controlled trial.

Evaluate efficacy, safety, and tolerability of adjunctive brivaracetam (BRV) in adult Asian patients with focal-onset seizures (FOS). Phase III, randomized, double-blind, placebo-controlled study (EP0083; NCT03083665) evaluating BRV 50 mg/day and 200 mg/day in patients (≥16-80 years) with FOS with/without secondary generalization (focal to bilateral tonic-clonic seizures) despite current treatment with 1 or 2 concomitant antiseizure medications. Following an 8-week baseline, patients were randomized 1:1:1 to placebo, BRV 50 mg/day, or BRV 200 mg/day, and entered a 12-week treatment period. Efficacy outcomes: percent reduction over placebo in 28-day FOS frequency (primary); 50% responder rate in FOS frequency; median percent reduction in FOS frequency from baseline; seizure freedom during treatment period (secondary). Primary safety endpoints: incidences of treatment-emergent adverse events (TEAEs); TEAEs leading to discontinuation; serious TEAEs. In this study, 448/449 randomized patients (mean age, 34.5 years; 53.8% female) received ≥1 dose of study medication (placebo/BRV 50 mg/BRV 200 mg/day: n = 149/151/148). Percent reduction over placebo in 28-day adjusted FOS frequency was 24.5% (p = 0.0005) and 33.4% (p < 0.0001) with BRV 50 mg/day and 200 mg/day, respectively, 50% responder rate was 19.0%, 41.1%, and 49.3% with placebo, BRV 50 mg/day, and BRV 200 mg/day, respectively (p < 0.0001 for both BRV groups vs. placebo). Median percent reduction in FOS frequency from baseline was 21.3%/38.9%/46.7% in patients on placebo/BRV 50 mg/BRV 200 mg/day, respectively. Overall, 0, 7 (4.6%), and 10 (6.8%) patients were classified as seizure-free during the treatment period on placebo, BRV 50 mg/day, and BRV 200 mg/day, respectively (p = 0.0146/p = 0.0017 for BRV 50 mg/200 mg/day vs. placebo, respectively). TEAE incidences were similar between patients on placebo (58.4%) and all patients receiving BRV (58.5%); TEAE incidences for BRV 50 mg/day and BRV 200 mg/day were 57.0% and 60.1%, respectively. Overall, 0.7% of patients on placebo and 2.0% of all patients on BRV reported serious TEAEs (incidences for BRV 50 mg/day and BRV 200 mg/day were 1.3% and 2.7%, respectively), 20.1% of patients on placebo and 33.1% of all patients on BRV reported drug-related TEAEs (incidences for BRV 50 mg/day and BRV 200 mg/day were 26.5% and 39.9%, respectively), and 4.7% of patients on placebo and 3.0% of all patients on BRV discontinued due to TEAEs (discontinuation incidences for BRV 50 mg/day and BRV 200 mg/day were 2.6% and 3.4%, respectively). Adjunctive BRV was efficacious and well tolerated in adult Asian patients with FOS. Efficacy and safety profiles were consistent with BRV studies in predominantly non-Asian populations. Brivaracetam is used to treat partial or focal seizures in people with epilepsy. Most studies with brivaracetam tablets have involved people from non-Asian racial backgrounds. In this study, 449 Asian adults with epilepsy took part. One third took 50 mg of brivaracetam, one third took 200 mg of brivaracetam, and one third took a placebo each day for 12 weeks. On average, those who took brivaracetam had fewer seizures than those given the placebo. Most of the side effects were mild and the number and type of side effects seen were as expected for this medication.

Trastuzumab deruxtecan in patients with metastatic non-small-cell lung cancer (DESTINY-Lung01): primary results of the HER2-overexpressing cohorts from a single-arm, phase 2 trial

DESTINY-Lung01 is a multicentre, open-label, phase 2 study evaluating the antitumour activity and safety of trastuzumab deruxtecan, a HER2-directed antibody-drug conjugate, in patients with HER2-overexpressing or HER2 (ERBB2)-mutant unresectable or metastatic non-small-cell lung cancer (NSCLC). The results of the HER2-mutant cohort (cohort 2) have been reported elsewhere. Herein, we report the primary analysis of cohorts 1 and 1A, which aimed to evaluate the activity and safety of trastuzumab deruxtecan 5·4 mg/kg and 6·4 mg/kg in patients with HER2-overexpressing NSCLC. Patients aged 18 years or older with unresectable or metastatic (or both unresectable and metastatic) non-squamous NSCLC who had relapsed following or were refractory to standard treatment or for whom no standard treatment was available, with an HER2 immunohistochemistry score of 3+ or 2+ (without known HER2 mutations) and an Eastern Cooperative Oncology Group performance status score of 0 or 1, were enrolled at 20 specialist hospitals in France, Japan, the Netherlands, Spain, and the USA. Patients were assigned to cohorts sequentially, first to cohort 1, to receive trastuzumab deruxtecan 6·4 mg/kg (cohort 1), then to cohort 1A, to receive trastuzumab deruxtecan 5·4 mg/kg, both administered intravenously once every 3 weeks. The primary endpoint was confirmed objective response rate by independent central review and was assessed in the full analysis set, which included all patients who signed an informed consent form and were enrolled in the study. Safety was assessed in all enrolled patients who received at least one dose of trastuzumab deruxtecan. This trial is registered with ClinicalTrials.gov, NCT03505710, and is ongoing (closed to recruitment). Between Aug 27, 2018, and Jan 28, 2020, 49 patients were enrolled in cohort 1 (median age 63·0 years [IQR 58·0-68·0], 30 [61%] male, 19 [39%] female, and 31 [63%] White), and from June 16 to Dec 9, 2020, 41 patients were enrolled in cohort 1A (median age 62·0 years [IQR 56·0-66·0], 22 [54%] male, 19 [46%] female, and 31 [76%] White). As of data cutoff (Dec 3, 2021), the median treatment duration was 4·1 months (IQR 1·4-7·1) in cohort 1 and 5·5 months (1·4-8·7) in cohort 1A, and median follow-up was 12·0 months (5·4-22·4) in cohort 1 and 10·6 months (4·5-13·5) in cohort 1A. Confirmed objective response rate by independent central review was 26·5% (95% CI 15·0-41·1; 13 of 49, all partial responses) in cohort 1 and 34·1% (20·1-50·6; 14 of 41; two complete responses and 12 partial responses) in cohort 1A. The most common treatment-emergent adverse events of grade 3 or worse were neutropenia (12 [24%] of 49 in cohort 1, none in cohort 1A), pneumonia (six [12%] and two [5%], respectively), fatigue (six [12%] and three [7%], respectively), and disease progression (six [12%] and four [10%], respectively). Drug-related treatment-emergent adverse events of grade 3 or worse occurred in 26 (53%) of 41 patients in cohort 1 and nine (22%) of 49 patients in cohort 1A. Drug-related serious adverse events were reported in ten (20%) patients and three (7%) patients, respectively. Deaths due to treatment-emergent adverse events occurred in ten (20%) patients in cohort 1 (disease progression in six (12%) patients and bronchospasm, hydrocephalus, respiratory failure, and pneumonitis in one [2%] patient each), and in seven (17%) patients in cohort 1A (due to disease progression in four (10%) patients and dyspnoea, malignant neoplasm, and sepsis in one (2%) patient each). One death due to a treatment-emergent adverse event was determined to be due to study treatment by the investigator, which was in cohort 1 (pneumonitis). Independent adjudication of interstitial lung disease or pneumonitis found that drug-related interstitial lung disease or pneumonitis occurred in ten (20%) patients in cohort 1 (two [4%] grade 1, five [10%] grade 2, and three [6%] grade 5) and two (5%) patients in cohort 1A (one [2%] grade 2 and one [2%] grade 5). An additional patient in cohort 1A had grade 4 pneumonitis after the data cutoff, which was subsequently adjudicated as drug-related grade 5 interstitial lung disease or pneumonitis. Given the low antitumour activity of existing treatment options in this patient population, trastuzumab deruxtecan might have the potential to fill a large unmet need in HER2-overexpressing NSCLC. Our findings support further investigation of trastuzumab deruxtecan in patients with HER2-overexpressing NSCLC. Daiichi Sankyo and AstraZeneca.

Vonoprazan is superior to lansoprazole for healing of severe but not mild erosive esophagitis: A systematic review with meta-analysis of randomized controlled trials.

Healing rates of severe erosive esophagitis (EE; Los Angeles [LA] Grade C/D) in patients treated with a proton pump inhibitor (PPI) is suboptimal (~60-70%). Vonoprazan, a potassium-competitive acid blocker, is suggested to have better healing rates in patients with severe EE. This meta-analysis compares the efficacy and safety of vonoprazan 20mg versus lansoprazole 30mg daily in healing EE, specifically in those with LA Grade C/D. We searched MEDLINE, Embase, and CENTRAL on May 24, 2023. Studies that randomized EE patients to vonoprazan 20mg daily or lansoprazole 30mg daily and compared healing rates were included. The risk of bias was assessed using Cochrane's Risk of Bias 2 tool. The fixed-effect model was used to obtain the pooled efficacy and safety outcomes. Subgroup analysis was done to compare healing rates in mild (LA Grade A/B) versus severe EE and based on study location. Four randomized controlled trials (RCTs) with low risks of bias comprising 2208 participants were included. Vonoprazan 20mg was superior to lansoprazole 30mg daily in healing severe EE at all weeks (Week 2 RR 1.294 [95% CI 1.169-1.433], Week 4 1.160 [1.059-1.270], and Week 8 1.175 [95% CI 1.107-1.247]), but was similar for mild EE at all weeks (P-interaction<0.01). Vonoprazan 20mg was more efficacious than lansoprazole 30mg at Week 8 in Western versus Asian studies (P-interaction<0.01). Any, serious, and drug-related treatment-emergent adverse events were comparable between groups. Vonoprazan 20mg is superior to lansoprazole 30mg for healing severe EE but not mild EE. Vonoprazan 20mg daily has a similar safety profile to lansoprazole 30mg daily.

Safety outcomes in patients with metastatic castration-resistant prostate cancer treated with radium-223 following external beam radiation therapy: REASSURE US subset.

106 Background: In the Phase 3 ALSYMPCA trial, radium-223 (Ra-223) demonstrated an overall survival (OS) benefit and a favorable safety profile in patients with metastatic castration-resistant prostate cancer (mCRPC). REASSURE (NCT02141438) is a global, prospective, single-arm, observational study of Ra-223 use in patients with mCRPC with bone metastases within routine clinical settings. Utilizing data from the second planned interim analysis, we evaluated safety outcomes in patients with mCRPC treated with Ra-223 following external beam radiation therapy (EBRT) in the US. Methods: In this descriptive analysis (data cutoff 3-20-2019), we included patients who received EBRT to bone prior to Ra-223 (≤2 years prior to Ra-223 first dose); results are presented relative to the overall US subset of patients enrolled into REASSURE. The focus of this abstract is on incidence of hematological toxicities, bone fractures, and second primary malignancies (SPM). Results: Of N=498 patients in the US subset, 118 patients received prior EBRT to bone. Median duration of observation was 11.7 months among patients who received EBRT and 11.9 months for the overall US subset. Any-grade drug-related hematological treatment-emergent adverse events (TEAEs) occurred in 8% (10/118) and 9% (47/498) of patients who received EBRT and the overall subset, respectively (Table). Grade ≥3 drug-related hematological TEAEs occurred in 5% (6/118) and 6% (32/498) of patients who received EBRT and the overall subset, respectively. Bone fractures occurred in 7% (8/118) and 4% (19/498) of patients who received EBRT and the overall subset, respectively. Six SPMs occurred in 5/118 patients who received EBRT (4%), and 11 SPMs occurred in 10/498 patients in the overall subset (2%). Results of bone fracture events by bone health agent use will be included in the full presentation. Conclusions: In this descriptive analysis of real-world data, patients who received EBRT prior to Ra-223 did not demonstrate an increased incidence of hematological toxicities relative to the overall US subset. Although percent of SPMs and bone fractures seems higher among patients treated with EBRT relative to the overall US subset, the real-world incidence of these events remains low. [Table: see text]