Dose Arm Research Articles

Therapeutic Doses of Efzofitimod Demonstrate Efficacy in Pulmonary Sarcoidosis

BackgroundIn a phase 1b/2a clinical trial of efzofitimod in patients with corticosteroid-requiring pulmonary sarcoidosis, treatment resulted in dose-dependent improvement in key endpoints. We undertook a post hoc analysis pooling dose arms that achieved therapeutic concentrations of efzofitimod (Therapeutic group)versusthose that did not (Subtherapeutic group).MethodsPeripheral blood mononuclear cells incubated with tuberculin-coated beads were exposed to varying concentrations of efzofitimod in anin vitroassay to determine concentrations that inhibited granuloma formation. In the post hoc analysis, we compared time-to-first-relapse and changes in pulmonary function after a protocolised corticosteroid taper in the Therapeutic and Subtherapeutic groups.ResultsEfzofitimod at ≥300 nM (19 µg·mL−1) inhibited granuloma formationin vitro. Based on average efzofitimod serum concentrations achieved in the phase 1b/2a study, the 3 and 5 mg·kg−1dose arms were pooled as the Therapeutic group, while the 1 mg·kg−1arm was pooled with the placebo arm as the Subtherapeutic group. Relapse rates were 54.4% and 7.7% in the Subtherapeutic group and Therapeutic group, respectively. Median time-to-first-relapse in the Subtherapeutic group was 126 days, whereas in the Therapeutic group, only one of 17 patients relapsed by the end of the 24-week study (p=0.017). Slopes analysis showed that forced vital capacity increased in the Therapeutic group, but decreased in the Subtherapeutic group, over the course of the trial (p=0.035).ConclusionTreatment with efzofitimod at therapeutic doses, as compared with a subtherapeutic dose or placebo, was associated with a lower rate of relapse as corticosteroids were tapered.

A multicenter, randomized, double-blind, placebo-controlled ascending dose study to evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamic (PD) effects of Posiphen in subjects with early Alzheimer’s Disease

BackgroundAmyloid beta protein (Aβ) is a treatment target in Alzheimer’s Disease (AD). Lowering production of its parent protein, APP, has benefits in preclinical models. Posiphen, an orally administered small molecule, binds to an iron-responsive element in APP mRNA and decreases translation of APP and Aβ. To augment human data for Posiphen, we evaluated safety, tolerability and pharmacokinetic and pharmacodynamic (PD) effects on Aβ metabolism using Stable Isotope Labeling Kinetic (SILK) analysis.MethodsDouble-blind phase 1b randomized ascending dose clinical trial, at five sites, under an IRB-approved protocol. Participants with mild cognitive impairment or mild AD (Early AD) confirmed by low CSF Aβ42/40 were randomized (within each dose arm) to Posiphen or placebo. Pretreatment assessment included lumbar puncture for CSF. Participants took Posiphen or placebo for 21–23 days, then underwent CSF catheter placement, intravenous infusion of 13C6-leucine, and CSF sampling for 36 h. Safety and tolerability were assessed through participant reports, EKG and laboratory tests. CSF SILK analysis measured Aβ40, 38 and 42 with immunoprecipitation-mass spectrometry. Baseline and day 21 CSF APP, Aβ and other biomarkers were measured with immunoassays. The Mini-Mental State Exam and ADAS-cog12 were given at baseline and day 21.ResultsFrom June 2017 to December 2021, 19 participants were enrolled, randomized within dose cohorts (5 active: 3 placebo) of 60 mg once/day and 60 mg twice/day; 1 participant was enrolled and completed 60 mg three times/day. 10 active drug and 5 placebo participants completed all study procedures. Posiphen was safe and well-tolerated. 8 participants had headaches related to CSF catheterization; 5 needed blood patches. Prespecified SILK analyses of Fractional Synthesis Rate (FSR) for CSF Aβ40 showed no significant overall or dose-dependent effects of Posiphen vs. placebo. Comprehensive multiparameter modeling of APP kinetics supported dose-dependent lowering of APP production by Posiphen. Cognitive measures and CSF biomarkers did not change significantly from baseline to 21 days in Posiphen vs. placebo groups.ConclusionsPosiphen was safe and well-tolerated in Early AD. A multicenter SILK study was feasible. Findings are limited by small sample size but provide additional supportive safety and PK data. Comprehensive modeling of biomarker dynamics using SILK data may reveal subtle drug effects.Trial registrationNCT02925650 on clinicaltrials.gov (registered on 10-24-2016).

Efficacy and Safety of Upadacitinib or Elsubrutinib Alone or in Combination for Patients With Systemic Lupus Erythematosus: A Phase 2 Randomized Controlled Trial.

The 48-week, phase 2 SLEek study (NCT03978520) evaluated the efficacy and safety of upadacitinib (JAK inhibitor) and elsubrutinib (BTK inhibitor) alone or in combination (ABBV-599) in adults with moderately to severely active systemic lupus erythematosus (SLE). Patients were randomized 1:1:1:1:1 to elsubrutinib 60 mg and upadacitinib 30 mg once daily (ABBV-599 high dose), elsubrutinib 60 mg and upadacitinib 15 mg once daily (ABBV-599 low dose), elsubrutinib 60 mg once daily (QD), upadacitinib 30 mg QD, or placebo QD. The primary endpoint was the proportion of patients achieving both Systemic Lupus Erythematosus Responder Index 4 (SRI-4) and glucocorticoid dose ≤10 mg QD at week 24. Additional assessments through week 48 included British Isles Lupus Assessment Group-Based Composite Lupus Assessment (BICLA) and Lupus Low Disease Activity State (LLDAS) responses, number of flares, time to first flare, and adverse events. The study enrolled 341 patients. The ABBV-599 low dose and elsubrutinib arms were discontinued after a planned interim analysis showed lack of efficacy (no safety concerns). More patients achieved the primary endpoint with upadacitinib (54.8%; P = 0.028) and ABBV-599 high dose (48.5%; P = 0.081) versus placebo (37.3%). SRI-4, BICLA, and LLDAS response rates were higher for both upadacitinib and ABBV-599 high dose versus placebo at weeks 24 and 48. Flares were reduced, and time to first flare through week 48 was substantially delayed with both upadacitinib and ABBV-599 high dose versus placebo. No new safety signals were observed beyond those previously reported for upadacitinib or elsubrutinib. Upadacitinib 30 mg alone or in combination with elsubrutinib (ABBV-599 high dose) demonstrated significant improvements in SLE disease activity and reduced flares and were well tolerated through 48 weeks.

A seamless phase II/III design with dose optimization for oncology drug development.

The US FDA's Project Optimus initiative that emphasizes dose optimization prior to marketing approval represents a pivotal shift in oncology drug development. It has a ripple effect for rethinking what changes may be made to conventional pivotal trial designs to incorporate a dose optimization component. Aligned with this initiative, we propose a novel seamless phase II/III design with dose optimization (SDDO framework). The proposed design starts with dose optimization in a randomized setting, leading to an interim analysis focused on optimal dose selection, trial continuation decisions, and sample size re-estimation (SSR). Based on the decision at interim analysis, patient enrollment continues for both the selected dose arm and control arm, and the significance of treatment effects will be determined at final analysis. The SDDO framework offers increased flexibility and cost-efficiency through sample size adjustment, while stringently controlling the Type I error. This proposed design also facilitates both accelerated approval (AA) and regular approval in a "one-trial" approach. Extensive simulation studies confirm that our design reliably identifies the optimal dosage and makes preferable decisions with a reduced sample size while retaining statistical power.

A phase 2/3 study of Bicycle toxin conjugate BT8009 targeting nectin-4 in patients with locally advanced or metastatic urothelial cancer (la/mUC): Duravelo-2.

TPS4619 Background: BT8009 is a Bicycle toxin conjugate (BTC), comprising a highly selective bicyclic peptide targeting nectin-4 linked to the cytotoxin monomethyl auristatin E (MMAE) via a cleavable linker. Nectin-4 is an adhesion molecule commonly expressed in many tumor types, including urothelial cancer (UC), and is a validated therapeutic target (Hoffman-Censits 2021). BT8009 has a low molecular weight and short plasma half-life, with potential to rapidly penetrate solid tumors and reduce toxicity by minimizing exposure to normal tissue (Rigby 2022). Results from the ongoing phase 1/2 clinical trial of BT8009 (NCT04561362) indicate preliminary antitumor activity and a tolerable safety profile in patients (pts) with advanced malignancies including UC (Baldini 2023). This global, open label, phase 2/3 multicenter adaptive study aims to evaluate the safety and efficacy of BT8009 as monotherapy, or combined with pembrolizumab (pembro), vs chemotherapy in pts with locally advanced or metastatic UC (la/mUC) (NCT06225596/BT8009-230; Duravelo-2). Methods: The trial will enroll up to 956 adult pts in 2 cohorts. Cohort 1 will include n≤641 previously untreated pts eligible for platinum-based chemotherapy. Cohort 2 will include n≤315 pts with ≥1 prior systemic therapy, excluding enfortumab vedotin or other MMAE-based therapy. Pts must have la/mUC of the renal pelvis, ureter, bladder, or urethra, ECOG performance status ≤2 (Cohort 1) or ≤1 (Cohort 2), and adequate organ function. Cohort 1 will be randomized 1:1:1 to receive: 1) BT8009 5 mg/m2 on days (D)1, 8, and 15 + pembro 200 mg on D1; 2) BT8009 6 mg/m2 on D1 and 8 + pembro 200 mg on D1; or 3) chemotherapy (gemcitabine + cisplatin / carboplatin, followed by avelumab maintenance). Cohort 2 will be randomized 1:1 to receive: 1) BT8009 5 mg/m2 on D1, 8, and 15 or 2) BT8009 6 mg/m2 on D1 and 8. Cycle lengths will be 21D (28D for avelumab). After 30 pts in each dose arm have 9 weeks follow-up, an interim analysis will determine the optimal dose of BT8009 + pembro (Cohort 1) or BT8009 monotherapy (Cohort 2) to be used for the rest of the study. An additional Cohort 2 arm, optimal dose of BT8009 + pembro, will open after completion of the interim analysis. Discontinuation criteria include planned completion of therapy, progressive disease, and intolerable toxicity. Primary endpoints are progression-free survival (PFS; Cohort 1) and objective response rate (ORR; Cohort 2) assessed by blinded independent central review. Secondary endpoints are ORR (Cohort 1), PFS (Cohort 2), and overall survival, duration of response, disease control rate, safety/tolerability, and health-related quality of life (Cohorts 1 and 2). Pharmacokinetics, incidence/titers of antidrug antibodies, and tumor/peripheral biomarkers are exploratory endpoints. Efficacy endpoints will be assessed per RECIST v1.1. This study is actively recruiting. Clinical trial information: NCT06225596 .

A phase 3 trial of IMC-F106C (PRAME x CD3) plus nivolumab versus standard nivolumab regimens in HLA-A*02:01+ patients with previously untreated advanced melanoma (PRISM-MEL-301).

TPS9602 Background: Current standard of care in newly diagnosed patients with metastatic cutaneous melanoma (CM) include anti-PD1 as monotherapy or in combination with other immune checkpoint inhibitors (ICI). However, most patients will eventually progress and the 5-year survival rate remains low, necessitating new therapies with novel mechanisms of action to combine with anti-PD1. T cell receptor (TCR) bispecifics have shown overall survival (OS) benefit with tebentafusp (gp100 ´ CD3) in a phase (Ph) 3 trial in metastatic uveal melanoma [1]. IMC-F106C is the first TCR bispecific protein targeting CD3 and PRAME (PRAME ´ CD3), redirecting T cells towards cancer cells presenting a PRAME peptide on the cell surface by HLA-A*02:01 proteins. PRAME is expressed in the vast majority of melanoma. In an ongoing Ph 1 study (NCT04262466), IMC-F106C monotherapy was well tolerated and demonstrated evidence of durable clinical activity in heavily pre-treated, advanced melanoma patients, including those who progressed on prior ICI and targeted therapy [2]. Two doses, 40 mcg and 160 mcg, were selected for further study based on exposure response modeling. Safety of combination TCR bispecifics with ICI has been demonstrated in the ongoing IMC-F106C Ph 1 study and in a prior study of tebentafusp + ICI [3]. Combining IMC-F106C with the anti-PD1 ICI nivolumab has the potential to improve progression free survival (PFS), OS, and response rate (RR). Methods: PRISM-MEL-301 is a randomized, global, open-label, Ph 3 study in previously untreated HLA-A*02:01+ patients with unresectable or metastatic non-uveal melanoma; up to 10% of patients can have a diagnosis of mucosal, acral, or other non-CM melanoma. The first 90 patients will be randomized 1:1:1 to receive IMC-F106C 40 mcg + nivolumab (Arm A), IMC-F106C 160 mcg + nivolumab (Arm B), or a nivolumab regimen (Arm C) from which a final IMC-F106C dose (Arm A or B) will be selected. Subsequently, approximately 590 additional patients will be randomized to Arm (A or B) vs. control Arm C, either nivolumab monotherapy or nivolumab + relatlimab, dependent on the country. Randomization will be stratified by 1) American Joint Committee on Cancer (8th Edition) M stage with lactate dehydrogenase (LDH; M0 or M1 with normal LDH vs M1 with elevated LDH); 2) prior anti-PD[L]1 adjuvant therapy (yes vs no); and 3) BRAF V600 mutation status (positive vs negative). Primary endpoint is PFS per RECIST 1.1 by blinded independent central review. Secondary endpoints include OS, ORR, and safety. Enrollment is ongoing globally. Clinical trial registration: NCT06112314 Nathan et al. N Engl J Med 2021; 385:1196 Hamid et al. Ann Oncol 2022; 33 (Supp7): S875 Hamid et al. J Immunother Cancer 2023; 11(6): e006747. Clinical trial information: NCT06112314 .

#2267 IL-33 Inhibition with tozorakimab for diabetic kidney disease: a randomized, placebo-controlled phase 2b study

Abstract Background and Aims In patients with type 2 diabetes (T2D) and chronic kidney disease (CKD), persistent, low-grade inflammation is a significant risk factor for adverse kidney outcomes. Previously, we identified interleukin-33 (IL-33) as an over-expressed inflammatory cytokine in kidney biopsies from patients with CKD and showed a significant benefit of inhibiting IL-33 signaling in a rodent model of diabetic kidney disease (DKD). Here, we investigate the therapeutic potential of tozorakimab, a high-affinity IL-33-neutralizing immunoglobulin G1 monoclonal antibody, in patients with DKD. Method FRONTIER-1 (NCT04170543) was a phase 2b, randomized, double-blind, placebo-controlled, multicenter study to evaluate the efficacy, safety, pharmacokinetics (PK), and immunogenicity of tozorakimab in patients with DKD; defined as T2D with an estimated glomerular filtration rate (eGFR) of 25-75 mL/min/1.73 m2, a urinary albumin-to-creatinine ratio (UACR) of 100-3,000 mg/g, and on angiotensin-converting-enzyme inhibitor (ACEi) or angiotensin-receptor blocker (ARB) for > 6 weeks before the treatment period. Participants were randomly assigned to four different doses of tozorakimab or volume-matched placebo, administered subcutaneously every 28 days for 24 weeks. The randomization process was stratified based on region and the use of SGLT2 inhibitors (SGLT2i). All participants received 10 mg of dapagliflozin Days 85–168, discontinuing existing SGLT2i if applicable. The primary objective of the study was to evaluate the effect of tozorakimab on UACR. A sample size of 565 patients provided at least 80% power to detect a 30% reduction in the change from baseline to week 24 in UACR between each tozorakimab treatment group and placebo. Efficacy endpoints were evaluated in the Per Protocol Population (PPP; initiated dapagliflozin treatment), whereas safety and tolerability were assessed for all dosed participants. Results Between 11 December 2019 and 16 May 2023, we assessed 1,575 patients for eligibility in Argentina, Canada, Chile, Peru, South Korea, Japan, and the United States. 599 (38%) participants were assigned to tozorakimab or placebo. Owing to the COVID-19 pandemic, the study was temporarily halted between March and June 2020. This precautionary measure resulted in the discontinuation of 26 participants. Upon resuming, the study incorporated significant modifications to adapt to the pandemic environment. 573 participants (Full Analysis Population) were randomized after the study was restarted: 29.7% were female; their mean age (±SD) was 67 years (±10); mean eGFR was 48 mL/min/1.73 m2 (±15); and the geometric mean UACR was 460 mg/g (coefficient of variation = 151%). Most participants were taking an ACEi (30%) or ARB (65%), and 28% an SGLT2i. 139 participants received placebo, while 96, 91, 95, and 152 participants received 30, 60, 120, and 300 mg tozorakimab, respectively. The baseline characteristics were balanced across treatment groups, and significant target engagement was observed in all dose arms. Tozorakimab was generally well tolerated and the incidences of adverse events (Aes), serious Aes, discontinuations, and death were similar to placebo. Initial evaluation identified 476 participants in the PPP with 109, 81, 80, 72, and 134 on placebo, 30, 60, 120, and 300 mg tozorakimab, respectively. The primary efficacy analysis demonstrated an inhibition of IL-33 signaling but failed to establish a statistically significant difference in UACR reduction between placebo and treatment groups. The median %-change from baseline was –22% (–46%, 24%) in the placebo group and ranged from –23% to –25% in the tozorakimab groups at week 24. Similarly, no significant effect on eGFR was observed. Following study completion, Good Clinical Practice concerns arose at one clinical trial site with 15 participants. The investigation of these issues is ongoing, but significant alterations to the study results are not anticipated. Conclusion This study did not demonstrate a clinically meaningful reduction in UACR with tozorakimab treatment in patients with T2D and CKD. Further investigation is warranted to clarify the role of IL-33 in DKD.

#425 Felzartamab (anti-CD38) in patients with IgA Nephropathy—interim results from the IGNAZ study

Abstract Background and Aims Most patients with IgA nephropathy (IgAN) will progress to kidney failure within 10-15 years of diagnosis. Sustained proteinuria is the best predictor of adverse long-term kidney outcomes and is a surrogate marker for efficacy. CD38+ plasma cells are likely the main source of pathogenic Gd-IgA1, and the related autoantibodies in IgAN. Felzartamab (felza; HIB202) is a recombinant purified human immunoglobulin G1 (IgG1) monoclonal antibody (mAb) that binds to CD38 on plasma cells and is being studied across immune-mediated kidney diseases such as IgAN, Primary Membranous Nephropathy, Lupus Nephritis, and Antibody Mediated Rejection. The primary aims of the IGNAZ study were to assess: 1) efficacy of felza compared to placebo on urine protein:creatinine ratio (UPCR) and estimated glomerular filtration rate (eGFR) change from baseline, and 2) the relationship between exposure, safety, and efficacy in each of 3 dose groups vs. placebo. Interim results with 15 months of follow-up from this 24-month trial are presented. Method In Part 1, 48 IgAN subjects were randomized in a 1:1:1:1 ratio across a placebo and 3 active arms in this multicenter, double-blind placebo-controlled, phase IIa trial. The M1, M2, and M3 active arms received 2 doses in 15 days, 5 doses in 2 months, and 9 doses in 5 months, respectively. In Part 2, 6 Japanese subjects received the M3 regimen, open-label, and have been followed for 9 months. Key inclusion criteria included ages 18-80 years, biopsy confirmed diagnosis of IgAN within the past 8 years, proteinuria at screening ≥1.0 g/d, eGFR ≥30 ml/min/1.73 m2 (by CKD-EPI), and background stable and maximally tolerated renin angiotensin system inhibitors. Results 48 randomized subjects were enrolled at 28 sites in the US and in 14 different countries in Europe and in Asia, of which 46 completed the treatment phase. Mean (SD) baseline characteristics (Parts 1 and 2 combined): age 41.6 (12.3) yrs, UPCR 1.67 (1.0) g/g, eGFR 74.6 (30.3) ml/min/1.73 m2. 67% of subjects were male. Intention-to-treat with felza demonstrated rapid, clinically meaningful reductions in UPCR with the maximal treatment effect being observed in the M3 9-dose regimen. In Part 1, percentage change from baseline in UPCR was −14% for placebo and −25% for M3 9-dose arm at month 3, and +9% for placebo and −35% for M3 at month 6 (Fig. A). Reductions in proteinuria observed at month 6 persisted until Month 15, 10 months after the last dose: +6% and −38% mean UPCR change from baseline for placebo and the M3 9-dose arm, respectively (Fig. B). Relatively stable eGFR values were observed for the felza arms compared to loss of eGFR in the placebo arm. Rapid, durable reductions in IgA and Gd-IgA1 levels were seen across the dosing arms, with reductions lasting 10 months after the last dose (Fig. C). IgG recovery occurred faster off-treatment than IgA. Results in the Part 2 subjects were similar to the Part 1 M3 cohort through 9 months. There were no apparent dose-dependent adverse events and no exposure-safety relationship. Treatment-emergent adverse events (TEAEs) were generally of mild or moderate intensity or toxicity grade. The most common TEAE assessed as related by study investigator was infusion related reactions (IRR), most of which occurred on the first infusion. There was one treatment-related serious AE due to an IRR. Five subjects discontinued treatment due to IRRs or drug hypersensitivity; for four of the five subjects, the infusion rate was higher than protocol-specified or had an error in pre-medication. TEAE infections were comparable between placebo and felza arms: Placebo (33.3%), M1 (33.3%), M2 (36.4%), M3 (38.5%), Part 2 (50.0%); all were Grades 1 or 2, and non-serious. Conclusion This proof-of-concept study highlights the potential for disease modification in IgAN with the anti-CD38 mAb felza and supports continued research as a potential treatment for high-risk IgAN patients. Felza treatment resulted in clinically meaningful, prolonged UPCR reductions and eGFR stabilization sustained ≥10 months after dosing was completed. Felza was generally well tolerated with rapid recovery of IgG with durable reductions in IgA and pathogenic Gd-IgA1 levels.

Cost-Effectiveness Analysis of Pharmacogenomics-Guided Versus Standard Dosing of Warfarin in Patients with Mechanical Prosthetic Heart Valve.

Warfarin is the only approved anticoagulant for antithrombotic treatment in patients with mechanical prosthetic heart valves (MPHV). However, dosing warfarin is challenging due to its narrow therapeutic window and highly variable clinical outcomes. Both low and high doses of warfarin can lead to thrombotic and bleeding events, respectively, with these complications being more severe in individuals with sensitive genetic polymorphisms. Incorporating genetic testing could enhance the accuracy of warfarin dosing and minimize its adverse events. This study aims to evaluate the utilities and cost-effectiveness of pharmacogenomics-guided versus standard dosing of warfarin in patients with MPHV in Iran. In this economic evaluation study, a cost-effectiveness analysis was conducted to compare pharmacogenomics-guided versus standard warfarin dosing. Data related to quality of life (QoL) were collected through a cross-sectional study involving 105 randomly selected MPHV patients using the EuroQol-5D (EQ-5D) Questionnaire. Costs were calculated with input from clinical experts and a review of relevant guidelines. Additional clinical data were extracted from published literature. The pharmacoeconomic threshold set for medical interventions within Iran's healthcare system was $1,500. A decision tree model was designed from the perspective of Iran's healthcare system with a one-year study horizon. Sensitivity analyses were also performed to assess the uncertainty of input parameters. The utility scores derived from the questionnaire for standard and pharmacogenomics-guided warfarin treatments were 0.68 and 0.76, respectively. Genotype-guided dosing of warfarin was more costly compared to the standard dosing ($246 vs $69), and the calculated incremental cost-effectiveness ratio (ICER) was $2474 per quality-adjusted life year (QALY) gained. One-way sensitivity analyses showed that our model is sensitive to the percentage of time in the therapeutic range (PTTR), the cost of genetic tests, and the utility of both pharmacogenomics-guided and standard dosing arms. However, the probabilistic sensitivity analysis demonstrates the robustness of our model. Warfarin dosing with pharmacogenomics testing is currently not cost-effective. However, if the cost of genotyping tests decreases to $118, the ICER would become cost-effective.

Abstract PS15-06: Results of the window-of-opportunity PIONEER trial evaluating addition of the progesterone receptor (PR) agonist megestrol to letrozole for early stage estrogen receptor (ER) positive breast cancer: exploiting ER-PR interaction

Abstract Background: Pre-clinical data suggest that combining anti-estrogen treatment with a progesterone receptor agonist leads to greater inhibition of tumor proliferation, due to molecular interactions between ER and PR [1]. A high dose of the PR agonist megestrol (160mg daily) is approved as monotherapy for the treatment of ER positive metastatic breast cancer. A lower dose of megestrol (20-40mg daily) can be an effective treatment for severe hot flashes associated with endocrine therapy [2] but whether this dose has anti-tumor activity is unknown. The PIONEER trial evaluated the potential anti-proliferative effect of low and high dose megestrol in combination with letrozole, relative to letrozole alone, using a short-term preoperative ‘window’ trial design assessing the direct effects of the trial treatment on tumor tissue before and after treatment. Methods: Eligible patients were post-menopausal women with histologically confirmed ER+ (Allred ≥ 3) HER2 negative breast cancer at least 10mm in size, with an ECOG performance status ≤ 2, planned for primary surgery or endocrine therapy. Enrolled patients were randomised 2:3:3 to Arm A: letrozole alone, Arm B: letrozole + lower-dose megestrol (40mg) or Arm C: letrozole + higher-dose megestrol (160mg). Treatment was given for 15 (13-19) days prior to surgery or end of treatment (EOT) core biopsy. The primary endpoint was change in tumor proliferation between baseline and EOT in Arm A vs (Arms B+C combined), measured by Ki67 immunohistochemistry (IHC). Secondary endpoints were comparison of Ki67 change in high versus low dose megestrol arms, absolute Ki67 at EOT, and change in tumor apoptosis (cleaved caspase 3 IHC), proliferation (Aurora Kinase A IHC), PR and androgen receptor expression. Exploratory analysis of ER chromatin binding (ChIP-Seq) was conducted on paired fresh-frozen samples from a subset of patients. Results: A total of 243 patients were randomised from July 2017 to October 2022 with recruitment paused for 3 months at onset of the COVID pandemic. 198 patients completed treatment and had evaluable tissue samples at baseline and EOT (Arm A: n = 51, Arm B: n = 74, Arm C: n = 73). Baseline mean Ki67 values were well balanced. Therapy was well tolerated and adverse events ≥ grade 3 were similarly rare across arms (A: 3.3%, B+C: 3.5%). The mean % reduction in Ki67 for each arm was: Arm A (letrozole): 71%, Arm B (letrozole + 40mg megestrol): 79%, Arm C (letrozole + 160mg megestrol): 80%. There was a statistically significantly greater reduction in Ki67 with megestrol combinations (B+C) versus letrozole alone (A) (P = 0.013). Analyses of secondary IHC endpoints and ER ChIP-Seq are ongoing and will be presented. Conclusion: Addition of the PR agonist megestrol enhanced the anti-proliferative effect of letrozole in this window-of opportunity trial. Megestrol combinations were well tolerated, and the anti-proliferative effect was observed in both low and high dose arms. These data support the potential use of low-dose megestrol as an inexpensive and well-tolerated means of improving aromatase inhibitor efficacy. Low dose megestrol can also ameliorate hot flashes and therefore might be a strategy to improve both treatment adherence and clinical outcomes for patients taking adjuvant endocrine therapy.

Results of a study examining the use of onabotulinumtoxinA in pediatric patients with overactive bladder

There is a lack of approved treatments for pediatric patients with overactive bladder (OAB) with inadequate response to anticholinergic therapy. OnabotulinumtoxinA 100U is approved to treat OAB in adults based on data from randomized, pivotal trials. To investigate the efficacy and safety of onabotulinumtoxinA treatment of OAB in children aged 12-17 years who were not adequately managed with anticholinergics. In this multinational, multicenter, randomized, double-blind, parallel-group, multiple-dose study (NCT02097121), pediatric patients with OAB were randomized 1:1:1 to receive onabotulinumtoxinA 25U, 50U, or 100U (≤6U/kg). Patients could request retreatment starting at week 12. The primary endpoint was change from baseline to week 12 after treatment 1 in daily frequency of daytime urinary incontinence (UI) episodes. Safety assessments evaluated treatment-emergent adverse events (TEAEs). Of 68 screened patients, 55 received ≥1 treatment. Mean age was 14 years; 85.5% of patients were female. At week 12 after treatment 1, least squares mean change from baseline in daily frequency of daytime UI episodes showed a numerically greater reduction in the 100U arm (-2.4) versus the 25U arm (-1.4; P=0.38), with a significant within-group change from baseline in the 100U arm (P=0.0027). Achievement of treatment response was significantly greater with onabotulinumtoxinA 100U vs 25U (Figure). Median time to request retreatment was ≥16 weeks in all groups. The most frequently reported TEAEs were nasopharyngitis (10.9%) and urinary tract infection (UTI; 10.9%). Urinary retention was observed in 1 patient during treatment cycle 2; there were no serious TEAEs of UTI or urinary retention. Throughout 2 additional treatment cycles continued efficacy for the 100U dose arm was observed along with a consistent safety profile. Change in daily frequency of UI episodes at week 12 in treatment cycle 1 was not significantly different between arms. However, ≥50% response rate was significantly higher with onabotulinumtoxinA 100U versus 25U. Enrollment challenges that lowered the sample size could have reduced statistical power. Also, the lack of a placebo arm and the observed benefit with the 25U comparator limited interpretation. OnabotulinumtoxinA injections were well tolerated in children with OAB at all doses studied. Although the primary endpoint was not met, the significantly greater treatment response rate observed with onabotulinumtoxinA 100U versus 25U suggests additional benefit of the higher dose, without additional safety concerns.

The effects of prehospital TXA on mortality and neurologic outcomes in patients with traumatic intracranial hemorrhage: A subgroup analysis from the prehospital TXA for TBI trial.

In the prehospital tranexamic acid (TXA) for traumatic brain injury (TBI) trial, TXA administered within 2 hours of injury in the out-of-hospital setting did not reduce mortality in all patients with moderate/severe traumatic brain injury (TBI). We examined the association between TXA dosing arms, neurologic outcome, and mortality in patients with intracranial hemorrhage (ICH) on computed tomography (CT). This was a secondary analysis of the Prehospital Tranexamic Acid for TBI Trial ( ClinicalTrials.gov [NCT01990768]) that randomized adults with moderate/severe TBI (Glasgow Coma Scale score < 13) and systolic blood pressure ≥ 90 mm Hg within 2 hours of injury to a 2-g out-of-hospital TXA bolus followed by an in-hospital saline infusion, a 1-g out-of-hospital TXA bolus/1-g in-hospital TXA infusion, or an out-of-hospital saline bolus/in-hospital saline infusion (placebo). This analysis included the subgroup with ICH on initial CT. Primary outcomes included 28-day mortality, 6-month Glasgow Outcome Scale-Extended (GOSE) ≤ 4, and 6-month Disability Rating Scale (DRS). Outcomes were modeled using linear regression with robust standard errors. The primary trial included 966 patients. Among 541 participants with ICH, 28-day mortality was lower in the 2-g TXA bolus group (17%) compared with the other two groups (1-g bolus/1-g infusion 26%, placebo 27%). The estimated adjusted difference between the 2-g bolus and placebo groups was -8·5 percentage points (95% confidence interval [CI], -15.9 to -1.0) and between the 2-g bolus and 1-g bolus/1-g infusion groups was -10.2 percentage points (95% CI, -17.6 to -2.9). Disability Rating Scale at 6 months was lower in the 2-g TXA bolus group than the 1-g bolus/1-g infusion (estimated difference - 2.1 [95% CI, -4.2 to -0.02]) and placebo groups (-2.2 [95% CI, -4.3, -0.2]). Six-month GOSE did not differ among groups. A 2-g out-of-hospital TXA bolus in patients with moderate/severe TBI and ICH resulted in lower 28-day mortality and lower 6-month DRS than placebo and standard TXA dosing. Therapeutic/Care Management; Level II.

Abstract CT087: A phase 1/2, open-label, randomized, dose-finding and dose expansion study of gedatolisib in combination with darolutamide in metastatic castration-resistant prostate cancer (mCRPC)

Abstract Background: Progression to metastatic castration-resistant prostate cancer (mCRPC) occurs in most patients treated with androgen receptor signaling inhibitors (ARSi) for advanced disease. Preclinical studies demonstrate that AR and PI3K - AKT - mTOR (PAM) pathways interact through reciprocal negative feedback, whereby inhibition of one pathway activates the other. Thus, combining a PAM inhibitor with an ARSi may deliver improved anti-cancer activity in patients with mCRPC. A Phase 2 trial in 129 patients with mCRPC who progressed on abiraterone demonstrated improved median radiographic progression-free survival (rPFS) when samotolisib, a dual PI3K-mTOR inhibitor, was added to enzalutamide. These results form the basis for this clinical trial of gedatolisib, a potent PAM inhibitor, in combination with darolutamide in men with mCRPC who have previously progressed on ARSi (NCT06190899). Methods: This open-label, multicenter, Phase 1/2 study will evaluate the safety and efficacy of gedatolisib in combination with darolutamide in men with mCRPC who have progressed on ARSi. In Phase 1, 36 patients will be randomized to one of two dose arms to evaluate dose limiting toxicities (DLTs) and determine the recommended Phase 2 dose (RP2D). Gedatolisib will be administered once weekly for 3-weeks-on/1-week-off: Arm 1 - 120 mg and Arm 2 - 180 mg, with darolutamide 600 mg orally administered twice daily. Arm 2 may be dose de-escalated depending on the number of DLTs observed. In Phase 2, 12 additional patients will be enrolled at the RP2D (n= 30). Key inclusion criteria include adult males (≥ 18 years) with mCRPC who have progressed on or after treatment with one next-generation ARSi. Key exclusion criteria include males with adenocarcinoma with a small cell component and with ≥10% neuroendocrine type cells; prior treatment with PI3K, AKT, or mTOR inhibitor; prior chemotherapy or radiopharmaceutical therapy for mCRPC; uncontrolled type 1/2 diabetes; or active brain or leptomeningeal metastases. Primary endpoints for Phase 1 are safety and tolerability (incidence of DLTs, adverse events, and determination of maximum tolerated dose) determination of the recommended Phase 2 dose (RP2D), PK, and Bayesian Optimal Interval utility score. Primary endpoints for Phase 2 are rPFS rate at 6 months based on Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 with modifications as specified in Prostate Cancer Working Group 3 criteria. Secondary endpoints include rPFS rates at 9 and 12 months, overall rPFS, prostate-specific antigen response of ≥50% decrease from baseline at 4, 8, 12, and 16 weeks, overall response rate, duration of response, clinical benefit rate, overall survival rate at 18 and 24 months, and safety. The trial is currently open for enrollment. Citation Format: Adam Sharp, Alice Bernard-Tessier, Delphine Borchiellini, Johann de Bono, Karim Fizazi, Gwenaelle Gravis, David Lorente, Hakim Mahammedi, Begona Mellado, David Olmos, Simon Pacey, Jose Piulats, Sara P. Ramirez, Igor Gorbatchevsky, Elisabeth Heath. A phase 1/2, open-label, randomized, dose-finding and dose expansion study of gedatolisib in combination with darolutamide in metastatic castration-resistant prostate cancer (mCRPC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT087.

501 Systemic Immunological Suppression in Glioblastoma Is Targeted by Concurrent VEGF and PD-1 Inhibition in a Dose-Dependent Manner: Cellular Indexing of Transcriptomes and Epitopes by Sequencing (CITE-Seq) From a Randomized Controlled Trial

INTRODUCTION: Anti-PD1 blockade has had poor efficacy in recurrent glioblastoma (rGBM) across three RCTs. VEGF, a proangiogenic factor that is upregulated in rGBM, contributes to tumor-associated immunosuppression and is widely targeted through bevacizumab. Preclinical data indicate a potential dose-dependent effect of anti-VEGF therapy on immunomodulation. Hence, a combination of anti-PD-1 and anti-VEGF agents is a promising approach for rGBM, for which an RCT was conducted. METHODS: Patients with rGBM were administered nivolumab (240mg IV q2weeks) plus either standard dose bevacizumab (10mg/kg) or low dose bevacizumab (3mg/kg) IV q2weeks, with 1:1 randomization. Stratification factors were age, performance status, extent of resection, and MGMT methylation status. Primary endpoint was overall survival (OS) at 12 months. CITE-Seq was performed on 16 patients across trial arms, both pre- and on-therapy, yielding total 32 immunological profiles. For control, CITE-seq was done on three patients receiving anti-VEGF therapy alone. RESULTS: 90 patients were enrolled with median age of 60.6 years and 45 patients per arm. Both arms had similar OS at 12 months (P = 0.14). Significantly higher OS was found in posthoc analysis for patients aged = 60 years with standard dose. Distinct immune cell populations were identified and differential changes in myeloid-derived suppressor cells (MDSCs) found across trial arms on-therapy. Network medicine approach identified VEGF as target to reduce MDSCs, with VEGF primarily expressed by responders’ MDSCs. Differential gene expression analysis identified increased pro-inflammatory signatures in standard dose arm. CONCLUSIONS: Standard dose bevacizumab was associated with increased inflammatory response and reduction of immunosuppressive MDSC. These mechanistic insights potentially explain survival benefit seen with concurrent VEGF and PD-1 inhibition in elderly rGBM patients.

Quantitative evaluation of trastuzumab deruxtecan pharmacokinetics and pharmacodynamics in mouse models of varying degrees of HER2 expression.

Trastuzumab deruxtecan (T-DXd; DS-8201; ENHERTU®) is a human epithelial growth factor receptor 2 (HER2)-directed antibody drug conjugate (ADC) with demonstrated antitumor activity against a range of tumor types. Aiming to understand the relationship between antigen expression and downstream efficacy outcomes, T-DXd was administered in tumor-bearing mice carrying NCI-N87, Capan-1, JIMT-1, and MDA-MB-468 xenografts, characterized by varying HER2 levels. Plasma pharmacokinetics (PK) of total antibody, T-DXd, and released DXd and tumor concentrations of released DXd were evaluated, in addition to monitoring γΗ2AX and pRAD50 pharmacodynamic (PD) response. A positive relationship was observed between released DXd concentrations in tumor and HER2 expression, with NCI-N87 xenografts characterized by the highest exposures compared to the remaining cell lines. γΗ2AX and pRAD50 demonstrated a sustained increase over several days occurring with a time delay relative to tumoral-released DXd concentrations. Invitro investigations of cell-based DXd disposition facilitated the characterization of DXd kinetics across tumor cells. These outputs were incorporated into a mechanistic mathematical model, utilized to describe PK/PD trends. The model captured plasma PK across dosing arms as well as tumor PK in NCI-N87, Capan-1, and MDA-MB-468 models; tumor concentrations in JIMT-1 xenografts required additional parameter adjustments reflective of complex receptor dynamics. γΗ2AX longitudinal trends were well characterized via a unified PD model implemented across xenografts demonstrating the robustness of measured PD trends. This work supports the application of a mechanistic model as a quantitative tool, reliably projecting tumor payload concentrations upon T-DXd administration, as the first step towards preclinical-to-clinical translation.

Outcomes in Adult Inflammatory Bowel Disease Clinical Trials: Assessment of Similarity Among Participants with Adolescent-onset and Adult-onset Disease.

Most paediatric inflammatory bowel disease [IBD] studies are performed after medications are approved in adults, and the majority of participants in these studies are adolescents. We hypothesised that adolescent-onset IBD is not fundamentally different from adult-onset IBD. If this is correct, the value of delaying access to novel drugs in adolescents becomes questioned. Data from 11 randomised, double-blind, placebo-controlled, adult Phases 2 and 3 trials of four biologics were analysed. Participants were categorised as having adolescent- or adult-onset disease [diagnosed 12 to <18, or ≥18 years]. Multivariable modelling explored the association between age at diagnosis and response to treatment, after adjustment for disease duration, extent, and severity at baseline. Data from dose arms were pooled to evaluate similarity of therapeutic response between adolescent- and adult-onset IBD within the same trial [not between doses or across trials]. Ratios of odds ratios [ORs] between the two groups were evaluated. Data from 6283 study participants (2575 with Crohn's disease [CD], 3708 with ulcerative colitis [UC]) were evaluated. Of 2575 study participants with CD, 325 were 12-<18 years old at diagnosis; 836 participants [32.4%] received placebo. Of 3708 participants with UC, 221 were 12-<18 years old at diagnosis; 1212 [33%] were receiving placebo. The majority of the ratios of ORs were within 2-fold, suggesting that responses in adolescent- and adult-onset participants are generally similar. Data presented lend support for extrapolating efficacy of biologics from adults to adolescents with IBD, which would facilitate earlier labelling and patient access.

Phase 1 Healthy Volunteer Study of AL01211, an Oral, Non-brain Penetrant Glucosylceramide Synthase Inhibitor, to Treat Fabry Disease and Type 1 Gaucher Disease.

Glycosphingolipid (GSL) storage diseases are caused by deficiencies in the enzymes that metabolize different GSLs in the lysosome. Glucosylceramide synthase (GCS) inhibitors reduce GSL production and have potential to treat multiple GSL storage diseases. AL01211 is a potent, oral GCS inhibitor being developed for the treatment of Type 1 Gaucher disease and Fabry disease. AL01211 has minimal central nervous system penetration, allowing for treatment of peripheral organs without risking CNS-associated adverse effects. AL01211 was evaluated in a Phase 1 healthy volunteer study with single ascending dose (SAD) and multiple ascending dose (MAD) arms, to determine safety, pharmacokinetics including food effect, and pharmacodynamic effects on associated GSLs. In the SAD arm, AL01211 showed a Tmaxof approximately 3.5 hours, mean clearance (CL/F) of 130.1 L/h, and t1/2of 39.3 hours. Consuming a high-fat meal prior to dose administration reduced exposures 3.5-5.5-fold, indicating a food effect. In the MAD arm, AL01211 had an approximately 2-fold accumulation, reaching steady-state levels by 10 days. Increasing exposure inversely correlated with a decrease in GSL with plasma glucosylceramide and globotriacylceramide reduction from baseline levels, reaching 78% and 52% by day 14, respectively. AL01211 was generally well-tolerated with no AL01211 associated serious adverse events, thus supporting its further clinical development.

(074) Safety and Efficacy Varying Doses of Prednisone Post Vasectomy Reversal: Results from a Randomized, Controlled Trials

Abstract Introduction There has been significant ongoing debate on the role and utility of prednisone post-vasectomy reversal to improve sperm counts and long-term patency. However, there are relatively limited data available on the efficacy, with essentially no data available on pregnancy outcomes. Objective To report outcomes of randomized, clinical trial evaluating varying protocols for prednisone administration post vasectomy reversal. Methods A randomized, controlled trial was performed (NCT04788823) with an anticipated 100 men randomized to one of four prednisone protocols post vasectomy reversal: no treatment (Control), prednisone 20 mg taper over 1 month beginning the first month post-op and then every other month x 6 months (High Dose), prednisone 20 mg taper over 1 month if declining sperm counts or a 0 count were identified (PRN), and prednisone 5 mg daily x 1 week, followed by no treatment x 1 week, continued for 6 months (Low Dose). Randomization tables were created a priori to ensure an equal representation of differing durations of time since the original vasectomy as well as an equal distribution of VV/VV vs VV/EV vs EV/EV procedures. All men had semen analyses obtained monthly for a first 12 months. Surveys were sent periodically to follow-up on subsequent pregnancies. Inclusion criteria included having a female partner &amp;lt;36 years of age with no known fertility factors. Results A total of 75 men were ultimately enrolled due to interim findings suggesting inferiority of the High Dose and PRN treatment arms and decision to close those arms before completing full enrollment. Final enrollment included: Control (n=25), High Dose (n=14), PRN (n=11), and Low Dose (n=25). The mean patient age was 38.5 years, mean partner age 29.6, and mean time since vasectomy 6.3 years (SD 5.0). 82% of men underwent VV/VV, while 15% VV/EV, and 3% EV/EV. All men underwent successful anastomosis bilaterally with no cases of one-sided or no anastomosis performed. At a mean follow-up of 16.5 months (range 7.6 to 25.1), an overall patency (sperm observed on sample) rate of 93% was noted (Control 96%, High Dose 93%, PRN 100%, Low Dose 88%, p=0.41). The mean sperm concentration post-op was 34.4 million/ml (Control 24.0, High Dose 38.4, PRN 21.0, Low Dose 49.8, p=0.33). Patency rates at 6- and 12-months were: 6-months (Control 88%, High Dose 80%, PRN 83%, Low Dose 94%, p=0.75); 12-months (Control 75%, High Dose 71%, PRN 75%, Low Dose 91%). Mean sperm concentrations at 6- and 12-months were: 6-months (Control 15.7, High Dose 21.5, PRN 6.9, Low Dose 25.7, p=0.50); 12-months (Control 12.6 million/ml, High Dose 17.1, PRN 36.1, Low Dose 50.4, p=0.64) At the 6-month post-op time point, the overall rate of pregnancy was 47%, with notable differences between cohorts: Control 57%, High Dose 10%, PRN 38%, and Low Dose 67%, p=0.02. No patients discontinued prednisone due to side effects. Conclusions Prednisone taper protocols appear to reduce the likelihood for pregnancy following vasectomy reversal. Use of low-dose prednisone results in non-statistically higher rates of patency at 6- and 12-months, mean sperm concentration at 6- and 12-months, and pregnancy at 6-months. Overall results suggest superiority of either no prednisone post-vasectomy reversal or a low dose protocol but argue against the use of higher dosages at any time due to its negative impacts on pregnancy rates despite maintained sperm counts. Disclosure No.

Safety, pharmacokinetics, and food effect of sudapyridine (WX-081), a novel anti-tuberculosis candidate in healthy Chinese subjects.

This study aimed to assess the safety, pharmacokinetics, and food impact on sudapyridine (WX-081), a novel drug designed to inhibit mycobacterium ATP synthase, with clinical applications for drug-resistant tuberculosis (TB) treatment. The research comprised two arms: a single ascending dose (SAD) arm (30 to 600 mg, N = 52) and a multiple ascending dose (MAD) arm (200 to 400 mg, N = 30). The influence of food was evaluated using a 400 mg dose within an SAD cohort. Plasma concentrations of WX-081 and M3 (main metabolite of WX-081) were analyzed using a validated liquid-chromatography tandem mass spectrometry method. In the SAD arm, mean residence time (MRT0-t), terminal half-life, and clearance of WX-081 ranged from 18.87 to 52.8 h, 31.39 to 236.57 h, and 6.4 to 80.34 L/h, respectively. The area under the curve from time zero to the last measurable timepoint (AUC0-t) of WX-081 showed dose-proportional increases in the SAD arm. The disparity between fasted and fed states of WX-081 was significant (p < 0.05), with fed dosing resulting in a 984.07% higher AUC0-t and 961.55% higher maximum plasma concentration. In both the SAD and MAD arms, one case each exhibited a 1 degree atrioventricular block. No QTc elongation was observed, and adverse events were not dose-dependent. Favorable exposure, tolerability, safety, and an extended MRT0-t suggest that WX-081 holds promise as a phase II development candidate for drug-resistant TB treatment.

SR1375: Phase 1 results of a novel, orally administered lipoprotein‐associated phospholipase A2 inhibitor targeting diabetic macular oedema

Aims/Purpose: Lipoprotein‐associated phospholipase A2 (Lp‐PLA2) activity have been linked to a higher risk of diabetic retinopathy and inhibiting Lp‐PLA2 activity showed improvement in vision and macular oedema for patients with diabetic macular oedema (DME). SR1375 is an orally available, selective inhibitor of Lp‐PLA2 that shows significant retinal vascular leakage reduction in preclinical studies, and is being developed for DME. A phase 1, randomized, double‐blind, placebo‐controlled study is conducted to evaluate the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of SR1375 in healthy subjects.Methods: A total of 72 healthy subjects were enrolled, with 54 had received SR1375. 48 subjects were in the single ascending dose arms (1, 3, 10, 30, 100 and 200 mg) while 24 subjects were in the multiple ascending dose arms (5, 15 and 50 mg once daily for 14 days).Results: SR1375 was safe and well tolerated across all doses. It had excellent oral absorption with the exposure level increasing in an approximately dose proportional manner after single and multiple doses. The elimination of SR1375 was slow with a long t1/2 ranging from 28.8 to 90.0 h. The accumulation of SR1375 was not significant after multiple administrations. The plasma inhibition on Lp‐PLA2 activity by SR1375 was strong (up to 95%) and enduring, which was correlated with the concentration of SR1375 (IC50 as 1.41 ng/mL) and almost returned to basal level when the concentration of SR1375 was low enough.Conclusions: SR1375 was safe and effective in inhibiting plasma Lp‐PLA2. The safety and PK/PD profile supports the once daily therapy. A Phase 2 study for DME patients is planned later this year. It would be a 12‐week randomized, double‐blind and placebo‐controlled trial. The primary objective is to assess the effect of SR1375 on vision and oedema.