Citations

AbstractBackgroundAs new anti‐amyloid immunotherapies emerge for Alzheimer’s disease (AD), it is clear that early diagnosis of AD pathology is crucial for treatment success. This can be challenging in atypical presentations of AD and, together with our reliance on CSF or PET scans, can, at times, lead to delayed diagnosis. Here, we further explore the possible role of plasma tau phosphorylated at threonine 217 (P‐tau217) for the detection of primary AD or AD co‐pathology when frontotemporal dementia spectrum disorders are the main clinical presentation.MethodParticipants were recruited through ALLFTD, a North American multisite research consortium for the longitudinal assessment of frontotemporal lobar degeneration. After excluding cases with known FTD‐causing mutations, 573 participants with sporadic disease, mild cognitive/behavioral impairment, or healthy familial controls evaluated between 2014 and 2023 were included in this analysis (45.8% female, median age 66 years). 39 of those cases underwent neuropathological evaluation. Plasma P‐tau217 was measured with the Eli Lilly electrochemiluminescence‐based assay. P‐tau217 concentrations were compared by phenotype, disease severity, genotype, and, when available, neuropathological diagnosis with non‐parametric tests. Its diagnostic performance was tested with ROC curves. Associations between plasma P‐tau217 concentrations and clinical scales of global cognition, memory, executive function, motor function, and social cognition with linear regressions and non‐parametric tests.ResultPlasma P‐tau217 concentrations were higher in logopenic variant primary progressive aphasia (lvPPA) and amnestic dementia (AmDem), compared to participants with normal cognition or other FTD phenotypes. P‐tau217 concentrations were higher in APOE e4 carriers, compared to non‐carriers, regardless of phenotype, but were not affected by disease severity. P‐tau217 concentrations showed associations with clinical measures of global cognition, memory, and executive function, but had no associations with measures of motor function or social cognition. Plasma P‐tau217 concentrations were elevated in high and intermediate ADNC scoring, or more advanced Braak stages, even when AD was not the primary pathology.ConclusionEven when FTD is suspected, high plasma p‐tau 217 concentrations are strongly associated with underlying AD as primary pathology or contributing co‐pathology. Plasma P‐tau217 could be a tool to support the development of disease‐modifying therapies for atypical Alzheimer’s disease presentations or for FTD cases with Alzheimer’s disease co‐pathology.

AbstractBackgroundMany treatments targeting frontotemporal lobar degeneration (FTLD) are in the developmental pipeline, but the rarity of the disease, coupled with the behavioral and motor features of FTLD, make it challenging to identify sufficient trial participants who can attend frequent in‐person visits. Decentralized clinical trial designs with remote evaluations are attractive alternatives but require validated tools for symptom tracking. Our previous cross‐sectional analyses showed that cognitive tasks deployed via the ALLFTD Mobile App are reliable and sensitive to early stages of disease. The current study seeks to evaluate whether unsupervised smartphone cognitive tests are sensitive to longitudinal changes that occur with increasing FTLD disease stage.MethodThe study included 194 participants (mean baseline age 54.30, SD = 15.66; mean education = 16.52, SD = 2.31; 55.2% women) who were asymptomatic (Clinical Dementia Rating plus FTLD (CDR®+NACC‐FTLD) = 0 [n = 109; 43 carriers of FTLD‐associated genetic variants]), prodromal (CDR®+NACC‐FTLD = 0.5 [n = 39]), or symptomatic (CDR®+NACC‐FTLD>0.5 [n = 46]) at baseline. Participants completed ALLFTD Mobile App smartphone versions of Stroop, flanker, and 2‐back tasks, as well as an adaptive associative memory task, every six months for up to two years. Linear‐mixed effects models investigated the effect of disease severity on cognitive trajectories by testing the interaction of baseline CDR®+NACC‐FTLD box score and time on smartphone test scores. Analyses were repeated in the subsample of asymptomatic/prodromal CDR®+NACC‐FTLD<1) familial FTLD mutation carriers (C9orf72, n = 27; MAPT, n = 16). All models controlled for age, education, and sex.ResultGreater baseline disease severity was associated with lower cognitive scores across all tasks (β range: ‐0.28 to ‐0.13; p’s < 0.001), and faster rates of decline on the memory and 2‐back tasks (β range: ‐0.15 to ‐0.07; p’s<0.04). When the sample was restricted to asymptomatic and prodromal individuals (CDR®+NACC FTLD<1), greater baseline disease severity was still associated with lower scores across most tasks (β range: ‐0.48 to ‐0.27; p’s<0.002; 2‐back: β = ‐0.19, p = 0.26). When the sample was restricted to asymptomatic/prodromal mutation carriers, disease severity remained associated with the memory and flanker tasks (β range: ‐0.85 to ‐0.45; p’s<0.01).ConclusionThis study provides initial evidence that longitudinal smartphone‐based cognitive measurements capture the accelerated cognitive worsening that accompanies increasing disease progression in FTLD.

AbstractBackgroundAutosomal dominant progranulin (GRN) mutations are a common genetic cause of frontotemporal lobar degeneration. Though clinical trials for GRN‐related therapies are underway, there is an unmet need for biomarkers that can predict symptom onset and track disease progression. We previously showed that presymptomatic GRN carriers exhibit thalamocortical hyperconnectivity that increases with age when they are presumably closer to symptom onset. However, whether hyperconnectivity arises concomitantly with markers of neurodegeneration remains unclear.MethodUtilizing T1 and task‐free functional magnetic resonance imaging (tf‐fMRI) from 49 presymptomatic and 26 symptomatic GRN mutation carriers, we determined the relationships between functional connectivity as measured by voxel‐wise whole brain degree and GRN‐relevant markers of disease progression, which included plasma neurofilament light chain (NfL) concentrations, CSF complement C1q and C3b protein levels, grey matter atrophy, and OCD symptom severity.ResultNfL concentrations were associated with frontotemporoparietal and thalamic hyperconnectivity in presymptomatic GRN carriers and extensive regions of atrophy in symptomatic carriers. Complement levels were associated with regions of hyperconnectivity, but not gray matter, in symptomatic carriers. Presymptomatic carriers with thalamic hyperconnectivity tended to have lower grey matter volume in bilateral insula and left lateral parietal cortex, which are among regions that deteriorate in GRN‐FTD. OCD symptom severity was associated with hypoconnectivity across all GRN carriers.ConclusionIn presymptomatic carriers, the co‐occurrence of hyperconnectivity, high NfL, and low gray matter suggests that tf‐fMRI hyperconnectivity may portend the onset of the neurodegenerative phase. These findings point toward hyperconnectivity as an indicator of approaching symptomatic onset.

Abstract Patients with NF1-PN experience pain and other symptoms that negatively impact functioning and quality-of-life. We present patient- and parent proxy-reported HRQoL outcomes from ReNeu (NCT03962543), a pivotal, phase 2b trial of mirdametinib, an investigational MEK1/2 inhibitor, in adults and children (≥2 y) with NF1-PN causing morbidities. Fifty-eight adults and 56 children received mirdametinib (2 mg/m2 BID; 3-weeks-on/1-week-off, 28-d cycles). Change in HRQoL was assessed by Pediatric QoL Inventory (PedsQL) 4.0 Generic Core Scales from baseline across the 24-cycle treatment phase; change from baseline at Cycle 13 (C13) was a prespecified secondary endpoint. PedsQL is a HRQoL measure for adults and children with a Total Score (TS) and 4 subscales: physical, emotional, social, and school/work. Items are reported on a 0-100 scale (higher scores=better HRQoL). Clinically meaningful improvement was defined as change from baseline &gt;9.7 points for adults, &gt;8.5 points for child self-report, and &gt;9.0 points for parent proxy-report. PedsQL-TS improvement (least-squares mean, LSM [SE] change) from baseline at C13 was 3.9 (1.6; P=.018; n=34) for adults, 4.0 (2.4; P=.096; n=38) for children by self-report, and 5.6 (1.9; P=.005; n=43) by parent proxy-report. PedsQL-TS improvements for adults and children by parent proxy-report (not by children self-report) were observed early (at C5 and C3, respectively) and sustained through C24. Clinically meaningful improvement in PedsQL-TS from baseline at C13 was achieved by 37% (10/27) adults, 45% (13/29) children by self-report, and 47% (15/32) children by parent proxy-report (among patients who could have achieved a clinically meaningful change from baseline). Significant (P&lt;.05) improvement from baseline to C13 was reported for physical (adults, children, and parent proxy-report), school/work (adults), and emotional and social (parent proxy-report) subscales. Adults and children (by parent proxy-report) with NF1-PN had clinically meaningful, early, and sustained improvement in HRQoL over the course of mirdametinib treatment.

Abstract BACKGROUND Patients with NF1-PN in the phase 2b ReNeu trial (NCT03962543) of mirdametinib in adults (N=58, ≥18y) and children (N=56, 2-17y) had a deeper median (range) best reduction (adults: -41% [-90% to 13%]; children: -42%, [-91% to 48%]) from baseline in target PN volume than previously published in trials of other agents in NF1-PN. METHODS In the 24-cycle (1-cycle=28d) treatment phase, objective response rate (ORR) was the percentage with confirmed objective responses (OR) of ≥20% target PN volume reduction from baseline on consecutive MRIs (by blinded independent central review). This analysis includes patients achieving deep response (&gt;50% best reduction from baseline in target PN volume) regardless of OR and inclusive of patients in the long-term follow-up. Exploratory analysis of baseline characteristics compared patients with deep response and patients with ≤50% volume reduction. RESULTS ORR was 41% (24/58) in adults and 52% (29/56) in children treated with mirdametinib. 62% (15/24) of adults and 52% (15/29) of children who achieved OR had deep response. To further characterize deep response, 2 adults and 3 children with deep response without confirmation or in long-term follow-up were included. Of those with a deep response, 35% (6/17) of adults and 72% (13/18) of children were investigator-defined as having progressing PN. Patients achieved deep response regardless of baseline age, sex, target PN volume, tumor location, or progression status. For adults and children, median time to best percent change from baseline in PN volume for patients achieving deep response was 25.4 and 21.8mo; for patients with reductions of ≥20% to ≤50% was 15.3 and 15.2mo; for patients with reductions of &lt;20% was 7.8 and 4.2mo, respectively. CONCLUSIONS Patients had a similar likelihood of achieving deep response across assessed baseline characteristics. A trend between deep response and longer treatment duration suggests a benefit of prolonged therapy with mirdametinib.

PURPOSE Pharmacologic therapies for neurofibromatosis type 1-associated plexiform neurofibromas (NF1-PNs) are limited; currently, none are US Food and Drug Administration–approved for adults. METHODS ReNeu is an open-label, multicenter, pivotal, phase IIb trial of mirdametinib in 58 adults (≥18 years of age) and 56 children (2 to 17 years of age) with NF1-PN causing significant morbidities. Patients received mirdametinib capsules or tablets for oral suspension (2 mg/m 2 twice daily, maximum 4 mg twice daily), regardless of food intake, in 3 weeks on/1 week off 28-day cycles. The primary end point was confirmed objective response rate (ORR; proportion of patients with a ≥20% reduction of target PN volume from baseline on consecutive scans during the 24-cycle treatment phase) assessed by blinded independent central review (BICR) of volumetric magnetic resonance imaging. RESULTS Twenty-four of 58 adults (41%) and 29 of 56 children (52%) had a BICR-confirmed objective response during the 24-cycle treatment phase; in addition, two adults and one child had confirmed responses during long-term follow-up. Median (range) target PN volumetric best response was –41% (−90 to 13) in adults and –42% (−91 to 48) in children. Both cohorts reported significant and clinically meaningful improvement in patient- or parent proxy-reported outcome measures of worst tumor pain severity, pain interference, and health-related quality of life (HRQOL) that began early and were sustained during treatment. The most commonly reported treatment-related adverse events were dermatitis acneiform, diarrhea, and nausea in adults and dermatitis acneiform, diarrhea, and paronychia in children. CONCLUSION In ReNeu, the largest multicenter NF1-PN trial reported to date, mirdametinib treatment demonstrated significant confirmed ORRs by BICR, deep and durable PN volume reductions, and early, sustained, and clinically meaningful improvement in pain and HRQOL. Mirdametinib was well-tolerated in adults and children.

Abstract BACKGROUND PN in patients (pts) with NF1 can cause pain, disfigurement, impaired quality of life (QoL), and it can undergo malignant transformation. ReNeu (NCT03962543), a multicenter, open-label, phase 2b study, evaluated efficacy and safety of the highly selective, oral, investigational MEK1/2 inhibitor mirdametinib in adults (≥18 y) and children (2-17 y) with inoperable NF1 PN causing significant morbidities. MATERIAL AND METHODS Mirdametinib was administered as a capsule or dispersible tablet (2 mg/m2 BID, max 4 mg BID) without regard to food in 3 wk on/1 wk off 28-d cycles. The primary endpoint was confirmed objective response rate (ORR; percentage of pts with confirmed MRI-assessed ≥20% reduction of target PN volume by blinded independent central review [BICR] within the 24-cycle treatment phase). The minimum clinically relevant ORR (null) was defined as 23% for adults and 20% for children. Pts could continue treatment in an optional long-term follow-up (LTFU) phase. Additional key endpoints were duration of response (DoR), time to response (TTR), change from baseline in target PN volume, worst pain severity (Numerical Rating Scale-11 [NRS-11]), pain interference (Pain Interference Index [PII]), health-related (HR) QoL (PedsQL), and safety. RESULTS All 114 pts (58 adult, 56 children) received mirdametinib. As of the 20 Sept 2023 data cutoff (DCO), BICR-confirmed ORR during the treatment phase was 41% (95% CI, 29-55; P&lt;.001 vs null) in adults and 52% (95% CI, 38-65; P&lt;.001 vs null) in children. Two adults and 1 child had a confirmed response in the ongoing LTFU. Median (range) target PN volumetric best response from baseline was -41% (-90, 13) and -42% (-91, 48) in adult and children, respectively. As of the DCO, median treatment duration was 22 mo for each cohort, and median DoR was not reached. Median (range) TTR was 7.8 (4-19) mo in adults and 7.9 (4-19) mo in children. Adults and children had statistically significant improvements from baseline to Cycle 13 in NRS-11, PII, and key PedsQL measures. Most frequent (≥35% pts) treatment-emergent adverse events (TEAEs) were dermatitis acneiform, diarrhea, nausea, and vomiting in adults and diarrhea, dermatitis acneiform, and vomiting in children. 16% and 25% of adults and children, respectively, had grade ≥3 treatment-related AEs, and 22% and 9%, respectively, discontinued due to TEAEs. CONCLUSIONS In ReNeu, the largest multicenter NF1 PN trial reported to date, mirdametinib demonstrated a statistically significant ORR by BICR, with deep and durable PN volume reductions, significant improvements in pain severity, pain interference, and HRQoL, and a manageable safety profile in both adults and children. Together with a dispersible tablet formulation, these results underscore the potential of mirdametinib to become an important new treatment option for NF1 PN pts across all ages.

3016 Background: PN in patients (pts) with NF1 can cause pain, disfigurement, impaired quality of life (QoL), and can undergo malignant transformation. ReNeu (NCT03962543), a multicenter, open-label, Phase 2b study, evaluated efficacy and safety of the highly selective, oral, investigational MEK1/2 inhibitor mirdametinib in adult (≥18 y) and pediatric (2-17 y) pts with inoperable NF1 PN causing significant morbidities. Methods: Mirdametinib was administered as a capsule or dispersible tablet (2 mg/m 2 BID, max 4 mg BID) without regard to food in 3 wk on/1 wk off 28-d cycles. The primary endpoint was confirmed objective response rate (ORR; percentage of pts with MRI-assessed ≥20% reduction of target PN volume by blinded independent central review [BICR] within the 24-cycle treatment phase). The minimum clinically relevant ORR (null) was defined as 23% for adults and 20% for pediatrics. Ptscould continue treatment in an optional long-term follow-up (LTFU) phase. Additional key endpoints were duration of response (DoR), time to response (TTR), change from baseline (BL) in target PN volume, pain severity (Numerical Rating Scale-11 [NRS-11]), pain interference (Pain Interference Index [PII]), health-related (HR) QoL (PedsQL), and safety. Results: All114 pts (58 adult, 56 pediatric) received mirdametinib. As of the 20 Sept 2023 data cutoff (DCO), BICR-confirmed ORR during the treatment phase was 41% (95% CI, 29-55; P<.001 vs null) in adults and 52% (95% CI, 38-65; P<.001 vs null) in pediatric pts. Two adult pts and 1 pediatric pt also had a confirmed response in the ongoing LTFU. Median (min, max) target PN volumetric best response from BL was -41% (-90, 13) and -42% (-91, 48) in adult and pediatric pts, respectively. As of the DCO, median treatment duration was 22 mo for each cohort and median DoR was not reached. Median (range) TTR was 7.8 (4-19) mo in adult pts and 7.9 (4-19) mo in pediatric pts. Adult and pediatric pts had statistically significant improvements from BL to cycle 13 in NRS-11, PII, and key PedsQL measures. Most frequent (≥35% pts) treatment-emergent adverse events (TEAEs) were dermatitis acneiform, diarrhea, nausea, and vomiting in adults and diarrhea, dermatitis acneiform, and vomiting in pediatric pts. 16% and 25% of adult and pediatric pts, respectively, had grade ≥3 treatment-related AEs, and 22% and 9%, respectively, discontinued due to TEAEs. Conclusions: In ReNeu, the largest multicenter NF1 PN trial reported to date, mirdametinib demonstrated a statistically significant ORR by BICR, with deep and durable PN volume reductions, significant improvements in pain severity, pain interference, and HRQoL, and a manageable safety profile in both adults and children. Together with a dispersible tablet formulation, these results underscore mirdametinib’s potential to become an important new treatment option for NF1 PN pts across all ages. Clinical trial information: NCT03962543 .