Dihexa for Frontotemporal Dementia (FTD): The Latozinemab Phase 3 Failure, Progranulin Biology & the 2026 UK Review

Around 31,000 people in the UK live with frontotemporal dementia — and only about 3,000 are formally diagnosed in NHS England primary-care data. FTD is the most common form of young-onset dementia, typically appearing between 45 and 64, and it remains a disease with no NICE-recommended disease-modifying treatment in 2026. On 21 October 2025, Alector announced that its anti-sortilin antibody latozinemab (AL001) had failed the pivotal Phase 3 INFRONT-3 trial in FTD-GRN: plasma progranulin doubled, but disease progression on the CDR-NACC-FTLD Sum of Boxes was not slowed. The company subsequently cut its workforce by 49% and discontinued the open-label extension. In April 2026, Denali Therapeutics regained full rights to DNL593 (PTV:PGRN) from Takeda. Vesper Bio's oral sortilin modulator VES001 is reading out in H2 2026. And in March 2026 the AFTD's Hope Rising 2026 Benefit raised $2.1 million and recognised Emma and Bruce Willis with the Susan Newhouse Award of Hope, alongside the launch of the Emma & Bruce Willis Fund for Dementia Research. This is the rigorous 2026 UK review: where, mechanistically, does Dihexa sit in the FTD picture — and what does the brutal honesty of the latozinemab failure say about chasing FTD biology with single-mechanism pharmacology?

Frontotemporal Dementia in the UK 2026: A Diagnosis Gap of 80%

Frontotemporal dementia is the second-most-common cause of young-onset dementia in the UK after early-onset Alzheimer's disease, and in some series the most common. It is also one of the most consistently under-diagnosed neurodegenerative conditions in the NHS. Alzheimer's Research UK estimates that around 31,000 people in the UK live with FTD, accounting for around 1 in 30 of all dementia diagnoses. NHS England primary-care dementia data for June 2024 record fewer than 3,000 formally-diagnosed FTD cases against an estimated 15,000 suspected — a diagnosis gap of around 80%.

This matters clinically. Behavioural variant FTD (bvFTD) typically presents not with memory loss but with personality and behaviour change — apathy, disinhibition, loss of empathy, compulsive behaviour, dietary changes — symptoms that are often misattributed to mid-life depression, burnout, marital problems or "having a breakdown" for years before a formal diagnosis is reached. The 2025 JAMA Neurology systematic review by Logroscino and colleagues put global incidence at 2.28 per 100,000 person-years and prevalence at 9.17 per 100,000 — but emphasised that these are underestimates of the underlying disease, given diagnostic delay.

The age curve is the defining feature for families. Typical onset is between 45 and 64, with cases occasionally diagnosed in the late 30s. This is the working-age, peak-earning, school-age-children cohort. The economic, family and social consequences of an FTD diagnosis at 55 are categorically different from a typical Alzheimer's diagnosis at 78. Median survival from symptom onset is around 6-8 years for behavioural variant FTD, 8-12 years for primary progressive aphasia, and considerably shorter when motor neurone disease enters the picture (FTD-MND or FTD-ALS spectrum disease).

The diagnosis gap fuels the search behaviour that brings readers to pages like this one. Families whose loved ones are deteriorating behaviourally, who have been told "it's stress" or "it's depression" or "it's a midlife crisis" for years, search hard for explanations and for help. The same gap fuels interest in unlicensed compounds. This page exists because that search happens whether or not it is informed by evidence; the editorial position remains that the highest-yield first steps are diagnostic clarification through a memory clinic referral and engagement with specialist UK FTD services, not an unstudied peptide.

The Biology of Frontotemporal Dementia: Three Genes, Two Proteins, One Synaptic Endpoint

FTD is a clinically and pathologically heterogeneous group of disorders unified by selective frontal and temporal lobe degeneration. The clinical subtypes overlap with distinct molecular pathologies and (in around 30-40% of cases) identifiable single-gene causes.

The Three Clinical Variants

Behavioural variant FTD (bvFTD) accounts for ~60% of FTD cases and is dominated by changes in personality, social conduct and executive function: disinhibition, apathy, loss of empathy, perseveration, hyperorality and dietary change. Memory is relatively spared early on, which is one reason for diagnostic delay. Semantic variant primary progressive aphasia (svPPA), sometimes still called semantic dementia, produces progressive loss of word meaning and object knowledge, with relatively preserved fluency and grammar early on. Non-fluent variant primary progressive aphasia (nfvPPA) produces progressive loss of speech production, agrammatism and apraxia of speech, with relatively preserved comprehension. A fourth, logopenic variant PPA, has historically been classified within the PPA spectrum but is now recognised as more often an atypical Alzheimer's presentation.

Beyond these, FTD overlaps clinically with corticobasal syndrome, progressive supranuclear palsy, and motor neurone disease (FTD-MND / FTD-ALS spectrum), particularly in C9orf72-associated disease. The clinical heterogeneity is one reason a single mechanism-targeted drug, in a trial enrolling broad FTD populations, faces structural difficulties — even before the biological complexities below.

Two Molecular Pathologies: FTLD-Tau and FTLD-TDP

At neuropathology, FTD divides into two main protein-aggregation categories that account for ~95% of cases:

• FTLD-tau (~40% of cases): aggregates of microtubule-associated protein tau, including Pick bodies (the classical Pick's disease pathology), corticobasal-degeneration tau and PSP tau. Tau mutations (MAPT gene) cause monogenic FTLD-tau.
• FTLD-TDP (~50% of cases): aggregates of TAR DNA-binding protein 43 (TDP-43). Subdivided into TDP-A through TDP-E based on inclusion morphology and distribution. GRN mutations and C9orf72 expansions both produce FTLD-TDP pathology.
• FTLD-FUS and other rare proteinopathies make up the remaining ~5%.

The Three Main Monogenic Causes

MAPT mutations cause FTLD-tau disease, typically with behavioural variant FTD and prominent parkinsonism. Many MAPT mutations disrupt the splicing balance between 3R and 4R tau isoforms or directly impair tau microtubule binding.

GRN (progranulin) mutations cause FTD-GRN. The mechanism is haploinsufficiency: one loss-of-function copy reduces secreted progranulin protein by approximately 50%, leading to lysosomal dysfunction, microglial activation, complement-mediated synaptic pruning and TDP-43 aggregation. The MDPI 2025 review by Bhandari and colleagues covers this in detail. The therapeutic logic for FTD-GRN has been clean on paper: raise progranulin back to normal levels and you should rescue the downstream pathology. The brutal answer from the latozinemab Phase 3 trial in October 2025 is that doubling plasma progranulin does not, in practice, slow clinical disease — at least not on the timescale and endpoints tested.

C9orf72 hexanucleotide (GGGGCC) repeat expansion is the single most common genetic cause of both ALS and FTD, accounting for ~25% of familial FTD and ~10% of sporadic FTD. The pathology involves loss of normal C9orf72 protein function, RNA foci sequestering RNA-binding proteins, and translation of toxic dipeptide repeat proteins (poly-GA, poly-GP, poly-GR, poly-PA, poly-PR) from both strands. We covered the C9orf72 ALS-FTD overlap in detail in the ALS & MND review.

Microglial Dysfunction and Synaptic Loss: The Final Common Pathway

Across all three monogenic causes and most sporadic FTD, two convergent mechanisms recur: microglial dysfunction (with disrupted lysosomal function and abnormal complement-mediated synaptic pruning) and frank synaptic loss in frontal and temporal cortex. Progranulin is itself a microglial homeostatic factor; tau aggregation drives microglial activation; C9orf72 protein has roles in autophagy and lysosomal function in microglia.

This convergence matters for any drug aimed at the synaptic substrate. The downstream cellular endpoint — loss of dendritic spines, reduced cortical connectivity, declining functional networks — is shared across FTD subtypes and overlaps mechanistically with the synaptic loss described in the MCI and brain aging review and the Long COVID brain fog review. A peptide that supports synaptogenesis is, at minimum, hitting a relevant cellular substrate. Whether it can do so in the face of ongoing upstream pathology is the question that no Dihexa trial has tested in FTD.

The HGF/c-Met System and the Synaptogenic Case for FTD

The mechanistic argument for a positive modulator of HGF/c-Met in FTD rests on a triple-cell biology: neuronal synaptic plasticity, microglial polarisation, and (in some cellular contexts) lysosomal homeostasis. None of these are speculative pathways; all are documented in the basic-science literature. The translational gap is the same as elsewhere on this site — no controlled human Dihexa trials in any FTD population exist.

HGF/c-Met in Synaptic Plasticity

The Wright laboratory's original Dihexa work was framed around angiotensin-IV-derived peptides for Alzheimer's and Parkinson's disease (Wright & Harding, Neuroscience 2015); Benoist and colleagues showed that the procognitive and synaptogenic effects of these peptides require HGF/c-Met activation. The cellular substrate is loss of dendritic spines and reduced synaptogenesis; the proposed restorative pathway is HGF-driven PI-3K/AKT signalling supporting spine formation and synaptic maintenance. This is the same synaptic substrate lost in FTD; the substrate fits.

HGF/c-Met on Microglia

c-Met is expressed on microglia and HGF signalling has been shown in multiple CNS contexts to shift microglial polarisation away from pro-inflammatory phenotypes and towards reparative ones. Given the central role of microglial dysfunction in FTD-GRN (where progranulin loss disrupts microglial lysosomal function and unleashes complement-driven synaptic pruning) and FTD-C9orf72 (where C9orf72 protein has microglial autophagy roles), an HGF/c-Met-positive modulator that nudges microglia towards repair is at least on the right side of the biology on paper. Whether peripheral or sublingual peptide administration translates to meaningful CNS microglial modulation in adult human disease is the question that no trial has answered.

HGF/c-Met and Lysosomal Function

The connection between HGF/c-Met and lysosomal biology is more nuanced. Progranulin is itself trafficked through the lysosomal system, where it is cleaved to granulins; loss of progranulin disrupts lysosomal proteolysis and lipid handling. HGF/c-Met signalling intersects with autophagy regulation via mTOR-related pathways in several cellular models. The mechanistic link is plausible enough to warrant biological investigation but not strong enough to claim that an HGF/c-Met modulator would correct progranulin-deficient lysosomal dysfunction in FTD-GRN neurons or microglia.

The BDNF Axis in FTD

BDNF — the dominant neurotrophin supporting adult human cortical synaptic maintenance — is reduced in FTD. CSF BDNF is lower in FTD patients than age-matched controls; cortical TrkB receptor signalling is disrupted. The biology overlaps directly with the Dihexa vs BDNF article: synaptogenic interventions that engage the BDNF-supported substrate of cortical plasticity are mechanistically aligned with the deficit FTD produces. The much-discussed "10 million times more potent than BDNF" claim does not directly close the BDNF deficit in FTD, but the synaptogenic logic at least overlaps with the documented neurotrophin and synaptic deficits.

Putting these strands together: the mechanistic case for an HGF/c-Met-targeted peptide in FTD is partial but not vacuous. It is at least as coherent as the case in MCI, post-stroke cognitive impairment or diabetic brain fog — and arguably more coherent than the case in pure neurotransmitter-deficit conditions like ADHD. What it conspicuously lacks is any experimental data in FTD — no in vitro work in FTD neuronal models, no in vivo work in FTD mouse models (the GRN+/- progranulin haploinsufficiency mouse, the MAPT-P301L tau mouse, the C9orf72 BAC mouse), and zero human trial data. The mechanism deserves a real experiment.

The Latozinemab INFRONT-3 Phase 3 Failure: The Defining 2025-2026 FTD Story

The single most important FTD drug-development event of 2025 happened on 21 October. Anyone considering an unlicensed neuroplasticity peptide for FTD in 2026 needs to understand what just happened to the most advanced disease-modifying programme the field has ever taken into Phase 3.

INFRONT-3 Design

INFRONT-3 was a Phase 3, randomised, double-blind, placebo-controlled trial of latozinemab (AL001), an anti-sortilin monoclonal antibody designed to block the sortilin receptor that targets progranulin for degradation. By inhibiting sortilin-mediated progranulin internalisation and lysosomal degradation, latozinemab raises plasma and CSF progranulin levels in carriers of heterozygous GRN loss-of-function mutations, with the therapeutic logic of correcting the ~50% progranulin haploinsufficiency that drives FTD-GRN pathology.

The trial enrolled 103 participants with FTD-GRN (symptomatic or at-risk presymptomatic). The clinical co-primary endpoint was the Clinical Dementia Rating-NACC FTLD Sum of Boxes (CDR plus NACC FTLD-SB) at 96 weeks. The biomarker co-primary endpoint was sustained plasma progranulin elevation. Secondary endpoints included neurofilament light (NfL), volumetric MRI, exploratory CSF biomarkers and functional measures. Baseline characteristics showed a population that was well-matched to GENFI cohort historical data, supporting external generalisability.

The mechanistic rationale was the cleanest in cognitive neurology: a defined haploinsufficiency, a drug that demonstrably raises the deficient protein, a homogeneous genetically-defined population. If a "raise the missing protein" approach was ever going to work in neurodegeneration, this was the trial design that would show it.

The Topline Result

On 21 October 2025, Alector announced topline INFRONT-3 results. Three things stood out:

• Biomarker co-primary endpoint: met. Plasma progranulin increased significantly versus placebo, sustaining roughly a 2-fold elevation throughout the trial. Target engagement was clean and durable.
• Clinical co-primary endpoint: not met. Latozinemab did not slow disease progression on the CDR plus NACC FTLD-SB. The confidence intervals around the treatment effect were narrow enough to exclude clinically meaningful benefit on the prespecified primary endpoint.
• Secondary and exploratory endpoints: no treatment effect. NfL, volumetric MRI, exploratory CSF biomarkers and functional measures showed no signal favouring latozinemab over placebo. NeurologyLive's analysis emphasised the comprehensiveness of the negative result.

Based on these results, Alector discontinued the INFRONT-3 open-label extension and the continuation studies, and on the same day announced a 49% workforce reduction. The AFTD's response statement emphasised gratitude to the trial participants and the importance of continuing FTD research despite the setback.

What INFRONT-3 Means for FTD Drug Development

The cleanest reading of INFRONT-3 is not "raising progranulin is wrong" but rather "raising plasma progranulin to roughly 2x baseline in already-symptomatic FTD-GRN does not, over 96 weeks, translate into measurable clinical slowing". The pattern — clear biomarker engagement, absent clinical benefit — recurs across neurodegeneration: solanezumab and crenezumab in mild Alzheimer's, BAN2401 nuances, and most recently the EVOKE / EVOKE+ semaglutide failure in early Alzheimer's covered in our diabetes brain fog review.

Several interpretations are still plausible and matter for the next wave of FTD trials. First, the timing may be wrong: by the time clinical symptoms are present, sufficient cortical neurons and synapses have been lost that downstream pathology is no longer rescuable by simply normalising progranulin levels. Presymptomatic intervention — which is exactly what the Vesper SORT-IN-2 expansion in asymptomatic GRN carriers is exploring — remains the strongest version of the hypothesis. Second, the compartment may matter: peripheral progranulin elevation may not adequately raise CNS lysosomal-active progranulin in microglia and neurons, where the proteolytic biology matters. Third, the magnitude may be insufficient: a 2-fold elevation may not be enough to reverse decades of accumulated lysosomal dysfunction. Fourth, the target may be incomplete: progranulin replacement may not address the downstream TDP-43 aggregation that has already begun.

For Dihexa specifically, the INFRONT-3 lesson is sobering. If a multimillion-dollar Phase 3 programme with a defined genetic target, a defined missing protein and a drug that demonstrably raises that protein 2-fold could not show clinical benefit at 96 weeks, the bar for an unstudied, untrialled, mechanism-only peptide is plainly higher, not lower. The 2026 reading on chasing FTD with pharmacology of any kind should be: yes, the biology is real; no, the translation is not easy. Mechanism alone is increasingly clearly not sufficient.

The Wider 2026 FTD Pipeline: Vesper, Denali, Passage Bio, NurOwn-FTD

The 2026 FTD pipeline beyond latozinemab is less mature but more diverse, and several programmes will read out within the next 18 months. The FTD Talk genetic FTD trial update from February 2026 is the cleanest single roundup; the Progranulin Navigator clinical trials directory is the patient-facing portal.

Vesper Bio VES001 (Sortilin Modulator, Oral)

Vesper Bio is developing VES001, a small-molecule oral sortilin modulator that targets the same biology as latozinemab but with two important differences: oral administration (rather than monthly IV infusion) and dynamic dose-titratable modulation (rather than antibody-driven receptor blockade). The Phase 1b/2a SORT-IN-2 trial in asymptomatic GRN mutation carriers reported that progranulin levels in CSF nearly doubled over 3 months across 6 participants, restoring them to roughly normal levels.

The expansion into a larger asymptomatic-carrier cohort is recruiting in 2026 with topline results expected in the second half of 2026. The critical question after INFRONT-3 is whether earlier-stage intervention (asymptomatic carriers, before substantial neuronal and synaptic loss) can succeed where later-stage intervention (symptomatic FTD-GRN) failed. The presymptomatic intervention hypothesis is the cleanest remaining version of the progranulin-replacement logic.

Denali Therapeutics DNL593 (Brain-Penetrant Progranulin)

DNL593 (PTV:PGRN) is a brain-penetrant recombinant progranulin protein engineered with Denali's Enzyme Transport Vehicle (ETV) technology to cross the blood-brain barrier via transferrin receptor binding. The therapeutic logic is direct: deliver progranulin protein into the CNS rather than rely on peripheral elevation. Interim Part A Phase 1/2 data in healthy volunteers showed dose-dependent CSF progranulin elevation and an acceptable safety profile.

On 3 April 2026, Denali announced that Takeda had terminated their co-development collaboration, citing strategic considerations (not efficacy or safety). Denali regained full rights to DNL593 and continues to advance the programme; Phase 1/2 biomarker data are expected by the end of 2026. The brain-penetrance angle distinguishes DNL593 from latozinemab and addresses one of the leading post-INFRONT-3 hypotheses for why peripheral progranulin elevation may not be sufficient.

Passage Bio PBFT02 (AAV-PGRN Gene Therapy)

PBFT02 is an AAV1-vectored gene therapy delivering a functional GRN gene via single intra-cisterna magna injection. The Nature Medicine publication of upliFT-D Phase 1/2 interim results demonstrated substantial and sustained CSF progranulin elevation following a single administration. Phase 1/2 expansion continues in 2026 with both FTD-GRN and FTD-C9orf72 cohorts.

Gene-therapy approaches address several limitations of antibody and protein replacement: single-administration durability, intrathecal delivery achieving CNS compartment exposure, and potential lifelong protein production. Whether the higher CSF progranulin levels achievable by AAV gene therapy translate to clinical benefit where the 2-fold plasma elevation of latozinemab did not is the key open question for this approach.

Wave Life Sciences WVE-004 (Discontinued)

WVE-004 was a stereopure antisense oligonucleotide targeting C9orf72 hexanucleotide-repeat-containing transcripts, with the therapeutic logic of reducing toxic dipeptide repeat protein production while sparing normal C9orf72 protein expression. The FOCUS-C9 Phase 1b/2a trial in C9-ALS and C9-FTD demonstrated dose-dependent reductions in CSF poly(GP) (a downstream biomarker), confirming target engagement.

Despite the biomarker signal, Wave Life Sciences discontinued WVE-004 after no clinical benefit was observed at 24 weeks. The pattern — biomarker engagement without clinical benefit — foreshadowed the INFRONT-3 outcome. Wave's discontinuation is also a reminder that even in conditions with a clearly-defined molecular target, knocking down the proximal driver may not be sufficient if downstream pathology has already established.

Other FTD-Focused Programmes

Several smaller programmes deserve mention. NurOwn (mesenchymal stem cells secreting neurotrophic factors) has been explored in FTD-ALS spectrum disease. Several tau-targeted antisense oligonucleotides are in early development for FTD-MAPT. TPN-101 (Transposon Therapeutics), a reverse transcriptase inhibitor targeting LINE-1 retroelements implicated in TDP-43 pathology, has reached Phase 2 in FTD-C9orf72. Latrepirdine (Dimebon) is the historical FTD reference failure that should keep expectations honest about cognition-targeted small molecules. The MDPI 2024 scoping review of registered FTD trials catalogues the wider pipeline; the UK Dementia Research Institute tracks the British academic landscape.

The cumulative picture from the 2024-2026 FTD pipeline is mixed. Two flagship programmes (latozinemab and WVE-004) have failed with clean biomarker engagement. Three remain active and approaching readout (Vesper VES001, Denali DNL593, Passage Bio PBFT02). The bar after October 2025 is higher: a successful FTD trial in 2026-2027 will have to show clinical and not merely biomarker effect, ideally in earlier-stage populations.

Bruce Willis, Emma Heming Willis and the AFTD Hope Rising 2026 Benefit

The public profile of FTD has been transformed in the four years since Bruce Willis's family first announced his aphasia diagnosis in March 2022. The February 2023 disclosure that his condition had progressed to frontotemporal dementia made FTD a household-level conversation in a way it had never been before. The downstream consequences for research funding, public awareness, family advocacy and policy attention have been substantial.

AFTD Hope Rising 2026 Benefit

In March 2026, the Association for Frontotemporal Degeneration (AFTD) held its tenth annual Hope Rising Benefit, which raised $2.1 million for FTD research, care advancement and awareness. The event marked a decade of the benefit and was the largest in its history.

Emma Heming Willis and Bruce Willis were honoured with the Susan Newhouse & Si Newhouse Award of Hope at the benefit, in recognition of their family's contribution to FTD visibility and advocacy. The award has historically gone to families and clinicians who have driven step-change in public understanding of the disease.

Emma & Bruce Willis Fund for Dementia Research

In March 2026, Emma Heming Willis announced the launch of the Emma & Bruce Willis Fund for Dementia Research and Caregiver Support, with the AFTD receiving the first gift. The fund's stated focus is research into FTD biology and therapeutics, and direct support for families and caregivers affected by the disease. The fund continues a pattern of celebrity-family-led philanthropy that has played a meaningful role in rare-disease research funding more broadly.

The "Willis Effect" on Research Funding

For families dealing with FTD privately, the Willis family's public openness has had a measurable consequence: more people recognise the early behavioural and language symptoms; more GPs consider FTD in their differential diagnosis; more researchers and biotech companies have moved into the FTD pipeline (the post-2023 expansion of FTD-focused investment is real and traceable). The October 2025 INFRONT-3 failure has dampened some of this enthusiasm, but it has not closed the field — if anything, the latozinemab data have crystallised the importance of earlier-stage intervention and brain-penetrant approaches that the next wave of trials is exploring.

For readers considering Dihexa for FTD in 2026, the Willis-effect-funded research landscape is the most relevant consequence. The realistic alternative to "self-experiment with an unlicensed peptide" is increasingly meaningful: more UK trial sites, more academic FTD programmes, broader inclusion criteria for genetic and sporadic FTD, and active recruitment via the Cambridge Centre for FTD and UCL Rare Dementia Support service. Those are the right next steps for an FTD-affected family in the UK in 2026 — not a research peptide.

FTD Care in the UK in 2026: The Diagnosis Pathway, the Support Network, the Treatment Gap

The honest comparison most families want is between Dihexa and the interventions a UK FTD pathway actually uses. The comparison is, as elsewhere, mechanism-level misleading — these interventions operate on completely different parts of the FTD trajectory — but worth working through.

The UK Diagnostic Pathway

Suspected FTD is typically referred from primary care into a memory clinic or cognitive neurology service via the standard NICE NG97 dementia diagnosis pathway. Initial assessment includes neuropsychological testing (often using the Addenbrooke's Cognitive Examination ACE-III or the more FTD-sensitive Cambridge Behavioural Inventory CBI-R), structural neuroimaging (MRI showing frontal/temporal atrophy patterns), and increasingly fluorodeoxyglucose-PET imaging for atypical presentations. CSF biomarkers (Abeta42, tau, phospho-tau, NfL) help distinguish FTD from atypical Alzheimer's presentations.

Genetic counselling and testing are increasingly offered for patients with positive family history (autosomal dominant inheritance pattern) or atypical features. The UK FTD Genetics Initiative and the GENFI international research network provide both research-grade testing and family support. The MAPT, GRN and C9orf72 panel is now reasonably accessible in NHS clinical genetics services with appropriate counselling.

Pharmacotherapy

UK pharmacotherapy options are limited. SSRIs (sertraline, citalopram, fluoxetine, paroxetine, trazodone) are used off-label for behavioural symptoms of bvFTD, particularly compulsive behaviour, dietary changes, disinhibition and agitation. Evidence is mostly from small open-label and retrospective studies; meaningful benefit for the most disabling symptoms is the realistic expectation.

Cholinesterase inhibitors (donepezil, rivastigmine, galantamine) are not effective in FTD and can worsen behavioural symptoms; they should not be used. Memantine is licensed for Alzheimer's only and has been formally tested in FTD without benefit. Antipsychotics for behavioural symptoms should be used cautiously: people with FTD have heightened sensitivity to antipsychotic side effects, particularly extrapyramidal symptoms, and a low-dose, time-limited approach with regular review is required if antipsychotics are unavoidable.

The 2026 UK reality is that there is no NICE-recommended disease-modifying treatment for any subtype of FTD. The licensed therapies that have transformed the international Alzheimer's discussion (lecanemab, donanemab) do not target FTD pathology — and were not designed for it. We covered the 2026 NICE lecanemab and donanemab rejections in the MCI review; the consequence for FTD is that even the imperfect anti-amyloid options that exist for Alzheimer's are not available for FTD.

Multidisciplinary Care

Where pharmacotherapy is empty, multidisciplinary care has substantial value. Speech and language therapy is the cornerstone of PPA management, with structured intervention shown to slow language decline in semantic variant and non-fluent variant PPA. Occupational therapy supports activities of daily living and home adaptation. Specialist dementia nurses (Admiral Nurses via Dementia UK, or memory-clinic-based clinical nurse specialists) provide care coordination, behavioural intervention support and family education. Social work input is critical for capacity assessment, lasting power of attorney, advance care planning and benefits navigation — particularly important in young-onset disease where the patient is often the family's main earner.

UK Support Organisations

For families affected by FTD, three organisations matter most in the UK in 2026:

• Alzheimer's Research UK (FTD information hub) is the leading dementia research charity in the UK and funds substantial FTD-specific research programmes including the FTD Genetics Initiative and the GENFI study.
• Dementia UK (FTD information and support) runs the Admiral Nurse Dementia Helpline (0800 888 6678) and the only specialist nurse service that provides expert advice and emotional support to families across the UK.
• Rare Dementia Support at UCL provides specialised support groups for rarer dementias including bvFTD, PPA, posterior cortical atrophy and familial Alzheimer's. The Cambridge Centre for Frontotemporal Dementia and Related Disorders is the UK research and tertiary-referral hub.

The contrast with the Dihexa proposition is sharp: established, free-at-the-point-of-use, multidisciplinary support exists in the UK and is consistently underused. Asking your GP for a memory clinic referral, accessing the Admiral Nurse helpline and engaging with Rare Dementia Support are evidence-grade interventions in a way that an unlicensed peptide is not.

FTD-ALS Spectrum Disease: Where the C9orf72 Biology Connects to the ALS Review

One of the most important conceptual shifts in FTD biology over the last decade has been the recognition that FTD and amyotrophic lateral sclerosis (ALS / motor neurone disease) are not separate diseases but rather a clinical and pathological continuum. Approximately 15% of people with FTD develop motor neurone disease symptoms during their illness, and approximately 30% of people with ALS develop cognitive symptoms consistent with FTD. The dominant shared genetic cause is the C9orf72 hexanucleotide repeat expansion.

This matters for several reasons. First, the FTD-ALS overlap means that families with a positive C9orf72 family history may see different clinical presentations in different members — one branch developing FTD-dominant disease, another ALS-dominant. Second, the molecular pathology (TDP-43 aggregation, RNA foci, toxic dipeptide repeat proteins) is shared, making C9-FTD and C9-ALS the same molecular disease with different clinical phenotypes. Third, the therapeutic implications are joint: WVE-004 (now discontinued) was developed for both indications; future C9orf72-targeted therapeutics will need to consider the full spectrum.

For an HGF/c-Met-targeted peptide, the FTD-ALS overlap matters mechanistically. HGF supports motor neuron survival (the basis of the VM202 / Engensis programme covered in detail in our ALS & MND review) and cortical neuronal survival. A peptide aimed at the synaptic and neurotrophic substrate is, at minimum, addressing biology relevant to both ends of the FTD-ALS spectrum. The same caveats apply: zero human data, no FTD-ALS spectrum trials, mechanism not evidence.

For families affected by C9orf72 disease specifically, the strongest 2026 UK resources are the MND Association, the Cambridge Centre for FTD (which spans both phenotypes), and the GENFI international research network. The MND-SMART, EXPERTS-ALS and other trial platforms covered in the ALS review include cohorts with cognitive involvement and accept C9-FTD-MND patients.

2026 FTD News: What Is Actually Happening This Year

The following 2025-2026 events frame the contemporary UK and global FTD landscape and are referenced where relevant in this article:

• 21 October 2025 — Alector latozinemab INFRONT-3 Phase 3 failure: Alector announced that latozinemab missed the clinical co-primary endpoint in FTD-GRN despite a 2-fold sustained plasma progranulin increase. Same-day announcement of 49% workforce reduction and discontinuation of the open-label extension.
• 3 April 2026 — Denali / Takeda DNL593 partnership terminated: Denali regained full rights to brain-penetrant progranulin DNL593 (PTV:PGRN) after Takeda's strategic withdrawal from the collaboration; Phase 1/2 biomarker data expected end of 2026.
• March 2026 — AFTD Hope Rising Benefit 2026: $2.1 million raised; tenth annual benefit; Emma and Bruce Willis received the Susan Newhouse & Si Newhouse Award of Hope; launch of the Emma & Bruce Willis Fund for Dementia Research and Caregiver Support announced shortly after.
• February 2026 — FTD Talk genetic FTD trial update: The FTD Talk roundup from the GENFI consortium summarised the post-INFRONT-3 pipeline, with Vesper VES001, Denali DNL593 and Passage Bio PBFT02 emerging as the leading remaining presymptomatic and brain-penetrant approaches in FTD-GRN.
• 2026 — Vesper Bio SORT-IN-2 expansion: The oral sortilin modulator VES001 in asymptomatic GRN-mutation carriers is recruiting throughout 2026 with expected topline H2 2026; first 6-participant cohort showed CSF progranulin doubling.
• 2025 — Passage Bio PBFT02 upliFT-D interim results: The Nature Medicine publication demonstrated single-dose AAV1-PGRN gene therapy achieving substantial sustained CSF progranulin elevation in FTD-GRN patients; expansion ongoing.
• 2024 — JAMA Neurology FTD prevalence meta-analysis: The Logroscino et al. systematic review reported global FTD incidence of 2.28 per 100,000 person-years and prevalence of 9.17 per 100,000, the most rigorous global FTD epidemiological estimate to date.
• 2024 — Lancet Commission on dementia prevention: The 2024 Lancet Commission expanded the modifiable dementia risk-factor list from 12 to 14. FTD-specific evidence on modifiable risk factors is far weaker than for Alzheimer's, but TBI, alcohol misuse, hearing loss and the cumulative neuroinflammatory burden are biologically relevant to FTD too.
• 2023 — Wave Life Sciences WVE-004 discontinuation: Wave Life Sciences discontinued WVE-004 for C9orf72-ALS/FTD after FOCUS-C9 Phase 1b/2a showed no clinical benefit despite biomarker engagement.
• February 2023 — Bruce Willis FTD diagnosis disclosed: The progression of his March 2022 aphasia diagnosis to frontotemporal dementia was publicly disclosed by his family, driving sustained mainstream media coverage of FTD for the first time and shifting public awareness markedly.
• Continuing — GENFI international research network: The Genetic FTD Initiative is the world's largest prospective FTD cohort study, tracking presymptomatic and symptomatic carriers of MAPT, GRN and C9orf72 mutations, and is the natural-history backbone for all FTD-GRN trials in 2026.

The 2026 trajectory for FTD is mixed. Two flagship Phase 3-or-equivalent programmes have failed; three brain-penetrant or single-administration alternatives remain active and approaching readout; the underlying biological understanding is the strongest it has ever been; and the public-awareness tailwind from the Willis family is real and translates into research-funding capacity. The clinical-treatment-toolkit cupboard, however, is essentially still bare. This is the gap into which interest in unlicensed compounds — Dihexa, Semax, Selank, cerebrolysin, citicoline — flows. Understandable patient and family demand in an environment where licensed options are zero.

Practical Realities: If a Family Affected by FTD Is Considering Dihexa

This site exists because people will research Dihexa whether or not we cover it. The honest editorial position for families considering Dihexa in the context of an FTD diagnosis is that the standard NHS pathway — specialist memory-clinic diagnosis, genetic counselling where appropriate, multidisciplinary care, support-organisation engagement and clinical-trial participation — should be in place first, full stop. For families nevertheless determined to explore, the harm-reduction frame looks like the following.

FTD-Specific Cautions

A reasonable list of absolute and relative reasons not to self-experiment in the FTD context, drawing on the broader side effects review:

• Anyone currently enrolled in an FTD trial (INFRONT-related extension cohorts, Vesper SORT-IN-2, Denali DNL593, Passage Bio upliFT-D, MND-SMART, EXPERTS-ALS) — concurrent unlicensed investigational agents would invalidate trial data and likely terminate participation.
• Anyone receiving off-label SSRIs or antipsychotics for behavioural symptoms — uncharacterised interactions, particularly relevant where antipsychotic sensitivity is already elevated in FTD.
• Anyone with C9orf72-positive disease and motor symptoms suggesting ALS-FTD spectrum involvement — the safety considerations of the ALS & MND review apply directly.
• Anyone with a personal or strong family history of breast, ovarian, lung, gastric, colorectal or pancreatic cancer (c-Met-implicated tissues).
• Anyone with significant capacity concerns — informed consent is fundamental and capacity is often partially impaired in FTD. Decisions about unlicensed therapy should involve the appointed lasting power of attorney for health and welfare; the editorial position is that such decisions should not be taken without specialist input.
• Anyone with established cerebrovascular disease, on dual antiplatelet therapy, or on anticoagulants for atrial fibrillation, without prescriber awareness.
• Anyone whose FTD diagnosis is uncertain or pre-formal — the diagnostic clarity of a clean baseline matters more than experimental neuroplasticity.

Dosing Considerations Specific to FTD

The community dose range for Dihexa, drawn from the 2026 review of self-reported protocols, is typically 8-25 mg/day orally or sublingually for 8-16 weeks, often cycled. Several considerations argue for the lower end of this range in FTD specifically:

• The behavioural-symptom profile of bvFTD includes disinhibition, impulsivity and impaired judgement. The vivid-dream and sleep-architecture effects (see the sleep & memory consolidation review) may interact unpredictably with already-disrupted FTD sleep patterns.
• Polypharmacy is common: SSRIs, atypical antipsychotics, trazodone for sleep, statins and antihypertensives are typical concurrent prescriptions. Interactions are uncharacterised.
• Caregiver oversight matters more than in any other indication on this site — capacity-related compliance, dose adherence and side-effect reporting all require involved caregiver engagement.
• Any unexpected behavioural change, new agitation, paradoxical disinhibition or sleep deterioration should trigger immediate cessation pending specialist input.

Monitoring

If self-experimentation proceeds despite the foregoing, minimum monitoring should include: baseline neuropsychological assessment (typically through the memory clinic) before and after each cycle; standardised symptom and behaviour diary kept by the caregiver (Cambridge Behavioural Inventory or Neuropsychiatric Inventory style); baseline blood panel before and after each cycle (FBC, U&Es, LFTs, lipids, B12, folate, ferritin, TFTs); blood pressure (sitting and standing); and prompt reporting to the responsible GP, neurology service and memory clinic of any behavioural, mood, motor or cognitive change.

When to Stop Immediately

New focal neurological symptoms (FAST-positive stroke features), new seizures, new severe behavioural escalation, paradoxical worsening of disinhibition or compulsive behaviour, suicidal ideation, sudden vision changes, new motor weakness or bulbar symptoms (FTD-MND red flag) all warrant urgent medical attention and immediate cessation pending specialist input. Any confirmed cancer diagnosis (particularly breast, lung, gastric, colorectal or pancreatic) should trigger immediate cessation pending oncology input.

The Evidence-Based 2026 Plan for FTD-Affected Families in the UK

If you take one section of this article seriously, take this one. For a UK family with a confirmed or suspected FTD diagnosis in 2026, here is the order of operations with the strongest evidence base.

1. Establish a clear diagnosis. If FTD has not been formally diagnosed in a memory clinic or specialist cognitive neurology service, ask your GP for that referral. The NHS NG97 pathway exists for this reason. Diagnostic clarity (FTD subtype, distinction from atypical Alzheimer's, distinction from primary psychiatric disease) materially changes prognosis and trial eligibility.
2. Engage UK FTD support organisations early. Alzheimer's Research UK for research-funded information; Dementia UK for the Admiral Nurse helpline (0800 888 6678); Cambridge Centre for Frontotemporal Dementia for tertiary-care expertise. UCL Rare Dementia Support runs specialist groups for bvFTD, PPA and related conditions.
3. Consider genetic counselling. A positive family history of dementia, ALS or atypical psychiatric disease in first-degree relatives warrants discussion with NHS clinical genetics. MAPT, GRN and C9orf72 testing is now reasonably accessible. The implications for at-risk family members (presymptomatic testing, predictive counselling, GENFI study participation) are substantial and benefit from specialist input.
4. Plan ahead while capacity permits. Lasting power of attorney (both for property/finance and health/welfare), advance care planning, will review, financial planning and family conversations should be done early, before behavioural symptoms compromise capacity. FTD is the cognitive condition where this matters most because of the relatively-preserved memory and the disproportionate impact on judgement, insight and behaviour.
5. Build multidisciplinary care. Speech and language therapy for any PPA component, occupational therapy for ADL support, social work for benefits and care planning, specialist dementia nursing for ongoing support. These are evidence-grade interventions in a way that no pharmacological option currently is.
6. Pharmacological symptom management as needed. SSRIs (sertraline or citalopram are common first choices) for behavioural symptoms of bvFTD; trazodone for sleep; antipsychotics only if absolutely necessary, low-dose and time-limited. Avoid cholinesterase inhibitors. The off-label evidence base is modest, but for selected symptoms (compulsive behaviour, hyperorality, agitation) SSRIs can be meaningfully helpful.
7. Consider clinical-trial participation. The NIHR Be Part of Research portal and Alzheimer's Research UK's Join Dementia Research register list actively-recruiting UK trials. For genetic FTD, the GENFI international study, Vesper SORT-IN-2, Denali DNL593 Phase 1/2 and Passage Bio upliFT-D upliFT-D are the leading 2026 options. Supervised access with safety monitoring is preferable to unsupervised self-experimentation in every dimension.
8. Address modifiable risk where applicable. The 2024 Lancet Commission's 14 modifiable dementia risk factors apply less specifically to FTD than to Alzheimer's, but TBI prevention, alcohol moderation, hearing-aid use, hypertension control and sleep optimisation all support cognitive reserve and cross-domain brain health.
9. Caregiver support and burnout prevention. FTD caregiving is among the most demanding forms of dementia caregiving because of the behavioural, age-related and capacity components. Caregiver support groups (Admiral Nurses, AFTD support groups, Rare Dementia Support) materially affect long-term outcomes for both patient and family. Carers UK and the local NHS carers assessment process should be engaged.
10. Plan for the FTD-MND possibility in C9orf72-positive disease. Where C9orf72 status is positive, motor symptom monitoring is part of standard care and the MND Association becomes a relevant resource.

The Bottom Line: A Coherent Mechanism, a Devastating Phase 3, and Zero Human Dihexa Data

The 2026 reading on Dihexa for frontotemporal dementia is one of the most cautious on this site. The mechanistic case is partial but not vacuous: FTD involves convergent synaptic loss, microglial dysfunction and (in some subtypes) lysosomal dysfunction; the HGF/c-Met system has documented roles in neuronal synaptogenesis, microglial polarisation and (in some cellular contexts) lysosomal homeostasis; Dihexa is a positive modulator of HGF/c-Met. The mechanism deserves a real experiment.

And yet: there is no controlled human trial of Dihexa in any FTD subtype — behavioural variant FTD, primary progressive aphasia, FTD-GRN, FTD-MAPT, FTD-C9orf72 or any spectrum overlap. The closest clinical-stage relative, fosgonimeton, was developed for Alzheimer's and Parkinson's-related dementia and never advanced into FTD-specific trials. And the dominant 2025-2026 FTD-specific story is the latozinemab INFRONT-3 Phase 3 failure: a drug with clean target engagement (sustained 2-fold plasma progranulin elevation), in a genetically-defined population, did not slow clinical FTD-GRN at 96 weeks. That outcome should keep expectations honest for any drug aimed at FTD biology, including HGF/c-Met-targeted peptides.

The honest 2026 reading: NHS specialist diagnosis and multidisciplinary care first, genetic counselling and family planning second, clinical-trial participation via Vesper SORT-IN-2 / Denali DNL593 / Passage Bio upliFT-D / GENFI third, support-organisation engagement throughout, and unlicensed peptides essentially last — if at all. The biology of FTD deserves serious experimental investigation. Self-experimentation with an unstudied research peptide in a population already losing capacity is not what serious investigation looks like, and it is not the right next step for most readers of this page.

Frequently Asked Questions

Related Reading on Dihexa.co.uk

• Dihexa for Huntington’s Disease: AMT-130, WVE-003, Votoplam & the 2026 UK Review — the autosomal-dominant single-gene neurodegeneration companion piece, covering the uniQure AMT-130 ~75% slowing of disease progression at 36 months (UCL/UCLH & Cardiff ANTC), the March 2026 FDA Type-A meeting requiring a sham-controlled Phase 3, the Wave Life Sciences WVE-003 SELECT-HD allele-selective mutant huntingtin lowering, the PTC votoplam PIVOT-HD 24-month extension & Novartis INVEST-HD, the corticostriatal BDNF axis and the HGF/c-Met synaptogenic case.
• Dihexa for Lewy Body Dementia (DLB) & Parkinson’s Disease Dementia (PDD) — the third-most-common dementia and the most encouraging 2025-2026 therapeutic trajectory in cognitive neurology, covering the CervoMed RewinD-LB extension, AAN 2026 basal-forebrain MRI signal, FDA-aligned Phase 3, the ANeED ambroxol trial, alpha-synuclein SAA biomarkers and the contrasting drug-development story to the FTD INFRONT-3 failure.
• Dihexa for ALS & Motor Neurone Disease (MND) — the FTD-ALS C9orf72 spectrum, the VM202 (Engensis) plasmid HGF gene therapy programme, the HGF motor-neuron-protection literature.
• Dihexa for MCI & Brain Aging — the synaptic-loss case directly relevant to FTD and the 2024 Lancet Commission's 14 modifiable risk factors.
• Dihexa & Alzheimer's Research — the Wright laboratory origin story, the 2026 NICE lecanemab and donanemab rejections, the broader cognitive evidence base.
• Dihexa for Parkinson's Disease — the FTD-parkinsonism overlap in MAPT-mutation carriers and the fosgonimeton SHAPE PDD signal.
• Dihexa for Stroke Recovery & PSCI — the speech and language therapy parallel for chronic aphasia management directly relevant to PPA.
• Dihexa for Vascular Dementia & Vascular Cognitive Impairment (VCI) — the 2nd-most-common dementia, the April 2026 UCLA brain-repair breakthrough, UNSW CHeBA Mendelian-randomization genetics, the Manchester Kir2.1 / amlodipine cerebrovascular rescue and the HGF/c-Met angiogenesis & blood-brain-barrier biology.
• Fosgonimeton & Athira — the closest clinical-stage relative and why no FTD-specific trials were ever run.
• Dihexa vs BDNF — the BDNF axis is reduced in FTD; the central potency claim, examined.
• Dihexa for Diabetic Brain Fog — the EVOKE / EVOKE+ Alzheimer's failure parallel and the broader biomarker-without-clinical-benefit pattern.
• Dihexa for Multiple Sclerosis (MS) — the HGF/c-Met remyelination biology and a related neurodegeneration review.
• Dihexa for Chemo Brain (CICI) — another cognitive-recovery indication with overlapping neuroinflammation biology.
• Dihexa for Long COVID Brain Fog — the shared microglial-neuroinflammation substrate that drives synaptic loss across very different upstream insults.
• Dihexa for TBI & Concussion — the shared synaptic-rebuilding rationale; TBI is a Lancet Commission FTD-relevant risk factor.
• Dihexa for CTE / Chronic Traumatic Encephalopathy (2026) — the behavioural early phase of CTE most closely resembles bvFTD; January 2026 Boston University 614-donor CTE-as-dementia paper; May 2026 TES 24% miss; UK rugby group claim (March 2026 review).
• Dihexa for Anxiety & Chronic Stress — bvFTD is frequently misdiagnosed as anxiety, burnout or stress for years before formal recognition.
• Dihexa for Depression & Mood — bvFTD's behavioural symptoms are frequently misdiagnosed as depression; the differential matters.
• Dihexa, Sleep & Memory Consolidation — the vivid-dream effect and FTD's frequently-disrupted sleep architecture.
• Dihexa for ADHD — the prefrontal cortex angle on the broader synaptic story; bvFTD-ADHD differential considerations.
• Dihexa for Menopause Brain Fog — another cognitive-symptom phenotype that can mimic early bvFTD in the 45-64 age band.
• Dihexa Review 2026 — effects timeline, oral vs sublingual, cycling protocols.
• Dihexa Stacking Guide — why combining Dihexa with SSRIs, antipsychotics or trazodone for FTD behavioural symptoms needs prescriber oversight.
• Dihexa for Cognitive Enhancement — the broader cognition conversation.
• Mechanism of Action — HGF/c-Met, PI-3K/AKT, dendritic spines, the microglial polarisation story.
• Benefits Overview — the broader claimed-benefit landscape, evidence-rated.
• Dosage Guide — community dose ranges and considerations.
• Side Effects & Risks — the general safety picture, including FTD-relevant polypharmacy and capacity concerns.
• UK Legal Status — where Dihexa sits in UK law.
• Research & Studies — the human and animal evidence base reviewed.
• Dihexa vs Other Nootropics — how Dihexa compares with Semax, Selank, Noopept, BPC-157, cerebrolysin and citicoline.
• Glossary — technical terms used on this page.
• Full Site FAQ — the broader question set across the site.

External Authoritative Sources Cited

• Alector. Topline results from Latozinemab Phase 3 INFRONT-3 trial in FTD-GRN (21 October 2025).
• NeurologyLive. Latozinemab shows no impact on disease progression in C9orf72 FTD despite increasing progranulin expression.
• AFTD. Alector Therapeutics announces results from their Phase 3 clinical trial evaluating latozinemab.
• Drug Discovery World. Alector discontinues dementia drug and cuts staff by 49% (October 2025).
• Denali Therapeutics. Regains full rights to investigational therapy DNL593 (PTV:PGRN) for FTD-GRN (3 April 2026).
• FTD Talk. Latest updates on clinical trials for genetic FTD (February 2026).
• AFTD. Hope Rising 2026 raises more than $2.1 million; Emma and Bruce Willis recognised with Susan Newhouse Award.
• NeurologyLive. Wave Life Sciences discontinues WVE-004 for C9orf72-ALS and FTD.
• Hinderer C et al. Progranulin AAV gene therapy for frontotemporal dementia: translational studies and Phase 1/2 trial interim results. Nature Medicine (2024).
• Logroscino G et al. Incidence and Prevalence of Frontotemporal Dementia: A Systematic Review and Meta-Analysis. JAMA Neurology (2025).
• Ward ME et al. Phase 1 study of latozinemab in progranulin-associated frontotemporal dementia. PubMed (2024).
• Targeting granulin haploinsufficiency in frontotemporal dementia: from genetic mechanisms to therapeutics. MDPI (2025).
• Update on disease-modifying pharmacological treatments for FTD: a scoping review of registered trials. MDPI (2024).
• Livingston G et al. Dementia prevention, intervention, and care: 2024 report of the Lancet standing Commission.
• Wright JW & Harding JW. The development of small molecule angiotensin IV analogs to treat Alzheimer's and Parkinson's diseases. Neuroscience (2015).
• Benoist CC et al. The procognitive and synaptogenic effects of angiotensin IV-derived peptides are dependent on activation of the HGF/c-Met system.
• Alzheimer's Research UK. Frontotemporal dementia (FTD): what is it and how close is a cure?
• Alzheimer's Research UK. Frontotemporal dementia treatments.
• NHS. Frontotemporal dementia.
• Dementia UK. Frontotemporal dementia information and support.
• UK Dementia Research Institute. Frontotemporal dementia research.
• Cambridge Centre for Frontotemporal Dementia and Related Disorders.
• Alzheimer's Society. Frontotemporal dementia (FTD).
• Association for Frontotemporal Degeneration (AFTD).
• Progranulin Navigator clinical trials directory.
• NIHR Be Part of Research portal.
• Join Dementia Research (NIHR).
• MND Association (UK).
• Young Dementia Network.
• NICE NG97 — Dementia: assessment, management and support for people living with dementia and their carers.