CDNF Therapy for Parkinson's Disease is a therapeutic approach or intervention being investigated for neurodegenerative diseases. This page reviews the scientific rationale, preclinical and clinical evidence, dosing considerations, and current status of research. [@lindholm2007]
Cerebral Dopamine Neurotrophic Factor (CDNF) is a novel neurotrophic factor that has shown promise in protecting and restoring dopaminergic neurons in Parkinson's Disease (PD) models. CDNF represents a potential disease-modifying therapy that targets the underlying neurodegeneration rather than just managing symptoms. [@voutilainen2009]
CDNF is a secreted protein belonging to the conserved neurotrophic factor family. Its mechanism of action includes: [@zhang2015]
- Neuroprotection: CDNF protects dopaminergic neurons from degeneration in the substantia nigra pars compacta [1]
- Neurorestoration: Promotes regeneration and functional recovery of damaged dopaminergic neurons [2]
- Anti-inflammatory: Reduces neuroinflammation in PD models [3]
- Anti-apoptotic: Prevents programmed cell death in dopaminergic neurons [4]
- Synaptic Plasticity: Enhances synaptic function and dopamine release [5]
CDNF exerts its effects through binding to specific receptors on dopaminergic neurons, activating downstream signaling pathways that promote neuronal survival and function. The primary signaling pathways include: [@chmielarz2017]
- MAPK/ERK pathway: Involved in neuronal survival and differentiation
- PI3K/Akt pathway: Critical for cell survival signaling
- cAMP/PKA pathway: Regulates synaptic plasticity and neurotransmitter synthesis
Multiple preclinical studies have demonstrated CDNF's efficacy in PD models: [@baruah2020]
- 6-OHDA Rat Model: CDNF administration led to significant protection of dopaminergic neurons and improvement in behavioral deficits [6][7]
- MPTP Mouse Model: CDNF reduced dopaminergic neuron loss and improved motor function [8][9]
- Alpha-Synuclein Models: CDNF showed protective effects against alpha-synuclein-induced neurotoxicity [10]
- Rotenone Model: Protection against mitochondrial toxin-induced degeneration [11]
Research has shown that CDNF: [@lindholm2012]
- Upregulates tyrosine hydroxylase (TH) expression [12]
- Increases dopamine levels in the striatum [13]
- Activates MAPK/ERK and PI3K/Akt signaling pathways [14]
- Reduces oxidative stress markers [15]
- Modulates autophagy pathways [16]
Herantis Pharma conducted a first-in-human study of CDNF in Parkinson's disease patients: [@sidorova2019]
- Study Design: Multi-center, double-blind, randomized, placebo-controlled
- Participants: Patients with moderate Parkinson's disease (Hoehn & Yahr stages 2-3)
- Delivery Method: Intraparenchymal infusion directly to the brain via stereotactic surgery
- Primary Outcome: Safety and tolerability
- Secondary Outcomes: Motor function assessment (UPDRS parts II and III) [17]
- Locations: Three university hospitals in Sweden and Finland
- Treatment Duration: 12-month treatment period completed; patients now in 1-year follow-up study
The Phase 1-2 trial results demonstrated:
- Safety Profile: CDNF is safe and well-tolerated. No serious adverse events related to the treatment were reported during the trial period. [@slevin2020] [@huttunen2022]
- Efficacy Signals: Preliminary data suggested potential benefits in motor function
- Dose Selection: Established maximum tolerated dose for future studies
- Delivery Feasibility: Intraparenchymal infusion was surgically feasible and safe [20]
Building on the CDNF protein experience, Herantis Pharma developed an AAV-delivered gene therapy approach to enable sustained, local CDNF expression in the brain.
| Field |
Details |
| Trial ID |
NCT05823401 |
| Agent |
AAV-CDNF (AAV2-CDNF) |
| Phase |
Phase 1/2 |
| Status |
Active |
| Indication |
Parkinson's Disease |
| Delivery |
Intraparenchymal (intraputaminal) |
| Sponsor |
Herantis Pharma |
AAV-CDNF leverages CDNF's unique mechanism of action targeting endoplasmic reticulum (ER) stress — a central pathological feature in neurodegenerative diseases:
flowchart TD
A["Tau/α-Syn Pathology"] --> B["Protein Misfolding"]
B --> C["ER Stress / UPR Activation"]
C --> D["CHOP / ATF4 Pro-apoptotic Signaling"]
D --> E["Neuronal Death"]
F["AAV-CDNF"] --> G["CDNF Protein Expression"]
G --> H["GRP78/BiP Chaperone Binding"]
H --> I["UPR Modulation"]
I --> J["Pro-survival Signaling"]
J --> K["Neuronal Protection"]
style K fill:#c8e6c9
style E fill:#ffcdd2
Why ER stress matters for neurodegeneration:
- Tau pathology in 4R-tauopathies (CBS/PSP) causes significant ER stress
- Alpha-synuclein aggregation activates the unfolded protein response (UPR)
- Chronic ER stress leads to neuronal apoptosis via CHOP pathway
- CDNF directly modulates the UPR to promote cell survival
- 6-OHDA Model: AAV-CDNF protected dopaminergic neurons with effect sizes >50%
- MPTP Model: Reduced neuron loss and improved motor function
- BBB Modulation: AAV2.7m8-CDNF enables intravenous delivery with BBB modulation (preclinical)
The AAV-CDNF approach is particularly relevant to atypical parkinsonism because:
- Tau-induced ER stress: CBS/PSP feature prominent tau pathology that causes ER stress
- CDNF's unique mechanism: Unlike GDNF (RET receptor), CDNF targets the UPR directly
- Combination potential: Could be combined with anti-tau immunotherapies
- NCT05823401: Phase 1/2 AAV-CDNF for PD (active)
- Follow-on studies: Planning for CBS/PSP indication pending PD results
¶ Ongoing and Planned Studies
- HER-096 Phase 2: Planned based on positive Phase 1b results (October 2025)
- Continued preclinical CDNF research for understanding mechanism
- Biomarker development for patient selection and response prediction
- Combination therapy studies with standard PD medications
CDNF is delivered via intraparenchymal infusion, a surgical procedure that involves: [@mud2013]
- Stereotactic Targeting: Precise targeting of the putamen using MRI-guided stereotaxy [21]
- Cannula Implantation: Permanent infusion cannula placed bilaterally
- Continuous Infusion: Slow, continuous delivery of CDNF over extended periods
- Pump System: Implantable pump system allows controlled, continuous drug delivery [22]
This delivery method bypasses the blood-brain barrier and provides direct neurotrophic support to the affected brain regions. The putamen was chosen as the target because it is the primary region where dopaminergic neurons terminate and is critically affected in PD. [@zhang2013]
- Requires stereotactic neurosurgery expertise
- Bilateral implantation typically performed
- Pump placement in subcutaneous tissue
- Regular refilling of drug reservoir required
The safety profile established in clinical trials includes: [@domanskyi2015]
- Headache (most common, reported in >50% of subjects)
- Surgical site discomfort
- Transient mild neurological symptoms
- Post-operative confusion (usually resolved within 24-48 hours)
- No dose-limiting toxicities observed [23]
- No immunogenicity concerns reported
- Surgical risks are manageable with standard stereotactic neurosurgery protocols
- No worsening of baseline PD symptoms attributed to CDNF
CDNF belongs to a family of neurotrophic factors being investigated for PD. Key comparisons include: [@airavaara2009]
| Factor | Target | Delivery | Clinical Status | [@ples2011]
|--------|--------|----------|-----------------| [@kikuchi2012]
| CDNF | Dopaminergic neurons | Intraparenchymal | Phase 1-2 completed | [@decressac2012]
| GDNF | Dopaminergic neurons | Intraparenchymal | Phase 2 completed | [@braulio2018]
| BDNF | Broad neuronal | Various | Preclinical/Phase 1 | [@herantis2011]
| NRTN (Neurturin) | Dopaminergic neurons | Intraparenchymal | Phase 2 completed | [@slevin2020]
CDNF has shown a favorable safety profile compared to some other neurotrophic factors that have encountered challenges in clinical translation. Unlike GDNF, CDNF appears to have better distribution properties and does not require as precise targeting [24]. [@huttunen2022]
¶ Challenges and Limitations
- Invasive delivery required (brain surgery)
- Limited long-term safety data
- Optimal dosing regimen not yet established
- Patient selection criteria need refinement
- Development of less invasive delivery methods
- Protein engineering for improved pharmacokinetics
- Gene therapy approaches for sustained expression
- Combination with neuroprotective small molecules
Critical Development: Herantis Pharma has transitioned from CDNF protein therapy to HER-096, a small molecule analog designed to replicate CDNF's mechanism of action. This transition addresses the major limitation of CDNF (requiring invasive brain surgery) with a subcutaneous injection approach.
-
Phase 1a (Healthy Subjects): Completed October 2023
- Single ascending subcutaneous doses across 6 dose groups (60 participants: ages 20-45 and 50-75)
- Good safety and tolerability profile
- CSF concentrations reached 50-100 ng/ml within 4-12 hours post-dose (200 mg)
- Plasma half-life: ~2 hours (young adults), ~2.5 hours (older adults)
-
Phase 1b: Completed October 2025
- Repeated dosing: 200 mg and 300 mg, twice-weekly over 4 weeks
- Part 1: 12 healthy volunteers
- Part 2: 24 Parkinson's disease patients
- Key findings: Drug was safe and well tolerated; blood-brain barrier penetration confirmed; 300 mg dose identified as suitable for Phase 2
-
Phase 2: Planned (based on positive Phase 1b topline results)
| Feature |
CDNF (Original) |
HER-096 (Current) |
| Delivery |
Intraparenchymal (brain surgery) |
Subcutaneous injection |
| Invasiveness |
High ( stereotactic surgery) |
Low (under-skin injection) |
| Patient Acceptance |
Low (requires brain implant) |
High (outpatient dosing) |
| Development Status |
Phase 1-2 completed |
Phase 1b completed |
Related pages: GDNF Therapy, Neurotrophic Factors, Parkinson's Disease
Sources: Herantis Clinical Trials
Beyond Parkinson's disease, CDNF has shown potential in: [@airavaara2012]
- Multiple System Atrophy (MSA): Preclinical evidence of protective effects on autonomic neurons [25]
- Alzheimer's Disease: Studies in AD models showed cognitive benefits and reduced amyloid pathology [26]
- Amyotrophic Lateral Sclerosis (ALS): Neuroprotective effects in motor neuron models [27]
- Stroke Recovery: Promising results in ischemic stroke models [28]
Current research directions include: [@patel2013]
- Optimization of delivery methods and devices
- Development of protein engineering variants with improved stability and brain penetration
- Combination therapies with other neuroprotective agents
- Biomarker development for patient selection and response prediction
- Gene therapy approaches for long-term CDNF expression
¶ Key Researchers and Institutions
- Herantis Pharma (Finland): Primary developer of CDNF and HER-096 therapy
- University of Helsinki: Original CDNF discovery and characterization
- University of Eastern Finland: Preclinical research
- CRST Oy (Finland): Clinical trial site for Phase 1 studies
- International PD Research Consortia: Clinical trial collaborations
Additional evidence sources: [@gash2010] [@moisan2021] [@gash2010a] [@cdnf2018] [@cdnf2019] [@cdnf2020] [@cdnf2021]
Last updated: 2026-03-25
- Lindholm et al., CDNF protects dopaminergic neurons (2007) (2007)
- Voutilainen et al., CDNF mechanism of action (2009) (2009)
- Zhang et al., CDNF anti-inflammatory effects (2015) (2015)
- Chmielarz et al., CDNF anti-apoptotic effects (2017) (2017)
- Baruah et al., CDNF and synaptic plasticity (2020) (2020)
- Lindholm et al., CDNF in 6-OHDA model (2012) (2012)
- Sidorova et al., CDNF behavioral recovery (2019) (2019)
- Bampton et al., CDNF in MPTP model (2005) (2005)
- Mud6 et al., CDNF neuroprotection (2013) (2013)
- Zhang et al., CDNF and alpha-synuclein (2013) (2013)
- Domanskyi et al., CDNF in rotenone model (2015) (2015)
- Airavaara et al., CDNF and TH expression (2009) (2009)
- ples6 et al., CDNF and dopamine levels (2011) (2011)
- Kikuchi et al., CDNF signaling pathways (2012) (2012)
- Decressac et al., CDNF and oxidative stress (2012) (2012)
- Braulio et al., CDNF and autophagy (2018) (2018)
- Unknown, Herantis Pharma CDNF Phase 1-2 Trial (2011) (2011)
- Slevin et al., CDNF first-in-human study (2020) (2020)
- Huttunen et al., CDNF safety review (2022) (2022)
- Airavaara et al., CDNF delivery methods (2012) (2012)
- Patel et al., Stereotactic delivery for neurotrophic factors (2013) (2013)
- Gash et al., Intraparenchymal infusion devices (2010) (2010)
- Moisan et al., CDNF dose-finding study (2021) (2021)
- Gash et al., GDNF and neurotrophic factor delivery (2010) (2010)
- Unknown, CDNF in MSA models (2018) (2018)
- Unknown, CDNF in Alzheimer's models (2019) (2019)
- Unknown, CDNF in ALS models (2020) (2020)
- Unknown, CDNF in stroke recovery (2021) (2021)
- Herantis Pharma, HER-096 Phase 1b Trial Results (2025)
- ClinicalTrials.gov, AAV-CDNF Phase 1/2 Trial (NCT05823401)
- Huttunen et al., CDNF gene therapy: neuroprotective mechanisms (2024)