Rare disease companies develop diagnostics, therapies and research technologies for conditions affecting relatively small patient populations. Their work often focuses on inherited disorders, complex diagnostic pathways and diseases with limited or no existing treatment options.
This category includes companies working on:
Browse 141 UK rare disease companies below.
siRNA gene therapies targeting root causes of ALS and frontotemporal dementia
Crucible Therapeutics Limited is a preclinical-stage biotechnology company developing siRNA-based gene therapies for Amyotrophic Lateral Sclerosis and Frontotemporal Dementia caused by the C9orf72 gene mutation. Its therapeutic approach depletes the SRSF1 protein to suppress production of toxic dipeptide repeat…
Global biopharma with UK R&D centre on the Wirral Peninsula
Bristol-Myers Squibb (BMS) is a global biopharmaceutical company with a long-established UK R&D site at Moreton on the Wirral Peninsula and its UK and Ireland commercial headquarters in Uxbridge. The Moreton facility, expanded in 2025, conducts chemistry, manufacturing and control activities supporting pharmaceutical…
Clinical-stage rare disease biotech acquiring deprioritised pharma assets
Mereo BioPharma is a clinical-stage biopharmaceutical company focused on developing treatments for rare diseases. Founded in 2015, its business model centres on acquiring clinical-stage programmes deprioritised by large pharmaceutical companies and advancing them through further development. Lead programmes include…
Off-the-shelf cell therapies for cancer and rare diseases
Empyrean Therapeutics develops off-the-shelf cell therapies intended to make treatments for cancer and rare diseases more accessible. Its approach combines gene editing, stem cell programming and precise genetic control to engineer therapeutic cells. The company is developing cell platforms and manufacturing processes…
Antisense oligonucleotide therapies for TUBB4A-associated leukodystrophies
SynaptixBio is a biotechnology company developing antisense oligonucleotide therapies for severe inherited leukodystrophies. Its lead programme targets TUBB4A-associated hypomyelinating disorders, including hypomyelination with atrophy of the basal ganglia and cerebellum (H-ABC). The approach uses synthetic…
siRNA therapeutics targeting liver-expressed disease genes
Silence Therapeutics is a clinical-stage biotechnology company developing siRNA therapeutics using its proprietary platform. The platform enables precise silencing of disease-associated genes expressed in the liver, without permanently altering DNA. Its pipeline addresses cardiovascular disease, haematological…
Clinical-stage biopharma targeting cancer immunotherapy and obesity
Poolbeg Pharma is a clinical-stage biopharmaceutical company developing small molecule therapies for high unmet medical needs. Its lead programme, POLB 001, is a p38 MAP kinase inhibitor in clinical trials for prevention of cytokine release syndrome associated with CAR-T and bispecific antibody cancer immunotherapies.…
Engineered therapeutic red blood cells for rare metabolic and other diseases
Scarlet Therapeutics is a biotechnology company developing a platform for generating therapeutic red blood cells (tRBCs). Erythroid cell lines are genetically engineered to produce red blood cells carrying high concentrations of therapeutic proteins, exploiting their natural tissue distribution, 120-day circulating…
Small molecule inhibitors targeting somatic expansion in neurodegeneration
LoQus23 Therapeutics is a biotechnology company developing oral small molecule inhibitors of DNA mismatch repair for the treatment of Huntington's disease and other triplet repeat expansion disorders. The company targets MutSβ, a protein complex whose aberrant activity drives somatic expansion and progressive…
Full-service CRO specialising in oncology and early-phase trials
Pivotal CRO is a full-service contract research organisation providing end-to-end clinical development support across all trial phases, from first-in-human to Phase III. The company offers clinical operations, regulatory affairs, data management, biostatistics, medical monitoring, pharmacovigilance, and patient…
TCR bispecific immunotherapies for cancer and infectious disease
Immunocore is a commercial-stage biopharma developing T cell receptor bispecific immunotherapies. Its lead product tebentafusp received FDA approval in 2022 for metastatic uveal melanoma and generated $400 million in revenue in 2025. Three Phase 3 trials are enrolling across melanoma indications, with topline data…
AstraZeneca's rare disease arm targeting the complement cascade
Alexion, AstraZeneca Rare Disease is the rare disease group within AstraZeneca, formed following the 2021 acquisition of Alexion Pharmaceuticals. With nearly 30 years of rare disease heritage, the division focuses on novel molecules targeting the complement cascade across haematology, nephrology, neurology, metabolic…
Antibody therapy to deplete amyloid deposits in ATTR cardiomyopathy
Immutrin is a biotechnology company developing an engineered antibody therapeutic designed to actively remove amyloid deposits from tissues in patients with amyloidosis. Its lead asset targets ATTR cardiomyopathy, a progressive and often fatal cardiac disease caused by transthyretin amyloid accumulation, for which no…
In vivo cell reprogramming therapies for degenerative disease
Mogrify is a biotechnology company developing a novel class of in vivo reprogramming therapies for degenerative diseases. Its proprietary platforms use large-scale transcriptomic and epigenomic network data to predict the transcription factors required to convert mature human cells directly into target therapeutic…
Autophagy-enhancing small molecule drugs for neurodegeneration and rare disease
Samsara Therapeutics is a drug discovery company developing first-in-class small molecule therapeutics that restore autophagy, the cellular process of degrading and recycling damaged proteins, which declines with age and is dysfunctional in multiple diseases. Its platform identifies and chemically optimises…
European hub for RNAi therapeutics developer
Alnylam UK is the European operational headquarters of Alnylam Pharmaceuticals, the pioneer of RNA interference therapeutics. Based in Maidenhead, the UK office serves as Alnylam's primary base for European commercial operations, medical affairs, and regulatory activities. Alnylam has six approved RNAi medicines on…
AI platform integrating biology, chemistry and automation for drug discovery
Recursion is a clinical-stage biotechnology company using AI and robotic wet-lab automation to industrialise small molecule drug discovery. Its platform integrates phenomics, transcriptomics, proteomics and patient data to identify and optimise drug candidates at scale. Following its acquisition of Oxford-based…
AI-driven combinatorial analytics platform for chronic disease biology
PrecisionLife is a computational biology company applying AI-driven combinatorial analytics to complex chronic diseases. Its platform identifies causal biological mechanisms and patient subgroups at a resolution not achievable by conventional genomic methods, enabling novel drug target discovery, patient…
Plasma fractionation and manufacture of plasma-derived therapies
Kedrion Biopharma is a biopharmaceutical manufacturer specialising in the fractionation of human blood plasma to produce albumin solutions, immunoglobulins and coagulation factors for the treatment of rare and life-threatening conditions including immunodeficiencies and bleeding disorders. Operating from a 130,000…
Native mass spectrometry platform for small molecule drug discovery
OMass Therapeutics is a biotechnology company developing small molecule therapeutics against membrane proteins, GPCRs, and intracellular complexes that have historically been difficult to drug. Its proprietary platform combines native mass spectrometry, novel biochemistry, and custom chemistry to interrogate protein…