Best Rare Diseases Companies in California, United States
The 87 best Rare Diseases companies in California, United States in 2026, ranked by funding and momentum. Funding, investors, founders, valuation, tech stack and live signals. Top: InspirationBio.
Ranked: Best Rare Diseases companies in California
| # | Company | Disclosed funding | Last round | Employees | Founder | Tech stack | Patents & IP focus | Recent signals |
|---|---|---|---|---|---|---|---|---|
| 1 | InspirationBio Develops treament for people with hemophilia. | $544M | 197 mo ago | — | Michael Griffith President & CEO | — | — | — |
| 2 | BridgeBio Developer of therapeutics for the treatment of genetic diseases | $434M | 25 mo ago | 383 | Neil Kumar Co-Founder & CEO | DrupalApple iCloud MailMicrosoft 365+27 | 32 patents Targeted small‑molecule cancer combos (KRAS, EGFR, SHP2) and metabolic kidney disease therapies | 1 award |
| 3 | Travere Therapeutics Developer of therapeutics to treat rare diseases | $275M | 51 mo ago | 380 380 → 508 (+34%) · sector median +59% | Eric Dube CEO | WordPressApple iCloud MailMicrosoft 365+23 | — | 1 job opening |
| 4 | Mammoth 🦄 Provider of molecular diagnostics platform by using CRISPR technology | $271M | 57 mo ago | 180 | Lucas Harrington Co-Founder & CSO | WordPressMySQLPHP+16 | 3 patents HVAC heating equipment and air‑handling cabinet components | — |
| 5 | Raptor Pharma Developer of small molecule therapeutics for rare diseases | $235M | 129 mo ago | 128 | — | — | — | — |
| 6 | Autobahn Therapeutics Provider of therapeutics for CNS disorders by the regenerative medicine | $228M | 24 mo ago | 23 | Kevin Finney Chairman and CEO | — | — | — |
| 7 | Terns Pharmaceutical Developer of therapies for treating liver disease and cancer | $208M | 65 mo ago | 46 46 → 66 (+43%) · sector median +59% | — | WordPressApple iCloud MailMicrosoft 365+27 | — | 1 award |
| 8 | Attralus Developer of drugs for the treatment of Amyloid diseases | $197M | 28 mo ago | 23 | Jonathan Wall Co-Founder | — | 50 patents Engineered Fc‑fusion and antibody‑peptide biologics for amyloid disease therapy | — |
| 9 | aTyr Pharma Developer of protein biologics for treating multiple rare diseases | $172M | 105 mo ago | 65 65 → 75 (+15%) · sector median +59% | Paul Schimmel Co-Founder | WordPressApple iCloud MailGoogle Workspace+27 | 534 patents Patents concentrated in chemistry & materials | — |
| 10 | Design Therapeutics Develops disease-modifying therapies for degenerative disorders | $171M | 64 mo ago | 58 | Aseem Ansari Co-Founder | DrupalApple iCloud MailMicrosoft 365+24 | — | — |
| 11 | Imago BioSciences Developer of epigenetic-based therapies for rare genetic cancers | $160M | 67 mo ago | 27 | — | — | 116 patents KDM1A (LSD1) inhibitor drugs and CAR‑T cell enhancement for hematologic therapies | — |
| 12 | Angitia Developer of drugs for muscle, bone, and joint diseases 29Funding top 16%Talent top 38%Moat top 47%Market bottom 40% All 7 signals ▾Fundingtop 16% Talenttop 38% Moattop 47% Marketbottom 40% Globalbottom 39% Innovationbottom 23% Patentsbottom 20% Funding: Raised $156M across 5 rounds · 5 rounds over 6 yrs (0.8/yr) Talent: 2 named leaders on record · 2 C-suite/founder profiles curated rank vs industry peers · Fliar Intelligence Index 29/100 | $156M | 4 mo ago | — | Muyu Li Co-Founder & COO | — | 4 patents Anti‑sclerostin biologics for osteoporosis and bone‑mass therapies | — |
| 13 | Hyperion Therapeutics Biotechnology pioneer discovering, developing, manufacturing, and delivering innovative human therapeutics | $148M | 144 mo ago | 80 | Timothy Walbert CEO & President | — | — | — |
| 14 | avidity biosciences Avidity Biosciences is a biotechnology company that develops oligonucleotide-based therapies for its patients. | $143M | 27 mo ago | 186 253 → 443 (+75%) · sector median +59% | — | DrupalMariaDBPHP+12 | 369 patents Antibody‑oligonucleotide conjugates for treating muscular dystrophy and related muscle disorders | — |
| 15 | True North Therapeutics Antibodies that selectively targets the Classical pathway of the Complement system to treat rare diseases. | $142M | 116 mo ago | 18 | — | — | — | — |
| 16 | AudentesTherapeutics Developer of therapeutics to treat rare genetic diseases | $138M | 128 mo ago | 404 | — | — | — | — |
| 17 | Ultragenyx Developer of therapeutics for the treatment of rare and ultra-rare metabolic diseases | $135M | 161 mo ago | 837 837 → 1,516 (+81%) · sector median +59% | — | DrupalApple iCloud MailPHP+28 | — | 1 internship |
| 18 | Verge Genomics Developer of artificial intelligence powered platform for drug discovery and development | $134M | 54 mo ago | 46 46 → 27 (-41%) · sector median +59% | Peyton Huang Non-Executive Director and Co-Founder | — | — | 1 launch · 1 partnership |
| 19 | Mirum Pharmaceuticals Developer of small molecule based therapeutics to treat rare diseases 82Funding top 17%Patents top 18%Innovation top 23%Product top 28% All 12 signals ▾Fundingtop 17% Patentstop 18% Innovationtop 23% Producttop 28% Growthtop 30% Fin. healthtop 31% Markettop 33% Moattop 35% Newstop 36% Techtop 45% Talentbottom 49% Globalbottom 47% Funding: Raised $120M across 3 rounds · 3 rounds over 8 yrs (0.4/yr) Patents: 135 patents matched (strict assignee match) · 115 filings since 2022 vs 20 in 2017-21 rank vs industry peers · Fliar Intelligence Index 82/100 | $120M | 4 mo ago | 196 196 → 465 (+137%) · sector median +59% | Christopher Peetz CEO | WordPressMySQLPHP+18 | 135 patents IBAT inhibitor drugs for treating cholestasis and pediatric liver disease | — |
| 20 | Neomorph Developer of therapeutic solutions for the treatment of multiple diseases based on protein degradation… 53Funding top 23%Moat top 28%Talent top 28%Patents top 39% All 10 signals ▾Fundingtop 23% Moattop 28% Talenttop 28% Patentstop 39% Innovationtop 44% Partnerstop 45% Marketbottom 48% Techbottom 42% Globalbottom 33% Newsbottom 20% Funding: Raised $109M across 2 rounds · 2 rounds over 6 yrs (0.3/yr) Moat: Editorial + unicorn rating 8/10 · IP moat: 25 patents rank vs industry peers · Fliar Intelligence Index 53/100 | $109M | 2 mo ago | 54 | Philip Chamberlain Co-Founder & CEO | WordPressMySQLPHP+14 | 25 patents Novel substituted piperidine-imide heterocycles for pharmaceutical active ingredient development | 5 job openings |
| 21 | Spruce Biosciences Clinical stage biopharma developing rare diseases affecting the stress pathway (HPA axis) | $108M | 40 mo ago | 15 15 → 36 (+140%) · sector median +59% | Alexis Howerton Founder | — | 116 patents Glucocorticoid receptor antagonists and formulations for endocrine disorder therapies | — |
| 22 | Archemix Aptamer therapeutics for rare hematological diseases | $102M | 266 mo ago | 79 | Kenneth Bate President & CEO | — | 297 patents Aptamer-based complement C5 inhibitors for treating ocular complement disorders | — |
| 23 | Humanigen Developer of small molecules and monoclonal antibodies for rare diseases | $93M | 72 mo ago | 9 | Cameron Durrant CEO | — | 108 patents GM‑CSF antagonism to mitigate cytokine‑storm toxicity in CAR‑T/immune therapies and viral lung injury | — |
| 24 | Phathom Pharmaceuticals Developer of therapies for treating gastrointestinal diseases | $90M | 85 mo ago | 113 | David Socks Co-founder | DrupalApple iCloud MailPHP+35 | — | 1 award |
| 25 | Emmaus Medical Developer of small molecule therapeutics for the treatment of sickle cell anemia and sickle ß0-thalassemia | $89M | 47 mo ago | 44 | — | Windows ServerMicrosoft ASP.NETIIS+5 | — | — |
| 26 | GBT Developer of small molecules for the treatment of sickle cell disease | $89M | 137 mo ago | 457 | — | — | — | — |
| 27 | Aeovian Pharmaceuticals Developer of therpeutics for treating rare diseases | $87M | 7 mo ago | 10 10 → 13 (+30%) · sector median +59% | Stelios Tzannis Founder & COO | WixSentryBootstrap+12 | — | — |
| 28 | BioElectron Developer of robust and predictive models of complex biological systems | $87M | 94 mo ago | 59 | — | — | — | — |
| 29 | Epirium Bio Developer of therapeutic solutions for the treatment of cancer patients | $85M | 78 mo ago | 17 | — | WordPressMySQLRedis+14 | — | — |
| 30 | Mendra Developer of AI-enabled therapeutics for rare diseases with high unmet need | $82M | 5 mo ago | — | Joshua Grass Co-Founder & CEO | WebflowGSAPTypekit+12 | — | — |
| 31 | Glycomine Provider of replacement therapies for rare genetic diseases | $80M | 14 mo ago | 20 | — | — | 73 patents Patents concentrated in health & consumer products | — |
| 32 | Rigel Developer of drugs for hematologic disorders, cancer, and rare immune disease | $76M | 64 mo ago | 147 147 → 292 (+99%) · sector median +59% | Raul Rodriguez President and CEO | Apple iCloud MailApache HTTP ServerMicrosoft Advertising+14 | 6 patents Patents concentrated in computing, sensing & instrumentation | 3 partnerships |
| 33 | Trefoil Therapeutics Developer protein engineering drugs to treat corneal endothelial diseases | $73M | 14 mo ago | 10 | Michael Blaber Co-Founder | — | — | — |
| 34 | Lumena Pharma Innovating health solutions through ethical biotechnology for a better future | $71M | 147 mo ago | 11 | Michael Grey President and Chief Executive Officer | — | — | — |
| 35 | Retrotope Developer of therapeutics to treat neurodegenerative and ophthalmological diseases | $70M | 65 mo ago | 21 | Mikhail Shchepinov Founder | — | 221 patents Deuterated polyunsaturated fatty acid therapeutics for neurodegenerative disease treatment | — |
| 36 | Epicrispr Bio Developer of therapeutics for multiple disease 35Funding top 23%Talent top 38%Moat top 42%Tech bottom 43% All 6 signals ▾Fundingtop 23% Talenttop 38% Moattop 42% Techbottom 43% Globalbottom 37% Marketbottom 32% Funding: Raised $68.0M across 1 rounds · 1 rounds over 1 yrs (1.0/yr) Talent: 2 named leaders on record · 2 C-suite/founder profiles curated rank vs industry peers · Fliar Intelligence Index 35/100 | $68M | 14 mo ago | — | Lei Qi Founder | WordPressMySQLPHP+21 | — | — |
| 37 | Longboard Pharmaceutical Provider of therapeutic solution for treating rare neurological diseases | $56M | 67 mo ago | 50 | Kevin Lind President and CEO | — | — | — |
| 38 | Actio Biosciences Developer of genetics-led therapies targeting shared biology between rare, common diseases | $55M | 12 mo ago | 21 | David Goldstein Co-Founder & CEO | WordPress Block EditorWordPressMySQL+9 | — | 1 job opening |
| 39 | Spruce Developer of therapies for rare endocrine disorders | $50M | 8 mo ago | 29 | Javier Szwarcberg CEO | WordPressMySQLPHP+25 | 5 patents Patents concentrated in electrical & electronics | — |
| 40 | Jasper Therapeutics Developer of therapeutics for chronic diseases by targeting mast cells and stem cells | $49M | 77 mo ago | — | Judith Shizuru Co-Founder | WordPressApple iCloud MailMicrosoft 365+21 | — | — |
| 41 | Creyon Bio Provider of drug design and oligonucleotide-based drug development platform | $40M | 51 mo ago | 38 | Swagatam Mukhopadhyay Chief Scientific Officer & Cofounder & Board Member | WordPressMySQLPHP+15 | — | — |
| 42 | Artelo Biosciences Modifying lipid-signaling pathways to improve cancer treatments 53Funding top 17%Growth top 20%News top 23%Product top 24% All 9 signals ▾Fundingtop 17% Growthtop 20% Newstop 23% Producttop 24% Innovationtop 43% Talenttop 46% Techbottom 46% Globalbottom 38% Marketbottom 24% Funding: Raised $39.9M across 13 rounds · 13 rounds over 8 yrs (1.6/yr) Growth: Web rank 50,000,000 → 10,000,000 YoY · Fresh capital in last 24 mo rank vs industry peers · Fliar Intelligence Index 53/100 | $40M | 2 mo ago | 7 | Greg Gorgas CEO & President | WordPressMySQLPHP+16 | — | — |
| 43 | BioMarin Pharmaceutical Developer of therapeutics for the treatment of rare genetic diseases | $36M | 73 mo ago | 2,124 | Jean-Jacques Bienaime CEO & Chairman | WordPressMySQLPHP+21 | — | — |
| 44 | Athos Therapeutics Developer of AI-based therapeutics for treating autoimmune diseases 35AI top 35%Funding top 36%Talent bottom 49%Moat bottom 45% All 6 signals ▾AItop 35% Fundingtop 36% Talentbottom 49% Moatbottom 45% Marketbottom 32% Globalbottom 25% AI: Product described with: ai-based, machine learning Funding: Raised $28.0M across 3 rounds · 3 rounds over 5 yrs (0.6/yr) rank vs industry peers · Fliar Intelligence Index 35/100 | $28M | 2 mo ago | 18 | Dimitrios Iliopoulos Co-founder | — | — | — |
| 45 | GEn1E Developer of therapeutics for the treatment of inflammatory and rare diseases | $17M | 8 mo ago | 19 | Ritu Lal Co-Founder & CEO | — | — | — |
| 46 | Rarity PBC Developer of gene therapies for rare genetic diseases | $5M | 7 mo ago | — | Donald Kohn Co-Founder | — | — | — |
| 47 | Celestial Therapeutics Developer of mRNA-based vaccines and therapies for multiple diseases | $1M | 14 mo ago | — | Leontis Teryazos Co-Founder | — | — | — |
| 48 | AcuraStem Developer of therapeutics for neurodegenerative diseases | $780K | 1 mo ago | 14 | Justin Ichida Co-Founder | — | 70 patents Antisense oligonucleotide therapeutics targeting SYF2, PIKfyve, UNC13A gene expression. | — |
| 49 | Cavalry Biosciences Developer of therapeutics to treat chronic and rare diseases | $549K | 17 mo ago | 6 | — | — | — | — |
| 50 | Uncommon Therapeutics Developer of therapeutics for rare, uncommon diseases | $500K | 15 mo ago | — | Noah Auerhahn Co-Founder & CEO | — | — | — |
Top 12 Rare Diseases companies in California
#1
Series B · San Diego, California · founded 2003 · 54 employees$109Mraised▾
Developer of therapeutic solutions for the treatment of multiple diseases based on protein degradation technology. The company has developed a protein degradation entity that mainly focused on molecular glue degraders that destroy proteins linked to disease. These degraders can be classified as heterobifunctional that solve critical problems.
- Apr 2026Series B$100M
- Dec 2020Series A$109M
#2
Series D · Woodland Hills, California · founded 2018$156Mraised▾
Developer of drugs for muscle, bone, and joint diseases. The company's products include AGAO1 for bone fusion, AGA02 for rare diseases, AGA03 for regeneration, AGA04 for osteoporosis, AGA05 for healing, and others. Also, developed many drugs for multiple disease treatments such as nonunion of fractures, osteoarthritis, rare diseases of skeletal muscle, and mineral metabolism diseases caused by diseases or disorders of endocrine organs.
- Feb 2026Series D$130M
- Dec 2024Series C$120M
- Jan 2024Series B$40M
- Oct 2023Series B$46M
#3
Public · Menlo Park, California · founded 2018 · 196 employees$120Mraised▾
Developer of small molecule based therapeutics to treat rare diseases. The company's lead product candidate Maralixibat inhibits a carrier protein called apical sodium-dependent bile acid transporter for reducing systemic levels of bile acids. It is used for the treatment of both Alagille syndrome (ALGS) and progressive familial intrahepatic cholestasis. The other product of the company Volixibat is used for the treatment of adult cholestasis.
- Jan 2026Post IPO$68.5M
- Dec 2020Post IPO$10M
- Nov 2018Series A$120M
#4
Public · San Diego, California · founded 2011 · 7 employees$39.9Mraised▾
Modifying lipid-signaling pathways to improve cancer treatments. This clinical-stage pharmaceutical manufacturing company focuses on oncology and endocannabinoid modulation. They develop treatments for conditions like cancer anorexia-cachexia syndrome, utilizing CBD, FABP5 inhibitors, and synthetic cannabinoids. Their pipeline includes ART27.13, ART26.12, and ART12.11. They aim to restore vitality and daily function in patients. The company is involved in medical innovation and cancer research, striving to improve the lives of those facing limited options. They are exploring novel non-opioid treatments for persistent pain and addressing stress-induced depression and anxiety symptoms.
- Mar 2026Post IPO$11M
- Jan 2026Post IPO$500K
- Oct 2025Post IPO$3.7M
- Aug 2025Post IPO$9.5M
#5
Series A · Torrance, California · founded 2019 · 18 employees$28Mraised▾
Developer of AI-based therapeutics for treating autoimmune diseases. The company has developed an innovative computational process based on machine learning algorithms that identify novel and safe drug/gene targets for individual patients. The product pipeline includes ATH-63, ATH-105, and ATH-120 for Ulcerative Colitis & Crohn’s Disease.
- Apr 2026Series A$10.3M
- Jan 2024Series A$7.6M
- Nov 2021Series A$20.4M
#6
Series A · San Francisco, California · founded 2026$82Mraised▾
Developer of AI-enabled therapeutics for rare diseases with high unmet need. The company focuses on accelerating clinical development and commercialization of breakthrough medicines. It leverages artificial intelligence to address diseases where there are significant unmet medical needs.
- Jan 2026Series A$82M
#7
Series B · San Francisco, California · founded 2012 · 10 employees$87.4Mraised▾
Developer of therpeutics for treating rare diseases. The company focused on developing selective small molecule inhibitors targeting the mTORC1 pathway for rare genetic and age-related diseases. The company's product line include AV078, is a CNS-penetrant selective mTORC1 inhibitor for TSC-related refractory epilepsy.
- Nov 2025Series B$55M
- Dec 2023Series B$50.4M
- Oct 2019Series A$37M
- Jun 2019Grant (prize money)$472K
#8
Public · San Francisco, California · founded 2016 · 29 employees$50Mraised▾
Developer of therapies for rare endocrine disorders. It offers a lead product tildacerfont whichis a CRF1 receptor antagonist for adult patients with classic congenital adrenal hyperplasia and other diseases characterized by elevated levels of adrenocorticotropic hormone.
- Oct 2025Post IPO$50M
- Feb 2023Post IPO—
#9
Series A · San Diego, California · founded 2014 · 10 employees$73.2Mraised▾
Developer protein engineering drugs to treat corneal endothelial diseases. The company's Lead candidate TTHX1114 is an engineered form of naturally-occurring Fibroblast Growth Factor -1 (FGF-1) that is designed to protect corneal endothelial cells and as well as restore vision loss due to corneal endothelial cell dystrophy by stimulating corneal endothelial cell proliferation and migration. Also, it develops another drug candidate an eye drop formulation of TTHX1114 for the treatment of ulcerative conditions.
- Apr 2025Series A$4.6M
- Mar 2022Series A$12M
- Dec 2021Series A$28M
- Jul 2019Series A$28M
#10
Series C · San Francisco, California · founded 2015 · 20 employees$80Mraised▾
Provider of replacement therapies for rare genetic diseases. The company is also developing nanocarriers to deliver proteins into affected cells and tissues. Its drug pipeline includes M1P substrate replacement therapy for Congenital Disorder of Glycosylation (CDG-Ia) and rhNgly1 enzyme replacement therapy for NGLY1 deficiency (or N-glycanase deficiency).
- Apr 2025Series C$115M
- Jun 2021Series B$35M
- Aug 2019Series B$33M
- Nov 2016Series A$12M
#11
Series A · Palo Alto, California · founded 2018 · 19 employees$17.2Mraised▾
Developer of therapeutics for the treatment of inflammatory and rare diseases. The company's platform is utilizing the drug development cycle by applying AI to multiple-mechanism-of-action protein targets and their natural platform to create novel therapies for rare and inflammatory diseases. The lead candidate molecule is "GEn-1124"- for lung chronic conditions and other candidate molecules are in the research and discovery phase.
- Oct 2025Series A$5.5M
- Dec 2022Series A$17M
- 2021Seed—
- Aug 2019Seed$125K
#12
Series B · San Diego, California · founded 2021 · 21 employees$55Mraised▾
Developer of genetics-led therapies targeting shared biology between rare, common diseases. It applies expertise in genetics, drug discovery, and data sciences. The focus is on pinpointing targets that cause rare diseases. The aim is to enhance understanding of both the target and disease. The approach guides therapeutic expansion to more prevalent diseases.
- Jun 2025Series B$66M
- Sep 2023Series A$55M
Funding & investor landscape
Notable founders
Market landscape — 10 sub-themes by coverage
Share of Rare Diseases coverage by sub-theme.
Regulatory-risk over time rising
Funding & growth over time
funding rising · growth rising
Common questions
Riya reads income statements for fun. She covers the real money in a sector — revenue, growth, who actually earns — and never met a vague claim she didn't want a number for.