Biotechnology · Exosome therapeutics
Entelexo Biotherapeutics
An Irvine company engineering exosomes into drug candidates for autoimmune disease, built on published UC Irvine research. It holds one granted US patent, has no registered clinical trial, and works in a product class the FDA has never approved.
Day 18
The mice had experimental autoimmune encephalomyelitis, the laboratory stand-in for multiple sclerosis. By day 18 the disease was at its peak.
A team at the University of California, Irvine gave them an intravenous injection of something very small. Not stem cells: exosomes, nanoscale vesicles shed by human bone marrow mesenchymal stem cells that had first been stimulated with interferon gamma. Whole stem cells pushed into a vein tend to lodge in filter organs. Vesicles a hundred nanometers across do not.
The results appeared in ACS Nano in June 2019. Treated animals scored better than saline controls. Demyelination fell. Neuroinflammation fell. The count of CD4+CD25+FOXP3+ regulatory T cells inside the spinal cord went up, which is the immunological point: the vesicles were not blanketing the immune system so much as retraining a piece of it.
One of the two co-lead authors was a doctoral student named Milad Riazifar. Less than a year later, on April 22, 2020, he incorporated Entelexo Biotherapeutics in Delaware.
The problem, and the shadow across it
Entelexo’s stated target is the set of autoimmune conditions that current biologics manage rather than resolve: rheumatoid arthritis, Crohn’s disease, psoriasis. Its argument is that a drug blocking one cytokine is a poor fit for a disease running through several cell types at once, and that an engineered exosome can carry instructions to more than one cell type in a single dose.
That is the company’s framing. The category it sits in carries a harder history.
Six months after the ACS Nano paper, and four months before Entelexo was incorporated, the FDA published a public safety notification about exosomes. Dated December 6, 2019, it described multiple reports of serious adverse events in patients in Nebraska treated with unapproved products marketed as containing exosomes. On the category it was unambiguous: “There are currently no FDA-approved exosome products.” On the law it was equally clear, stating that exosomes used to treat disease in humans are regulated as drugs and biological products subject to premarket review and approval. The notice targeted clinics selling injections, not drug developers, and the agency said it remains committed to an efficient path for developing regenerative medicine therapies. A 2024 review in Clinical and Translational Science noted that the FDA “has alerted consumers that no exosome products are currently approved.”
Three founders, three inventors
Entelexo reported three employees in its 2021 securities filing and is still listed as three people. Milad Riazifar is chief executive, Charles Cameron Taylor chief technology officer, Todd Schurr chief operating officer. All three signed the SEC filing and all three are named inventors on the company patent.
Riazifar is the scientific origin. Y Combinator’s page says that during his doctoral work at the Stem Cell Research Center at UC Irvine “he pioneered a cell-free exosome-based approach to treat Multiple Sclerosis,” and that at City of Hope he joined a translation team working toward a first-in-world trial of stem cell exosomes in type 1 diabetes. In 2019 he told UC Irvine’s news office human testing would begin in early 2020. No such trial appears in the ClinicalTrials.gov registry.
Patent granted, record quiet
Y Combinator took the company into its Winter 2021 batch, and Endless Frontier Labs at NYU Stern later listed it. The company roadmap runs from founding through lab setup, patent filings, a completed pre-seed, lead candidate selection and a J.P. Morgan showcase appearance, then shifts into future tense: IND-enabling animal studies begin, preparations begin to file for pre-IND with FDA.
The patent landed on December 26, 2023. US 11,851,470 B2, Platforms, compositions, and methods for therapeutic delivery, is assigned to Entelexo Biotherapeutics, Inc. of Irvine, with Riazifar, Taylor and Schurr as inventors. Its priority chain reaches back to two provisional applications filed in June and July 2019, before the company existed, and the specification incorporates the 2019 ACS Nano paper by reference.
After that the record thins. The last SEC filing is dated July 2, 2021. The website still carries a 2022 copyright line, and a Wayback Machine capture from November 27, 2025 shows the same text as the live page. No trial registration names the company. No NIH or NSF award does either.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| Founding science | Riazifar et al., ACS Nano, Jun 25, 2019 (PMID 31117376). Exosomes from interferon gamma stimulated human MSCs cut mean clinical score, demyelination and neuroinflammation in EAE mice and raised spinal cord regulatory T cells. Done at UC Irvine before the company existed; the company patent incorporates it by reference. | Public record |
| US patent 11,851,470 B2 | Granted Dec 26, 2023 on application 17/855,305, filed Jun 30, 2022. Assignee Entelexo Biotherapeutics, Inc. Inventors Riazifar, Taylor, Schurr. Publication 20220389078. | Public record |
| Patent family | Continuation of PCT/US2020/038816 (Jun 19, 2020) from provisionals filed Jun 21 and Jul 17, 2019. A second application, PCT/US2021/064186, drew an international search report dated Mar 22, 2022. A Justia assignee search returns one granted US patent. | Public record |
| Registered trials | A ClinicalTrials.gov query for Entelexo returns no studies as of Sep 24, 2026. | Not found |
| FDA record | No 510(k), PMA or approved biologic. Across the category, FDA stated in Dec 2019 that no exosome products are approved, and none has been approved since. | Public record |
| First-in-world trial claim | Y Combinator says Riazifar “was part of a clinical translation team initiating the world’s first clinical trial using stem cell exosomes for the treatment of type I diabetes.” Wefunder says the CEO “led the 1st clinical trials in the world evaluating exosomes as a treatment for autoimmune disease.” No such study appears in ClinicalTrials.gov; City of Hope exosome studies in the registry are cancer liquid biopsy work. | Differs from registry |
| Federal grants | No NIH or NSF award found for the company. NSF hits under the name belong to other firms. | Not found |
| Capital raised | Form C filed Jun 24, 2021, amended Jul 2, 2021, offering SAFEs through Wefunder. Wefunder reports $32,890 from 80 investors. No Form D on EDGAR. | Public record |
| Pipeline status | The company says it selected lead candidates and has “de-risked these drug candidates using human cell assays.” No supporting data published; no engineered Entelexo construct appears in the literature. | Company-stated |
| Current activity | Last SEC filing Jul 2, 2021. Website copy unchanged since a 2022 copyright line, matching a Nov 27, 2025 archive capture. No independent coverage of the company found after 2021. | Not found |
Read plainly: the science under Entelexo is real and well cited, but it belongs to a university lab and describes unmodified stem cell exosomes, not the company’s engineered versions. What the company itself has put on the record is one granted patent and a small crowdfunding round. The pipeline, the de-risking and the lead candidates rest on company statements no outside party has tested, in a product class that has never been approved for anything.
What to watch
- A Form C-AR annual report or a Form C-TR termination notice on EDGAR. Either would show whether the issuer is still reporting.
- A Form D, the first public sign of a priced or institutional round.
- An investigational new drug application or a trial registration. The roadmap puts a pre-IND meeting next.
- Continuations out of PCT/US2021/064186, which would show the platform is still being prosecuted.
- Published preclinical data on the engineered exosomes, as opposed to the 2019 university work on unmodified ones.
In their words
“Until now, stem cell therapies for autoimmune and neurodegenerative diseases have produced mixed results in clinical trials, partly because we don’t know how the treatments work.”
Weian Zhao, UC Irvine, corresponding author, 2019 · Independent
“This novel treatment will be tested on humans in early 2020, initially on people with Type 1 diabetes.”
Milad Riazifar, co-lead author, UC Irvine news, June 2019 · Independent
“If successful, it could pave the way for treating other autoimmune diseases, including multiple sclerosis.”
Milad Riazifar, UC Irvine news, June 2019 · Independent
“they normalized the subjects’ immune systems, something conventional drugs can’t do”
Reza Mohammadi, co-lead author, June 2019 · Independent
“There are currently no FDA-approved exosome products.”
FDA, Public Safety Notification on Exosome Products, Dec 6, 2019 · Public record
“During his Ph.D studies at the Stem Cell Research Center at the University of California Irvine, he pioneered a cell-free exosome-based approach to treat Multiple Sclerosis.”
Founder biography, Y Combinator company page · Company-stated
“We have built an initial pipeline of products, and we have de-risked these drug candidates using human cell assays.”
Entelexo Biotherapeutics website · Company-stated
Related companies
Sources
- Public recordStem Cell-Derived Exosomes as Nanotherapeutics for Autoimmune and Neurodegenerative Disorders
- Public recordUS Patent 11,851,470 B2, assignee and inventor listing
- Public recordPublic Safety Notification on Exosome Products
- Public recordForm C, Entelexo Biotherapeutics Inc., CIK 0001867546
- Public recordForm C/A amended offering statement
- Public recordRegistry queries for Entelexo and City of Hope exosome studies
- IndependentNanotechnology Treatment Shows Promise Against Multiple Sclerosis
- IndependentNanotechnology treatment reverses multiple sclerosis in mice
- IndependentNanotechnology treatment shows promise against multiple sclerosis
- IndependentRegulation of exosomes as biologic medicines
- IndependentNavigating the Global Regulatory Landscape for Exosome-Based Therapeutics
- CompanyEntelexo Biotherapeutics website and roadmap
- CompanyCompany page and founder biography
- CompanyEntelexo (YC W21) offering page
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
