Legacy biotechnology · research stage
VICAPSYN™: cell replacement for type 1 diabetes, designed to work without systemic immunosuppression.
Insulin-producing cells encapsulated in a matrix that releases CXCL12, a signal that keeps the immune system from attacking the graft. Developed at Massachusetts General Hospital in the laboratory of Mark C. Poznansky, MD, PhD, the company's scientific founder; licensed exclusively to Vicapsys and held directly by Vicapsys Life Sciences, Inc.
The problem that is still open
Managing it. Insulin from outside the body, by injection or pump, keeps people alive but does not restore what was lost. Tzield® (teplizumab), approved in 2022, can delay the onset of clinical type 1 diabetes in at-risk patients by a median of about two years (50 months to diagnosis versus 25 on placebo); it does not replace the lost beta cells.17
Replacing the cells, with immunosuppression. Vertex Pharmaceuticals bought Semma Therapeutics for US$950 million in 2019 for its stem-cell-derived islet program.12 That program, zimislecel, has delivered results: in the Phase 1/2 study, 10 of 12 patients were free of supplemental insulin a year after a single infusion into the liver's portal vein. It also requires chronic immunosuppressive drugs to stop rejection, and the most common serious adverse event was neutropenia, a drop in infection-fighting white cells.13 14 Vertex expects to file for approval in 2026.
Replacing the cells without immunosuppression: not solved. Vertex's attempt to avoid immunosuppression by putting the same cells in an encapsulation device, VX-264, was discontinued in March 2025: safe, but insulin production (C-peptide) did not reach a level that would benefit patients.13 Immune isolation that keeps the cells alive and working is the open problem in islet replacement.
The VICAPSYN approach
The signal
CXCL12 is a chemokine, a protein the body uses to direct immune cells. At high local concentration it repels the T cells that would attack a transplant and recruits regulatory T cells that calm the response, while also reducing the fibrous overgrowth that normally smothers encapsulated cells.
The capsule
Islet cell clusters are encapsulated in an alginate matrix that releases CXCL12. The cells inside are shielded without drugs that suppress the whole immune system. In primates, CXCL12 microbeads came out at six months intact, vascularized and free of the fibrous capsule that normally smothers an implant; identical beads without CXCL12 were walled off and destroyed.21
The site
Islet transplants, including zimislecel, are infused into the liver through the portal vein, where many cells do not survive. VICAPSYN is placed on the omentum, the blood-rich membrane that covers the abdominal organs, by minimally invasive cell-transplantation surgery, a site used in clinical islet research and shown to support islet grafts in primates.18 22 A subcutaneous route is also being evaluated.
The cells
Insulin-producing islet cell clusters from a qualified source. The encapsulation is designed to work with donor islets and with stem-cell-derived beta cells, which is what the published mouse work used.15
The evidence so far
Mice. Human stem-cell-derived beta cells encapsulated in alginate with CXCL12 corrected blood glucose in immunocompetent diabetic mice and kept working for more than 150 days with no systemic immunosuppression; the CXCL12 capsules avoided the fibrotic overgrowth that usually kills encapsulated cells.15 The cells came from the laboratory of co-author Douglas Melton, whose stem-cell-derived beta cells became the Semma program that Vertex acquired: the VICAPSYN capsule has already been tested with the cell lineage the market leader uses.
Non-human primates, first study. In a preliminary four-animal study, CXCL12-containing alginate microbeads were associated with a markedly reduced foreign-body reaction over six months.16
Non-human primates, 2023 pilot. Five cynomolgus monkeys, four healthy and one diabetic, received adult pig islets in alginate microbeads placed in the omental bilayer sac, with no systemic immunosuppression. Microbeads containing CXCL12 were retrieved at day 90 and day 180 with no microscopic sign of degradation or foreign-body response, no adhesions or fibrosis at the implant site, and new blood vessels growing around them. Functional islets were present at day 30 in every animal biopsied, and viable islets were still detectable in retrieved beads at six months. Beads without CXCL12 were walled off by a severe foreign-body reaction that destroyed the graft. Inflammatory signals in the blood changed only two- to six-fold and mostly settled within four weeks, and xenoantigen-specific T-cell responses were minimal. In the diabetic animal, a deliberately sub-therapeutic dose lowered its insulin needs and produced measurable C-peptide for about four weeks.21
Who did the work. Both primate studies and the mouse study come from the Vaccine and Immunotherapy Center at Massachusetts General Hospital under Mark C. Poznansky, with the Harvard Stem Cell Institute and the University of Arizona's Institute for Cellular Transplantation. James F. Markmann, Chief of Transplant Surgery at MGH and a co-author, is a scientific consultant to Vicapsys.21
Why a pig-islet result matters. A graft from another species is the hardest case for the immune system to tolerate. Protecting it without drugs is a strong test of the mechanism, and pig islets are a potential unlimited cell supply. The 2023 study was a pilot, and the authors call for a larger, appropriately powered study with a therapeutic dose, which is the proof-of-concept study the company plans.
Next steps
| Step | Purpose |
|---|---|
| Engage a cGMP contract development and manufacturing organization (CDMO) | Produce the encapsulated cell product to clinical-grade standards |
| Proof-of-concept study in non-human primates | Show that encapsulated islets placed on the omentum survive and control blood glucose without systemic immunosuppression |
| IND-enabling work; engage a contract research organization | Prepare and run a first-in-human Phase 1 study |
VICAPSYN is a research-stage program. No clinical trial has begun, and there is no assurance that preclinical results will be reproduced in people or that the program will receive regulatory approval.
Beyond diabetes, and the patents
VYBRIN™. The same CXCL12 mechanism that turns the immune response away from a graft also dampens fibrosis. A second direction, VYBRIN, explores anti-fibrotic use in post-surgical settings, on its own regulatory and preclinical path.
Intellectual property. The core family, "Eluting Matrix and Uses Thereof," comprises four issued U.S. patents plus European, Japanese, Australian and Russian counterparts running to about 2033; a 2018 family is pending in the U.S. and at the European Patent Office, with protection to about 2038 if granted.20 Massachusetts General Hospital remains a major legacy shareholder of Vicapsys.
Patent-family scope per management; being confirmed with MGH. VICAPSYN is a trade name for the type 1 diabetes application, not a legal entity; the MGH license sits with the parent company.
Sources
- Vertex Pharmaceuticals, press release, September 3, 2019: acquisition of Semma Therapeutics for US$950 million in cash.
- Vertex Pharmaceuticals, program updates for the type 1 diabetes portfolio, March 28, 2025: VX-264 discontinued after C-peptide did not reach levels needed for benefit; zimislecel with standard immunosuppression; global regulatory submissions expected in 2026.
- Vertex Pharmaceuticals, zimislecel Phase 1/2 results (American Diabetes Association Scientific Sessions and New England Journal of Medicine, June 2025): 12 patients, 10 insulin-independent at one year; hepatic portal vein infusion; chronic immunosuppression; neutropenia the most common serious adverse event.
- Alagpulinsa DA, Cao JJL, Driscoll RK, et al.; Melton DA, Poznansky MC. Alginate-microencapsulation of human stem cell-derived β cells with CXCL12 prolongs their survival and function in immunocompetent mice without systemic immunosuppression. American Journal of Transplantation 2019;19(7):1930–1940.
- Preliminary studies of the impact of CXCL12 on the foreign body reaction to pancreatic islets microencapsulated in alginate in nonhuman primates. Transplant Direct 2019;5(5):e447.
- Provention Bio, press release, November 17, 2022: FDA approval of Tzield® (teplizumab-mzwv); TN-10 study median time to Stage 3 type 1 diabetes 50 months versus 25 months on placebo.
- Diabetes Research Institute, University of Miami, August 26, 2015: first transplant of islets onto the omentum in the BioHub pilot trial, and the rationale for the omentum as a site.
- Centers for Disease Control and Prevention, National Diabetes Statistics Report: about 2 million Americans have type 1 diabetes.
- U.S. Patents 9,775,816; 9,849,094; 9,849,159; 10,580,262, "Eluting matrix and uses thereof" (USPTO).
- Sremac M, Luo H, Deng H, Parr MFE, Hutcheson J, Verde PS, Alagpulinsa DA, Kitzmann JM, Papas KK, Brauns T, Markmann JF, Lei J, Poznansky MC. Short-term function and immune-protection of microencapsulated adult porcine islets with alginate incorporating CXCL12 in healthy and diabetic non-human primates without systemic immune suppression: a pilot study. Xenotransplantation 2023;e12826 (doi:10.1111/xen.12826). Supported by JDRF and the VIC Innovation Fund; Vicapsys co-authored.
- Deng H, Zhang A, Pang DRR, et al. Bioengineered omental transplant site promotes pancreatic islet allografts survival in non-human primates. Cell Reports Medicine 2023;4(3):100959.