Semma Therapeutics announces positive pre-clinical data for stem cell islet infusion and immunoprotective device– July 2, 2019

First positive data from Semma/Defymed’s MAILPAN macroencapsulation system collaboration; Clinical studies to roll out in 2020

Semma Therapeutics announced yesterday positive pre-clinical proof-of-concept data for its two lead programs of stem cell-derived islet (SC-islet) therapies in both non-human primates and pigs.

In one study of cell therapy in non-human primates under immunosuppression, SC-islet infusion into the portal vein resulted in a >60% reduction of insulin requirement. SC-islets engrafted successfully and had persistent function for more than six weeks in the liver.

In a second pre-clinical trial, pigs were administered SC-islets encapsulated in an immunosuppression device designed to eliminate the need for immunosuppression. Results show that the device provides immunoprotection in vivo, and SC-islets are able to rapidly secrete insulin, as measured by C-peptide. Although not specified, we assume this second program stems out of Semma’s 2016 collaboration with Defymed’s preclinical MAILPAN macroencapsulation system. Using the system, cells within the device chamber are intimately associated with a vascularized tissue matrix and are locally protected within the device.

  • Building off of this positive preclinical data, Semma plans to roll out its first clinical trial in patients with “difficult to treat diabetes” and hypoglycemia unawareness in the first half of 2020. A second clinical trial for the broader type 1 adult population will begin in the second half of 2020 using the immunoprotective device without immunosuppression.

  • Looking more broadly in the beta cell encapsulation and replacement field, Semma now joins ViaCyte and Sernova as the most advanced players in the competitive landscape. ViaCyte’s phase 1/2 PEC-Encap/VC-o1 and PEC-Direct/VC-02 and Sernova’s phase 1/2 Cell Pouch System are the only candidates in the beta cell encapsulation competitive landscape to reach clinical development, suggesting a product will not be on the market for quite some time.

Close Concerns Questions:

  • What is the efficacy of macroencapsulated SC-islets in animals with diabetes?

  • What is the duration of SC-islet functionality using the macroencapsulation system?

  • Is there any evidence of foreign-body reaction with periods of longer implantation?


--by Rhea Teng, Martin Kurian, and Kelly Close