TxCell SA, a biotechnology company developing innovative, personalized cellular immunotherapies using regulatory T cells (Treg) to treat severe chronic inflammatory and autoimmune diseases, announced that it has received authorization from European regulatory authorities to restart its phase IIb, placebo-controlled clinical trial with lead product Ovasave in patients with moderate to severe Crohn’s disease refractory to existing treatments (CATS29).

The authorization for TxCell to restart the CATS29 clinical study includes using a new manufacturer, the Contract Manufacturing Organization (CMO) MaSTherCell, and an amended protocol, through the Voluntary Harmonized Procedure (VHP). In February 2016, TxCell achieved the key milestone in the transfer of its manufacturing technology to MaSTherCell – the successful conduct of a series of contractually defined validation runs of Ovasave at MaSTherCell’s site.

TxCell is therefore preparing to resume CATS29 as soon as possible. Topline data are expected within 18 to 21 months of trial resumption.

“Obtaining the authorization to restart our phase IIb study in refractory Crohn’s patients as per the timeline announced mid-2015 is an important milestone for TxCell,” said Stéphane Boissel, CEO of TxCell. “TxCell has made major internal structural changes over the past year. These decisions include the reacquisition of the full rights to Ovasave, the decision to outsource our manufacturing activities, the appointment of MaSTherCell and PCT as our CMOs in Europe and in the US respectively and the start of ENTrIA, TxCell’s second platform, based on CAR-Treg cells. TxCell is now entirely focused on value-added activities in a new chapter for the company. With the CATS29 study, TxCell should obtain important controlled clinical data that will help us to position both our lead product as well as TxCell’s wider technology for the treatment of severe autoimmune and inflammatory disorders.”

The CATS29 clinical study aims primarily at comparing Ovasave at the 106 dose vs. placebo. The objective is to achieve a response rate of 70 per cent in the experimental arm vs. 30 per cent in the control arm. 56 patients with moderate to severe refractory Crohn’s disease will be evaluated. The patients will be recruited in 29 clinical centers in 6 European countries. The 32-week treatment will be split into two phases: firstly an 8-week blinded phase, where patients will receive at week 0 either placebo or Ovasave 106 (randomized 1:1) and secondly a 24-week unblinded phase, where all patients will receive Ovasave 106 (three further open label injections at 8-week intervals). TxCell now plans to amend its US IND (Investigational New Drug) accordingly.

The CATS29 Data and Safety Monitoring Board (DSMB) met ahead of the VHP approval to review all available data on previously treated patients, as well as updates on the study design and plans for the resumption of the study. The objective of the DSMB is to monitor patient safety during the conduct of the study. Upon reviewing of the data, the DSMB also allowed TxCell to proceed with the resumption of the CATS29 study as planned.

ASTrIA (Antigen Specific Treg for Inflammation and Autoimmunity) is a TxCell proprietary cellular immunotherapy product platform composed of autologous antigen specific Type 1 Regulatory T cells (Ag-Treg). Ag-Treg based products from the ASTrIA platform are produced from the peripheral blood of patients. After white blood cell isolation, CD4+ T cells are educated to recognize a specific antigen. Antigen educated Treg cells are then isolated and expanded ex vivo. Ovasave, the first Ag-Treg drug candidate from the ASTrIA platform, has been developed for the treatment of Inflammatory Bowel Disease (IBD) and is composed of ovalbumin-specific Type 1 Treg cells. Ovasave is currently in a European phase IIb clinical study in severe Crohn's Disease, entitled CATS29. Col-Treg is the second drug candidate from the ASTrIA platform and is composed of type-2 Collagen-specific Type 1 Treg cells. Col-Treg is developed for the treatment of steroid-refractory non-infectious uveitis.

ENTrIA (Engineered Treg for Inflammation and Autoimmunity) is the second TxCell proprietary cellular immunotherapy product platform and is composed of Chimeric Antigen Receptor engineered FoxP3+ Regulatory T cells (CAR-Treg). After their isolation from the blood of patients, FoxP3+ Treg cells are genetically modified by transduction with Chimeric Antigen Receptors (CAR). The CAR introduced into FoxP3+ Treg cells is designed to allow FoxP3+ Treg cell activation and immuno-modulation through in vivo recognition of a protein present in inflamed areas in patients suffering from autoimmune and chronic inflammatory diseases.