Another clinical hold for Cellectis


Yesterday’s US clinical hold for Cellectis’s allogeneic multiple myeloma Car-T therapy UCARTCS1A is a troubling development for the group; it was only two years or so ago that a phase I hold on another of its wholly owned assets, UCART123, was lifted after the first subject dosed died. UCARTCS1A had been cleared to begin phase I over a year ago, but it took another seven months for the Melani-01 trial to begin. The reason for its halting is the death from cardiac arrest of a heavily pretreated subject on a second dose level. UCARTCS1A seems to be a variation on Cellectis’s UCARTCS1 project, and targets the CS1 antigen, also known as SlamF7, which is said to be present on multiple myeloma cells as well as some T cells, necessitating its editing out on Car-T cells to prevent T-cell fratricide. CS1 is best known as the target of Bristol-Myers Squibb’s Empliciti, and hitting it with an antibody is said to activate NK cells as well as marking target tumour cells for destruction. Relatively few other projects use this approach, and one, Abbvie/Seattle Genetics’ azintuxizumab vedotin, was canned owing to modest activity.

Selected industry projects targeting CS1 (SlamF7) in multiple myeloma
Project Mechanism Company Status
Emplicity Anti-CS1 MAb Bristol Myers Squibb/Abbvie Marketed for 2-4L multiple myeloma (failed 1L study)
UCARTCS1/ UCARTCS1A Anti-CS1 Car-T Cellectis (ex Ohio State) Phase 1 trial on hold
MB-104 Anti-CS1 Car-T Fortress Biotech/Mustang Bio (ex City of Hope) Phase 1
BCMA-CS1 cCAR T Anti-BCMA/CS1 Car-T Icell Gene Phase 1
NEXI-002 Patient-derived T cells against WT1, CD138 & CS1 Neximmune IND approved
Caramba Anti-CS1 Car-T T-Curx Preclinical
Azintuxizumab vedotin (ABBV‑838) Anti-CS1 ADC Abbvie Discontinued
Source:, EvaluatePharma & company statements.

Related Topics

Share This Article