Arcellx (ACLX) closed down ~17% Monday after privately held Kelonia Therapeutics released early-stage results from a small trial of a CAR-T therapy for multiple myeloma that could have advantages over existing CAR-T treatments.
Although Kelonia’s phase 1 study of KLN-1010 only enrolled three people, the results showed early responses. Data indicated all participants achieved minimal residual disease negativity at month 1. CAR-T cell expansion and persistence of memory CAR-T cells was observed without lymphodepleting chemotherapy, apheresis, or ex vivo cell manufacturing. However, the maximum follow-up was only three months and the best overall response reported was a very good partial response.
In phase 3, Arcellx has anitocabtagene autoleucel (anito-cel), an autologous anti–B-cell maturation antigen (BCMA)-directed CAR-T for MM. The T-cells in it have been modified ex-vivo. If approved, anito-cel, which is in partnernered with Gilead Sciences (GILD) subsidiary Kite Therapeutics, would likely compete against approved MM CAR-T therapies Carvykti (ciltacabtagene autoleucel) from Johnson & Johnson (JNJ) and Abecma (idecabtagene vicleucel) from Bristol Myers Squibb (BMY).
Guggenheim analyst Michael Schmidt noted that while Kelonia’s in-vivo approach may be more feasible as it could end the need for apheresis, cell manufacturing, and lymphodepletion, given the small patient enrollment, short follow-up, and lack of long-term safety data, Arcellx’s stock decline is likely overblown.
He maintained his buy rating on Arcellx.
Citi’s Geoff Meachem, who also has a buy rating, echoed much of Schmidt’s comments, adding “the perceived threat to anito-cel’s established or more advanced clinical position is overstated, and as such, we are buyers on the weakness.
Arcellx and Kelonia will present abstracts on anito-cel and KLN-1010 at December’s American Society of Hematology 2025 Annual Meeting.
Earlier in November, Kelonia signed a collaboration agreement with Johnson & Johnson to develop in-vivo CAR-T therapies.