Fate Therapeutics (NASDAQ:FATE) CEO Bob Valamehr outlined the company’s clinical and manufacturing strategy for FT819, an off-the-shelf allogeneic CAR T-cell therapy, during a conference fireside chat hosted by Leerink Partners senior equity research analyst Daina Graybosch. Valamehr emphasized that FT819 is currently the company’s lead allogeneic cell therapy program and that it represents a shift in investor perception for a company often associated with NK cell therapies.
FT819 manufacturing model and product design
Valamehr described FT819 as an allogeneic CD8 CAR T-cell targeting CD19, noting that the name “FT819” reflects CD8 (the “8”) and CD19 (the “1” and “9”). He highlighted Fate’s use of a master cell bank approach, arguing it provides uniformity and consistency from batch to batch compared with donor-to-donor variability in other allogeneic approaches.
Valamehr contrasted Fate’s clonal starting material with what he described as the heterogeneous engineering outcomes often seen when starting from donor T-cell populations, where engineering events can be stochastic and yield mixed cell populations.
Balancing activity and safety: why durability differed by indication
Valamehr said FT819 was engineered with safety as a priority, and that Fate “tuned down” activity to control expansion and avoid adverse events associated with excessive CAR T-cell proliferation. He explained that two of the three activating motifs (ITAMs) in the CD3ζ signaling domain were mutated out, allowing expansion and activity, but at a controlled level.
In aggressive diffuse large B-cell lymphoma (DLBCL), Valamehr said Fate observed complete response rates of about 40% in CAR patients, but durability was not sufficient in high tumor burden disease. He framed this as a design tradeoff: FT819 was not built to fully clear very large disease burdens (he cited tumor burdens on the order of 1010 cells).
Valamehr argued the same product characteristics could be well suited for autoimmune disease, where the target burden is lower. He estimated B-cell disease burden in rheumatology as roughly 108 to 109 cells, and said FT819’s activity-safety balance becomes favorable in that context. He also noted CAR T therapies differ from monoclonal antibodies or T-cell engagers because CAR T cells can expand in response to antigen burden rather than declining from the start after dosing.
Autoimmune focus: lupus nephritis and outpatient administration
Valamehr said Fate is advancing FT819 in lupus nephritis and renal lupus, and also in myositis, systemic sclerosis, and vasculitis. He pointed to progress in lupus that he attributed to the therapy’s off-the-shelf accessibility and a safety profile he described as including no ICANS and no GVHD, along with low-grade CRS.
He also said Fate has begun administering FT819 in an outpatient setting, describing a model where patients receive therapy and go home the same day, rather than staying hospitalized for 14 days—an approach he suggested could be important for lupus patients managing work and daily life.
On efficacy, Valamehr cited improvements observed in lupus patients, including decreases in disease burden measured by SLEDAI scores and improvements in PGA and FACIT-fatigue. He characterized the change as meaningful, describing patients who were bedridden becoming able to resume activities within one to two months.
Clinical plans: potential registration-enabling Phase II in 2H
Valamehr said Fate has held several FDA meetings under RMAT designation and is preparing to start a Phase II, potential registration-enabling trial in lupus nephritis in the second half of the year. He said the study is planned as a single-arm trial with complete renal response as the primary endpoint, and that the company believes it can enroll quickly.
Discussing results to date, Valamehr said the first two patients who reached six months achieved complete renal response. He said Fate expects to strengthen these observations with additional conference updates and anticipated treating approximately 25 lupus patients by the summer timeframe, with about 15 patients having six-month follow-up by mid-year. He added that not all of those will be nephritis patients, since Fate is treating “all comers” in lupus, which he said results in about half being lupus nephritis.
For extra-renal lupus, Valamehr said Fate is discussing endpoints with the FDA, describing a strategy between SRI-4 and DORIS. He noted DORIS has not previously been used for approval, while existing therapies have been approved using SRI-4. He also said Fate has achieved DORIS in the first patient with meaningful durability, while arguing that a less stringent endpoint could still represent significant patient benefit if the product is safe and accessible.
Conditioning regimens and next-generation programs
Valamehr said Fate is using less intensive conditioning than traditional CAR T approaches. He stated that while some CAR T programs use three days of cyclophosphamide plus fludarabine, investigators in Fate’s experience did not select that option; instead, they used cyclophosphamide alone or bendamustine alone. He also referenced a “Regimen B” approach with no conditioning, where FT819 is administered on top of maintenance therapy with the goal of improving disease and potentially enabling withdrawal of maintenance medications over time.
He acknowledged that responses in the no-conditioning setting have been less deep than when using cyclophosphamide or bendamustine, but said Fate has approval to explore higher doses and multi-dosing within a treatment cycle. On cost, Valamehr said current cost of goods is about $3,000 per dose at a 100-liter scale, and suggested it could decline with larger-scale manufacturing. He also cautioned that extensive multi-dosing (for example, five to seven doses of 1 billion cells) could become less desirable.
Asked to choose between bendamustine and cyclophosphamide, Valamehr said he prefers bendamustine and that Fate plans to use it for the Phase II trial. He cited prior patient exposure to cyclophosphamide and said bendamustine appears to provide improved initial kinetics in B-cell depletion and may help enrollment. He added that translational data can help distinguish bendamustine’s short-lived effects from subsequent FT819-driven B-cell control.
Valamehr also briefly outlined next-generation multiplex-edited candidates FT839 and FT836, describing a “Sword and Shield” strategy intended to eliminate the need for conditioning. He said FT839 includes both CD19 and CD38 targeting to broaden activity across immune compartments and potentially address complex autoimmune diseases, and he emphasized it is designed for greater activity than FT819. He said FT839 retains intact CD3ζ ITAMs and includes an additional T-cell enhancer, while remaining a CD8-only product—an approach he said supports more controlled behavior by avoiding CD4 helper cell contributions.
About Fate Therapeutics (NASDAQ:FATE)
Fate Therapeutics, Inc is a clinical‐stage biopharmaceutical company focused on the development of first‐in‐class cellular immunotherapies for cancer and immune disorders. The company leverages its proprietary induced pluripotent stem cell (iPSC) platform to create off‐the‐shelf natural killer (NK) and T‐cell products designed to overcome limitations of donor‐derived approaches. Fate’s research aims to deliver therapies with consistent quality, increased potency and scalable manufacturing for broad patient access.
Central to Fate’s pipeline are multiple iPSC‐derived cell therapy candidates in active clinical development.
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