{"id":2653,"date":"2026-08-21T13:00:00","date_gmt":"2026-08-21T17:00:00","guid":{"rendered":"https:\/\/www.insilens.com\/?p=2653"},"modified":"2026-08-21T20:12:21","modified_gmt":"2026-08-22T00:12:21","slug":"ucl-and-great-ormond-street-report-first-in-human-data-for-base-edited-be-car33-in-aml","status":"publish","type":"post","link":"https:\/\/www.insilens.com\/?p=2653","title":{"rendered":"UCL and Great Ormond Street Report First-in-Human Data for Base-Edited BE-CAR33 in AML"},"content":{"rendered":"

Institutions:<\/strong> UCL · Great Ormond Street Hospital · Asset:<\/strong> BE-CAR33 · Modality:<\/strong> Base-Edited Allogeneic CAR-T · Indication:<\/strong> Acute Myeloid Leukemia · Date:<\/strong> August 21, 2026<\/p>\n

\"20260821_UCL_GOSH_BE_CAR33_Technology_and_Modalities\"<\/p>\n

Summary<\/h4>\n

Researchers at UCL and Great Ormond Street Hospital have published first-in-human feasibility data for BE-CAR33 in Science Translational Medicine, a donor-derived, “off-the-shelf” anti-CD33 CAR-T cell therapy engineered using multiplex cytosine base editing to disrupt the TRAC, CD52, and CD7 genes. The study treated three pediatric patients and one adult under compassionate use; the trial’s primary endpoints were not met, but two patients showed reduced measurable residual disease (MRD) and were able to proceed to allogeneic stem cell transplant.<\/p>\n

What Happened<\/h4>\n

BE-CAR33 is a base-edited, donor-derived (allogeneic) CAR-T therapy targeting CD33, an antigen expressed on acute myeloid leukemia (AML) blasts. The cell engineering approach used multiplex cytosine base editing, rather than older nuclease-based gene editing, to knock out three genes simultaneously: TRAC (to prevent graft-versus-host disease from the donor T-cell receptor), CD52 (to enable use of an anti-CD52 lymphodepletion regimen without killing the therapeutic cells themselves), and CD7 (to prevent CAR-T fratricide, since CD7 is co-expressed on some engineered T cells). In this first-in-human study, three pediatric patients and one adult (treated under compassionate use) received BE-CAR33; the study’s primary endpoints were explicitly not met, but two of the four patients had reduced MRD and were able to bridge to allogeneic stem cell transplant, a clinically meaningful outcome in relapsed\/refractory AML even without full remission.<\/p>\n

Deep Analysis<\/h4>\n

This is a feasibility and safety study, not an efficacy trial, and the honest reporting that primary endpoints were not met is scientifically important context that should not be glossed over. What the data does establish is that multiplex base-edited allogeneic CAR-T manufacturing is achievable at a small scale and can be administered safely enough to bridge some patients to transplant, which is a real, if modest, clinical benefit in a disease as difficult to treat as relapsed AML. Base editing’s advantage over first-generation CRISPR nuclease editing is that it makes precise single-nucleotide changes without generating double-strand DNA breaks, which reduces the risk of large chromosomal rearrangements or translocations, an important safety consideration when editing three genes simultaneously in a cell product intended for infusion into patients with a life-threatening cancer.<\/p>\n

The CD33 target itself carries known biological risk: CD33 is expressed not only on AML blasts but also on normal myeloid progenitor cells, meaning CAR-T targeting CD33 can be expected to cause on-target, off-tumor myelosuppression, a toxicity that needs careful management, particularly in a study where patients may need to proceed to transplant with adequate marrow reserve.<\/p>\n

Company and Product Background<\/h4>\n

This work originates from academic groups at University College London (UCL) and Great Ormond Street Hospital (GOSH), building on prior base-edited allogeneic CAR-T programs from the same collaboration (including base-edited CAR-T for pediatric T-cell leukemia, which reached the clinic previously). BE-CAR33 extends the allogeneic, “off-the-shelf” CAR-T concept, using donor rather than patient-derived T cells, to myeloid malignancies, a historically difficult target class for CAR-T given the shared antigen expression between leukemic and healthy myeloid cells.<\/p>\n

Signal Extraction<\/h4>\n\n\n\n\n\n\n\n
Factor<\/th>\nAssessment<\/th>\n<\/tr>\n
Study Type<\/td>\nFirst-in-human feasibility, 3 pediatric + 1 adult (compassionate use)<\/td>\n<\/tr>\n
Editing Approach<\/td>\nMultiplex cytosine base editing (TRAC, CD52, CD7 knockouts)<\/td>\n<\/tr>\n
Primary Endpoints<\/td>\nNot met<\/td>\n<\/tr>\n
Clinical Outcome<\/td>\n2 of 4 patients had reduced MRD and proceeded to allogeneic stem cell transplant<\/td>\n<\/tr>\n
Target-Related Risk<\/td>\nCD33 shared with normal myeloid progenitors; expected on-target, off-tumor myelosuppression<\/td>\n<\/tr>\n<\/table>\n

Reading the Signal<\/h4>\n

Bull case:<\/strong> Demonstrates feasibility and manageable safety for a triple-edited, off-the-shelf allogeneic CAR-T in a notoriously difficult solid myeloid target, with two patients achieving a clinically useful bridge to transplant.<\/p>\n

Bear case:<\/strong> Primary endpoints were not met in a very small (n=4) study, and CD33-directed myelosuppression risk plus the early feasibility stage mean this is years away from being a validated therapeutic option.<\/p>\n

InSilens Take<\/h4>\n

The honest framing, primary endpoints not met, is what makes this a credible early-stage academic signal rather than a promotional one. The real value here is manufacturing and safety feasibility for multiplex base-edited allogeneic CAR-T against a myeloid target, which is a platform capability question as much as an AML-specific efficacy question.<\/p>\n

Signal Assessment<\/h4>\n

Importance:<\/strong> 4\/5 · Direction:<\/strong> Uncertain · Confidence:<\/strong> Medium<\/p>\n","protected":false},"excerpt":{"rendered":"

Researchers at UCL and Great Ormond Street Hospital have published first-in-human feasibility data for BE-CAR33 in Science Translational Medicine, a donor-derived, “off-the-shelf” anti-CD33 CAR-T cell therapy engineered using multiplex cytosine base editing to disrupt…<\/p>\n","protected":false},"author":1,"featured_media":2661,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4],"tags":[76,269,377],"class_list":["post-2653","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-technology-modalities","tag-acute-myeloid-leukemia","tag-base-editing","tag-car-t-cell-therapy-2"],"blocksy_meta":[],"_links":{"self":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2653","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2653"}],"version-history":[{"count":1,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2653\/revisions"}],"predecessor-version":[{"id":2667,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/posts\/2653\/revisions\/2667"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=\/wp\/v2\/media\/2661"}],"wp:attachment":[{"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2653"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2653"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.insilens.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2653"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}