Preliminary Safety and Efficacy of PBCAR0191, an Allogeneic 'Off-the-Shelf' CD19-Directed CAR-T for Patients with Relapsed/Refractory (R/R) CD19+ B-ALL
Bibliographic record
Abstract
Abstract Introduction: CD19-directed autologous CAR-T products induce high response rates in adults with R/R B-ALL, yet many patients relapse within the first year. Additionally, cell manufacturing timelines, and poor t-cell fitness may imperil efficacy, especially among those with proliferative disease. This makes access to a donor-derived, readily available CAR-T product of great interest in this patient population, particularly when consolidation with allogeneic stem cell transplant (allo-SCT) is possible. We report preliminary safety, efficacy, and correlative data for the R/R B-ALL patients dosed with at least 3 x 10 6 CAR-T cells/kg of PBCAR0191, an allogeneic 'off-the-shelf' CD19-directed CAR-T. Methods: Subjects were 18 years or older with CD19+ R/R B-ALL after at least 2 prior lines of therapy. Patients were required to have adequate organ function and no active GvHD, CNS disease, active infections, or other active medical issues. Prior allo-SCT and/or autologous CAR-T therapy were allowed. Subjects received either standard (sLD; 30mg/m2/day and 500mg/m2/day x 3 days fludarabine and cyclophosphamide, respectively) or enhanced (eLD; 30mg/m2/day x 4 days flu and 1000mg/m2/day x 3 days cy) lymphodepletion preceding PBCAR0191 infusion. Correlative laboratory samples were taken for CAR-T expansion, persistence, molecular response to treatment and safety assessments. Results: As of August 2, 2021, 15 subjects with R/R CD19+ B-ALL have been dosed with dose Dose level 3/4a (3 X 10 6 CAR-T cells/kg or equivalent, n=11) or a Dose level 4b (flat dose of 5 X 10 8 CAR-T cells, n=4). Demographics, baseline disease, and prior treatment data are presented in the table. Most of the Adverse events (AE) reported to date were mild, with no cases of GvHD, no Grade ≥3 CRS and 1 case of Grade 3 ICANS which resolved within 48 hours. 67% of subjects treated (10/15) experienced PBCAR0191 related AEs, with 60% (9/15) of subjects experiencing serious AEs (one related to PBCAR0191, ICANS Grade 3). The complete response (CR) or CRi (incomplete marrow recovery) rate at Day ≥28 is 33% (2/6) in DL3/4a and sLD, 80% (4/5) in DL3/4a with eLD and 75% (3/4) in DL4b with sLD. Importantly, 4/15 (27%) responding subjects underwent allo-SCT, with one additional subject not able to receive transplant due to eligibility yet maintaining an MRD- CR for >250 days, and one refusing to proceed with transplant. Product accessibility was evident compared to autologous CAR-T products, with median time from screening completion to PBCAR0191 infusion of 7 days (median of 1 day until start of LD) and all eligible subjects receiving PBCAR0191 infusion. Conclusion: PBCAR0191 has demonstrated a manageable safety profile and high complete response rate at day 28 or later, providing an adequate window for potential bridge to allo-SCT. Figure 1 Figure 1. Disclosures Jain: Adaptive Biotechnologies: Honoraria, Research Funding; Precision Biosciences: Honoraria, Research Funding; Cellectis: Honoraria, Research Funding; Pfizer: Research Funding; Janssen: Honoraria; Genentech: Honoraria, Research Funding; AstraZeneca: Honoraria, Research Funding; Beigene: Honoraria; TG Therapeutics: Honoraria; Bristol Myers Squibb: Honoraria, Research Funding; Aprea Therapeutics: Research Funding; Incyte: Research Funding; AbbVie: Honoraria, Research Funding; Fate Therapeutics: Research Funding; Servier: Honoraria, Research Funding; ADC Therapeutics: Honoraria, Research Funding; Pharmacyclics: Research Funding. Kantarjian: KAHR Medical Ltd: Honoraria; Ascentage: Research Funding; Immunogen: Research Funding; Jazz: Research Funding; Aptitude Health: Honoraria; Ipsen Pharmaceuticals: Honoraria; Precision Biosciences: Honoraria; Novartis: Honoraria, Research Funding; Astra Zeneca: Honoraria; AbbVie: Honoraria, Research Funding; NOVA Research: Honoraria; BMS: Research Funding; Daiichi-Sankyo: Research Funding; Pfizer: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Astellas Health: Honoraria; Taiho Pharmaceutical Canada: Honoraria. Sauter: Bristol-Myers Squibb: Research Funding; GSK: Consultancy; Celgene: Consultancy, Research Funding; Gamida Cell: Consultancy; Kite/Gilead: Consultancy; Precision Biosciences: Consultancy; Genmab: Consultancy; Novartis: Consultancy; Spectrum Pharmaceuticals: Consultancy; Juno Therapeutics: Consultancy, Research Funding; Sanofi-Genzyme: Consultancy, Research Funding. Heery: Precision BioSciences: Current equity holder in publicly-traded company, Ended employment in the past 24 months; Arcellx: Current Employment, Current holder of stock options in a privately-held company. List: Halia Therapeutics: Consultancy, Current holder of individual stocks in a privately-held company; CTI Biosciences: Consultancy; Precision BioSciences: Current Employment, Current equity holder in publicly-traded company; Aileron Therapeutics: Consultancy. Johnson: Precision BioSciences, Inc: Current Employment, Current equity holder in publicly-traded company. Lou: Precision BioSciences: Current Employment, Current equity holder in publicly-traded company. Vainorius: Precision BioSciences: Current Employment, Current equity holder in publicly-traded company; Abbvie: Current equity holder in publicly-traded company; United Therapeautics: Current equity holder in publicly-traded company. Olszewski: Genentech, Inc.: Research Funding; TG Therapeutics: Research Funding; PrecisionBio: Research Funding; Celldex Therapeutics: Research Funding; Acrotech Pharma: Research Funding; Genmab: Research Funding. Stein: Amgen: Consultancy, Speakers Bureau; Celgene: Speakers Bureau; Stemline: Speakers Bureau. Shah: Adaptive Biotechnologies: Consultancy; Bristol-Myers Squibb/Celgene: Consultancy, Other: Expenses; Novartis: Consultancy, Other: Expenses; Pfizer: Consultancy, Other: Expenses; Amgen: Consultancy; Precision Biosciences: Consultancy; Kite, a Gilead Company: Consultancy, Honoraria, Other: Expenses, Research Funding; Pharmacyclics/Janssen: Honoraria, Other: Expenses; Acrotech/Spectrum: Honoraria; BeiGene: Consultancy, Honoraria; Incyte: Research Funding; Jazz Pharmaceuticals: Research Funding; Servier Genetics: Other. OffLabel Disclosure: PBCAR0191 is not FDA approved
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".