briquilimab (JSP191) / Amgen, Jasper Therap - LARVOL DELTA

A Phase 2, Open-Label Extension Study to Evaluate the Long-Term Safety and Efficacy of Briquilimab in Adults with Chronic Urticaria (Trial in Progress) (EAACI 2026) - No abstract available

Clinical • P2 data • Immunology

Mast cell depletion and repopulation dynamics define briquilimab efficacy in a mouse model of allergic asthma. (PubMed, J Allergy Clin Immunol) - No abstract available

Journal • Preclinical • Asthma • Immunology • Pulmonary Disease • Respiratory Diseases

CAN WE ELIMINATE TBI/BUSULFAN AND GVHD IN FANCONI ANEMIA TRANSPLANTATION? RESULTS FROM A PROSPECTIVE HAPLOIDENTICAL TRANSPLANT APPROACH (EBMT 2026) - "Both regimens also include rabbit anti-thymoglobulin (rATG), cyclophosphamide, fludarabine, and rituximab for immunosuppression, followed by transplantation with TCRαβ+ T-cell/CD19+ B-cell depleted grafts. Patients with FA with BMF and without MSDs were eligible for allo-HCT with TCRαβ+ T-cell/CD19+ B-cell depleted hematopoietic grafts from MUD or haploidentical family donors with preference given to haploidentical family donors unless. Haploidentical allo-HCT using TCRαβ/CD19-depleted grafts is feasible, safe, and effective in patients with FA, providing near-universal donor access with low rates of severe acute and cGVHD. Briquilimab-based, genotoxicity-sparing conditioning offers a compelling alternative to TBI- or busulfan-containing regimens, achieving reliable engraftment and outcomes comparable to a similar irradiation-based protocol. These findings support further development of antibody-based conditioning as a next-generation platform for FA and other bone..."

Clinical • Acute Graft versus Host Disease • Anemia • Aplastic Anemia • Chronic Graft versus Host Disease • Graft versus Host Disease • Hematological Disorders • Immunology • Transplantation • CD34 • KIT • NCAM1

ALLOGENEIC HEMATOPOIETIC CELL TRANSPLANTATION WITH BRIQUILIMAB ANTI-CD117 ANTIBODY-BASED NONMYELOABLATIVE CONDITIONING FOR GATA2 DEFICIENCY (EBMT 2026) - P2 | "Haploidentical related donor recipients received fludarabine 30 mg/m2 for five days (TD-6 to -2) and cyclophosphamide 12.5 mg/kg for two days (TD-6, -5). Graft-versus-host disease (GVHD) prophylaxis consisted of cyclophosphamide (50 mg/kg on TD +3, +4), tacrolimus, and mycophenolate mofetil...One patient experienced secondary graft failure at TD+73 and was successfully retransplanted from a different donor with busulfan and fludarabine conditioning... HCT with briquilimab-based nonmyeloablative conditioning resulted in sustained donor engraftment with full donor myeloid chimerism and minimal toxicity in patients with GATA2 deficiency. There may, however, be an increased risk of graft failure than with standard myeloablative conditioning."

Acute Graft versus Host Disease • Aplastic Anemia • Chronic Graft versus Host Disease • Graft versus Host Disease • Hematological Malignancies • Immunology • Infectious Disease • Myelodysplastic Syndrome • Pneumonia • Pulmonary Disease • Respiratory Diseases • Transplantation • KIT

Nonmyeloablative Conditioning Combined with Anti-CD117 Antibody Briquilimab in Older Adults with High-Risk AML and MDS. (PubMed, Blood) - P1 | "Based on preclinical data demonstrating the antibody clears hematopoietic stem and progenitor cells (HSPC) and myeloid malignant cells, we conducted a phase 1 trial examining briquilimab plus non-myeloablative fludarabine (flu) and total body irradiation (TBI) as conditioning for older adults with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) undergoing matched donor allogeneic hematopoietic cell transplantation (HCT)...Graft-versus-host disease prophylaxis consisted of tacrolimus, sirolimus, and mycophenolate mofetil...In summary, we demonstrate the feasibility, safety, and proof of concept of CD117 targeting with briquilimab as HCT conditioning for AML/MDS. The trial is registered at clinicaltrials.gov; using identifier: NCT04429191."

Journal • Acute Myelogenous Leukemia • Graft versus Host Disease • Hematological Malignancies • Immunology • Leukemia • Myelodysplastic Syndrome • Oncology • Transplantation • KIT

Results from SPOTLIGHT, a Phase 1b/2a Dose Escalation Study of the anti-c-Kit Briquilimab Antibody in Adults with Inducible Urticaria (CIndU) Who Remain Symptomatic Despite H-1 Antihistamine Treatment (AAAAI 2026) - "Overall, AEs were reported in 24 (88.9%) participants: Grade 1 (33.3%), Grade 2 (51.9%), Grade 3 (3.7%). Conclusions Briquilimab was well tolerated and demonstrated dose-dependent efficacy, producing rapid and substantial clinical improvement in poorly controlled CIndu."

Clinical • P1/2 data • Cardiovascular • Dermatology • Immunology • Pruritus • Urticaria • KIT

New SubmissionInitial Results From A Phase 2, Open-label Extension Study To Evaluate The Long-term Safety And Efficacy Of The Anti-KIT Briquilimab Antibody In Adults With Chronic Urticaria (AAAAI 2026) - "Data from CIndU patients is pending analysis and will be included in the presentation for the conference. Conclusions In this open label extension study, briquilimab demonstrated rapid onset and durable control of CSU symptoms with a well-tolerated and favorable safety profile."

Clinical • P2 data • Chronic Spontaneous Urticaria • Dermatology • Immunology • Urticaria

A Phase 2, Open-Label, Extension Study to Evaluate Long Term Safety and Clinical Activity of Briquilimab in Participants From Jasper-Sponsored Chronic Urticaria Trials (clinicaltrials.gov) - P2 | N=67 | Active, not recruiting | Sponsor: Jasper Therapeutics, Inc. | Enrolling by invitation ➔ Active, not recruiting | Trial primary completion date: Dec 2026 ➔ Aug 2026

Enrollment closed • Trial primary completion date • Dermatology • Immunology • Urticaria

Depleted Donor Stem Cell Transplant in Children and Adults With Fanconi Anemia After Being Conditioned With a Regimen Containing Briquilimab (clinicaltrials.gov) - P1/2 | N=18 | Recruiting | Sponsor: Porteus, Matthew, MD | N=12 ➔ 18 | Trial completion date: Dec 2027 ➔ Dec 2028 | Trial primary completion date: Dec 2025 ➔ Dec 2027

Enrollment change • Trial completion date • Trial primary completion date • Anemia • Hematological Disorders • Transplantation

BEACON: Dose Escalation Trial Of Safety, Pharmacokinetic/Pharmacodynamic And Preliminary Clinical Activity of Briquilimab In Adult Patients With Chronic Spontaneous Urticaria (CSU) (clinicaltrials.gov) - P1/2 | N=88 | Active, not recruiting | Sponsor: Jasper Therapeutics, Inc. | Recruiting ➔ Active, not recruiting | Trial completion date: Apr 2026 ➔ Oct 2026 | Trial primary completion date: Apr 2026 ➔ Oct 2026

Enrollment closed • Trial completion date • Trial primary completion date • Chronic Spontaneous Urticaria • Dermatology • Immunology • Urticaria

Preliminary Data from a Phase 1 Study of JSP191, an Anti-CD117 Monoclonal Antibody, in Combination with Low Dose Irradiation and Fludarabine Conditioning Is Well-Tolerated, Facilitates Chimerism and Clearance of Minimal Residual Disease in Older Adults with MDS/AML Undergoing Allogeneic HCT (TCT-ASTCT-CIBMTR 2022) - "GVHD prophylaxis was tacrolimus, sirolimus, and mycophenolate mofetil. These early results demonstrate that targeting CD117 with JSP191 together with TBI/Flu as a novel conditioning regimen is safe, well-tolerated, facilitates full donor myeloid chimerism, and clearing MDS/AML MRD in older adults undergoing NMA AHCT. ."

Clinical • Combination therapy • Late-breaking abstract • Minimal residual disease • P1 data • Residual disease • Acute Graft versus Host Disease • Acute Myelogenous Leukemia • Geriatric Disorders • Graft versus Host Disease • Immunology • Myelodysplastic Syndrome • Transplantation • KIT

Subanalysis from Phase 1 Study of JSP191, an Anti-CD117 Monoclonal Antibody, in Combination with Low Dose Irradiation and Fludarabine Conditioning, Shows Durable Remissions in Older Adults with Acute Myleoid Leukemia in Complete Remission Undergoing Allogeneic Hematopoietic Cell Transplantation (TCT-ASTCT-CIBMTR 2023) - "GVHD prophylaxis was tacrolimus, sirolimus, and mycophenolate mofetil. These results demonstrate that targeting CD117 with JSP191 together with TBI/Flu as a novel conditioning regimen is safe, well-tolerated, can facilitate full donor myeloid chimerism, and can result in clearance of AML MRD in older AML in CR patients undergoing NMA HCT."

Clinical • Combination therapy • P1 data • Acute Graft versus Host Disease • Acute Myelogenous Leukemia • Chronic Graft versus Host Disease • Graft versus Host Disease • Hematological Malignancies • Immunology • Leukemia • Oncology • Transplantation • KIT

Open Label Extension Study Design and Updated Data Summary (GlobeNewswire) - "Briquilimab treatment continued to drive deep and durable disease control in the open label extension. At the 12 week assessment, 58% of CSU patients (n=36) achieved a complete response and 75% achieved either complete response or well controlled disease (UAS7≤6). In the CIndU portion of the open label extension study, efficacy measurements were taken every 8 weeks, and 65% of patients (n=17) achieved a complete response or partial response at 16 weeks, which was 8 weeks following administration of the second dose....'With these additional data from the BEACON and open label extension studies, we now have sufficient efficacy and safety data to enable dose selection for our planned Phase 2b study in CSU, which we expect to commence in the second half of 2026.'"

New P2b trial • P2 data • Chronic Spontaneous Urticaria • Urticaria

Jasper Therapeutics Reports Positive Updated Data from Briquilimab Studies in Chronic Spontaneous Urticaria (GlobeNewswire) - "Treatment with briquilimab resulted in rapid disease control in the additional participants enrolled in the 240mg / 180mg Q8W cohort (n=6) in the BEACON study, with 83% of participants achieving a complete response by week 3 after the initial 240mg dose, and 67% reporting a complete response at 12 weeks. Similarly high levels of efficacy were demonstrated in the open-label extension study evaluating a 180mg Q8W dosing regimen, with 58% of CSU participants (n=36) achieving a complete response at 12 weeks....Briquilimab continued to be well-tolerated in the BEACON study, with no dose limiting toxicities observed."

P1/2 data • Chronic Spontaneous Urticaria

BEACON Cohort 8 & Cohort 9 Internal Investigation Concluded (GlobeNewswire) - "In response, Jasper’s internal investigation included: switching all US patients to a new lot of drug product for the remainder of their doses on study to determine if drug product played a role, a comprehensive review of all manufacturing records, drug handling, site training/ logs and data handling; recovery and testing by Jasper and independent labs of drug product samples from across the supply chain; a review of all US sites and all US patients, including protocol adherence patient medical histories, patient screening and all pharmacokinetics, pharmacodynamics and efficacy data, and assembling a KOL panel to review the internal investigation findings, including full patient dossiers, which provided its input and conclusions from the findings....'BEACON data expected in Q1 2026 that will enable us to select final doses for the Phase 2b CSU study, planned to commence mid-2026.'"

New P2b trial • P1/2 data • Trial status • Chronic Spontaneous Urticaria

Hematopoietic stem cell transplantation using briquilimab (Anti-CD117 Antibody-Conditioning), immunosuppression and TCRαβ+ T-cell/CD19+ B-cell depleted haploidentical grafts in patients with fanconi anemia: An approach without irradiation, busulfan and calcineurin inhibitors. (ASH 2025) - "FA patients have renal abnormalities and are prone to renal toxicities.Therefore, avoiding calcineurin inhibitors increases the renal safety during transplant.Objective: To reduce acute and long-term treatment-related toxicities, we have developed a first of itskind treatment intended to improve the safety of allo-HSCT using: 1) a TBI- and busulfan-freeconditioning regimen consisting of briquilimab, rabbit ATG (rATG - Thymoglobulin), fludarabine,cyclophosphamide and rituximab - briquilimab is a monoclonal antibody (mAb) that targets humanCD117 to clear host HSCs from their niches enabling blood and immune reconstitution with minimaltoxicity with other agents being used for immune suppression to prevent immunologic rejection; 2)transplantation of TCRαβ+ T-cell/CD19+ B-cell hematopoietic grafts - a stem cell therapy that enhancesdonor hematopoietic and immune reconstitution while decreasing GvHD; and 3) pharmacokineticanalysis for briquilimab, rATG and fludarabine to..."

Clinical • Acute Graft versus Host Disease • Anemia • Aplastic Anemia • Bone Marrow Transplantation • Chronic Graft versus Host Disease • Genetic Disorders • Graft versus Host Disease • Immunology • Transplant Rejection • Transplantation • CD34 • KIT • NCAM1

Radiation and Busulfan-Free Hematopoietic Stem Cell Transplantation Using Briquilimab (JSP191) Anti-CD117 Antibody-Conditioning, Transient Immunosuppression and TCRαβ+ T-Cell/CD19+ B-Cell Depleted Haploidentical Grafts in Patients with Fanconi Anemia (ASH 2023) - "Objective: To reduce acute and long-term treatment-related toxicities, we have developed a first of its kind treatment intended to improve the safety of allo-HSCT through: 1) a TBI- and busulfan-free conditioning regimen consisting of briquilimab, rabbit ATG (rATG - Thymoglobulin), fludarabine, cyclophosphamide and rituximab - briquilimab (formerly called JSP191) is a monoclonal antibody (mAb) that targets human CD117 to deplete host HSCs enabling blood and immune reconstitution with minimal toxicity with the other agents being used for transient immune suppression to prevent immunologic rejection; 2) transplantation of TCRαβ+ T-cell/CD19+ B-cell hematopoietic grafts - a stem cell therapy that enhances donor hematopoietic and immune reconstitution while decreasing GvHD; and 3) a pre- and post-transplant monitoring protocol to maximize engraftment. All three patients in the Phase 1b portion of the study show early safety and efficacy of this approach. Briquilimab was..."

Clinical • Acute Graft versus Host Disease • Anemia • Aplastic Anemia • Bone Marrow Transplantation • Chronic Graft versus Host Disease • Genetic Disorders • Graft versus Host Disease • Hematological Disorders • Immunology • Transplant Rejection • Transplantation • CD34 • KIT • NCAM1

ETESIAN Study Design and Preliminary Data Summary (GlobeNewswire) - "The preliminary data includes the results from 14 participants, 8 receiving a single dose of 180mg briquilimab and 6 receiving placebo, who completed at least 6 weeks of allergen challenge testing following initial dosing with investigational product. Compared to baseline, briquilimab reduced the allergen induced LAR (measured by the mean maximum percentage fall in FEV1 (%Max FEV1) and fall in area under the FEV1 time response curve (AUC)) at both 6 and 12 weeks. Patients who received briquilimab showed an improvement in the LAR %Max FEV1 of 10.4% at 6 weeks and 8.7% at 12 weeks compared to baseline and an improvement in the LAR AUC of 25.4% at 6 weeks and 23.3% at 12 weeks."

P1/2 data • Asthma • Immunology

Final Results from Phase 1 Study of Briquilimab, an Anti-CD117 Monoclonal Antibody, in Combination with Low Dose Irradiation and Fludarabine Conditioning, Shows Durable Remissions in Older Adults with Acute Myeloid Leukemia in Complete Remission and Myelodysplastic Syndrome Undergoing Allogeneic Hematopoietic Cell Transplantation (ASH 2023) - "GVHD prophylaxis was tacrolimus, sirolimus, and mycophenolate mofetil. These results demonstrate that targeting CD117 with briquilimab together with TBI/Flu as a novel conditioning regimen is safe, well-tolerated, facilitates full donor myeloid chimerism, and sustained clearance of MRD in older adults with AML in CR and MDS without TP53 undergoing NMA AHCT."

Clinical • Combination therapy • P1 data • Acute Graft versus Host Disease • Acute Myelogenous Leukemia • Chronic Graft versus Host Disease • Graft versus Host Disease • Hematological Malignancies • Immunology • Infectious Disease • Leukemia • Myelodysplastic Syndrome • Oncology • Septic Shock • Transplantation • DNMT3A • KIT • TP53

Adding CD117 Antibody to Alemtuzumab, Low Dose Total Body Irradiation (TBI), and Sirolimus for Matched Related Donor (MRD) Hematopoietic Cell Transplant (HCT) in Sickle Cell Disease (SCD): Initial Results (ASH 2024) - "13 patients with homozygous sickle (HbSS) and 1 patient with sickle-beta 0 thalassemia (age range 5-34 years) received briquilimab 0.6 mg/kg on day -11, alemtuzumab 1.0 mg/kg divided over day -7 through -3, 300 cGy TBI on day -2, sirolimus to target trough level of 10 ng/mL starting on day -1, and unmanipulated filgrastim mobilized peripheral blood stem cells on day 0 (10.8-20.4 x 10e6 CD34 cells/kg and 1.9-7.5 x 10e8 CD3 cells/kg). Longer follow-up is needed to detail the trajectory of myeloid and CD3 chimerism. Strategies to increase myeloid and CD3 chimerism are warranted."

Acne Vulgaris • Beta-Thalassemia • Genetic Disorders • Graft versus Host Disease • Hematological Disorders • Hepatology • Immunology • Sickle Cell Disease • Transplantation • CD34 • KIT

Evaluation of Bone Marrow in Fanconi Anemia Patients Treated with Briquilimab Antibody-Based Conditioning and TCRαβ+ T-Cell/CD19+ B-Cell Depleted Haploidentical Grafts (ASH 2024) - P1/2 | "We also observed correction of BMF with DNA-damage resistance in all seven patient BM cells challenged with 10 nM and 50 nM mitomycin C (MMC), and a significant increase in colony counts (P= 0.0238) in patients over 24-52 weeks post-HSCT. Notably, this was accomplished without the use of busulfan or total body irradiation, which is extremely toxic to FA patients. However, additional analyses and assessment of more samples with longer follow-up time points are needed and underway to further understand the full effects of this treatment on the BM microenvironment."

Clinical • Anemia • Aplastic Anemia • Bone Marrow Transplantation • Hematological Disorders • Inflammation • Pediatrics • ANGPT1 • CD34 • CSF2 • FANCA • FANCC • FANCG • FLT3LG • KIT

Allogeneic Hematopoietic Cell Transplantation with Briquilimab (JSP191)-Based Conditioning for GATA2 Deficiency (ASH 2024) - No abstract available

Transplantation

Highlights for Third Quarter 2025 and Recent Weeks (GlobeNewswire) - "Jasper plans to report final conclusions from the investigation in the fourth quarter of 2025, supported by a key opinion leader panel that will review findings and provide clinical and chemistry, manufacturing and controls recommendations for integration into the planned Phase 2b CSU study; Continued to enroll additional patients across the 240mg/180mg Q8W and 240mg Q8W cohorts of the BEACON study, and continued to enroll CSU and CIndU patients in the open-label extension (OLE) study as they rolled off the BEACON and SPOTLIGHT studies. Jasper expects that the additional data from these BEACON cohorts and from the OLE study, anticipated in the first half of the first quarter of 2026, should be adequate to complete dose selection for the planned Phase 2b CSU study, which is now expected to commence mid-2026."

Clinical data • Trial status • Chronic Spontaneous Urticaria • Urticaria

Human KIT Antibody Briquilimab Diminishes Anaphylactic Responses in Mice Expressing Chimeric Human-Mouse KIT. (PubMed, Allergy) - No abstract available

Journal • Preclinical

SPOTLIGHT: A Dose Escalation Trial of Safety, Pharmacokinetic/Pharmacodynamic and Preliminary Clinical Activity of Briquilimab in Adult Patients With Chronic Inducible Urticaria (CIndU) Who Remain Symptomatic Despite Treatment With H1- Antihistamines (clinicaltrials.gov) - P1/2 | N=27 | Terminated | Sponsor: Jasper Therapeutics, Inc. | Trial completion date: Nov 2025 ➔ Jul 2025 | Active, not recruiting ➔ Terminated | Trial primary completion date: Nov 2025 ➔ Jul 2025; Enrollment was completed and primary efficacy endpoint was completed. Study was terminated before safety follow up was completed due to changes in company priorities and not related to safety concerns

Trial completion date • Trial primary completion date • Trial termination • Dermatology • Immunology • Urticaria