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

Beyond Omalizumab: Emerging Biologic and Small Molecule Therapies in Chronic Spontaneous Urticaria. (PubMed, Clin Exp Allergy) - "The oral BTK inhibitor remibrutinib is now licensed for adults in the United States and European Union; Dupilumab, approved from 12 years of age in 2025, was extended to children aged 2-11 years in 2026 on basis of extrapolated efficacy supported by paediatric pharmacokinetic and safety data. Barzolvolimab has completed Phase 3 enrolment of 1939 adults, briquilimab, EVO756, EP262 and rilzabrutinib are advancing in adults and ligelizumab failed to demonstrate superiority over omalizumab...Adults dominate the trial populations; adolescents are enrolled as underpowered subgroups; dedicated paediatric evidence is essentially confined to dupilumab; and older adults-in whom comorbidity, polypharmacy and the cardiovascular and malignancy signals of JAK inhibition matter most-are almost never analyzed separately. Head-to-head and sequencing trials, endotype-stratified patient selection, age-inclusive trial design and long-term safety data are the immediate priorities if..."

Journal • Review • Cardiovascular • Chronic Spontaneous Urticaria • Dermatology • Immunology • Oncology • Pediatrics • Urticaria • IL13 • IL4

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

Corporate Updates for Second Quarter 2026 and Recent Weeks (GlobeNewswire) - "KP-104 is currently being evaluated in a Phase 2 basket trial in rare renal indications and interim data from Stage 1 of the trial is expected in the fourth quarter of 2026. Based on previous, positive results in treatment-naïve PNH, the combined company is also planning for an end-of-Phase 2 meeting with the U.S. Food and Drug Administration (FDA) and plans to announce next steps for development in PNH in the first half of 2027...Based on positive, long-term data generated in SCID, the combined company is progressing its efforts towards a pre-BLA meeting with the FDA and expects to announce next steps in the first quarter of 2027....The combined company expects to file a clinical trial application (CTA) and/or an investigational new drug (IND) for Phase 1 evaluation in the first quarter of 2027."

IND • New P1 trial • New P2 trial • P2 data • Glomerulonephritis • Immunology • Paroxysmal Nocturnal Hemoglobinuria • Systemic Lupus Erythematosus • 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=87 | Completed | Sponsor: Jasper Therapeutics, Inc. | Active, not recruiting ➔ Completed | Trial completion date: Oct 2026 ➔ Jul 2026 | Trial primary completion date: Oct 2026 ➔ Jul 2026

Trial completion • Trial completion date • Trial primary completion date • 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 | Terminated | Sponsor: Jasper Therapeutics, Inc. | Active, not recruiting ➔ Terminated; Sponsor Decision - terminated due to changes in company priorities and not related to safety concerns.

Trial termination • Dermatology • Immunology • Urticaria

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) - P1/2, P2 | "This study is currently enrolling patients across the US and Germany. The data to date support further development of briquilimab for CSU and CINDU."

Clinical • P2 data • Immunology

Hematopoietic Stem and Progenitor Cells Mobilization Enhances Monoclonal Antibody–Based Conditioning to Achieve Robust and Durable Engraftment in hematopoietic transplant (ASGCT 2026) - "In early clinical trials for primary immunodeficiencies, clinical-grade anti-c-Kit antibodies, such as briquilimab (AMG191/JSP191), have demonstrated favorable tolerability; however, reported engraftment levels in myeloid compartment remain modest and may decline over time...Importantly, our data indicate that both anti-CD47 inclusion and HSPC mobilization are required to achieve optimal engraftment. Conclusion Together, these findings establish mobilization-enhanced monoclonal antibody conditioning as a potent and low-toxicity alternative to chemotherapy-based regimens, with the potential to expand HSCT applicability to a broader range of diseases and patient populations."

Bone Marrow Transplantation • Hematological Disorders • Immunology • Primary Immunodeficiency • Transplantation • CD8 • KIT

Jasper Therapeutics…today reported results for the fiscal quarter ended March 31, 2026 and provided a corporate update. (The Manila Times) - “In recent months, we have continued to advance the briquilimab development program in CSU…we have also updated and refiled the Phase 2b protocol with the FDA as we work to secure additional funding to enable commencement of the study in the second half of this year as planned.”

New P2b trial • Chronic Spontaneous Urticaria

We are finalizing dose selection for the Phase 2b portion of our planned Phase 2b/3 study in CSU where we will evaluate two efficacious doses versus placebo to demonstrate the differentiated profile based on briquilimab’s unique biological properties. (GlobeNewswire) - "We remain on track to commence patient enrollment in the second half of 2026, pending capital availability."

New P2/3 trial • Chronic Spontaneous Urticaria

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

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

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

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