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CLINICAL NEWS On Location Progress in Transplant and Cellular Therapy Bangkok, Thailand presented the results at the 2019 Transplantation & Cellular Therapy Meetings of the ASBMT and CIBMTR. The LentiGlobin gene-therapy product is designed to overcome a key limitation of allogeneic hematopoietic cell transplanta- tion – lack of a compatible donor – for pa- tients who require long-term red blood cell (RBC) transfusions, Dr. Anurathapan ex- plained. To manufacture this gene therapy, investigators obtained mobilized autologous CD34-positive cells from patients, then transduced the cells ex vivo with the Lenti- Globin BB305 vector, which encodes adult hemoglobin (HbA) with a T87Q amino- acid substitution (HbAT87Q). Patients underwent conditioning with busulfan prior to the modified cells being re-infused. Earlier results from 22 patients en- rolled in the two companion trials were published in the New England Journal of Medicine, and data from the HGB trials FEIBA (anti-inhibitor coagulant complex) for intravenous use, lyophilized powder for solution Brief Summary of Prescribing Information: Please see package insert for Full Prescribing Information WARNING: EMBOLIC AND THROMBOTIC EVENTS • Thromboembolic events have been reported during post-marketing surveillance following infusion of FEIBA, particularly following the administration of high doses and/or in patients with thrombotic risk factors. • Monitor patients receiving FEIBA for signs and symptoms of thromboembolic events. INDICATIONS AND USAGE FEIBA is an Anti-Inhibitor Coagulant Complex indicated for use in hemophilia A and B patients with inhibitors for: • Control and prevention of bleeding episodes • Perioperative management • Routine prophylaxis to prevent or reduce the frequency of bleeding episodes. FEIBA is not indicated for the treatment of bleeding episodes resulting from coagulation factor deficiencies in the absence of inhibitors to coagulation factor VIII or coagulation factor IX. CONTRAINDICATIONS • Known anaphylactic or severe hypersensitivity reactions to FEIBA or any if its components, including factors of the kinin generating system. • Disseminated intravascular coagulation (DIC). • Acute thrombosis or embolism (including myocardial infarction). WARNINGS AND PRECAUTIONS Embolic and Thrombotic Events Thromboembolic events (including venous thrombosis, pulmonary embolism, myocardial infarction, and stroke) can occur with FEIBA, particularly following the administration of high doses (above 200 units per kg per day) and/or in patients with thrombotic risk factors [see Adverse Reactions]. Patients with DIC, advanced atherosclerotic disease, crush injury, septicemia, or concomitant treatment with recombinant factor VIIa have an increased risk of developing thrombotic events due to circulating tissue factor or predisposing coagulopathy. Potential benefit of treatment with FEIBA should be weighed against the potential risk of these thromboembolic events. Monitor patients receiving more than 100 units per kg of body weight of FEIBA for the development of DIC, acute coronary ischemia and signs and symptoms of other thromboembolic events. If clinical signs or symptoms occur, such as chest pain or pressure, shortness of breath, altered consciousness, vision, or speech, limb or abdomen swelling and/or pain, discontinue the infusion and initiate appropriate diagnostic and therapeutic measures. The safety and efficacy of FEIBA for breakthrough bleeding in patients receiving emicizumab has not been established. Cases of thrombotic microangiopathy (TMA) were reported in a clinical trial where subjects received FEIBA as part of a treatment regimen for breakthrough bleeding following treatment with emicizumab. Consider the benefits and risks with FEIBA if considered required for patients receiving emicizumab prophylaxis. If treatment with FEIBA is required for patients receiving emicizumab, the hemophilia treating physician should closely monitor for signs and symptoms of TMA. In FEIBA clinical studies thrombotic microangiopathy (TMA) has not been reported. Hypersensitivity Reactions Hypersensitivity and allergic reactions, including severe anaphylactoid reactions, can occur following the infusion of FEIBA. The symptoms include urticaria, angioedema, gastrointestinal manifestations, bronchospasm, and hypotension. These reactions can be severe and systemic (e.g., anaphylaxis with urticaria and angioedema, bronchospasm, and circulatory shock). Other infusion reactions, such as chills, pyrexia, and hypertension have also been reported. If signs and symptoms of severe allergic reactions occur, immediately discontinue administration of FEIBA and provide appropriate supportive care. Transmission of Infectious Agents Because FEIBA is made from human plasma it may carry a risk of transmitting infectious agents, e.g., viruses, and the variant Creutzfeldt-Jakob disease (vCJD) agent, and theoretically, the Creutzfeldt-Jakob disease (CJD) agent. The risk has been minimized by screening plasma donors for prior exposure to certain viruses, by testing for the presence of certain current virus infections and by inactivating and removing certain viruses during the manufacturing process [see Description in full prescribing information]. Despite these measures, the product may still potentially transmit human pathogenic agents. There is also the possibility that unknown infectious agents may still be present. All infections thought by a physician to have been possibly transmitted by this product should be reported by the physician or other healthcare providers to Baxalta US Inc., at 1-800-423-2090 (in the U.S.) and /or to FDA Med Watch (1-800-FDA-1088 or www.fda.gov/medwatch). Presence of Isohemagglutinins and Interference with Laboratory Tests FEIBA contains blood group isohemagglutinins (anti-A and anti-B). Passive transmission of antibodies to erythrocyte antigens, e.g., A, B, D, may interfere with some serological tests for red cell antibodies, such as antiglobulin test (Coombs test). were recently used to support the E.U. regulatory review of LentiGlobin for transfusion-dependent thalassemia. During his presentation, Dr. Anuratha- pan shared longer-term follow-up from each study. As of September 14, 2018, 18 patients (median age = 20 years; range = 12-35 years) had been treated in the HGB-204 trial and 16 patients (median age = 19 years; range = 8-34 years) had been treated in HGB-207. HGB-204 included patients with either ADVERSE REACTIONS The most frequently reported adverse reactions observed in >5% of subjects in the prophylaxis trial were anemia, diarrhea, hemarthrosis, hepatitis B surface antibody positive, nausea, and vomiting. The serious adverse reactions seen with FEIBA are hypersensitivity reactions and thromboembolic events, including stroke, pulmonary embolism and deep vein thrombosis. Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in clinical practice. The safety assessment of FEIBA is based on the review of the data from two prospective clinical trials in which FEIBA was used for the treatment of acute bleeding episodes and a prospective trial that compared the use of FEIBA prophylactically versus on-demand treatment. The adverse reactions reported from two prospective clinical trials in which FEIBA was used for the treatment of acute bleeding episodes were chills, chest pain, chest discomfort, dizziness, dysgeusia, dyspnea, hypoesthesia, increase of inhibitor titer (anamnestic response), nausea, pyrexia, and somnolence. Specifically, the first trial was a multicenter randomized, double-blind trial in 15 hemophilia A subjects with inhibitors to factors VIII. The second trial was a multicenter FEIBA study conducted in 44 hemophilia A subjects with inhibitors, 3 hemophilia B subjects with inhibitors and 2 acquired factor VIII inhibitor subjects. Of the 489 infusions used to treat acute bleeds during the second trial, 18 (3.7%) caused minor transient reactions of chills, fever, nausea, dizziness and dysgeusia. Out of 49 subjects, 10 (20%) had a rise in their inhibitor titers after treatment with FEIBA. Five of these subjects (50%) had increases that were, tenfold or more, and 3 (30%) of these subjects received factor VIII or IX concentrates within 2 weeks prior to treatment with FEIBA. These anamnestic rises were not associated with decreased efficacy of FEIBA. Table 1 lists the adverse reactions in >5% of subject reported in the randomized, prospective prophylaxis trial comparing FEIBA prophylaxis with on-demand treatment in 36 hemophilia A and B subjects with inhibitors to factors VIII or IX. The trial population included 33 (92%) subjects with hemophilia A and 3 (8.3%) subjects with hemophilia B. Four (11%) subjects were ≥7 to <12 years of age, 5 (14%) were ≥12 to <16 years of age, and 27 (75%) were ≥16 years of age. A total of 29 (80.6%) subjects were Caucasian, 3 (8.3%) Asian, 2 (5.6%) Black/African American, and 2 (5.6%) other. The subjects received a total of 4,513 infusions (3,131 for prophylaxis and 1,382 for on-demand). Table 1 Prophylaxis Study Adverse Reactions (ARs) in >5% of Subjects MedDRA System Organ Class Adverse Reaction Blood And Lymphatic System Disorders Gastrointestinal Disorders Anemia Investigations Musculoskeletal And Connective Tissue Disorders Diarrhea Nausea Vomiting Hepatitis B Surface Antibody Positive Hemarthrosis Number Number of Percent of of ARs Subjects Subjects (N=36) 2 2 5.6 2 2 2 2 2 2 5.6 5.6 5.6 4 4 11.1 5 3 8.3 Postmarketing Experience The following adverse reactions have been identified during post-approval use of FEIBA. Because post-marketing reporting of adverse reactions is voluntarily and from a population of uncertain size, it is not always possible to reliably estimate the frequency of these reactions or establish a causal relationship to product exposure. Blood and Lymphatic System Disorders: disseminated intravascular coagulation Cardiac Disorders: tachycardia, flushing Respiratory, Thoracic, and Mediastinal Disorders: bronchospasm, wheezing Gastrointestinal Disorders: abdominal discomfort Skin and Subcutaneous Tissue Disorders: pruritus General Disorders and Administration Site Conditions: malaise, feeling hot, injection site pain DRUG INTERACTIONS Concomitant Medications Consider the possibility of thrombotic events when systemic antifibrinolytics such as tranexamic acid and aminocaproic acid are used during treatment with FEIBA. No adequate and well-controlled studies of the combined or sequential use of FEIBA and recombinant factor VIIa antifibrinolytics, or emicizumab have been conducted. Use of antifibrinolytics within approximately 6 to 12 hours after the administration of FEIBA is not recommended. Clinical experience from an emicizumab clinical trial suggests that a potential drug interaction may exist with emicizumab when FEIBA was used as part of a treatment regimen for breakthrough bleeding (see Warnings and Precautions above; see also Oldenburg et al. Emicizumab Prophylaxis in Hemophilia A with Inhibitors. N Engl J Med 2017:377:809-818). BAXALTA ® and FEIBA ® are trademarks of Baxalta Incorporated, a wholly-owned, indirect subsidiary of Shire plc., a Takeda company. Takeda and the Takeda Logo are trademarks or registered trademarks of Takeda Pharmaceutical Company Limited. Baxalta US Inc., Lexington, MA 02421 USA U.S. License No. 2020 Issued: 12/2018 S45732 02/19 non-β 0 /β 0 or β0/β 0 genotypes, while HGB- 207 included those with only non-β0/β 0 genotypes. All participants were transfu- sion dependent at the time of enrollment (defined as the receipt of ≥8 transfusions or ≥100 mL/kg of packed RBCs per year in the 2 years before enrollment). In both studies, participants were treated with a median of 8.0×10 6 cells/kg (median = 5.0-19.4×10 6 cells/kg). Two-thirds of patients (n=23/34) experi- enced an any-grade bleeding-related adverse event (AE) within two years of infusion. “The safety profile was generally con- sistent with a myeloablative conditioning regimen,” Dr. Anurathapan noted. Most treatment-related AEs were grade 1 (includ- ing abdominal pain, dyspnea, and dyspla- sia), but two patients in HGB-204 and one patient in HGB-207 experienced serious AEs (1 thrombosis and 2 instances of veno- occlusive liver disease [VOD]). After a median follow-up of 38.9 months (range = 29.3-48.1 months), 16 of 18 patients in HGB-204 (89%) achieved the study’s pri- mary endpoint of Hb improvement (defined as ≥2 g/dL of HbAT87Q between 18 and 24 months after infusion). Hb levels were stable in all patients, ranging from 9.1 g/dL to 12.5 g/dL at the last study visit. Eleven patients achieved transfusion independence, which ranged from 22.8 to 46.3 months at last follow-up. A greater proportion of patients with non-β0/β0 genotypes achieved transfusion indepen- dence (n=8/10; 80%), compared with pa- tients with β0/β0 genotype (n=3/8; 37.5%). After a median follow-up of 9.3 months (range = 0.7-20.4 months), 11 patients in HGB-207 had at least three months of follow-up and were evaluable. Ten of these patients (91%) had stopped RBC transfusions, with all achieving Hb levels of at least 11 g/dL at last study visit. Three patients had at least 12 months of follow-up and were evaluable for the primary endpoint analysis; two patients met the criteria for the primary endpoint (Hb ≥9 g/dL without RBC transfusions for ≥12 months post-infusion). These data suggest that patients can achieve “near-normal” Hb levels without transfusions or any additional safety signals compared with myeloablative transplant conditioning, Dr. Anurathapan concluded. The patient population in each trial was small, which limits the broad applicability of the studies’ results. Dr. Anurathapan added that the small number of enrolled patients limits the investigators’ ability to identify potential factors that caused delayed platelet engraftment in some patients. ● The authors report relationships with Bluebird Bio, the manufacturer of Lenti- Globin and the sponsor of this trial. REFERENCES Anurathapan U, Locatelli F, Kwiatkowski JL, et al. Lentiglobin gene therapy for transfusion-dependent ß-thalassemia: outcomes from the phase 1/2 Northstar and phase 3 Northstar-2 studies. Abstract #84. Presented at the Transplantation & Cellular Therapy Meetings of ASTCT and CIBMTR, February 23, 2019; Houston, TX. May 2019