bluebird bio, Inc. (BLUE) to Present New Data from Clinical Studies

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bluebird bio to Present New Data from Clinical Studies of LentiGlobinTM Gene Therapy in Transfusion-Dependent β-Thalassemia and Severe Sickle Cell Disease and bb2121 in Relapsed/Refractory Multiple Myeloma at ASH Annual Meeting

 

bluebird bio, Inc. (BLUE), a clinical-stage company committed to developing potentially transformative gene therapies for severe genetic diseases and T cell-based immunotherapies for cancer, today announced that four oral and seven poster presentations will feature data from bluebird programs during the 59th Annual Meeting of the American Society for Hematology (ASH). The data will highlight bluebird’s advancement of its LentiGlobin product candidate in patients with transfusion-dependent β-thalassemia (TDT) and severe sickle cell disease (SCD), and its bb2121 product candidate in patients with relapsed/refractory multiple myeloma. Preliminary data from these abstracts will be available on the ASH conference website at 9:00 am ET today.

“This year at ASH, we have the opportunity to share updated data across our clinical studies in severe genetic diseases and cancer, and to provide a look at some of the preclinical work that will inform the next phase of clinical development at bluebird,” said Dave Davidson, chief medical officer. “The new data in sickle cell disease suggest that the changes made to the HGB-206 protocol and to our manufacturing process are having a favorable impact on the engraftment of the gene-modified stem cells. The two patients treated in Group B have consistently higher DP VCN and in vivo VCN than Group A patients, and patient 1313 has the highest Month 3 HbAT87Q level seen to date in the study. We plan to share updated clinical data on these patients at ASH. Additionally, we are very encouraged by the emerging profile of plerixafor mobilization in patients with sickle cell disease. Early data show a more favorable safety profile and substantial improvement in the collection of CD34+ cells compared to bone marrow harvest, suggesting that plerixafor may offer a more effective and less burdensome means to collect stem cells in patients with sickle cell disease.”

Clinical Presentations Summary

Interim Results from a Phase 1/2 Clinical Study of LentiGlobin Gene Therapy for Severe Sickle Cell Disease (Oral Abstract #527)
Presenter: Julie Kanter, M.D., Medical University of South Carolina, Charleston, SC
Date & Time: Sunday, December 10 at 5:30 pm
Location: Bldg C, Lvl 1, C101 Auditorium

Abstract Results as of July 21, 2017:

  • 9 patients with severe SCD have received LentiGlobin drug product (DP). All successfully underwent bone marrow harvest (median 2 harvests, range 1–3) to collect the stem cells used to produce LentiGlobin drug product.
  • Patients in this study are divided into three cohorts: A, B and C. Patients in Group A were treated under the original study protocol. Patients in Group B were treated under an amended study protocol that included changes intended to address drug product vector copy number (VCN) and engraftment challenges seen in Group A. Patients in both Group A and B had drug product made from stem cells collected using bone marrow harvest. Group C will be composed of patients treated under the amended study protocol and with drug product made from stem cells collected using apheresis with plerixafor rather than via bone marrow harvest.
  • 7 patients were treated in Group A; initial results in these patients were presented at ASH 2016. The median cell dose was 2.1 (1.8–5.1) x 106 CD34+ cells/kg, median DP VCN was 0.6 (0.3–1.3) copies/diploid genome, and 8%–42% CD34+ cells were transduced. As of the data cutoff:
    • Median follow-up was 18.3 (14.9–23.8) months since LentiGlobin infusion
    • Median VCN in peripheral blood was 0.1 (0.1–0.2) copies/genome and median HbAT87Q level was 0.9 (0.4–2.4) g/dL at last measurement.
    • Patients experiencing multiple vaso-occlusive crises (VOCs) prior to study entry (n=6; median annualized frequency 4, range 2–28 VOCs annually) have had numerically fewer VOCs since LentiGlobin DP infusion (median annualized frequency 1, range 0–24 annually, 14%–100% reduction).
  • 2 patients were treated in Group B. As of the data cutoff:
    • Patient 1313, whose DP VCNs were reported at ASH 2016, was treated with two DP lots, one of which was manufactured using the original process, and the other using the refined process.
      • The total DP cell dose was 2.2 x 106 CD34+ cells/kg. DP VCNs were 1.4 (old process) and 3.3 (refined process) copies/genome. 46% (old process) and 83% (refined process) of CD34+ cells were transduced.
      • VCN in peripheral blood was 0.5 copies/genome and HbAT87Q level was 1.5 g/dL at 3 months after LentiGlobin infusion
    • Patient 1312 was treated with two DP lots manufactured using the refined process.
      • The total DP cell dose was 3.2 x 106 CD34+ cells/kg. DP VCNs were 5.0 and 2.9 copies/genome. 95% and 90% of CD34+ cells were transduced.
      • VCN in peripheral blood was 2.6 copies/genome at 1 month after LentiGlobin infusion.
      • HbAT87Q was not yet available at time of data cut for abstract
  • Additional patients have been enrolled in HGB-206, and data including mobilization results and DP characteristics for these patients will also be presented at ASH.
  • The toxicity profile observed from start of conditioning to latest follow-up was consistent with myeloablative conditioning with single-agent busulfan.

Successful Plerixafor-Mediated Mobilization, Apheresis, and Lentiviral Vector Transduction of Hematopoietic Stem Cells in Patients with Severe Sickle Cell Disease (Poster Abstract #990)
Presenter: John Tisdale, M.D., National Heart, Lung and Blood Institute (NHLBI), Bethesda, MD
Date & Time: Saturday, December 9 at 5:30 pm
Location: Bldg A, Lvl 1, Hall A2

Abstract Results:

  • Three patients with severe sickle cell disease (SCD) have undergone plerixafor mobilization.
  • A total of 15.3, 5.6, and 9.0 x 10CD34+ cells/kg were collected in a single day of apheresis. In contrast, bone marrow harvest collections for all prior patients in the study yielded a mean of 5.0 (range 0.3—10.8) x 106 CD34+ cells/kg per harvest (N=21).
  • Ex vivo cultured CD34+ cells isolated from bone marrow harvests consisted of an average of 41.0% (17.3%—50.7%) CD34dim cells. In contrast, ex vivo cultured CD34+ cells isolated from plerixafor mobilized peripheral blood (PB) contained an average of 8.2% (1.5—19.5%) CD34dim cells. CD34dim cells, which express low levels of CD34, are generally less primitive/less likely to be true primitive stem cells than other CD34+ positive cells.
  • Similar drug product vector copy numbers were observed after research-scale transduction of CD34+ cells collected from a bone marrow harvest and from plerixafor mobilized cells from the same patient.

The mobilization and apheresis procedures had an acceptable toxicity profile. No dose-limiting toxicities were observed after plerixafor dosing.

Clinical Outcomes up to 3 Years Following LentiGlobin Gene Therapy for Transfusion-Dependent β-Thalassemia in the Northstar HGB-204 Study (Oral Abstract #360)
Presenter: Janet Kwiatowski, M.D., MSCE, Children’s Hospital of Philadelphia, Philadelphia, PA
Date & Time: Sunday, December 10 at 10:45 am
Location: Building B, Lvl 2, B213-B214

Abstract Results, as of June 2, 2017:

  • As previously reported, the study has completed its treatment phase and eighteen patients with TDT (8 with β00 and 10 with non-β00 genotypes) received LentiGlobin drug product (DP).
  • The median drug product vector copy number (VCN) was 0.7 (range: 0.3–1.5) copies/diploid genome, the median cell dose was 8.1 (range: 5.2–18.1) x 106 CD34+ cells/kg, and the proportion of transduced CD34+ cells was 17–58%.
  • Of the 10 patients with non- β00 genotypes, 8 have been free of transfusions for a median of 27.1 (range 12.5–35.2) months.
  • The 2 patients with non-β00 genotypes who still require intermittent transfusions had annual transfusion volumes reduced by 30% and 94%; both received DP with a VCN in the lower range (DP VCNs: 0.3 and 0.4 copies/diploid genome).
  • Two patients with β00 genotypes have not received a transfusion in more than a year. At the patients’ last study visit (Month 24/Month 12), total Hb levels were 9.0 and 10.2 g/dL, HbAT87Q levels were 8.2 and 6.8 g/dL, and peripheral VCNs were 0.9 and 0.6, respectively.
  • Six patients with β00 genotypes have continued transfusions. Their annual transfusion volumes have decreased by a median of 63% (range: 19% to 81%).
  • The safety profile continues to be consistent with myeloablative conditioning with single-agent busulfan. No drug-product related serious adverse events (AEs) have been observed, and there is no evidence of clonal dominance.

Additional Clinical Presentations
Results from the HGB-207 (Northstar-2) Trial: A Phase 3 Study to Evaluate Safety and Efficacy of LentiGlobin Gene Therapy for Transfusion-Dependent β-thalassemia (TDT) in Patients with non-β00 Genotypes (Oral Abstract #526)
Presenter: Mark C. Walters, M.D., UCSF Benioff Children’s Hospital, Oakland, Calif
Date & Time: Sunday, December 10 at 5:15 pm
Location: Bldg C, Lvl 1, C101 Auditorium

Abstract contains data presented at European Hematology Association (EHA) 2017 annual meeting. Updated data to be included in ASH presentation.

Longer Term Follow-up on the First Patients with Severe Hemoglobinopathies Treated with LentiGlobin Gene Therapy (Poster Abstract #4609)
Presenter: Marina Cavazzana, M.D., Necker-Enfants Malades Hospital, Paris, France
Date & Time: Monday, December 11 at 6:00 pm
Location: Bldg A, Lvl 1, Hall A2

Abstract contains data presented at European Hematology Association (EHA) 2017 annual meeting. Updated data to be included in ASH presentation.

Durable clinical responses in heavily pretreated patients with relapsed/refractory multiple myeloma: Updated results from a multicenter study of bb2121 anti-BCMA CAR T cell therapy (Oral Abstract #740)
Presenter: Jesus Berdeja, M.D., Sarah Cannon Research Institute and Tennessee Oncology, Nashville, TN
Date & Time: Monday, December 11 at 3:00 pm
Location: Bldg C, Lvl 1, Hall C1

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