On December 3, 2018 Celgene Corporation (NASDAQ:CELG) reported initial safety data from its ongoing proof-of-concept trial of JCARH125 in patients with relapsed/refractory multiple myeloma. JCARH125 is an investigational BCMA-targeting CAR T cell therapy being developed by Juno Therapeutics, A Celgene Company (Press release, Celgene, DEC 3, 2018, View Source [SID1234531848]). Results were presented by Sham Mailankody, MBBS, in an oral presentation at the 60th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition in San Diego, CA (Abstract #957).

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The data reported from the multicenter, phase 1/2 EVOLVE trial includes patients who have been treated with JCARH125 in the dose escalation study. The primary objectives of the phase 1 portion of the trial are safety and identification of a recommended phase 2 dose. The patients enrolled in the study had to have received at least three prior lines of multiple myeloma therapy, including an autologous stem cell transplant for transplant eligible patients, a proteasome inhibitor, an immunomodulatory drug, and an anti-CD38 monoclonal antibody. Dose escalation is currently ongoing.

"We believe that cellular therapies targeting BCMA will play an important role in the future treatment of patients with multiple myeloma," said Mark Gilbert, M.D., Chief Medical Officer for Juno Therapeutics, A Celgene Company. "These data from 44 patients in the EVOLVE trial further support our commitment to innovation in multiple myeloma clinical research."

At data cut off, 44 patients have been infused with JCARH125 in three dose escalation cohorts. These patients were heavily pretreated, with a median of seven prior lines of therapies (range, 3-23), and 77% had high-risk cytogenetics. Seventy-one percent of patients experienced grade 1 and 2 cytokine release syndrome (CRS) with 9% of patients experiencing grade 3/4 CRS. In addition, 18% of patients experienced grade 1 and 2 neurological events with 7% of patients experiencing a grade 3/4 event. Other frequent grade 3/4 AEs included neutropenia (86%), anemia (50%), thrombocytopenia (43%) and infection (14%).

In this first report of JCARH125 data, the median follow up was only 11 weeks, yet among infused patients, the overall response rate (ORR) was 82%. At the lowest dose level of 50×106 CAR T cells, the ORR was 79% and 43% of patients achieved stringent complete response (sCR) or complete response (CR).

JCARH125 is investigational and has not been approved in any country

On December 3, 2018 Oncopeptides AB (Nasdaq Stockholm: ONCO) reported that Professor Paul G. Richardson presented updated interim data with melflufen (Ygalo) from the ongoing HORIZON trial at the 60th ASH (Free ASH Whitepaper) meeting in San Diego, California, USA (Press release, Oncopeptides, DEC 3, 2018, View Source [SID1234531865]).

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Overall conclusions

The updated phase II data with melflufen in late-stage relapsed-refractory multiple myeloma patients refractory to pomalidomide and/or daratumumab after failing on immunomodulatory drugs (IMiDs) and proteasome inhibitors (PIs) shows:

An Overall Response Rate (ORR) of 33%, in patients where 46% had received 3+ regimens of treatments over the last 12 months
A vast majority of patients, 84%, achieved disease stabilization (SD or better)
The first evaluation of Progression Free Survival (PFS) shows a median of 4.0 months in the ongoing trial with a median of 6.4 months for responding patients
Activity was observed regardless of underlying refractory status and the traditional prognostic factor albumin was a strong predictor of ORR
The treatment was well tolerated with mainly reversible and manageable hematological adverse events. The incidence of non-hematological toxicity was low
Professor Paul G. Richardson comments

"Over the last decade, initial treatments in myeloma have been radically improved, and in particular with the advent of the widespread adoption of novel agent combination approaches as well as continuous therapy. However, the number of patients who become resistant to immunomodulatory agents, proteasome inhibitors and anti-CD38 monoclonal antibodies is increasing, and there is thus a clear need for effective treatment options with new mechanisms of action. Melflufen is a first in class peptidase-enhanced compound that does not share resistance pathways seen with currently used treatments and has general manageable toxicity with favorable tolerability. Melflufen is showing considerable promise in the relapsed and refractory setting, with clinical development ongoing" said Paul Richardson MD, the RJ Corman Professor of Medicine at Harvard Medical School and Director of Clinical Research at the Jerome Lipper Multiple Myeloma Center, Dana-Farber Cancer Institute, Boston, USA.

About the HORIZON study

Patient recruitment to the study is ongoing. The interim data presented at the ASH (Free ASH Whitepaper) meeting is based on a data cut-off dated October 22ed 2018 with 83 patients treated and 82 patients included in the response analysis. The patients in the study are refractory to pomalidomide and/or daratumumab after failing on IMiDs and PIs.

Summary of the HORIZON interim data

The study continues to develop positively in this heavily pretreated patient group that is refractory to pomalidomide and/or daratumumab after failing on IMiDs and PIs with few remaining treatment options.

61% of patients in the study had high-risk cytogenetics, 36% of patients were ISS stage III, the median number of prior lines of therapy was 5 and the median time since initial diagnosis was 6.5 years.
All patients in the study were investigator assessed as non-responsive or non-tolerant to IMiDs and PIs, 100% of patients were also refractory to pomalidomide or daratumumab, 60% were refractory to IMiDs, PIs and anti-CD38, 55% were alkylator refractory and 93% had disease progression on or within 60 days of completion of the last therapy.
Analysis of the preliminary efficacy results showed an ORR of 32,9% and that 84,1% of the patients achieved disease stabilization (SD or better).
Overall response rate (N=82)
ORR sCR VGPR PR MR SD PD NE
total, N=82 32,9% 1,2% 11% 20,7% 6,1% 45,1% 14,6% 1,2%
Subgroup analysis suggests that response does not vary across refractory subsets but rather with the underlying disease and health status of the patient (confirming the observation made in Oncopeptides phase II study O-12-M1).
This study confirms earlier results from the O-12-M1 study in a more resistant patient population. The efficacy results in this interim analysis are encouraging with an ORR of 32,9%.

Melflufen showed a manageable safety and tolerability profile. Treatment-related grade 3/4 AEs were reported in 62 (75%) patients with the majority being hematological. Treatment-related non-hematological grade 3/4 AEs were rare with infections in only 7% of patients. 13% of the patients discontinued treatment due to AEs.

About melflufen

Melflufen (Ygalo), a peptide conjugated alkylator belonging to a novel class of peptidase-enhanced compounds, targets multiple myeloma (MM) cells with a unique mechanism of action. Aminopeptidases are enzymes found in all cells but are over-expressed in several cancers including MM. Melflufen selectively targets MM cells through aminopeptidase-driven accumulation. In vitro experiments show a 50-fold enrichment of the active substance in MM cells compared with administration of equal amount of an alkylator not enriched by aminopeptidases. The enrichment results in selective cytotoxicity (increased on-target potency and decreased off-target toxicity), and that resistance pathways of existing myeloma treatments (including alkylators) is overcome. Melflufen also demonstrates strong anti-angiogenic properties.

Melflufen in clinical development

Melflufen (Ygalo) has been used to treat late-stage RRMM patients in both phase I and phase II clinical studies (O-12-M1) with favorable results. Currently, melflufen is being studied in four clinical trials for the treatment of multiple myeloma. The current studies are OCEAN, HORIZON, ANCHOR and BRIDGE.

The current clinical study program is intended to demonstrate better results from treatment with melflufen compared to established alternative drugs for patients with late-stage multiple myeloma. Melflufen could potentially provide physicians with a new treatment option for patients suffering from this serious disease.

Melflufen has been investigated in the treatment of late-stage relapsed refractory multiple myeloma (RRMM) patients. This was done in the clinical study O-12-M1 where strong final results were reported in December 2017. Currently, four clinical studies are ongoing with melflufen.

OCEAN is Oncopeptides´ pivotal Phase III study where melflufen is compared directly with current standard of care, pomalidomide, in late-stage RRMM patients.

HORIZON is a Phase II study that studies the effect of melflufen in late-stage RRMM patients with few or no remaining established treatment options. Updated interim data from this study were presented at ASH (Free ASH Whitepaper) in December 2018.

ANCHOR is a phase I/II study where melflufen is administered in combination with either bortezomib or daratumumab in RRMM patients. The results of this study aim to create understanding and knowledge among treating physicians for how melflufen can be used in combination with these drugs. In addition, the results could open up for the use of melflufen in earlier lines of treatment. The first interim data from the study was presented in a poster presentation on December 1, 2018 at ASH (Free ASH Whitepaper).

BRIDGE is a phase II study, where melflufen is used in RRMM patients with impaired renal function. This is a positioning study to show melflufen’s treatment profile in these patients.

On December 3, 2018 Atara Biotherapeutics, Inc. (Nasdaq: ATRA), a leading off-the-shelf, allogeneic T-cell immunotherapy company developing novel treatments for patients with cancer, autoimmune and viral diseases, reported results presented by collaborators at the 60th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting. One study presents details of a next-generation CAR T technology that increases T cell persistence and decreases T cell exhaustion (Press release, Atara Biotherapeutics, DEC 3, 2018, View Source [SID1234531881]). Another important study presents positive Phase 2 clinical results in patients with EBV+ PTLD involving the CNS. PTLD patient treatment patterns and health outcomes are described in additional ASH (Free ASH Whitepaper) presentations.

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"Our highlighted ASH (Free ASH Whitepaper) presentations this year demonstrate the promise of Atara’s next-generation CAR T and off-the-shelf, allogeneic T-cell immunotherapy pipeline," said Dietmar Berger, M.D., Ph.D., Global Head of Research and Development of Atara Biotherapeutics. "Cutting-edge CAR T discoveries by our Moffitt Cancer Center collaborators may have wide applications including as a component of our CAR T programs in acute myeloid leukemia (AML) and B-cell malignancies. Our collaborating investigators at Memorial Sloan Kettering also showed promising Phase 2 clinical results for patients with EBV+ PTLD involving the CNS, a difficult-to-treat and often lethal complication of bone marrow and organ transplantation. We are encouraged by these robust results and the broad potential of our CAR T technologies and T cell immunotherapy platform."

60th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting Summary:

Abstract 966: Mutation of the CD28 Costimulatory Domain Confers Increased CAR T Cell Persistence and Decreased Exhaustion
Session: 703. Adoptive Immunotherapy: Preclinical Studies to Improve Safety and Efficacy of CAR-T Cells
Oral Presentation Date and Time: Monday, December 3, 2018 at 5:45 pm PST
Location: Marriott Marquis San Diego Marina, San Diego Ballroom B
Authors: Justin C Boucher, Gongbo Li, Bishwas Shrestha, Maria L Cabral, Dylan Morrissey, Lawrence Guan, Marco L Davila
Affiliations:Moffitt Cancer Center

Abstract 4590: Adoptive Therapy with EBV-Specific T Cells for Treatment of CNS EBV Post-Transplant Lymphoproliferative Disease Arising after Hematopoietic Stem Cell Transplant or Solid Organ Transplant
Session: 723. Clinical Allogeneic and Autologous Transplantation: Late Complications and Approaches to Disease Recurrence: Poster III
Poster Presentation Date & Time: Monday, December 3, 2018 from 6:00 pm – 8:00 pm PST
Location:San Diego Convention Center, Hall GH
Authors: Susan Prockop, MD, Stephanie Suser, Ekaterina Doubrovina, MD, PhD, Hugo R. Castro-Malaspina, MD, Esperanza B. Papadopoulos, MD, James W. Young, MD, Victoria Szenes, PNP, Alison Slocum, MA, Karim Baroudy, MS and Richard J. O’Reilly, MD
Affiliations: Memorial Sloan Kettering Cancer Center
Overview:

This poster presentation evaluated EBV-specific T-cells generated from primary and third party (tab-cel) donors.
Patients with EBV+ PTLD involving the CNS following allogeneic hematopoietic stem cell transplant (HCT) or solid organ transplant (SOT) who failed prior rituximab from the Phase 2 studies 95-024 (NCT00002663) and 11-130 (NCT01498484) were included in the analysis.
Abstract 4777: Treatment Patterns for Patients with Post-Transplant Lymphoproliferative Disorder Who Fail Rituximab after Allogeneic Hematopoietic Stem Cell Transplantation: Findings from a Systematic Literature Review
Session: 902. Health Services Research—Malignant Diseases: Poster III
Poster Presentation Date & Time: Monday, December 3, 2018 from 6:00 pm – 8:00 pm PST
Location:San Diego Convention Center, Hall GH
Authors: Hairong Xu, MD, PhD, Crystal Watson, MS, Shan Ashton Garib, MA, Anna Forsythe, PharmD, MSc, MBA and Arie Barlev, PharmD
Affiliations:Atara Biotherapeutics, Purple Squirrel Economics

Abstract 3556: Estimating Long-Term Survival in a Cohort of Allogeneic Hematopoietic Stem Cell Transplant Patients
Session: 902. Health Services Research—Malignant Diseases: Poster II
Poster Presentation Date & Time: Sunday, December 2, 2018 from 6:00 pm – 8:00 pm PST
Location:San Diego Convention Center, Hall GH
Authors: Stephen Palmer, MSc, Casey Quinn, PhD, MPhil, Crystal Watson, MS and Arie Barlev, PharmD
Affiliations:Centre for Health Economics, University of York, PRMA Consulting Ltd., Atara Biotherapeutics

Abstract 4596: Dual-Sensitized T-Cells Responding to EBV Blcl and Either CMVpp65 or WT-1 Peptide Pools Have Distinct or Shared HLA Restrictions That May Depend on the Presenting HLA Alleles
Session: 723. Clinical Allogeneic and Autologous Transplantation
Poster Presentation Date & Time: Monday, December 3, 2018 from 6:00 pm – 8:00 pm PST
Location: San Diego Convention Center, Hall GH
Authors: Ekaterina Doubrovina, MD, PhD, Aisha N. Hasan, MD, Susan Prockop, MD, Karim Baroudy, MS, and Richard O’Reilly, MD
Affiliations: Memorial Sloan Kettering Cancer Center

Abstract 5839: A Systematic Literature Review of Real-World Evidence in Post-Transplant Lymphoproliferative Disorder
Authors: Hairong Xu, MD, PhD, Anna Forsythe, PharmD, MSc, MBA, Arie Barlev, PharmD, Nazia Rashid, PharmD and Crystal Watson, MS
Affiliations:Atara Biotherapeutics, Purple Squirrel Economics

Abstract 5841: Younger Patients Are Impacted By Post-Transplant Lymphoproliferative Disorder: Findings from a Systematic Literature Review of Real-World Evidence
Authors: Crystal Watson, MS, Hairong Xu, MD, PhD, Anna Forsythe, PharmD, MSc, MBA, Shan Ashton Garib, MA and Arie Barlev, PharmD
Affiliations:Atara Biotherapeutics, Purple Squirrel Economics

Abstract 5840: Risk of Patients Developing Post-Transplant Lymphoproliferative Disorder within the First Year after an Allogeneic Hemopoietic Stem Cell Transplant, 2011 to 2016: A US Claims Database Analysis
Authors: Arie Barlev, PharmD, Hairong Xu, MD, PhD, Nicole Fulcher, MA, Crystal Watson, MS, Ila Sruti, MPH and Akshay Sudhindra, MD
Affiliations:Atara Biotherapeutics, IBM Watson Health

About EBV+ PTLD
Since its discovery as the first human oncovirus, Epstein-Barr virus (EBV) has been implicated in the development of a wide range of lymphoproliferative disorders, including lymphomas, and other cancers. EBV is widespread in all human populations and persists as a lifelong, asymptomatic infection. In immunocompromised patients, such as those undergoing allogeneic hematopoietic cell transplants (HCT) or solid organ transplants (SOT), EBV-associated post-transplant lymphoproliferative disorder (EBV+ PTLD) represents a life-threatening condition. The expected median survival for patients with EBV+ PTLD following HCT who have failed rituximab first line therapy is 16-56 days. In EBV+ PTLD following SOT, patients failing rituximab are considered to have increased risk for chemotherapy-induced treatment-related mortality compared to other lymphoma patients. One- and two-year survival in patients with high-risk EBV+ PTLD following SOT is estimated to be 36% and 0%, respectively.

About tab-cel (tabelecleucel)
Atara’s most advanced T-cell immunotherapy in development, tab-cel, is a potential treatment for patients with Epstein-Barr virus (EBV) associated post-transplant lymphoproliferative disorder (EBV+ PTLD) who have failed rituximab, as well as other EBV-associated hematologic and solid tumors, including nasopharyngeal carcinoma (NPC). In February 2015, the FDA granted tab-cel Breakthrough Therapy Designation for EBV+ PTLD following allogeneic hematopoietic cell transplant (HCT), and in October 2016, tab-cel was accepted into the EMA Priority Medicines (PRIME) regulatory pathway for the same indication, providing enhanced regulatory support. In addition, tab-cel has orphan status in the U.S. and EU. Tab-cel is in Phase 3 clinical development for the treatment of EBV+ PTLD following an allogeneic hematopoietic cell transplant (MATCH study) or solid organ transplant (ALLELE study), and Atara recently initiated a Phase 1/2 study in NPC.

On December 2, 2018 Magenta Therapeutics (NASDAQ:MGTA), a clinical-stage biotechnology company developing novel medicines to bring the curative power of bone marrow transplant to more patients, reported that the Company presented preclinical research on its targeted conditioning programs at the 60th annual meeting of the American Society of Hematology (ASH) (Free ASH Whitepaper) (Press release, Magenta Therapeutics, DEC 2, 2018, View Source [SID1234531798]).

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Patients undergoing bone marrow transplant or stem cell gene therapy are first prepared, or conditioned, with non-specific, genotoxic chemotherapy alone or in combination with total body irradiation. This conditioning process is associated with significant toxicity, including development of cancers, infertility, organ toxicities, or even death. As a result, many patients do not consider undergoing a bone marrow transplant or gene therapy. Magenta is developing a portfolio of targeted antibody drug conjugates (ADCs), including non-genotoxic agents, that selectively remove the specific cells to enable a successful transplant or gene therapy procedure.

"This year’s five ASH (Free ASH Whitepaper) data presentations from our portfolio of targeted conditioning programs give further insight into our progress in addressing one of the major challenges of the transplant and gene therapy process: the genotoxic conditioning that leaves patients infertile and puts them at risk for malignancies and organ toxicity," said Michael Cooke, Ph.D., chief scientific officer, Magenta Therapeutics. "Our most advanced targeted conditioning program, C200, is focused on ADCs directed at CD117, a target expressed on stem cells and many types of leukemia cells. Preclinical data at ASH (Free ASH Whitepaper) this year show potent and selective depletion of human and non-human primate stem cells with our non-genotoxic CD117 ADC conjugated to amanitin. In addition, both this ADC and our CD45-targeted ADC from our C100 program demonstrated the additional benefit of anti-leukemia activity and survival advantage in patient-derived leukemia models. Based on these promising data, we are finalizing the CD117 and CD45 ADCs, and we expect to select a lead for development for the CD117 program to launch IND-enabling studies in 2019."

CD117-Amanitin Antibody Drug Conjugates Effectively Deplete Human and Non-Human Primate HSCs: Proof of Concept as a Targeted Strategy for Conditioning Patients for Bone Marrow Transplant, Abstract #3314

Key results, presented by Brad Pearse, Ph.D., Magenta Therapeutics:

An anti-CD117 ADC conjugated with amanitin potently depleted human and non-human primate hematopoietic stem cells and progenitors in vivo.
An anti-CD117 amanitin ADC with engineered fast half-life showed potent stem cell depletion and rapid clearance, providing appropriate pharmacokinetics for patient preparation for bone marrow transplant.
The ADCs were well tolerated at the efficacious doses.
Potent and selective depletion of stem cells with rapid clearance of the ADC could provide a significant improvement over current approaches to patient preparation with an acceptable safety profile prior to BMT for malignancies, autoimmune diseases and gene therapies, broadening patient access to these potentially curative therapies.
Magenta will next finalize the linker-toxin construct and select a lead for development in 2018, then begin IND-enabling studies in 2019.
Single Doses of Antibody Drug Conjugates (ADCs) Targeted to CD117 or CD45 Have Potent In Vivo Anti-Leukemia Activity and Survival Benefit in Patient-Derived AML Models, Abstract #3316

Key results, presented by Jennifer Proctor, Magenta Therapeutics:

CD117 is expressed on human hematopoietic stem and progenitor cells and on leukemia cells in 80% of patients with acute myeloid leukemia (AML) and in 65% of patients with myelodysplastic syndromes (MDS); CD45 is expressed on all lympho-hematopoietic cells and in nearly all blood cancers, other than multiple myeloma.
Both the anti-CD117 amanitin ADC (C200 program) and the anti-CD45 amanitin ADC (C100 program) showed potent killing of human hematopoietic stem cells and human leukemia cell lines expressing these targets in vitro.
A single dose of either ADC showed potent in vivo anti-leukemia activity in mice bearing established human leukemia cell lines.
Both ADCs also significantly improved the survival of mice engrafted with human leukemia cells from AML patients, including leukemias that were resistant to multiple lines of therapy including previous allogeneic bone marrow transplant.
Magenta Therapeutics’ C200 and C100 programs are designed with the dual intent of selectively eliminating the necessary cells to enable a successful transplant and reducing disease burden in patients with active disease or in patients who are at high risk of disease relapse.
Magenta will next finalize the linker-toxin constructs, select anti-CD117 and anti-CD45 leads for development and continue to progress ADC-based conditioning approaches targeting CD45 and CD117 toward clinical development.
Antibody Drug Conjugates Targeted to CD45 or CD117 Enable Allogeneic Hematopoietic Stem Cell Transplantation in Animal Models, Abstract #3324

Key results, presented by Sharon Hyzy, M.S., Magenta Therapeutics:

ADCs targeted to mouse CD45 or mouse CD117 have been shown to effectively condition immunocompetent mice for autologous bone marrow transplant.
To investigate the utility of these murine-specific tool ADCs conjugated to saporin to enable allogenic transplant, Magenta assessed these ADCs as single agents or in combination with immunosuppressive agents to facilitate transplant in a murine allogeneic transplant model.
Both anti-CD45 and anti-CD117 saporin ADCs, when combined with additional immunosuppressants, enabled successful minor mismatch whole bone marrow transplants in mouse models.
Conditioning with the anti-CD45 saporin ADC plus post-transplant cyclophosphamide to prevent graft vs. host disease enabled successful engraftment across minor histocompatibility antigens.
The ADCs were more effective than an unconjugated anti-CD45 antibody, pre-transplant cyclophosphamide, or sublethal irradiation in combination with post-transplant cyclophosphamide.
Magenta will next investigate other linker-toxins as well as ADC-based conditioning in various allogeneic mouse models.
Non-genotoxic conditioning facilitates robust HSPC engraftment and multi-lineage development in a dose dependent manner in Fanconi anemia, Abstract #2041

Key results, presented by Meera Srikanthan, Ph.D., Fred Hutchinson Cancer Research Center:

Conditioning with genotoxic chemotherapy in patients with Fanconi anemia is currently utilized to open the bone marrow niche prior to infusion of hematopoietic stem cells in a bone marrow transplant but is often associated with genotoxic effects.
ADCs targeting hematopoietic stem cells are an emerging non-genotoxic method of conditioning, particularly in diseases associated with DNA damage and cancer predisposition, such as Fanconi anemia.
Researchers at the Fred Hutchinson Cancer Research Center sought to study the application of non-genotoxic ADC-based conditioning targeting hematopoietic stem cells to eliminate leukemogenic host HSCs and to facilitate the engraftment of donor cells.
Results showed that the immunotoxin-based conditioning drugs from Magenta are of similar if not superior efficacy compared to cyclophosphamide, facilitating multi-lineage engraftment of autologous stem cells, as would be used in gene therapy.
Researchers at the Fred Hutchinson Cancer Research Center will next determine whether immunotoxin conditioning facilitates engraftment of gene-modified stem cells using FancA (-/-) mice and optimize dosing of immunotoxin platform to completely eliminate host hematopoiesis in order to decrease the risk of leukemogenesis.
Targeting CD45 with an Amanitin Antibody-Drug Conjugate Effectively Depletes Human HSCs and Immune Cells for Transplant Conditioning, Abstract #4526

Key results will be presented by Rahul Palchaudhuri, Ph.D., Magenta Therapeutics, on Monday, December 3, 2018.

A human/primate cross-reactive anti-CD45 amanitin ADC potently depletes human hematopoietic stem cells and immune cells in culture.
The anti-CD45 ADC achieved efficient depletion of immune cells in the periphery and hematopoietic stem cells in the bone marrow of humanized mice.
Simultaneous depletion of immune and hematopoietic stem cells using an anti-CD45 ADC may enable safer conditioning for allogeneic transplant and enable immune-reset in autoimmune disease transplantation.
Magenta plans to optimize the anti-CD45 ADC and select a development candidate in 2019, with IND-enabling studies to begin in 2020.

On December 2, 2018 Celgene Corporation (NASDAQ: CELG) reported initial data from the dose-escalation part of an ongoing, open-label multicenter phase 1/2 study of investigational lisocabtagene maraleucel (liso-cel; JCAR017) in patients with relapsed/refractory chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL), including patients with cytogenetic features of high-risk disease, who were previously treated with ibrutinib (Press release, Celgene, DEC 2, 2018, View Source [SID1234531784]). The data were presented by Tanya Siddiqi, M.D. in an oral presentation at the 60th American Society of Hematology (ASH) (Free ASH Whitepaper) Annual Meeting and Exposition in San Diego, C.A. (Abstract #300).

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Data presented today from TRANSCEND CLL-004 include 16 patients from the ongoing phase 1 monotherapy dose-escalation part of the study. The median number of lines of prior therapy was 4.5, and 75% of patients had high-risk cytogenetic features. All patients had previously received treatment with ibrutinib, 81% had relapse/refractory disease on ibrutinib and 50% received prior treatment with ibrutinib and venetoclax. Following lymphodepletion with fludarabine (30 mg/m2) and cyclophosphamide (300 mg/m2) for three days, patients received liso-cel at dose level 1 (5×107 CAR+ T cells) or dose level 2 (1×108 CAR+ T cells).

The overall response rate (ORR), which was an exploratory objective, was 81%, with 43% of patients demonstrating a complete response (CR). As of September 2018, five patients have six-month follow-up and all have maintained a response and undetectable minimal residual disease (uMRD) in the blood as measured by flow cytometry (10-4). The median time-to-peak expansion was 16 days, and CAR+ T cells remained detectable in patients at three months.

"Ibrutinib is a standard of care for patients with CLL, but outcomes are poor for patients whose disease progresses on or after ibrutinib," said Alise Reicin, M.D., President, Global Clinical Development for Celgene. "These initial findings support further research with liso-cel in CLL and reinforce Celgene’s commitment to cellular therapy across a broad spectrum of blood cancers."

The most common treatment-emergent adverse events reported included anemia (88%), thrombocytopenia (81%), cytokine release syndrome (75%), neutropenia (63%), leukopenia (56%), hypokalemia (50%), pyrexia (38%), lymphopenia (31%), nausea (31%), diarrhea (25%), febrile neutropenia (25%), headache (25%), insomnia (25%), and tremor (25%). One patient (6.3%) experienced grade 3 cytokine release syndrome and three patients (18.8%) experienced grade 3 neurologic events. No patients experienced grade 4 cytokine release syndrome or neurologic events.

"In CLL, undetectable MRD correlates with improved outcomes for patients and is particularly difficult to achieve in patients who have progressed on ibrutinib," said lead study investigator Tanya Siddiqi, M.D., City of Hope National Medical Center. "The high response rates we observed in heavily pretreated patients in this initial data set, along with undetectable MRD status, that appears to be maintained over time, warrants further investigation of liso-cel in this area of high unmet need."

Liso-cel is not approved in any country.

About Liso-cel

Liso-cel is an investigational defined composition CD19-directed CAR T cell product candidate using a 4-1BB costimulatory domain. Celgene’s lead CAR T trial, TRANSCEND NHL-001, is studying liso-cel in adult patients with relapsed or refractory diffuse large B cell lymphoma, primary mediastinal B-cell lymphoma, follicular lymphoma Grade 3B, and mantle cell lymphoma.