Cellectis Provides Business Updates and Preliminary Financial Results for Second Quarter 2023

* Updated clinical & translational data on BALLI-01 trial (evaluating UCART22 in r/r B-cell ALL) presented at the EHA annual meeting

* Clinical trials ongoing: BALLI-01 (evaluating UCART22), NATHALI-01 (evaluating UCART20x22) and AMELI-01 (evaluating UCART123) studies for patients with r/r B-cell ALL, r/r B-cell NHL and r/r AML, respectively

* Preclinical data presented on HBB gene correction of sickle cell mutation & TALE Base Editors (TALE-BE) at ISCT 2023 annual event

* Appointment of Cécile Chartier, Ph.D., as Director to Cellectis’ Board of Directors

* Cash position^[1] of $89 million as of June 30, 2023. Cash runway into Q3 2024

* Full financial statements for the second quarter of 2023 will be released in the coming days

* Conference call scheduled for 8AM ET/2PM CET on August 4, 2023

 

 New York, NY – August 3, 2023 - Cellectis (the “Company”) (Euronext Growth: ALCLS - NASDAQ: CLLS), a clinical-stage biotechnology company using its pioneering gene-editing platform to develop life-saving cell and gene therapies, today provided business updates and preliminary financial results for the six-month period ending June 30, 2023. Full report of the financial results for the second quarter of 2023 will be released in the coming days.

“We are proud of our team and the strong execution this quarter. Our clinical data presented for UCART22 at the European Hematology Association (EHA) were positive for patients with r/r B-ALL who have failed multiple lines of treatment including multi-agent chemoimmunotherapy, CD19 directed CAR T-cell therapy, and allogeneic stem cell transplant. We are looking forward to releasing new data later this year on our UCART22 product candidate manufactured in-house,” said André Choulika, Ph.D., Chief Executive Officer at Cellectis.

“In addition, we have made progress with our pipeline in 2023 and continue to focus on our core clinical trials BALLI-01 (evaluating UCART22), NATHALI-01 (evaluating UCART20x22) and AMELI-01 (evaluating UCART123). This quarter, Cellectis presented an encore of the clinical data on the AMELI-01 clinical trial at the American Society of Gene and Cell Therapy (ASGCT) 2023 annual meeting. These preliminary data support the continued administration of UCART123 after FCA lymphodepletion in patients with r/r AML.

Cellectis’ innovation team also presented preclinical data on a gene editing process to develop a bona fide HBB gene correction of sickle cell mutation, and a comprehensive analysis to better design efficient TALE Base Editors (TALE-BE) at the International Society for Cell and Gene Therapy (ISCT) 2023 annual meeting. These achievements showcase once more the power of our gene-editing platform and our TALEN®, the technology of choice for therapeutic gene editing, and that we are continuing to deliver constant breakthrough innovation to treat diseases with unmet medical needs.

Despite an unprecedented challenging market environment for cell and gene therapy companies, Cellectis remains focused in its mission to develop innovative cancer therapy product candidates.”

 

Pipeline Highlights

UCART Clinical Development Programs

BALLI-01 (evaluating UCART22) in relapsed or refractory B-cell acute lymphoblastic leukemia (r/r B-ALL)

• UCART22 is an allogeneic CAR T-cell product candidate targeting CD22 and is being evaluated in patients with r/r B-ALL in the BALLI-01 Phase 1/2a clinical study.

• On June 9, Cellectis presented updated clinical and translational data at the European Hematology Association (EHA). These data support the preliminary safety and efficacy of UCART22 in a heavily pretreated r/r B-ALL population. UCART22 is currently the most advanced allogeneic CAR T-cell product in development for r/r B-ALL.

• In the poster presented at EHA, Cellectis included data from patients who received UCART22 after fludarabine, cyclophosphamide (FC) and FC with alemtuzumab (FCA) lymphodepletion (LD). Compared to the clinical update on BALLI-01 at ASH 2021, we have included data from six additional patients who received UCART22 at dose level 3 (DL3), as of the December 31, 2022 data cutoff.

• UCART22 administered after FC or FCA LD regimen was well tolerated. No dose limiting toxicities (DLTs) nor immune effector cell-associated neurotoxicity syndrome (ICANS) were observed.

• For FCA-dose level 3, 50% of the six patients responded. Host lymphocytes remained suppressed through Day 28 for all patients who received FCA LD. Peak ferritin levels correlated with UCART22 cell expansion and cytokine release syndrome (CRS). UCART22 continues to be well tolerated, with no treatment emergent serious adverse events (TESAEs) or DLTs reported. UCART22 cell expansion was detected in 9 of 13 patients in the FCA LD arm and associated with clinical activity.

• The BALLI-01 study is currently enrolling patients after FCA LD with Cellectis’ in-house manufactured product. The next data set is expected to be released later this year.

 

NATHALI-01 (evaluating UCART20x22) in relapsed or refractory B-cell non-Hodgkin lymphoma (r/r B-NHL)

• UCART20x22 is Cellectis’ first dual allogeneic CAR T-cell product candidate targeting both CD20 and CD22 and is being evaluated in patients with r/r B-NHL in the NATHALI-01 Phase 1/2a clinical study[2].

• The NATHALI-01 clinical study is ongoing. Cellectis expects to provide first-in-human data later this year.

 

AMELI-01 (evaluating UCART123) in relapsed or refractory acute myeloid leukemia (r/r AML)

• UCART123 is an allogeneic CAR T-cell product candidate targeting CD123 and is being evaluated in patients with r/r AML in the AMELI-01 Phase 1 dose-escalation clinical study.

• On May 17, Cellectis presented an encore of the clinical data on the AMELI-01 clinical trial that were unveiled at the ASH 2022 annual meeting, at the American Society of Gene and Cell Therapy (ASGCT) 2023 annual meeting. These preliminary data support the continued administration of UCART123 after FCA lymphodepletion in patients with r/r AML.

• The oral presentation reviewed preliminary data from patients who received UCART123 at one of the following dose levels: dose level 1 (DL1) 2.5x10⁵ cells/kg; dose level 2 (DL2) 6.25x10⁵ cells/kg; intermediate dose level 2 (DL2i) 1.5x10⁶ cells/kg; or dose level 3 (DL3) 3.30x10⁶ cells/kg after lymphodepletion with FC ([n=8], DL1 – DL3) or FCA ([n=9], DL2 & DL2i).

• The data presented showed that adding alemtuzumab to the FC LD regimen was associated with sustained host lymphodepletion and significantly higher UCART123 cell expansion, that correlated with improved anti-tumor activity.

• 25% (n=2) of patients at DL2 in the FCA arm achieved meaningful response; one patient who failed five prior lines of therapy including allogeneic stem cell transplant experienced a durable minimal residual disease (MRD)-negative complete response that continued beyond 12 months, as of December 2022.

• The AMELI-01 study is currently enrolling patients after FCA lymphodepletion in a two-dose regimen arm.

 

Research Data & Preclinical Programs

UCART20x22

• On June 5, 2023, Cellectis presented preclinical data on its product candidate UCART20x22, at the International Society for Cell & Gene Therapy (ISCT) 2023 annual event.

• Cellectis provided pre-clinical proof-of-concept data for UCART20x22 to overcome current mechanisms of resistance to CAR T-cell therapies in B-NHL, while providing a potential therapeutic alternative to CD19 targeting and allowing a reduction in the time from treatment decision to infusion.

• Cellectis demonstrated that UCART20x22 displays robust activity in vitro and in vivo, against targets expressing heterogeneous levels of CD22 and CD20. We have used in vitro cytotoxicity assays against different tumor cell lines, showing strong activity whether these cells express a single antigen (CD20 or CD22) or both antigens simultaneously, as well as IFNg release in response to antigen specific stimulation.

 

Article published in Cancer Immunology Research

• On May 31, 2023, Cellectis published an article in Cancer Immunology Research demonstrating pre-clinical proof-of-concept data of UCART20x22 product candidate, to overcome current mechanisms of resistance to CAR T-cell therapies in B-NHL.

• In this study, we demonstrated that allogeneic CD20x22 CAR T-cells exhibit robust, sustained and dose-dependent activity in vitro and in vivo, while efficiently targeting primary Non-Hodgkin Lymphoma samples with heterogeneous levels of CD20 and CD22.

 

HBB gene correction of sickle cell mutation

• Encouraging preclinical data on gene editing process using Cellectis TALEN® technology to develop highly efficient HBB gene correction of sickle cell mutation, were presented in a poster presentation at the ISCT 2023 annual event.

• These results showed that non-viral DNA delivery associated with TALEN® gene editing reduces the toxicity usually observed with viral DNA delivery and allows high levels of HBB gene correction in long-term repopulating hematopoietic stem cells.

• Cellectis leveraged TALEN® technology to develop a gene editing process leading to highly efficient HBB gene correction via homology directed repair, while mitigating potential risks associated to HBB gene knock-out. Furthermore, we compared viral (TALEN-V) and non-viral (TALEN-NV) DNA template delivery strategies in mobilized healthy donor (HD) or non-mobilized homozygous sickle patient (HbSS) hematopoietic stem and progenitor cells (HSPCs).

• Both strategies led to high and comparable efficiencies of HBB gene correction in vitro in HD and HbSS, without affecting viability, purity or clonogenic potential of corrected HSPCs.

The poster presentation highlighted the following data:

• TALEN®-mediated engineering efficiently corrects the mutated HBB gene in clinically relevant HSPCs and promote phenotype correction in fully mature RBCs.
• Cellectis optimized TALEN® gene editing process mitigates potential safety challenges by reducing the frequency of HBB gene inactivation (<10% β-thal cells).
• Non-viral DNA template-mediated HBB repair mitigates p53 DNA damage response activation, preserves edited LT-HSCs fitness and enables their efficient engraftment in vivo using an immunodeficient murine model.

 

TALE Base Editors (TALE-BE)

• A comprehensive analysis to better design efficient TALE Base Editors (TALE-BE) using Cellectis’ TALEN® technology was presented in a poster at ISCT annual meeting.

• Cellectis developed a strategy that allowed to comprehensively characterize editing efficiencies in function of the TC position within the TALE-BE editing windows. This method is specifically taking advantage of the highly precise and efficient TALEN® mediated ssODN knock-in in primary T cells, allowing to focus on how target composition and spacer variations can affect TALE-BE activity/efficiency.

The poster presentation highlighted the following data:

• Determined optimal spacer length (13/15 bp) for highly efficient TALE-BE for both C40/C40 and C11/C11 scaffolds.
• Determined optimal common sequence context for high editing rates.
• Determined that editing efficiency of the C11/C11 scaffold is highly dependent on Cytosine position requirements, resulting in more stringent activity in a context of 15 bp spacer size and decreasing the effects of bystander editing.

We believe that the knowledge obtained will allow to better design efficient TALE-BE while improving the specificity profiles of this innovative editing platform.

 

Novel treatment paradigm for successful CAR T immunotherapy against stroma-rich solid tumors

• On May 12, 2023, Cellectis published an article in Frontiers Bioengineering demonstrating the efficacy of its TALEN® engineered FAP UCART-cells in cancer-associated fibroblast (CAF) depletion, reduction of desmoplasia and tumor infiltration.

• Over 90% of epithelial cancers including breast, colorectal, pancreatic and lung adenocarcinomas express the CAF-specific surface marker, fibroblast activation protein α (FAP), which makes it a promising CAR T-cell target. In this study, Cellectis proposed a novel and versatile approach of combination CAR T-cell therapy that can be extended to most stroma-rich cold tumors with relevant tumor-antigen targeting CAR T-cells which otherwise are recalcitrant to cell therapy.

Preclinical data showed that:

• In a mouse xenograft model, successful implantation of injected CAFs in the tumors was confirmed by positive staining of spindle-like cells with human-specific FAP antibody, recapitulating a physiologically relevant TNBC tumor with tumor and stromal compartments.
• FAP UCART-cells alone significantly reduced tumor growth.
• In vitro and in vivo results show that FAP UCART-cells enable the reprogramming of the cold, stroma-rich triple negative breast cancer (TNBC) TME, making the tumor susceptible to subsequent Meso UCART infiltration and cytotoxicity and improving the overall antitumor activity of the treatment.
• In the context of combination therapy with anti-PD1 checkpoint inhibitor, maximal anti-tumor activity and survival benefits were observed upon FAP UCART-cell treatment followed by Meso UCART-cell treatment.

 

Licensed Allogeneic CAR T-cell Development Programs

Servier and Allogene: anti-CD19 programs

• Allogene announced that it is enrolling patients “in the industry’s first potentially pivotal Phase 2 allogeneic CAR T clinical trial with ALLO-501A across sites in the United States and Canada”. The European Medicines Agency (EMA) recently approved the ALPHA2 Clinical Trial Application (CTA).

• Allogene’s single-arm ALPHA2 trial in relapsed/refractory (R/R) large B cell lymphoma (LBCL) will enroll approximately 100 patients who have received at least two prior lines of therapy and have not received prior anti-CD19 therapy. Allogene has announced that it expects to complete enrollment in 1H 2024 with the first data readout by the end of 2024.

• Long-term follow up data from the Phase 1 of Allogene’s ALPHA/ALPHA2 trials in LBCL was presented at both the American Society of Clinical Oncology (ASCO) Annual Meeting with an encore presentation at the European Hematology Association Congress and International Conference on Malignant Lymphoma (ICML) Lugano in June 2023. The Phase 1 trials enrolled heavily pre-treated patients with a median of three prior lines of therapy. Data from 33 CAR T-naïve LBCL patients receiving Alloy™ cell product including 12 patients treated with the Phase 2 regimen, are the first to demonstrate the potential for an allogeneic CAR T product to induce complete responses at rates and durability similar to approved autologous therapies. 

 

Allogene: anti-BCMA and anti-CD70 program

• The ongoing Phase 1 dose escalation of Allogene’s TRAVERSE study is enrolling patients with advanced or metastatic renal cell carcinoma (RCC) who have progressed on standard therapies including an immune checkpoint inhibitor and a VEGF-targeting therapy.

• Allogene’s TRAVERSE trial is now deploying an investigational in vitro companion diagnostic (IVD) assay designed to prospectively assess CD70 expression levels in patients. Allogene has announced that dose escalation in the TRAVERSE trial is expected to be completed in 2023.

 

Corporate Updates        

• On June 28, 2023, Cellectis reported results from the annual shareholders’ general meeting held on June 27, 2023, at the Company’s Paris headquarters. At the meeting, during which more than 72% of shares were exercised, Resolutions 1 through 28 were adopted and resolution 29 was rejected, according to the management recommendations. The detailed results of the vote and the resolutions are available on the company’s website: https://www.cellectis.com/en/investors/general-meetings/

At the end of the meeting, the terms of office of Ms. Annick Schwebig and Mr. Hervé Hoppenot ended and Ms. Annick Schwebig and Mr. Hervé Hoppenot departed the board of directors as of such date.

During the annual shareholders meeting, Cécile Chartier, Ph.D., was appointed as a director of the Cellectis’ Board of Directors, with immediate effect.

Cécile Chartier currently serves as Chief Scientific Officer at NextVivo, Inc. Prior to her tenure at NextVivo, Dr. Chartier was Vice President of Research at Iovance Biotherapeutics, Inc. where she led the development of next generation tumor-infiltrating lymphocytes (TIL) therapies through research to early-stage clinical trials. Cécile’s extensive experience in the development of next generation cell and gene therapies coupled with her deep knowledge of the U.S. biotechnology industry will be a huge asset to Cellectis.