Cellectis: Offering Proof of Concept is What Led to the Stock Rally


UCART19 is one of the Cellectis’ (CLLS) lead allogeneic anti-CD19 CAR T-cell products. The word allogeneic is important as it makes the difference between Cellectis’ CAR T products and the two approved chimeric antigen receptor (CAR T) products and some of the investigational CAR T immuno-oncology products. Except for Cellectis’ and a few other  biotechs including  Celyad’s (CYAD)  products all other CAR T treatments are non-allogeneic (autologous) treatments. Being allogeneic, Cellectis’ products UCARTs, can be manufactured in large scale, using cells from healthy donors, instead of autologous treatments that relies on the patient’s own cells. This advantage makes Cellectis’ UCARTs products easy to make, easy to find, and fitting the firm’s descriptoion of its products as a “frozen, off-the-shelf T-cell-based medicinal product.”

In the NEWS

At the 59th American Society of Hematology (ASH) Annual Meeting and Exposition in Atlanta, the large French private Company Servier, Pfizer (PFE) and Cellectis presented preliminary results from two phase 1 studies of UCART19, an investigational allogeneic anti-CD19 CAR T-cell product, in adult and pediatric patients with relapsed or refractory (R/R) CD19-positive B-cell acute lymphoblastic leukemia (B-ALL).

The first-in-human data from the trials demonstrated the safety, tolerability and efficacy of UCART19, resulting in an 83% complete remission rate across the adult and pediatric patient population. 


Results from the CALM (UCART19 in Advanced Lymphoid Malignancies) study:

– Five out seven patients achieved molecular remission1 at Day 28 post UCAR191

 1 Molecular remission is defined by negative minimal residual disease (MRD). MRD is a measurement of the number of residual leukemic cells that remain after treatment.

– Only one Grade 1 cutaneous acute graft versus host disease (GvHD) occurred.

– No severe neurotoxicity was observed.

– Cytokine release syndromes (CRS) were mild and manageable except in one patient treated with UCART19 at the first dose level, who developed CRS Grade 4 and neutropenic sepsis leading to death at Day 15.

Results from the PALL (Pediatric Acute Lymphoblastic Leukemia) Trial:

The PALL study is a phase 1, open label study designed to evaluate the safety and ability of UCART19 to induce molecular remission defined by MRD negativity at Day 28 to enable allogeneic stem cell transplantation in pediatric patients with high-risk R/R B-ALL.

– All five children achieved MRD negativityenabling them to proceed to allogeneic stem cell transplant.

– Only one Grade 1 cutaneous acute GvHD occurred.

– No severe neurotoxicity was observed.

– Cytokine release syndromes were mild in the most cases and were all manageable.

 Servier is the sponsor of both studies that are active in Europe and the United States.

Prohost Observations

The importance of UCART19 positive results is that they offered proof of concept that Cellectis’   allogeneic CAR T is safe and effective. Many investors were in doubt of what has now become a reality. The exciting results have also confirmed the efficacy of Cellectis’ proprietary gene editing technology TALEN®, which was used in editing the firm’s product UCART19, which aims at treating CD19-expressing hematological malignancies and of course in editing the rest of Cellectis’ pipeline other  UCARTS aiming at other targets for the treatment of various malignancies.

As described in the beginning of this article, UCART19 has the potential to overcome the limitation of autologous approaches by providing an allogeneic, frozen, “off-the-shelf” T cell based medicinal product.

Some Important History

In November 2015, Cellectis gave Servier exclusive rights to UCART19. Following further agreements, Servier and Pfizer began collaborating on a joint clinical development program for this cancer immunotherapy. Pfizer has been granted exclusive rights by Servier to develop and commercialize UCART19 in the United States, while Servier retains exclusive rights for all other countries.

Cellectis received $38.2 million from Servier upon signature of the agreement and it eligible for over $300 million of milestone payments, R&D financing, and royalties on sales from Servier, based on annual net sales of commercialized products.

Cellectis’ Pipeline

In addition to UCART19, Cellectis’ pipeline has other products comprising:

UCART123: Targets CD123, an antigen expressed at the surface of leukemic cells in acute myeloid leukemia (AML), as well as on leukemic and other tumoral cells in BPDCN3.

3 BPDCN: Blastic plasmacytoid dendritic cell neoplasm

In February 2017, Cellectis received an Investigational New Drug (IND) approval from the U.S. Food and Drug Administration (FDA) to conduct Phase 1 clinical trials with UCART123 in patients with acute myeloid leukemia (AML) and blastic plasmacytoid dendritic cell neoplasm (BPDCN). This marks the first allogeneic, “off-the-shelf” gene-edited CAR T-cell product candidate that the FDA has approved for clinical trials. The drug is in early clinical trials

UCART22: Targets CD22 for B-acute lymphoblastic leukemia (B-ALL) and B-Non-Hodgkin lymphoma (B-NHL). UCART22 is at the manufacturing stage of development. Translational activities on UCART22 in B-ALL is performed in collaboration with the MD Anderson Cancer Center in view of a clinical trial.

UCARTCS1: This product is being developed in multiple myeloma (MM). The firm expect to manufacture it in 2018. Cinical trials are expected to be conducted at MD Anderson Cancer Center. Translational activities for UCARTCS1 in MM will also be performed in with MD Anderson Cancer Center.

UCART38: This product targets CD38 for the treatment of CD38-expressing hematologic malignancies. UCART38 is being developed in Multiple Myeloma, T-cell ALL, Non-Hodgkin lymphoma and Mantle cell lymphoma. UCART38 is at an early preclinical stage. Preclinical and translational activities on UCART38 in T-ALL are to be performed in collaboration with the MD Anderson Cancer Center.

Prohost added Cellectis to its Portfolio on January 21, 2016 at $22.36. The stock is now trading at $28.30 UP $1.51. This is the third day of the stock rallying following the exciting clinical trial results from its product UCART19.

Again we say that the above results mark the first validation of Cellectis’ UCART allogeneic products and also validates the utility of the Company’s Talen™gene-editing technology.

It is, indeed, good news.

Coming Soon, under Today’s Highlights from Prohost, the reason for the Wednesday rallying of a dozen of the Prohost Portfolio picked biotech stocks.           

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