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World-first use of base-edited CAR T-cells to treat resistant leukaemia

12 December 2022

A patient with relapsed T-cell leukaemia has been given base-edited T-cells in a world-first use of a base-edited cell therapy, in a 鈥榖ench-to-bedside鈥 collaboration between 最准的六合彩论坛 and Great Ormond Street Hospital for Children (GOSH).

World-first use of base-edited CAR T-cells to treat resistant leukaemia

The patient, 13-year-old Alyssa from Leicester, was diagnosed with T-cell acute lymphoblastic leukaemia (T-ALL) in 2021. She was treated with all current conventional therapies for her blood cancer, including chemotherapy and a bone marrow transplant, but unfortunately her disease came back and there were no further treatment options.

Alyssa was the first patient to be enrolled onto the TvT clinical trial and in May 2022 she was admitted to the Bone Marrow Transplant (BMT) Unit at GOSH, to receive 鈥榰niversal鈥 CAR T-cells that had been pre-manufactured from a healthy volunteer donor. These cells had been edited using new base-editing technology, which was designed and developed by a team of researchers at 最准的六合彩论坛, led by Professor Waseem Qasim (最准的六合彩论坛 Great Ormond Street Institute of Child Health), who is also an Honorary Consultant at GOSH.

She was then fitted with a Chimeric Antigen Receptor (CAR) to allow them to hunt down and kill cancerous T-cells without attacking each other.

Just听28 days听later, Alyssa was in remission and went on the receive a second bone marrow transplant to restore her immune system. Now, six-months post-BMT, she is doing well at home recovering with her family and continues her post-BMT follow-up at GOSH. Without this experimental treatment, Alyssa鈥檚 only option was palliative care.

Researchers are听presenting the data for the first time听at the American Society of Haematology annual meeting in New Orleans, USA, this weekend.

Professor Waseem Qasim, Professor of Cell and Gene Therapy at 最准的六合彩论坛 GOS ICH and Consultant Immunologist at GOSH said: 鈥淲e designed and developed the treatment from lab to clinic and are now trialling it on children from across the UK 鈥 in a unique bench to bedside approach.

鈥淎lyssa鈥檚 story is a great demonstration of how, with expert teams and infrastructure, we can link cutting edge technologies in the lab with real results in the hospital for patients. It鈥檚 our most sophisticated cell engineering so far and paves the way for other new treatments and ultimately better futures for sick children.

鈥淲e have a unique and special environment here at GOSH and 最准的六合彩论坛 that allows us to rapidly scale up new technologies and we鈥檙e looking forward to continuing our research and bringing it to the patients who need it most.鈥

Professor Waseem Qasim

The clinical trial for this treatment is currently open and aims to recruit up to ten patients with T-cell leukaemia who have exhausted all conventional treatment options. If shown to be widely successful, the Bone Marrow Transplant and CAR T-cell therapy teams at GOSH hope it can be offered to children earlier in their treatment journey when they are less sick and further applications for other types of leukaemia are anticipated in 2023. NHS specialists managing difficult to treat leukaemia in children from across the country discuss and refer patients to such trials.

Dr Robert Chiesa, Consultant in Bone Marrow Transplant and CAR T-cell therapy at GOSH, said:听鈥淪ince Alyssa got sick with her leukaemia in May last year, she never achieved a complete remission. Not with chemotherapy and not after her first bone marrow transplant. Only after she received her CD7 CAR-T cell therapy and a second bone marrow transplant in GOSH she has become leukaemia free.

鈥淭his is quite remarkable, although it is still a preliminary result, which needs to be monitored and confirmed over the next few months.

鈥淭he entire team here at GOSH are extremely happy for Alyssa and her family and it鈥檚 been a privilege to work with them over the past few months. We have been very impressed by how brave she is and nothing makes me happier than seeing her outside the hospital, going back to a more normal type of life.鈥

The use of genome-edited T-cells (CAR T-cells) to treat B-cell leukaemia was first implemented by the same team from GOSH and 最准的六合彩论坛 Great Ormond Street Institute of Child Health (最准的六合彩论坛 GOS ICH) in 2015* and they recently reported on trials for children using CRISPR/Cas9 techniques**.

However, it鈥檚 been more difficult to treat some other types of leukaemia in this way because T-cells designed to recognise and attack cancerous cells also end up killing each other during the manufacturing process in the lab.听 Multiple additional DNA changes were needed to generate banks of 鈥榰niversal鈥 anti-T-cell CAR T-cells for this study.

To create these cells, healthy donor T-cells, arranged by the Anthony Nolan registry, were engineered at the Great Ormond Street Hospital clean room facility with four separate changes. These steps were:

  1. Removing existing receptors so that T-cells from a donor can be banked and used without matching听鈥 making them 鈥榰niversal鈥.听听
  2. Removing a 鈥榝lag鈥 called CD7 that identifies them as T-cells (CD7 T-cell marker).听Without this step T-cells programmed to kill T-cells would simply end up destroying the product through 鈥榝riendly-fire鈥
  3. Removing a second 鈥榝lag鈥 called CD52.听This makes the edited cells invisible to some of the strong drugs given to the patient during the treatment process.
  4. Adding a Chimeric Antigen Receptor (CAR) which recognises the CD7 T-cell receptor on leukemic T-cells.听听The cells become armed against CD7 and recognise and fight T cell leukaemia.

These edits were achieved by 鈥榖ase editing鈥 - chemically converting single nucleotide bases (letters of the DNA code) which carry instructions for a specific protein. For example, changing specific nucleotide bases in the gene for CD7 from a cytosine to a thymine creates a 鈥榮top codon鈥 - the equivalent of a genetic full stop - that prevents the cell machinery reading the full instructions and production of CD7 is terminated.

Alyssa

The result is edited CAR T-cells that can be given to the patient so that they rapidly find and destroy T-cells in the body, including leukemic T-cells. If successful, the patient then receives a bone marrow transplant to restore their depleted immune system.听

Previous treatments have relied on techniques called TALENS or CRISPR/Cas9 to deliver changes to genes through cuts made by molecular 鈥榮cissors鈥. The new base editing approach acts without causing breaks in the DNA, allowing more edits, with less risks of unwanted effects on chromosomes. The technique is also being investigated to try and correct harmful changes in DNA code for a variety of inherited conditions

Dr Louise Jones, Head of Translation at the Medical Research Council, who funded the project through their Developmental Pathway Funding Scheme, said: 鈥淲e are delighted to hear of the promising results of this treatment and the hope it has provided for Alyssa and her family. Advanced therapies -听medicines based on genes, tissues or cells -听have the potential to transform the lives of those with difficult to treat diseases and remain a priority for the MRC. If replicated, this 鈥榦ff the shelf鈥 universal cell therapy will mark a huge step forward in these types of therapies providing life-changing benefits to more patients.鈥

This trial was funded by the Medical Research Council. Support for the broader research programme also comes from Wellcome, Blood Cancer UK and the National Institute of Health and Care Research (NIHR) and the NIHR GOSH Biomedical Research Centre.

The cells were manufactured as part of a long-standing research programme led by Professor Waseem Qasim at 最准的六合彩论坛 Great Ormond Street Institute of Child Health, who is also an Honorary Consultant at GOSH. Thanks to early funding from Great Ormond Street Hospital Children鈥檚 Charity (GOSH Charity), Professor Qasim has been a pioneer in developing new CAR T-cell treatments using innovative gene editing techniques.

The research team wish to thank Anthony Nolan for providing the donor T-cells and all of the donors who donate to the register.

Alyssa鈥檚 story

Alyssa is the first patient in the world reported to have received a base-edited cell therapy and is currently at home recovering from her treatment. Alyssa and her family are feeling positive that the leukaemia is now undetectable, but know she will need to be monitored closely for some time.

Alyssa

Alyssa, 13, has always been at the centre of decisions about her care. She said:听鈥淥nce I do it, people will know what they need to do, one way or another, so doing this will help people 鈥 of course I鈥檓 going to do it.鈥

Alyssa was diagnosed with T-cell leukaemia in May 2021, after a long period of what the family thought were colds, viruses and general tiredness. While she was treated in Hospitals in Leicester and Sheffield with standard therapies - chemotherapy and a bone marrow transplant听 - unfortunately the teams were unable to get her cancer under control and into remission.

With the only other option as palliative care, Alyssa and her family extensively discussed this clinical trial with the Bone Marrow Transplant and CAR T-cell therapy experts at GOSH and undertook the decision to be the first to try an experimental treatment for her leukaemia.

Kiona, Alyssa鈥檚 mum said: 鈥淭he doctors have said the first six months are the most important and we don鈥檛 want to get too cavalier but we kept thinking 鈥業f they can just get rid of it, just once, she鈥檒l be ok.鈥 And maybe we鈥檒l be right.鈥

鈥淎lyssa is very mature and you can forget she is just a child but hopefully this can prove the research works and they can offer it to more children - all of this needs to have been for something. It just feels so senseless. Now we are trying to live between appointments. Alyssa wants to go back to school and that could be a reality soon. She鈥檚 already teasing her brother as he has had to go back for Autumn term.鈥

鈥淲e鈥檙e on a strange cloud nine to be honest 鈥 it鈥檚 amazing to be home.鈥

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*In 2015, scientists at GOSH and 最准的六合彩论坛 GOS ICH, led by Prof Qasim, used gene editing to create modified T-cells to treat a one-year-old child with an aggressive form of B-cell acute lymphoblastic leukaemia who had unsuccessful chemotherapy and for whom palliative care was deemed the only option left. This was the world鈥檚 first use of gene-edited immune cells in humans. The modified T-cells were edited using TALENs, an earlier form of gene editing.

** In 2021 a further trial demonstrated the application of CRISPR/Cas9 technology for B-ALL.听 The results are published in Science Translational Medicine:听

Links

Images

  • Alyssa
  • Professor Waseem Qasim
  • 痴颈诲别辞:听An animated explainer video about base editing. Illustrated by Dr Maryam Clark (as part of an NIHR GOSH BRC Research Communications Internship), edited by Maisie Hardy.

Media contact听

Poppy Danby听

E: p.danby [at] ucl.ac.uk