New Therapy Shows Promise in Battling Aggressive Blood Cancers

A groundbreaking therapy, once thought to be the stuff of science fiction, has reversed aggressive and incurable blood cancers in some cases, according to medical professionals. This innovative treatment involves carefully editing the DNA in white blood cells, effectively transforming them into a cancer-fighting “living drug.”

The first patient treated with this method, a girl whose story was shared in 2022, continues to be free from the disease and now aspires to be a cancer scientist herself. Recently, eight more children and two adults affected by T-cell acute lymphoblastic leukemia received the therapy, with about 64% of the patients entering remission.

T-cells, which should normally safeguard the body by targeting and eliminating threats, unfortunately grow uncontrollably in this form of leukemia. Those participating in the trial were left with few options; previous treatments like chemotherapy and bone marrow transplants had failed, and without this experimental medicine, the only recourse would have been to ease their suffering.

“I genuinely believed I was going to die and that I wouldn’t grow up to do all the things every child should have the chance to do,” said Alyssa Tapley, a 16-year-old from Leicester, who was the first person globally to receive the treatment at Great Ormond Street Hospital. Thankfully, she is now leading a fulfilling life.

Alyssa’s treatment three years ago involved erasing her existing immune system and cultivating a new one. During this time, she spent four months in the hospital, isolated from her brother to avoid infections. Now, her cancer is undetectable, and she requires only annual check-ups. She’s focused on her A-levels, has her sights set on her Duke of Edinburgh Award, and is looking into driving lessons with a future in mind.

“I’m considering an apprenticeship in biomedical science, and hopefully, I’ll pursue blood cancer research as well,” she expressed.

The team at University College London and Great Ormond Street Hospital utilized a technique known as base editing. This method allows scientists to pinpoint a specific segment of the genetic code and modify one base, rewriting the genetic instructions. Their goal was to enhance the natural capabilities of healthy T-cells to effectively identify and destroy cancerous cells.

This task is rather complex. Researchers had to re-engineer the healthy T-cells to target the malignant ones while ensuring the treatment didn’t destroy itself in the process.

Starting with T-cells from donors, they modified these cells through several crucial edits. The initial edit disabled their targeting mechanism, preventing them from attacking the patient’s body. Following that, they removed a chemical marker called CD7 present on all T-cells to stop the treatment from self-destruction. The third adjustment acted as an “invisibility cloak,” protecting the cells from being killed by chemotherapy. Finally, they programmed the T-cells to hunt for anything exhibiting the CD7 marker.

This complex mechanism allows the modified cells to attack any T-cell with the marker while sparing themselves. The treatment is then infused into patients, and if their cancer is undetectable after four weeks, they can undergo a bone marrow transplant to rejuvenate their immune system.

“Just a few years back, this would have seemed like pure science fiction,” remarked Prof. Waseem Qasim from UCL and Great Ormond Street. “It’s a rigorous, intensive treatment that is demanding on patients, but the results can be very rewarding.” The findings were published in the New England Journal of Medicine and highlight that out of the first 11 patients treated across two hospitals, nine attained deep remission, allowing them to proceed with bone marrow transplants. Seven of these individuals remain cancer-free from three months to three years post-treatment.

However, the treatment carries risks, including possible infections due to the complete shutdown of the immune system. In a couple of instances, the cancers managed to shed their CD7 markers, enabling them to evade detection and resurface in the body.

“Given the aggressive nature of this leukemia, these results are remarkable, offering hope to patients who have otherwise lost it,” stated Dr. Robert Chiesa from the bone marrow transplant department at Great Ormond Street Hospital. Dr. Deborah Yallop, a hematologist at King’s, added, “The responses we’ve seen in clearing what appeared to be incurable leukemia are quite powerful.”

Dr. Tania Dexter, a senior medical officer with the stem cell charity Anthony Nolan, commented on the research, saying, “Considering these patients had previously low survival chances, these results instill hope that such treatments will continue to evolve and become accessible to more individuals.”