Immunotherapy is one of the faster developing cancer treatments currently being advanced. It offers a lot of hope to patients who are not responding to other kinds of treatment. Now researchers at UCL report hugely positive results of the new CAR T-cell therapy Phase I clinical trial conducted at University College London Hospitals.
Smear of B-cell acute lymphoblastic leukaemia. Image credit: James Grellier via Wikimedia (CC BY-SA 3.0)
The goal of immunotherapy is to convince immune system cells to attack cancer cells. This is quite hard to do, because cancer cells are not some kind of pathogens from the environment. However, this new treatment offers new hope to adult patients with relapsed B-cell acute lymphoblastic leukaemia shortened as r/r B-ALL. This will be slightly confusing, but this therapy is built on the ongoing efforts to offer tailored treatment to cancer patients.
20 r/r B-ALL patients in this trial had their own T cells genetically modified with CAT-41BB-Z, a new type of CD19 CAR. These genetic alterations were done to coerce these cells to kill leukaemia cells. In this new therapy obe-cels, as these modified immune cells are called, were coerced to attack cancer cells, but do it for shorter. This allows them to jump from one cancer cell to the next, killing them quickly and avoiding adverse immune overreaction. This kind of immunotherapy design is known as a “fast off-rate CAR”. Furthermore, these cells should remain in the body for longer providing a long-acting response to cancer.
Karl Peggs, chief investigator in this trial, commented: “The immune system can become over-activated causing a toxic reaction called ‘cytokine release syndrome’; another consequence of over-activation is that the engineered T-cells become immunologically exhausted and no longer persist in the patient’s body. This lack of persistence can allow the cancer to relapse.”
The trial showed promising results. Obe-cel was shown to be safe – none of the patients having cytokine release syndrome. 85% of the participants were in complete remission at one month, 50% remained in remission at 12 months. Scientists are delighted to see the speed and efficiency of the new immunotherapy. But what will happen next?
Well, a phase Ib/II global registration study of obe-cel in adults with relapsed B-ALL has been initiated. It is going to enroll approximately 100 patients across 30 of the leading academic and non-academic centers in the United Kingdom (including UCLH), Europe and the United States. This will further confirm the effectiveness and safety of the new therapy. And then after some years it should eventually make its way to full clinical use.
Source: UCL