Cell therapy QT-019B shows strong response rate in hard-to-treat ITP
Most participants in early clinical trial see platelet counts restored to normal
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Use of the experimental cell therapy QT-019B showed promise for people with treatment-resistant immune thrombocytopenia (ITP) in early clinical testing, restoring platelet counts — levels of cell fragments needed for blood clotting — to normal in six patients with ITP and underlying systemic lupus erythematosus (SLE).
That’s according to new data presented earlier this month at the 67th American Society of Hematology (ASH) Annual Meeting, held in Orlando, Florida, and virtually.
“In conclusion, … [QT-019B] demonstrated encouraging [pharmacological properties,] safety, and efficacy in this limited group of patients with refractory [hard-to-treat] SLE-ITP,” the researchers wrote, noting that “QT-019B led to high [response] rates and enabled patients to become medication-free.”
QT-019B is an off-the-shelf, or readily available, cell therapy being developed by Qihan Biotech for people with hard-to-treat autoimmune diseases. These include ITP and SLE, a chronic immune disorder in which virtually every part of the body can come under attack. The cell therapy is being tested in patients in China in an investigator-initiated clinical trial (NCT06941129).
The data were shared in a poster at ASH, titled “Rapid normalization of platelet counts in patients with refractory thrombocytopenia associated with systemic lupus erythematosus (SLE) following treatment with allogeneic dual-target CD19/BCMA CAR T-cell therapy (QT-019B).
ITP and SLE are both autoimmune diseases caused by antibodies that attack the body’s own healthy tissues. ITP results in low levels of platelets, while SLE can cause damage to various organs in the body.
Of the six ITP-SLE patients involved in this trial, five had a complete response — normalization of platelet levels — following QT-019B treatment. The sixth participant had a partial response, meaning platelet levels improved, but were still abnormal.
All the patients who responded were able to stop or cut back on other ITP treatments, such as corticosteroids, according to the researchers.
Developer planning launch of new trial testing QT-019B in US, China
Other data at ASH covered five patients with ITP associated with another autoimmune disorder called antiphospholipid syndrome. Four of these patients also had complete normalization of platelet counts following treatment with QT-019B.
Collectively, these data offer “a compelling reason to advance QT-019B … for other difficult-to-treat autoimmune disorders,” the researchers wrote.
Data from these patients, as well as participants with different autoimmune diseases, have shown QT-019B to be generally well tolerated, with no serious side effects reported so far. Qihan recently secured regulatory clearance in the U.S. and China to launch a new trial testing QT-019B in hard-to-treat SLE.
We believe we are overcoming the key barriers that have constrained the field and opening the door to broadly accessible, off-the-shelf [readily available] cell therapies.
The antibodies that drive ITP are made by immune cells called B-cells. QT-019B is a CAR T-cell therapy designed to deplete B-cells, thus reducing levels of disease-driving antibodies.
T-cells are another type of immune cell that act as the body’s assassins, eliminating infected or cancerous cells. With CAR T-cell therapy, these deadly cells are equipped with a chimeric antigen receptor or CAR, which is basically a molecular weapon that directs the cells to attack a specific target. With QT-019B, the CAR targets two B-cell proteins called CD19 and BCMA.
The first CAR T-cells, which were developed to treat blood cancers, are autologous — that is, they use T-cells that are collected from the patient, engineered in a lab, then put back into the patient’s body. First-generation CAR T-cell therapies also generally required lymphodepletion, where patients undergo intensive treatment with chemotherapy to wipe out their existing immune cells and make way for the engineered cells. These considerations make first-generation CAR T-cell treatment expensive and difficult to produce, the team noted.
QT-019B is designed to be an allogeneic CAR T-cell therapy, meaning it uses T-cells that are collected from a donor and then stored, to later be used as a so-called off the shelf treatment. The cell therapy is also designed to interact with the body’s existing immune system in a way that eliminates the need for lymphodepletion, according to Qihan.
“Autologous therapies have shown what cell therapy can achieve, but they are not scalable for autoimmune disease. Efforts to develop off-the-shelf allogeneic approaches have been challenging due to immune rejection, limited expansion and persistence, and the need for lymphodepletion. Our data show a different path,” Luhan Yang, PhD, CEO of Qihan, said in a company press release detailing the data shared in the ASH presentation.
“We believe we are overcoming the key barriers that have constrained the field and opening the door to broadly accessible, off-the-shelf cell therapies,” Yang added.
