National drug trial shows early promise for treatment of rare blood cancer

Encouraging early results from a SAHMRI-led clinical trial offer new hope to people diagnosed with chronic myelomonocytic leukemia (CMML), a rare and aggressive form of blood cancer.

CMML is notoriously difficult to treat, with limited options and a low survival rate. Current therapies often lead to only short-term responses in a small number of patients.

The PREACH-M trial is investigating a combination of the standard therapy azacitidine with an investigational antibody called Lenzilumab. Invented in Australia, the drug works by blocking a key signaling molecule that drives the overproduction of abnormal blood cells and inflammation in people with CMML and related leukemias. By neutralizing this molecule, lenzilumab aims to restore balance in the blood and reduce disease-related symptoms.

Interim results published in Blood show that of the 34 participants enrolled to date, 22 have shown significant improvements within the first year of treatment. Blood test results reveal that harmful cells and inflammatory markers dropped dramatically after three months, with further improvements at the six-month mark.

Many participants are experiencing sustained benefits. Fifteen have now been on treatment for more than a year without relapse. Three have continued for over three years, and one participant remains in remission after four years on therapy.

Trial lead investigator and head of SAHMRI’s Blood Cancer Program, Associate Professor Dan Thomas, recently presented the preliminary findings at the European Hematology Association meeting in Milan.

“To see this kind of response in such a difficult-to-treat disease is extraordinary,” A/Prof Thomas said. “Not only are patients experiencing short-term improvements in their blood counts and symptoms; they’re maintaining those improvements for years. That’s something we haven’t been able to achieve before.”

There’s some evidence to suggest the treatment may also benefit people with related blood cancers, including acute myeloid leukemia (AML). In one particular case, a patient whose disease had become resistant to standard treatment responded well when lenzilumab was added to their regimen, with cancerous cells in their bone marrow dropping from 20% to around 7%.

While further research is needed to assess long-term outcomes, these early signs suggest the combination treatment has the potential to improve the outlook for people with CMML and potentially other related blood cancers.