Dr Nicola Gökbuget (University Hospital, Frankfurt, Germany) explained, also on behalf of Prof Max Topp (Würzburg University Hospital, Würzburg, Germany), the results of two abstracts that were presented on the treatment of acute lymphoblastic leukaemia (ALL)

ALL is a rare type of blood cancer which is mainly treated by intensive chemotherapy.

If the disease is resistant to initial treatment or reoccurs (relapse) the chance to survive is unfortunately very poor.

Often the leukaemia cells then become resistant to chemotherapy.

With regards to abstract S722, the bispecific antibody blinatumomab was designed to connect with one side to a surface marker on the leukaemia cells (CD19) and with the other side to attract T-cells of the patient.

These T-cells kill the leukaemia cells.

The treatment was given to patients with relapsed/refractory B-precursor ALL (r/r ALL) as a 4 week continuous infusion, followed by two weeks break and another four weeks of treatment.

The goal was to achieve a complete remission (CR), which means that no leukaemia cells are detected by microscopy in the bone marrow or at other sites of the body.

189 patients with r/r ALL in an unfavourable setting were treated.

The CR rate was 43%. 

In patients with prior stem cell transplantation the CR rate was 45%.

The most frequent side effects were fever, headache and low white blood cell counts associated with fever.

Overall it was demonstrated that blinatumomab as a single agent therapy was effective in r/r ALL including patients with resistance to prior treatment approaches.

Moving on to abstract S1314, in ALL response to therapy is usually measured by microscopic analysis of the bone marrow.

The detection level for leukaemic cells by this method is 5%.

With molecular biologic tests the sensitivity is increased and 0.01% leukaemia cells can be detected.

This low level of leukaemia cells is called minimal residual disease (MRD).

In a clinical trial with the bispecific antibody blinatumomab (abstract 4572) 189 patients with relapsed/refractory (r/r) ALL were treated.

43% achieved a complete remission (CR), which means that no leukaemia cells were detectable with microscopy.

One explorative goal of the trial was the measurement of MRD in patients with CR.

MRD evaluation was conducted in a central laboratory.

With MRD detection it could be demonstrated that 82% of the patients with CR showed a low level of MRD (<0.01%) and 70% had no detectable MRD.

Patients with low MRD after first therapy usually have a higher chance to maintain complete remission.

It will be analysed whether this is also relevant in r/r ALL and whether MRD detection allows to discriminate good risk patients better than conventional remission evaluation.

Source: EHA