This study recruited 198 people with myeloma that had come back after treatment. They all had lenalidomide and dexamethasone.
Side effects caused by treatments are given a grade. This goes from grade 1 (mild) to grade 4 (more severe). In this study, the researchers were looking at people who had a grade 3 or 4 drop in white blood cells (
neutropenia).
The results showed that:
- 62 people (31%) had a low white blood cell count at least once during treatment
- half of these people had a low white blood cell count 3 times or more
- the drop in white blood cells usually happened about 2 months (8.8 weeks) after starting treatment
Some people were more likely to have a low white blood cell count after treatment, including people:
- whose kidneys didn’t work as well as normal
- whose myeloma was more advanced
- who were generally less fit and well
- who had other medical conditions
The research team also looked at changes the doctors made during treatment.
They found that doctors reduced the dose of lenalidomide in 48 people (24%). A drop in white blood cells was the main reason to reduce the dose for only 4 of these people.
Doctors delayed the next dose of lenalidomide in 88 people (44%). A drop in white blood cells was the main reason to delay treatment for only 5 of these people.
They gave 46 people (23%) a growth factor injection to stimulate the growth of new blood cells.
The research team concluded that neutropenia is a common side effect of lenalidomide and dexamethasone. They suggest that work needs to be done to improve recommendations on how to treat it.
We have based this summary on information from the research team. The information they sent us has been reviewed by independent specialists (
peer reviewed 
) and published in a medical journal. The figures we quote above were provided by the trial team who did the research. We have not analysed the data ourselves.