16 October 2013
Thalidomide therapy can extend the lives of myeloma patients, but it isn’t suitable for everyone with the disease, researchers have found.
In a study from The Institute of Cancer Research, London, scientists found that patients at low risk of developing recurrent myeloma who were treated with thalidomide saw increased survival rates, whereas patients with high risk had lower survival rates.
Thalidomide was given to patients as a maintenance therapy, where a drug is given to reduce the chance of a cancer coming back after initial treatment. While thalidomide can cause birth defects when taken by pregnant women, strict guidelines are observed when giving thalidomide treatment to patients.
Researchers believe that screening myeloma patients for biological risk of recurrence will help identify the patients most likely to benefit from thalidomide treatment.
Myeloma is a type of blood disease that causes plasma cells to grow uncontrollably in the bone marrow and become stuck there, disrupting normal blood cell production. In the UK nearly 5,000 people are diagnosed with the illness every year.
The disease can often come back after initial therapy so thalidomide, which can stop cancerous tumours from growing their own blood vessels, can be given to prevent or delay relapse. Previous research shows that patients respond differently to thalidomide, but it was not possible to predict which ones would do well on the therapy.
Now scientists from the Institute of Cancer Research (ICR) have studied the impact of thalidomide maintenance therapy on different biological risk groups.
369 multiple myeloma patients were categorised into groups of standard risk, high risk, or ultra-high risk, based on the number of DNA lesions, or damage to their DNA at specific locations, recorded by fluorescence in situ hybridisation (FiSH) analysis – a method to visualise areas within chromosomes.
182 patients were given maintenance thalidomide treatment, while 187 received no maintenance treatment, and the researchers recorded each group’s length of progression free-survival (PFS), or how long before their myeloma worsened, and their overall survival rate over five years.
They found that for myeloma patients categorised as standard risk, thalidomide maintenance therapy extended their progression free-survival by an average of nine months compared to patients not receiving thalidomide maintenance, surviving 29.6 months to 20.3 months respectively.
However, this trend was reversed for patients categorised as high risk. Thalidomide maintenance reduced PFS time to an average of 11.3 months compared to patients on standard treatments, who survived an average of 13.4 months, while overall survival times were also affected. Only 32% of myeloma patients classed as high risk were still alive after 5 years of maintenance treatment, whereas over half of the high risk patients who received no maintenance therapy, 54%, survived more than 5 years.
Ultra-high risk patients saw little change in PFS time or overall survival whether they took maintenance thalidomide treatment or not.
Study leader Professor Gareth Morgan, Professor of Haematology at The Institute of Cancer Research (ICR) and Head of the Myeloma Unit at The Royal Marsden NHS Foundation Trust, said:
“Myeloma is a difficult disease to treat because many patients relapse after treatment, so therapies which can manage the disease over time are desperately needed.
“Thalidomide has shown promise for treating myeloma, but we knew that it wasn’t working for all patients. We probed the DNA of patients to put them into different risk groups, allowing us to show that thalidomide can extend the lives of some myeloma patients, but not others. Now we have this information we need to translate our findings to the clinic so that patients will benefit from this therapy.
“Our research shows that we need to screen myeloma patients to ensure that they get the most effective treatment possible and develop new strategies to prevent myeloma returning in high risk patients.”