The study involved 101 patients diagnosed with non-muscle-invasive bladder cancer. They had previously been treated with BCG, an intravesical attenuated tuberculosis vaccine that is also effective against bladder cancer. For these patients, this standard treatment had not worked: the tumor did not respond or it simply came back. Currently, the next step of treatment would be removal of the bladder, a major operation heavily affecting quality of life.
No tumor activity
In the study, participants were treated with pembrolizumab – a form of immunotherapy given via an infusion. Pembrolizumab is already used for metastatic bladder cancer and other cancers. The drug stimulates the body’s immune system to recognize and kill cancer cells.
Results of the study show that pembrolizumab is a viable treatment option for patients with non-muscle-invasive bladder cancer. Three months after treatment, no tumor activity could be detected in the bladder or urine in 41 percent of study participants. For about half of this group, this effect persisted for at least one year after treatment. Regarding patients for whom pembrolizumab failed, progression to muscle-invasive bladder cancer or metastatic disease did not occur. Two-thirds of patients experienced well known side effects because of pembrolizumab, including but not limited to: diarrhea, itching and fatigue.
The researchers report their findings in the scientific journal The Lancet Oncology.
Study co-leader and internist-oncologist Prof. Dr. Ronald de Wit and urologist Dr. Joost Boormans of the Erasmus MC Cancer Institute state that the results of the study provide great news for patients with difficult-to-treat bladder cancer. Thanks to their good cooperation and contacts with regional hospitals, De Wit and Boormans included 14 of the 101 study participants in the worldwide study.
Boormans: “We estimate that pembrolizumab treatment would enable about 50 patients in the Netherlands to retain their bladder each year. That’s good, because not all patients are eligible for surgery. Sometimes patients decide not to undergo surgery because of potential drastic consequences such as erectile dysfunction in men and obtaining a urinary stoma.”
The study results prompted the U.S. drug authority FDA to approve pembrolizumab for treatment of non-muscle-invasive bladder cancer that does not respond to BCG treatment. In Europe, there is no such approval yet. A follow-up study is currently being conducted in which BCG treatment on its own is compared to BCG treatment combined with pembrolizumab. ‘If the results are positive for pembrolizumab, it is expected that we will also receive approval in Europe’, explains De Wit.
- Every year, about 7,000 people in the Netherlands are diagnosed with bladder cancer
- The main risk factor for getting bladder cancer is smoking
- Treatment can include bladder irrigation, chemotherapy, radiation, immunotherapy or surgery
- The Bladder Cancer Center at Erasmus MC Cancer Institute is one of the largest multidisciplinary bladder cancer centers in the Netherlands
- Surgical removal of the bladder is done at the Bladder Cancer Center using a surgical robot. The video (in Dutch) below shows how.