An Independent Data Monitoring Committee has asked Bayer to unblind a Phase 3 clinical trial of a Xofigo (radium-223)-based therapy for prostate cancer after data indicated more bone fractures in study participants.
The study randomly assigned prostate cancer patients to treatment with Xofigo or a placebo — both given in combination with Zytiga (abiraterone acetate) and prednisone or prednisolone. Neither patients nor study staff were aware of the treatment assignment — a set-up called blinding.
To allow a proper examination of the potential safety issue, scientists, however, need to know which patients received Xofigo.
For now, patients will continue to be monitored according to the study protocol while researchers examine the data identified by the monitoring committee.
“Patient safety is our top priority. We are therefore unblinding the study to thoroughly analyze the data,” Mike Devoy, a member of the Pharmaceuticals’ Division Executive Committee and chief medical officer at Bayer, said in a press release.
Meanwhile, the company underscored that earlier studies of this combination treatment had not spotted any safety issues.
“It is important to note that, based on available data from previous trials as well as real-world use, the benefit-risk profile of Xofigo in its approved indication remains favorable. We remain committed to further exploring the potential of radium-223 across multiple tumor types with significant unmet medical need, including prostate cancer,” Devoy said.
The Phase 3 trial, called ERA 223 (NCT02043678), included prostate cancer patients whose disease had spread to the bones while giving rise to no or only mild symptoms. The patients had never received chemotherapy and their cancer did not respond to treatment with testosterone-lowering drugs alone.
The main aim of the study was to prolong the time it takes for the cancer to get worse in the bones.
Currently, no patients are receiving Xofigo as patients received a maximum of six doses a month apart. The trial completed recruitment in Sept. 2016, indicating that patients are now at least nine months past their last Xofigo dose.
Bayer has shared the information with health authorities in the 19 countries where the global trial is running. They have also informed investigators of Xofigo studies. The company is now preparing information for healthcare professionals.
It will share the detailed study findings with health authorities and healthcare staff once they have gathered enough data.
Patients who are concerned about their use of Xofigo should contact their physicians, the company advised.