Cretostimogene bladder cancer study points to bladder-sparing option
A phase 3 trial led by Mayo Clinic found many high-risk bladder cancer patients avoided bladder removal after experimental immunotherapy.
By Priya Raghavan · Science Reporter
3 min read
A Mayo Clinic-led phase 3 trial of cretostimogene bladder cancer treatment found that many patients with high-risk disease avoided bladder removal surgery and stayed cancer-free for extended periods. The findings, published in The Lancet Oncology, matter because bladder removal is often the recommended next step after standard BCG therapy fails.
The experimental treatment is called cretostimogene grenadenorepvec. Mayo Clinic said the study involved patients whose high-risk bladder cancer had returned despite treatment with bacillus Calmette-Guérin, or BCG, a standard therapy for this setting.
Researchers reported a complete response, meaning no detectable signs of cancer, in 75% of patients. Among those whose cancer disappeared after treatment, about 60% remained cancer-free two years later, according to Mayo Clinic.
What is cretostimogene for bladder cancer?
Cretostimogene grenadenorepvec is an oncolytic immunotherapy being studied as a bladder-sparing treatment for high-risk, BCG-unresponsive, non-muscle-invasive bladder cancer with carcinoma in situ. In this trial, it was given to patients who otherwise had limited options beyond surgical removal of the bladder, according to the study authors.
Bladder removal, or cystectomy, can be effective cancer treatment but can also change daily life. Mayo Clinic urologist Dr. Mark Tyson II, the study’s lead author, said the results suggest many patients may be offered another option without giving up cancer control.
What did the trial find?
The trial enrolled 115 patients at 41 medical centers in North America, Asia and Australia, according to Mayo Clinic. Two years after treatment began, researchers estimated that 81% of patients had not undergone surgery to remove the bladder.
The durability of response varied. Mayo Clinic said one patient had gone more than four years after finishing treatment without the cancer returning.
Side effects tied to treatment were mainly mild and temporary bladder symptoms, the researchers reported. Mayo Clinic said the study found no severe treatment-related side effects.
The study was a single-arm phase 3 trial, meaning all participants received the experimental therapy rather than being assigned to a comparison group. The researchers said cretostimogene grenadenorepvec has not been directly tested against other bladder-sparing treatments in clinical trials.
What does this mean for patients?
The results support cretostimogene grenadenorepvec as a potential option for patients whose high-risk bladder cancer returns after BCG therapy, according to the researchers. Mayo Clinic said the treatment could become an important way to preserve the bladder in this group if further use confirms the findings.
The publication identified the study as BOND-003 Cohort C and listed the full trial focus as intravesical cretostimogene grenadenorepvec oncolytic immunotherapy in high-risk, BCG-unresponsive, non-muscle-invasive bladder cancer with carcinoma in situ. The paper was authored by Tyson and colleagues and published in The Lancet Oncology.
This story draws on original reporting from Medical Xpress.