Rationale for Adding Atezolizumab to SOC in Patients With MIBC

Parminder Singh, MD, a hematologist, internist, and medical oncologist at Mayo Clinic, discusses the safety associated with standard-of-care (SOC) tri-modality therapy for muscle-invasive bladder cancer and the addition of atezolizumab (Tecentriq) to SOC.

The current SOC consists of maximal trans urethral resection of bladder tumor followed by chemoradiation, explains Singh. This method of treatment does not preserve the bladder, therefore bladder-preserving therapy is an unmet need in MIBC space, Singh says.

Adding atezolizumab to standard chemoradiation may preserve the bladder, and the theory was explored in the phase 3 INTACT clinical trial (NCT03775265).

Transcript:

0:07 | With receiving chemoradiation, some of the toxicity also depends on the type of chemotherapy regimen being used by the oncologist for combining the radiation. Each physician has their own choice of regimen and some physicians use cisplatin as the accommodation agent. Others use gemcitabine, and some of them will use mitomycin with 5-FU.

0:35 | Now, these ae drugs has their own specific toxicities. For example, cisplatin can cause nephrotoxicity or may cause nausea more than the other agents. Gemcitabine combined with radiation has been known to cause more cytopenia, and mitomycin with 5-FU can cause more GI toxicity since diarrhea is a common adverse event of 5-FU. So, the oncologists using this modality of treatment for their patients with bladder cancer are used to handling these toxicities which come with the chemotherapy. The bladder toxicity which is the inflammation of the bladder caused by radiation is something that will be seen across all chemotherapy regimens and is managed with pain medication or by improving hydration. Some patients may even have so much frequency that we may have to offer them catheterization so that it will alleviate the need of getting up in the night to go to the bathroom. But these are more decisions taken at the clinic based on the experience of the patient. Some patients may also have hematuria, and it may require cystoscopy, or cloud evacuation during radiation. But more or less, most of the patients will tolerate this regimen and finish the treatment without any severe toxicities, and their bladder function will recover.

2:14 | There are certain long-term toxicities that community oncologists need to be aware of, that the patients may notice a decrease in function of the bladder, the capacity of the bladder may go down post-radiation, so a proper selection of the patient for this type of intervention may help reduce the risk for long-term complications. In my practice, I've seen some patients having long-term radiation cystitis that causes disabling symptoms, but this is very uncommon. However, it's possible that since I see more patients with this modality that I've seen those AEs. In general, most of the patients do okay and require a 3-month follow-up visit with their urologist to make sure there's no recurrence of the disease.