First Targeted Therapy for Metastatic Bladder Cancer Approved by FDA
Last week, the United States Food and Drug Administration (the US FDA) approved Balversa (erdafitinib) for the treatment of locally advanced or metastatic bladder cancer. Specifically, Balversa is indicated for use by individuals whose cancer has an FGFR2 or FGFR3 genetic alteration that has progressed during or following platinum-containing chemotherapy treatments.
A breakthrough therapy & accelerated approval
Balversa, made by Janssen Pharmaceuticals (a Johnson & Johnson company), received Accelerated Approval from the FDA. It also qualified as a Breakthrough Therapy, which aided in its relatively speedy approval. Both the Accelerated Approval and Breakthrough Therapy designations are assigned to unique medications in development that treat life-threatening or serious conditions, especially when there is a need for new treatment options or when these treatments are thought to be more effective than the current options based on preliminary data.
What are FGFRs?
Although more data is needed to determine the true efficacy of Balversa, the main clinical trial results that supported the drug’s approval came from an 87-person, Phase 2 safety study. The study included adults with locally advanced or metastatic bladder cancer whose cancer cells tested positive for either FGFR2 or FGFR3 genetic alterations. FGFR stands for fibroblast growth factor receptor, and it may play a role in cancer growth and development in certain types of cancer cells. Balversa is a FGFR kinase inhibitor, which means it blocks the action of FGFR, potentially slowing down or stopping tumor cells who use this growth factor to replicate. About 20% of all recurrent or refractory bladder cancers have a mutation or alteration in this specific receptor, and may benefit from treatment with an FGFR inhibitor.
Results from the Balversa clinical trial
Participants in the Balversa clinical trial had cancer that previously progressed while taking platinum-containing chemotherapy, and some had previously not responded to anti PD-L1/PD-1 treatments, another relatively new treatment option that is commonly used for certain types of cancers. Overall, 32.3% of participants responded to Balversa, with 2.3% showing a complete response, and about 30% experiencing a partial response. The average response time across the 87 participants was 5.5 months. Another interesting finding from the study was that some patients who had previously not responded to other treatment options, like PD-L1/PD-1, did respond to Balversa. These results were presented at the American Society of Clinical Oncology (ASCO) 2018 Annual Meeting.
Side effects of Balversa
The most common side effects experienced while taking Balversa included fatigue, change in kidney or liver functioning, constipation, diarrhea, dry mouth, stomach pain, nausea, decreased appetite, increased levels of phosphate or sodium in the blood, mouth sores, changes in nail appearance, dry skin, dry eyes, low red blood cell counts (anemia), hair loss, and muscle pain. A condition called hand-foot syndrome was also experienced by some taking Balversa, which can present as swelling, peeling, redness, or tenderness of the hands and feet. Individuals taking Balversa should have their phosphate levels monitored as well as their eye functioning examined, as Balversa can cause inflammation of the eye. If you are taking Balversa and notice changes in vision, contact your healthcare provider immediately.
Balversa may cause harm to a developing fetus, and therefore should not be taken by pregnant women, and women on Balversa should be utilizing appropriate contraceptives while taking the medication. Balversa should also not be taken by women who are currently breastfeeding. Men taking Balversa who have partners of reproductive potential should use an appropriate contraceptive during and one month after taking Balversa.
An accompanying diagnostic tool
In addition to Balversa, the FDA also approved a companion kit used to help determine whether an individual is eligible for treatment with the new medication. This diagnostic tool, therascreen FGFR RGQ RT-PCR Kit is made by Qiagen Manchester, Ltd., and should be consulted before an individual is started on Balversa.
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