SAN FRANCISCO – (BCG), new research suggests.
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Dr. Stephen A. Boorjian
The therapy, nadofaragene firadenovec, is a recombinant adenovirus that is instilled into the bladder and delivers the human interferon alpha-2b gene, leading to expression of the immune cytokine.
At 3 months, nadofaragene firadenovec had produced a complete response in 53.4% of patients with carcinoma in situ (CIS), and the rate of high-grade recurrence-free survival was 59.6% in all patients. Although most patients (70.1%) experienced adverse events in this trial, few had serious events (1.9%).
Stephen A. Boorjian, MD, of the Mayo Clinic in Rochester, Minn., presented these results at the 2020 Genitourinary Cancers Symposium, sponsored by the American Society for Clinical Oncology, ASTRO, and the Society of Urologic Oncology.
“The optimal management for patients with BCG-unresponsive non–muscle invasive bladder cancer remains to be established,” Dr. Boorjian said. “National and organizational guidelines recommend radical cystectomy in this setting, but we have to acknowledge that many of our patients will be either unwilling or unfit to undergo what is often a highly morbid operation.”
Dr. Boorjian and coinvestigators tested nadofaragene firadenovec in 107 patients with CIS, with or without high-grade Ta or T1 papillary disease, as well as 50 patients with high-grade Ta or T1 papillary disease only.
All patients received nadofaragene firadenovec once every 3 months for up four doses, with additional dosing at the investigator’s discretion. Although the trial was designated as phase 3, it did not have the typical randomized comparative design.
“The challenge in the BCG-unresponsive disease state is that, historically, there has been no validated good comparator to use here; there’s no standard of care for these patients,” Dr. Boorjian explained, noting that the design was chosen after discussion with the Food and Drug Administration.
Efficacy
The complete response rate among CIS patients at any time after instillation, the trial’s primary objective, was 53.4%. All of these responses occurred after a single dose of nadofaragene firadenovec. Responses were considered durable, as 45.5% of CIS patients who had a complete response at 3 months still had a complete response at 12 months.
The rate of high-grade recurrence-free survival at 3 months was 59.6% in the overall population, 53.4% in patients with CIS, and 72.9% in patients with papillary disease. At 12 months, the rate of high-grade recurrence-free survival was 30.5%, 24.3%, and 43.8%, respectively.
The rate of high-grade recurrence without muscle invasive bladder cancer was 71.8% in the CIS group and 52.1% in the papillary group. The rate of progression to muscle invasive bladder cancer or more advanced disease was 4.9% and 6.3%, respectively. The overall 2-year rate of cystectomy-free survival was 64%, and there were no bladder cancer deaths.
Safety
Nadofaragene firadenovec was considered safe and well tolerated. The most common study drug–related adverse events were irritative voiding symptoms, such as discharge, bladder spasm, micturition urgency, and hematuria.
Although 70.1% of patients experienced a local or systemic adverse event related to the study drug or procedure, few experienced serious adverse events (1.9%), grade 3 adverse events (3.8%), or treatment-emergent adverse events leading to discontinuation (1.9%). The serious adverse events were sepsis, syncope, and hematuria.
Next steps
“Nadofaragene firadenovec represents a promising option for patients with BCG-unresponsive [non–muscle invasive bladder cancer],” Dr. Boorjian said. “What we want to see going forward is durability of response, cystectomy-free survival, and metastasis-free and cancer-specific survival. Those are the harder endpoints that, as these data mature, we will want to see so that we are able to counsel our patients accordingly.”
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Dr. Guru Sonpavde
The FDA recently approved pembrolizumab for this patient population, noted session cochair Guru Sonpavde, MD, of the Dana-Farber Cancer Institute in Boston.
“But nadofaragene firadenovec is much less toxic, it is given intravesically, and it’s only given once every 3 months,” he said. “The outcomes at the 1-year point look similar in terms of the durable complete response rate. So we hope that this therapy will be able to get to the clinic, but we have to wait for the FDA to decide.”
It remains to be seen how nadofaragene firadenovec compares with other emerging therapies for high-risk BCG-unresponsive non–muscle invasive bladder cancer, including pembrolizumab and potentially intravesical oportuzumab monatox (a targeted immunotoxin) and intravesical combination BCG and superagonist interleukin-15 (ALT-803), according to Dr. Boorjian.
“A unique feature of the trial I presented was that the results were validated by a mandatory 12-month study biopsy, which has not been the case in other trials,” he pointed out. “So this separates it a little bit when you are looking at pathologic response rates and high-grade recurrence–free rates. They are based on pathologic confirmation.”
Evaluators will ultimately compare these therapies on safety, efficacy, ease of administration, delivery schedule, and cost, Dr. Boorjian said. “At this stage, it’s very difficult to start to say which agent is going to be placed where in our management paradigm. We have to go step by step: Do the trial that we did, show our data, put it out for review, and then allow the community to engage in a discussion about which agent, and why, for which patient.”
This trial was funded by FKD Therapies Oy. Dr. Boorjian disclosed relationships with Ferring and Sanofi. Dr. Sonpavde disclosed relationships with many companies.
SOURCE: Boorjian SA et al. GUCS 2020, Abstract 442.