Anktiva's Papillary-Only Win: Novel Extrapolation Approval Masks Thin Evidence Base

FDA Expands Anktiva Approval for BCG-Unresponsive Papillary Bladder Cancer

The U.S. FDA has expanded the approval of Anktiva (nogapendekin alfa inbakicept-pmln), in combination with Bacillus Calmette-Guérin (BCG), to treat adults with high-grade papillary-only bladder cancer that has not spread into the bladder muscle and has not responded to BCG treatment. This marks the first FDA-approved therapy specifically for this patient population. The decision was based on evidence from Anktiva's earlier approval for carcinoma in situ (CIS) and scientific similarities between CIS and high-grade papillary-only disease. The initial CIS approval trial (NCT03022825) showed a 62% complete response rate, with 58% maintaining response for at least 12 months and 40% for at least 24 months in 77 adults. This approval signifies a new FDA approach to evaluating treatments for BCG-unresponsive non-muscle invasive bladder cancer.

• Anktiva, combined with BCG, received FDA approval for adults with high-grade papillary-only bladder cancer that is BCG-unresponsive and has not invaded the bladder muscle. This approval addresses a significant unmet need, making Anktiva the first treatment specifically sanctioned for this distinct patient group within non-muscle invasive bladder cancer.
• The FDA's decision was based on a novel strategy, leveraging existing evidence from Anktiva's prior approval for carcinoma in situ (CIS) and recognizing the scientific similarities between CIS and high-grade papillary tumors. This approach aims to streamline development pathways for future treatments in BCG-unresponsive non-muscle invasive bladder cancer.
• The initial approval for CIS was supported by a trial (NCT03022825) involving 77 adults, which demonstrated a 62% complete response rate. Crucially, 58% of these responders maintained their complete response for at least 12 months, and 40% sustained it for at least 24 months, highlighting the durable efficacy of the Anktiva-BCG combination.

Addressing the Unmet Need in BCG-Unresponsive Papillary NMIBC

BCG-unresponsive, high-grade papillary-only NMIBC represents a distinct and underserved disease subtype, with the treatment landscape shaped largely by data from CIS-predominant cohorts. The absence of an approved agent carrying a papillary-only indication leaves clinicians navigating a preference-sensitive trade-off between bladder-sparing strategies and radical cystectomy.

• No approved agent holds a papillary-only indication. Across the BCG-unresponsive space, approvals for pembrolizumab, nadofaragene firadenovec, and the combination of BCG with nogapendekin alfa inbakicept are specifically for carcinoma in situ with or without papillary tumors; no approved agent holds a papillary-only indication.

• Systemic pembrolizumab shows modest efficacy with notable toxicity in papillary disease. In KEYNOTE-057 cohort B — patients with BCG-unresponsive high-grade Ta or T1 disease without CIS — the 12-month disease-free survival was 43.5% (95% CI 34.9–51.9%). Treatment-related adverse events occurred in 73% of patients, with 14% experiencing grade 3 or 4 events; serious treatment-related adverse events were reported in 13% of patients.

• Real-world data for nadofaragene firadenovec in papillary-only disease show declining disease control over time. Among 19 patients with papillary-only disease, high-grade recurrence-free survival at 3, 6, and 12 months was 68%, 53%, and 26%, respectively, with a median follow-up of 7.6 months — indicating rapid attrition of disease control.

• TAR-200 monotherapy data in papillary-only disease are promising but limited to a single-arm phase IIb study. In the SunRISe-1 study (Cohort 4, n=85), 6-, 9-, and 12-month disease-free survival rates were 85.3% (95% CI 71.6–92.7), 81.1% (95% CI 66.7–89.7), and 70.2% (95% CI 51.6–82.8), respectively; no comparative data exist, and no approval for a papillary-only indication has been established.

• Evidence base is dominated by single-arm and retrospective studies, limiting cross-study comparisons. Many gemcitabine studies enrolled mixed BCG-failure cohorts that do not satisfy the contemporary BCG-unresponsive definition, and cross-study comparisons are descriptive, establishing neither superiority nor equivalence among available options.

• T1 disease within the papillary subgroup carries a distinctly worse prognosis. Among BCG-unresponsive patients undergoing bladder-sparing therapies, T1 ± CIS disease was associated with significantly increased disease progression (p < 0.001), metastasis (p < 0.001), and bladder cancer mortality (p = 0.009) compared with Ta alone, underscoring the heterogeneity within the papillary-only category and the risk of grouping T1 and Ta together.

• Molecular and urinary biomarkers for patient selection remain investigational. Urinary tumor DNA and transcriptomic subtypes are not yet validated selection tools, leaving clinicians without biomarker-driven guidance to identify which patients with papillary-only disease are most likely to benefit from bladder-sparing approaches versus early cystectomy.

Anktiva's Expanded Approval: A New Regulatory Path

Several trials have evaluated bladder-sparing approaches in BCG-unresponsive, high-grade papillary-only NMIBC, with disease-free survival (DFS) and progression-free survival (PFS) as the dominant endpoints. The studies below span intravesical drug-releasing systems, combination immunotherapy, and chemotherapy doublets, each offering distinct design parameters and outcome data for this difficult-to-treat population.

Anktiva's Efficacy and Safety Profile in NMIBC

The knowledge base does not have sufficient information to answer this question.

Reshaping the BCG-Unresponsive NMIBC Treatment Landscape

The treatment landscape for BCG-unresponsive, high-grade papillary-only non-muscle-invasive bladder cancer (NMIBC) has undergone substantial evolution, driven by a growing portfolio of bladder-sparing alternatives to radical cystectomy. Historically, radical cystectomy with pelvic lymph node dissection represented the guideline-supported standard for BCG-unresponsive disease, yet many patients are ineligible for or decline major surgery. This unmet need has catalyzed the clinical development of intravesical gene therapies, immunostimulatory agents, sustained-release drug delivery systems, and combination chemotherapy regimens. Among the most clinically significant advances, the IL-15 superagonist nogapendekin alfa inbakicept (NAI) combined with BCG demonstrated 12-, 24-, and 36-month disease-free survival (DFS) rates of 58.2% (95% CI 46.6–68.2), 52.1% (95% CI 40.3–62.7), and 38.2% (95% CI 25.6–50.6), respectively, in BCG-unresponsive high-grade Ta/T1 papillary NMIBC (QUILT-3.032). Progression-free survival at 36 months reached 83.1% (95% CI 69.5–91.0), cystectomy avoidance at 36 months was 81.8% (95% CI 68.1–90.1), and the majority of treatment-related adverse events were grade 1–2 (61%), with only 3% grade 3 and no grade 4–5 events. NAI has since received FDA approval, representing a meaningful regulatory milestone for this population.

Intravesical drug-releasing systems have also emerged as a transformative modality. TAR-200, a first-in-class device providing sustained intravesical delivery of gemcitabine, demonstrated a centrally confirmed complete response rate of 82.4% (95% CI 72.6–89.8) with a median duration of response of 25.8 months (95% CI 8.3–not estimable) in BCG-unresponsive carcinoma in situ (CIS) patients in the phase IIb SunRISe-1 study (Cohort 2). For BCG-unresponsive high-grade papillary-only disease (Cohort 4), 6-, 9-, and 12-month DFS rates were 85.3% (95% CI 71.6–92.7), 81.1% (95% CI 66.7–89.7), and 70.2% (95% CI 51.6–82.8), respectively, with grade ≥3 treatment-related adverse events occurring in only 13.5% of patients. TAR-200 has since been approved in the United States as INLEXZO for BCG-unresponsive CIS with or without papillary tumors, though no approved agent currently holds a papillary-only indication. Nadofaragene firadenovec, an adenoviral vector-based gene therapy, also demonstrated durable activity in BCG-unresponsive NMIBC, with 5-year cystectomy-free survival of 59% (95% CI 43.1–71.4) in the Ta/T1 cohort and Kaplan-Meier-estimated high-grade recurrence-free survival of 33% (95% CI 19.5–46.6) at 57 months.

Sequential intravesical gemcitabine and docetaxel (Gem/Doce) has accumulated substantial multicenter observational experience as a bladder-sparing option across BCG-failure populations. A 2026 meta-analysis of nine studies comprising 883 patients reported a pooled 12-month recurrence-free survival of 73.75% and high-grade recurrence-free survival of 75.78%, with progression-free survival of 95.57% and cystectomy-free survival of 94.41% at 12 months. BCG-failure cohorts demonstrated 12-month RFS of 60.00% and HG-RFS of 63.79%, both significantly inferior to BCG-naïve patients (p < 0.001). A separate 2026 meta-analysis of 14 studies involving 1,634 patients reported 24-month RFS of 41% (95% CI 34%–47%) and 24-month PFS of 85% (95% CI 63%–95%) in BCG-treated or BCG-unresponsive cohorts, with grade ≥3 adverse events in only 3.6% of Gem/Doce patients. Notably, a 2026 retrospective comparison did not demonstrate improved high-grade recurrence-free survival for sequential Gem/Doce over gemcitabine monotherapy, underscoring that the comparative positioning of these regimens remains to be definitively established. Collectively, these data reflect a rapidly diversifying therapeutic armamentarium, with intravesical approaches consistently demonstrating superior safety profiles and meaningful cystectomy avoidance rates compared with systemic therapies.

Anktiva's Expanded Approval: A New Era for Papillary NMIBC

The recent FDA approval expanding Anktiva's (nogapendekin alfa inbakicept-pmln) indication to include high-grade papillary-only non-muscle invasive bladder cancer (NMIBC) that is unresponsive to BCG represents a significant advancement for a patient population facing limited bladder-sparing options. This decision, building upon its earlier approval for carcinoma in situ (CIS), underscores a strategic recognition of the urgent need for effective treatments beyond radical cystectomy. Anktiva, an IL-15 superagonist, works by stimulating the immune system, particularly CD8 T-cells, to mount a robust anti-tumor response when combined with BCG. Studies indicate this combination can achieve durable complete responses and high rates of cystectomy avoidance, offering patients a chance to preserve bladder function and improve their quality of life.

However, the evolving landscape of BCG-unresponsive NMIBC also presents considerations. While Anktiva's efficacy in papillary disease is promising, much of the supporting data comes from single-arm trials. This highlights a broader challenge in the field: the lack of head-to-head comparative studies among the growing number of novel agents, which complicates decisions regarding optimal treatment sequencing. Furthermore, as an intravesical therapy, Anktiva, like other agents, can induce irritative lower urinary tract symptoms and bladder spasms. Effective management of these adverse events is crucial to ensure patient adherence and maximize therapeutic benefit. Finally, the continued reliance on BCG as a combination partner means Anktiva's accessibility remains tied to the stability of the global BCG supply chain, a factor that has historically posed challenges for NMIBC treatment. As the armamentarium for NMIBC expands, future efforts will likely focus on identifying predictive biomarkers and developing combination strategies that target multiple immune escape mechanisms to further refine patient selection and optimize long-term outcomes.