Multiple Clinical Complete Responses Demonstrated Following Single Low Dose Administration of Bel-sar in Patients with Non-Muscle-Invasive Bladder Cancer (NMIBC) in Ongoing Phase 1 Trial

  • Clinical Complete Responses Observed in 4 out of 5 Patients in Subset of Patients with Low Grade Disease; Evidence of Bladder Urothelial Field Effect in Non-Target Tumors
  • Favorable Safety Profile Observed; Only Grade 1 Drug-Related Adverse Events Reported in Less Than 10% of Patients
  • Aura Hosting Virtual Urologic Oncology Investor Event with Key Opinion Leaders at 4.30 pm ET Today
Reno, Nevada (UroToday.com) -- Aura Biosciences, Inc. (NASDAQ: AURA), announced positive early data from an ongoing Phase 1 clinical trial of bel-sar (AU-011) in patients with NMIBC. To date, the trial includes 13 patients, with the primary endpoints of evaluating the safety and feasibility of local administration of bel-sar alone (n=5) and belsar with light activation (n=8). The secondary endpoints are to evaluate biological activity and immune mediated changes in the tumor microenvironment (TME). 10 of 13 study participants had low grade disease, approximating the 70% incidence of this patient population among all NMIBC patients. The other 3 study participants had high grade disease. In patients receiving bel-sar with light activation (n=8), 4 out of 5 patients with low grade disease demonstrated a clinical complete response with no tumor cells remaining on histopathological evaluation. 2 out of 3 patients with high grade disease demonstrated visual tumor shrinkage observed on cystoscopy. Aura will host a Virtual Urologic Oncology Investor Event at 4:30 pm ET today.

“We are highly encouraged by this positive early data, which shows that bel-sar has the potential to be a transformative cancer treatment,” said Sabine Brookman-May, MD,FEBU, Senior Vice President, Therapeutic Area Head Urologic Oncology of Aura Biosciences. “A potentially differentiating aspect of this novel treatment is the rapid tumor response accompanied by an immune oncology (IO) effect such as a marked CD8+ T-cell infiltration observed in just a matter of days with a single low dose. We believe this could have the potential to translate into a durable response. In parallel with expanding the ongoing Phase 1 trial, we are preparing for a Phase 2 trial to further evaluate bel-sar’s clinical activity and durability of response.”
“Bel-sar has the potential to change the treatment paradigm for NMIBC,” said Neal Shore, M.D., FACS, Medical Director, Carolina Urologic Research Center, AUC Urology Specialists. “Based on this early data, bel-sar’s positive clinical activity and evidence of a bladder urothelial field effect with a single dose, may position bel-sar to be the first immune ablative treatment option for early-stage bladder cancer patients delivered with an in-office procedure.”

Bel-sar is a virus-like drug conjugate, designed to have a dual mechanism of action, that induces direct tumor cell necrosis and elicits a robust and durable anti-tumor immune response.

Trial Design: The ongoing Phase 1 trial (NCT05483868) is a two-part, open-label clinical trial, designed to assess the safety and feasibility of bel-sar as a monotherapy. The study treatment is administered 7 to 12 days before the scheduled transurethral resection of bladder tumor (TURBT), the standard of care procedure. The participants are followed for safety monitoring over a 56-day period. The trial is also evaluating bel-sar’s biological activity with histopathological evaluation of tissue samples collected at the time of TURBT (regardless of tumor response) with evaluation of focal necrosis and immune changes in the tumor microenvironment. Part 1 (n=5) of the trial is complete, with patients receiving a single bel-sar dose without light activation. Part 2 (n=10) of the trial is ongoing. 8 patients with a confirmed tumor at time of treatment have received either 100ug or 200ug of bel-sar as a single dose. Of these 8 patients, 5 had low grade disease and 3 had high grade disease. 7 of these 8 patients had a history of recurrent bladder cancer and had undergone multiple TURBTs and adjuvant treatments such as Bacillus Calmette-Guerin (BCG), mitomycin, gemcitabine, cetrelimab and tamoxifen prior to trial enrollment. In the Phase 1 trial expansion, Aura plans to test additional doses and treatment regimens.

Safety Data: In the safety analysis as of the September 9, 2024 data cut-off date (n=12), bel-sar was well-tolerated, with less than 10% of patients reporting Grade 1 and no Grade 2 or higher drug-related adverse events reported. No serious adverse events have been reported. No significant differences between the light-activated and non-light activated cohorts have been observed.

Biological Activity: The data in these 8 patients receiving bel-sar with light activation showed clinical activity detectable as soon as 7 days after a single low dose of bel-sar with light activation. This was demonstrated by histopathological evidence of clinical complete response, necrosis, immune activation or visual tumor shrinkage observed on cystoscopy. For this analysis, “clinical complete response” was defined as the absence of tumor cells on histopathologic evaluation. Of the patients with low-grade disease, 4 out of 5 exhibited a clinical complete response (1 of 4 based on local pathology with central review ongoing), with no tumor cells detected in histopathological evaluation post-treatment in the target and in several non-target bladder tumors. 2 of 3 of the patients with high grade disease demonstrated visual tumor shrinkage observed on cystoscopy, while tumor cells were still present on histopathological evaluation. Immune activation was noted in all patients in both treated target and untreated non-target bladder tumors with infiltration of effector CD8+ and CD4+ T-cells (where immune staining was available). This data provides evidence of a bladder urothelial field effect with a single low dose of bel-sar with light activation, potentially indicating a broader immune response in the bladder beyond the target tumor in these patients.

Aura Virtual Urologic Oncology Investor Event

Aura will host a Virtual Urologic Oncology Investor Event featuring Max Kates, MD (Johns Hopkins), Joe Jacob, MD (Syracuse University), Neal Shore, MD (Carolina Urologic Research Center) and Gary Steinberg, MD (RUSH University) to discuss the early Phase 1 data on Thursday, October 17, 2024, at 4:30 pm Eastern Time. To register for the event, click here. A live question and answer session will follow the formal discussion.

The live webcast of Aura’s Virtual Urologic Oncology Investor Event will be available on the “Investors & Media” page under the “Events & Presentations” section of Aura’s website at https://ir.aurabiosciences.com/events-and-presentations, where a replay of the webcast will be archived for 90 days following the presentation date.

Source: Aura Biosciences, Inc. (2024). Multiple Clinical Complete Responses Demonstrated Following Single Low Dose Administration of Bel-sar in Patients with Non-Muscle-Invasive Bladder Cancer (NMIBC) in Ongoing Phase 1 Trial [Press release]. https://ir.aurabiosciences.com/news-releases/news-release-details/multiple-clinical-complete-responses-demonstrated-following.