A recent study demonstrated that a peptide-based hydrogel could improve the delivery of bacillus Calmette–Guérin (BCG) immunotherapy for patients with bladder cancer.
The research, published in ACS Applied Materials & Interfaces, focused on developing an enzyme-responsive peptide, D-Nap-GFFYp, that is placed in the bladder alongside BCG solution.
While intravesical BCG remains the gold standard immunotherapy for intermediate- and high-risk nonmuscle-invasive bladder cancer (NMIBC), its effectiveness is often hindered by “washout,” where the medication is flushed out during urination. To compensate for this loss, higher dosing is often required, but this can lead to side effects like tuberculous cystitis and hematuria (blood in the urine).
Estimates suggest that up to 70% of patients experience adverse events during BCG therapy, with 8% forced to discontinue treatment entirely. This peptide-based hydrogel could potentially change that by ensuring the medication stays exactly where it is needed.
Once inside the bladder, the peptide undergoes a process of “in-situ self-assembly,” meaning it automatically organizes itself into a hydrogel directly on the tumor site. This transformation is triggered by alkaline phosphatase, an enzyme found in much higher concentrations in bladder cancer cells than in healthy tissue.
The resulting hydrogel encapsulates the BCG, allowing for a longer release of the therapy over time. When the method was used in mouse models of bladder cancer, the authors found this targeted approach not only improved overall treatment response but also helped protect healthy, noncancerous bladder cells from unnecessary exposure to the drug.
Beyond improved delivery, this targeted approach helped support the body’s natural defenses by activating both humoral and cellular immunity. By keeping the therapy localized, the system seems to enhance the immune system’s ability to recognize and attack cancer cells more effectively than standard BCG therapy.
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Although these promising results were observed in mouse models, the study establishes a strong foundation for future clinical research.
“This work presents a rational and clinically translatable approach to improve the efficacy and biosafety of bladder cancer immunotherapy,” the authors concluded.
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