Intravaginal chemotherapy represents a promising non-invasive approach to treat cervical tumors locally, in the early stages, before it becomes invasive. However, challenges abound: chemo drugs can be rapidly absorbed into systemic circulation, which depletes drug from the vicinity of the tumor and may cause systemic toxicity. Nanoparticle-based drug delivery systems may overcome these limitations by releasing drug in a sustained manner. However, cervical tumors are covered by a sticky mucus layer that has multiple important functions, including defense against infections, but also traps and rapidly clears potentially life-saving drug-loaded nanoparticles.
To overcome these challenges, Yang et al. have developed polymer-based mucus-penetrating particles (MPP) loaded with paclitaxel, a frontline chemo drug. The MPP effectively avoids adhesion to mucus and, thus, is able to efficiently reach the cervical tumours in the underlying tissue. The group show in a mouse model that MPP achieves closer proximity to tumors than conventional mucoadhesive nanoparticles, and also provides much longer drug retention in the mouse vagina compared with the unencapsulated drug. Finally, paclitaxel-loaded MPP suppresses cervical tumor growth more effectively and doubled median survival time as compared to treatment with the same drug loaded in conventional nanoparticles or Taxol, a clinically used paclitaxel formulation.
Another unique advantage of the MPP platform is that it is composed entirely of materials used in FDA-approved pharmaceutical products, which may accelerate clinical translation of the technology. Drug-loaded MPP may find use in the treatment of many diseases that affect the mucosal surfaces in the human body, including the vagina, gastrointestinal tract, respiratory tract, eye, and more.