Continuous Manufacturing of Nanomedicines for the Treatment of Breast Cancer Brain Metastases

250,000 new cases of breast cancer are diagnosed each year in the United States, 15-20% of which are the triple-negative (TNBC) subtype. TNBC is highly aggressive, with patients demonstrating higher incidence of recurrence and metastasis. Selinexor, an FDA-approved multiple myeloma drug, targets nuclear export protein XPO1, which is commonly overexpressed in TNBC compared to normal tissue. Interestingly, Selinexor is also capable of crossing the blood-brain barrier, which may enable it to treat the brain metastases that approximately one-third of TNBC patients experience. So, Selinexor presents a promising anticancer treatment for TNBC. Selinexor has demonstrated toxicity at normal to high doses in clinical trials. Selinexor’s toxicity could be addressed by engineering a delivery system to improve its pharmacokinetic profile. Liposomal nanoparticles have shown success in slowing the release of other chemotherapies, thus increasing their tolerability. If the plasma concentration of Selinexor can be more tightly controlled, it may be administered at effective doses without exceeding a patient’s tolerated limit. To mitigate Selinexor’s toxicity while eyeing clinical translation, we first needed to produce and characterize liposomes with an appropriate quality target product profile and assess their efficacy in vitro. We began by creating and characterizing a liposomal formulation and testing its kill ability in relevant tumor models. We hypothesized that liposomal Selinexor would potently kill cells in a genetically relevant TNBC model. We created multiple batches of liposomal Selinexor via thin film hydration to ensure compatibility of the structural lipids with each other and with the drug. Then, we moved on to a continuous manufacturing approach that utilized a microfluidic system, the NanoAssemblr Ignite, to produce liposomes at a milliliter scale in a fraction of the time. We characterized key physical parameters such as zeta potential, hydrodynamic diameter, and encapsulation efficiency using dynamic light scattering and HPLC-UV. The thin film batches require further optimization to increase encapsulation efficiency, but the continuously manufactured sample demonstrated comparable physical attributes to the quality target product profiles indicated in literature. Next, we assessed the efficacy of free Selinexor in killing MDA-MB-468 cells, an immortalized TNBC cell line. We administered our liposomes at the same concentrations to compare efficacy. The liposomal formulations showed high biological activity, efficiently killing the TNBC cells. Moving forward, we seek to repeat experiments for replicability, control for potential cytotoxic effects of the liposome nanocarriers, and test our formulations in vivo.