Synthetic glycopolymers that emulate cell-surface mucins have been used to elucidate the role of mucin overexpression in cancer. However, because they are internalized within hours, these glycopolymers could not be used to probe processes that occur on longer time scales. Here, we tested a panel of glycopolymers bearing a variety of lipids to identify those that persist on cell membranes. Strikingly, we found that cholesterylamine (CholA)-anchored glycopolymers are internalized into vesicles that serve as depots for delivery back to the cell surface, allowing for the display of cell-surface glycopolymers for at least 10 days, even while cells are dividing. As with native mucins, cell-surface display of CholA-anchored glycopolymers influenced focal adhesion distribution. Furthermore, we show that these mimetics enhance survival of nonmalignant cells in a zebrafish model of metastasis. CholA-anchored glycopolymers therefore expand applications of glycocalyx engineering in glycobiology.

While systemic immuno-oncology therapies have shown remarkable success, only a limited subset of patients benefit from them. The Click Activated Protodrugs Against Cancer (CAPAC) platform is a click chemistry-based approach that activates cancer drugs at a specific tumor with minimal systemic toxicity. The CAPAC Platform is agnostic to tumor characteristics that can vary across patients and hence applicable to several types of tumors. The benefits of SQ3370 (lead candidate of CAPAC) are described to achieve systemic anti-tumor responses in mice bearing two tumors. SQ3370 consists of a biopolymer, injected in a single lesion, followed by systemic doses of an attenuated protodrug of doxorubicin (Dox). SQ3370 is well-tolerated at 5.9-times the maximum dose of conventional Dox, increased survival by 63% and induces a systemic anti-tumor response against injected and non-injected lesions. The sustained anti-tumor response also correlates with immune activation measured at both lesions. SQ3370 can potentially benefit patients with micro-metastatic lesions.

The Click Activated Protodrugs Against Cancer (CAPAC) platform uses click chemistry to activate cytotoxic drugs directly at a target site with minimal toxicity, overcoming limitations of conventional chemotherapy and traditional targeted therapies.

Systemic administration of antibiotics can cause severe side-effects such as liver and kidney toxicity, destruction of healthy gut bacteria, as well as multidrug resistance. Here, we present a bio-orthogonal chemistry-based strategy toward local prodrug concentration and activation. The strategy is based on the inverse electron-demand Diels–Alder chemistry between trans-cyclooctene and tetrazine and involves a biomaterial that can concentrate and activate multiple doses of systemic antibiotic therapy prodrugs at a local site. We demonstrate that a biomaterial, consisting of alginate hydrogel modified with tetrazine, is efficient at activating multiple doses of prodrugs of vancomycin and daptomycin in vitro as well as in vivo. These results support a drug delivery process that is independent of endogenous environmental markers. This approach is expected to improve therapeutic efficacy with decreased side-effects of antibiotics against bacterial infections. The platform has a wide scope of possible applications such as wound healing, and cancer and immunotherapy.

Background: SQ3370 is the first demonstration of the Click Activated Protodrugs Against Cancer (CAPACTM) platform that uses click chemistry to activate drugs directly at tumor sites, maximizing therapeutic exposure. SQ3370 consists of a tumor-localizing biopolymer (SQL70) and a chemically-attenuated doxorubicin (Dox) protodrug SQP33; the protodrug is activated upon clicking with the biopolymer at tumor sites. Here, we present data from preclinical studies and a Phase 1 dose-escalation clinical trial in adult patients with advanced solid tumors (NCT04106492) demonstrating SQ3370's activation at tumor sites, safety, systemic pharmacokinetics (PK), and immunological activity. Methods: Treatment cycles consisting of an intratumoral or subcutaneous injection of SQL70 biopolymer followed by 5 daily intravenous doses of SQP33 protodrug were evaluated in tumor-bearing mice, healthy dogs, and adult patients with solid tumors. Results: SQL70 effectively activated SQP33 at tumor sites, resulting in high Dox concentrations that were well tolerated and unachievable by conventional treatment. SQ3370 was safely administered at 8.9x the veterinary Dox dose in dogs and 12x the conventional Dox dose in patients, with no dose-limiting toxicity reported to date. SQ3370's safety, toxicology, and PK profiles were highly translatable across species. SQ3370 increased cytotoxic CD3+ and CD8+ T-cells in patient tumors indicating T-cell-dependent immune activation in the tumor microenvironment. Conclusions: SQ3370, the initial demonstration of click chemistry in humans, enhances the safety of Dox at unprecedented doses and has the potential to increase therapeutic index. Consistent safety, toxicology, PK, and immune activation results observed with SQ3370 across species highlight the translatability of the click chemistry approach in drug development.