Assessing the safety and efficacy of SQ3370 in a phase 1b dose-expansion cohort at the recommended Phase 2 dose in patients with advanced sarcoma - Abstract
In 2018, the global incidence of new cancer diagnoses was estimated at over 18 million cases, and cancer-
related deaths were estimated at over 9.6 million. Of these cases, the vast majority were solid tumors,
accounting for more than 16 million new cases and 8 million cancer deaths. This includes soft tissue sarcoma
(STS), a heterogeneous group of aggressive malignant tumors that have a poor 5-year survival rate of only
65%. In the U.S., an estimated 13,000 people will be diagnosed with STS in 2020, and more than 5,000 will die
of the disease. For patients diagnosed with STS, treatment often involves chemotherapy with a cytotoxic agent
such as doxorubicin (Dox), an anthracycline that has been used to induce tumor regression in a variety of
neoplastic conditions. Dox is also known to induce immunogenic cell death and enhance tumor
responsiveness to immune checkpoint blockade therapies. Unfortunately, the extended use of Dox in patients
is limited by severe toxic side effects—most notably irreversible cardiotoxicity and bone marrow suppression—
which can be life threatening. Therefore, there is an immediate need for new methods to reduce the systemic
toxicity and off-target effects of Dox while maintaining its antitumor efficacy Shasqi has developed SQ3370, a
novel drug product that will improve the treatment of patients with injectable solid tumors undergoing
doxorubicin (Dox)-based chemotherapy. Preclinical studies done to-date have shown that SQ3370 results
in significant inhibition of tumor growth (both injected and non-injected tumors), immune activation,
prolonged survival, and protection against tumor rechallenge, while exhibiting reduced systemic side
effects compared to conventional Dox. Extensive preclinical data with SQ3370 has led to an open
investigational new drug (IND) application with the U.S. Food and Drug Administration (FDA). A Phase 1, first-
in-human, dose-escalation study is currently enrolling to evaluate the safety/tolerability, pharmacokinetics, and
preliminary efficacy of SQ3370 in patients with locally advanced or metastatic solid tumors. This Direct to
Phase II application seeks to expand this trial once the recommended Phase 2 dose (RP2D) has been reached
by adding a dose expansion cohort of 30 patients with soft-tissue sarcoma using a Simon two-stage design.
The aims of this project are to assess 1) safety/tolerability and 2) efficacy of SQ3370 in this cohort to determine
if the study should proceed to a Phase 2 clinical trial. These aims will accelerate development of SQ3370, a
novel therapy that promises to ultimately result in improved treatment and outcomes for millions of patients
with solid tumors.
