Technology & Development
Unique local injection technology
Synartro develops local injection treatments using a patented local injection technology that enables a sustained drug release. By locally injecting the treatment, a very low dose of the active substance is needed. For other indications where local slow release of compounds with systemic safety concerns is beneficial, our technology could provide significant improvement.
Lead program, SYN321
Drug candidate SYN321 is an intraarticular injection in development for the treatment of symptomatic knee OA. It is the slow release of diclofenac inside the joint that enables therapeutic benefits of SYN321 such as reduced side effects, prolonged pain relief as well as reduction of inflammation and pain. Further, SYN321 will also provide lubrication to the joint.
SYN321 has the potential to become the preferred second line treatment for knee OA.
Clinical development
The first-in-human trial of SYN321 in osteoarthritis patients (phase 1/2a) was initiated in August 2025. The trial focuses on safety and tolerability of SYN321, but will also provide indicative efficacy data. The trial is expected to be concluded in the first quarter of 2026.
More information about the ongoing trial can be found here: EU Clinical Trials – SYN321.
Preclinical development
In the preclinical stage of SYN321 a study in horses at the Swedish University of Agricultural Sciences (SLU) compared SYN321 joint injections to a mixture of unbound hyaluronic acid and diclofenac. Diclofenac remained in the joint 10 times longer with SYN321 than with the unbound version. Minimal systemic exposure (plasma and urine) was observed, demonstrating excellent tolerability and favorable pharmacokinetics. You can find the publication here.
Efficacy for SYN321 was confirmed in an in vitro miniaturized model of human OA cartilage on a chip (uKnee®), in collaboration with BiomimX. The study revealed that SYN321 decreased the OA inflammatory response, slowed matrix-degrading events, and importantly, caused no damage to the cartilage.
The preclinical program also involved various GLP-Tox studies, which demonstrated favorable safety and local tolerability, as well as manufacturing the substance under GMP standards (Good Manufacturing Practice).
Patent portfolio
The original patent for our core technology was filed in 2015 and was granted in the US in 2020, in Europe in 2021 and Canada in 2022. This family of compound patents cover the unique and versatile platform technology of hyaluronan enhanced with a linker, that can be connected to different pharmaceutical active substances. Thus, this patent family protects not only SYN321, but also other compounds based on the platform.
The patent is valid until 2035, with a possible extension of five years. It is the company’s assessment that the patent provides strong immaterial protection. Two additional patent applications have been filed regarding the manufacturing method and there is continuous work to expand our patent portfolio.