Mallinckrodt Submits Clinical Trial Application for SLN501
24 March 2022 - UK-based novel short interfering ribonucleic acid (siRNA) therapeutics developer Silence Therapeutics plc (NASDAQ: SLN) said that Dublin-based biopharmaceutical company Mallinckrodt plc (OTC: MNKKQ) has filed a clinical trial application for SLN501, an siRNA targeting the complement C3 protein, triggering a USD 3m milestone payment to Silence, the company said.

Under the collaboration, Silence is responsible for executing the development program for SLN501 until the end of phase I, after which Mallinckrodt will assume responsibility for clinical development and global commercialization.

The phase I study is expected to start in the first half of 2022.

In July 2019, Silence and Mallinckrodt initiated a collaboration focused on leveraging Silence's proprietary mRNAi GOLD platform to develop siRNAs for complement-mediated diseases.

Under the agreement, Silence received an upfront payment of USD 20m from Mallinckrodt for an exclusive worldwide license to siRNAs developed against one complement target, C3, and options to license siRNAs against up to two additional complement targets, each of which Mallinckrodt exercised in 2021 at USD2 m per target.

Silence is responsible for preclinical activities and for executing development of each target through phase 1, after which Mallinckrodt will assume responsibility for clinical development and global commercialization.

Silence is also eligible to receive tiered double-digit royalties on net sales for each product candidate and up to USD 2bn in total milestone payments across all three targets.

Silence Therapeutics is developing a new generation of medicines by harnessing the body's natural mechanism of RNA interference, or RNAi, to inhibit the expression of specific target genes thought to play a role in the pathology of diseases with significant unmet need.

Silence's proprietary mRNAi GOLD platform can be used to create siRNAs (short interfering RNAs) that precisely target and silence disease-associated genes in the liver, which represents a substantial opportunity.

Silence's wholly owned product candidates include SLN360 designed to address the high and prevalent unmet medical need in reducing cardiovascular risk in people born with high levels of lipoprotein(a) and SLN124 designed to address rare hematological diseases.

Silence also maintains ongoing research and development collaborations with AstraZeneca, Mallinckrodt Pharmaceuticals, and Hansoh Pharma, among others.

Mallinckrodt is a global business consisting of multiple wholly owned subsidiaries that develop, manufacture, market and distribute specialty pharmaceutical products and therapies.

The company's Specialty Brands reportable segment's areas of focus include autoimmune and rare diseases in specialty areas like neurology, rheumatology, nephrology, pulmonology, ophthalmology, and oncology; immunotherapy and neonatal respiratory critical care therapies; analgesics; cultured skin substitutes and gastrointestinal products.

Its specialty generics reportable segment includes specialty generic drugs and active pharmaceutical ingredients.