Attralus Raises $116m To Advance Amyloidosis-Clearing Pipeline

The company intends to use the series B cash to bring the first of its pan-amyloid removal (PAR) therapies into the clinic, while also advancing a diagnostic tool for systemic amyloidosis.

Attralus quickly adds $116m series B cash to the $25.9m raised last September

Attralus, Inc. has raised a $116m series B financing that it says will bring the first of its pan-amyloid removal (PAR) drug candidates into the clinic and advance development of a diagnostic for detecting systemic amyloidosis. The South San Francisco, CA-based firm announced the round on 8 September, less than a year after its introduction with a series A financing.

Attralus drew some attention this past May when it hired former Purdue Pharma L.P. CEO Mark Timney as its new top executive. Timney tried unsuccessfully to diversify Purdue’s focus beyond opioid analgesic medicine before the company filed for bankruptcy over a deluge of lawsuits related to its sale and marketing of opioid therapeutics. (Also see "Purdue Pharma: From Blockbuster Success To Bankrupt Villain " - Scrip, 16 Sep, 2019.)

Timney moved in 2018 to helm The Medicines Company through a buyout process, and saw the hospital product specialty firm sold off to Novartis AG for $9.7bn in November 2019. (Also see "It Has Been A Long Farewell To The Medicines Company" - Scrip, 26 Nov, 2019.) A familiar name now follows Timney to Attralus as Sarissa Capital Management, headed by activist shareholder Alex Denner, is among the series B investors. Denner, who is taking a seat on the Attralus board, was chairman of The Medicines Company and drove the Novartis transaction after selling off the firm’s commercial products. (Also see "Novartis To Pay $9.7bn For The Medicines Company" - Scrip, 24 Nov, 2019.)

Logos Capital led the series B and was joined in the round by Sarissa, Janus Henderson Investors, Redmile Group, Samsara BioCapital, Surveyor Capital and Vivo Capital. Also participating was venBio Partners, which led Attralus’s $25.9m series A financing in September 2020. (Also see "Finance Watch: $320m In New VC Deals Includes $110m Round For Neogene" - Scrip, 15 Sep, 2020.)

Attralus claims its PAR therapeutic pipeline and diagnostic candidate offer the potential of a new treatment approach for systemic amyloidosis, a set of rare diseases caused by aberrant protein misfolding that includes transthyretin amyloidosis (ATTR), immunoglobulin light-chain (AL) amyloidosis and LECT2 amyloidosis (ALECT2).

Although amyloid deposit build-up is also seen as a root cause of Alzheimer’s disease, Attralus has no plans to investigate its platform technology in that disease. “At this time, Attralus is focused on advancing our PAR therapeutics and diagnostic to address the vast unmet need in systemic amyloidosis,” chief medical officer Gregory Bell said.

Novel Approach To Clearing Amyloid Deposits

The company’s PAR therapeutics are first- and only-in-class, the company told Scrip, designed to bridge the gap in current amyloidosis therapies by targeting the underlying pathology of systemic amyloidosis. Attralus contends that this approach targets toxic, disease-causing amyloid in all organs and all stages with high specificity, thereby limiting off-target effects. PAR therapeutics will offer strong binding affinity, avidity and immune-mediated phagocytosis, the company added.

AT-03, which fuses a single-chain Fc antibody with Attralus’s PAR-SAP (Serum Amyloid Protein) technology, is slated to be first into the clinic in a Phase I biodistribution study in systemic amyloidosis patients. Each of its candidates will enable binding to all types of amyloid deposits, Attralus claims, with the Fc component stimulating the immune system to remove the deposits.

In preclinical development are AT-02, a full-length IgG1 monoclonal antibody attached to a pan-amyloid peptide, and AT-04, which fuses a pan-amyloid peptide with the Fc component of an IgG1 antibody. A Phase I biodistribution study of AT-02 is also anticipated, while plans for AT-04 are still being determined, the company said.

Attralus’s pan-amyloid peptide – an amyloid-specific radiotracer – also is a key component of AT-01, the companion diagnostic already in clinical testing. Used in PET or CT imaging, AT-01 has demonstrated the ability to detect amyloid deposits in the heart, kidney, liver and spleen, according to the biotech, and has detected cases of ATTR and AL amyloidosis.

The company said it is developing AT-01 as a separate product, rather than as a companion diagnostic for its therapeutic candidates, but added that the whole-body imaging, non-invasive tool will support the development of its therapies.

Alnylam Pharmaceuticals Inc.’s Onpattro (patisiran) and Akcea Therapeutics, Inc.’s Tegsedi (inotersen), both RNA-interference therapies, obtained US Food and Drug Administration approval in 2018 to treat the hereditary form of ATTR. (Also see "Alnylam's Onpattro Carries Narrower hATTR Indication Without Cardiac Data" - Pink Sheet, 13 Aug, 2018.) (Also see "Akcea Expects Convenience Edge For Tegsedi, Despite Monitoring Requirements" - Scrip, 8 Oct, 2018.) Pfizer Inc.’s Vyndaqel (tafamidis) is approved to treat ATTR in Europe and obtained FDA approval in 2019 for transthyretin amyloid cardiomyopathy (ATTR-CM). (Also see "Pfizer Wins Tafamidis Approval; Now It Will Need To Build The Market" - Scrip, 6 May, 2019.) Alnylam has a second RNAi therapeutic, vutrisiran, under FDA review for ATTR, with an April 2022 approval date.

Biomedtracker lists five other therapies in clinical development for ATTR, including a pair of Phase III candidates: Akcea’s eplontersen, a second-generation ligand-conjugated antisense (LICA) drug, and BridgeBio Pharma, Inc.’s AG10, a small molecule stabilizer of tetrameric transthyretin.

Therapeutic candidates in development for amyloidosis
Company	Drug	Development stage	Mechanism
Alnylam	vutrisiran	FDA review	RNA interference
BridgeBio	AG10	Phase III	Stabilizer of tetrameric transthyretin
Akcea	eplontersen	Phase III	Ligand-conjugated antisense
Corino Therapeutics, Inc.	CRX-1008	Phase I/II	COMT inhibitor
Intellia Therapeutics, Inc.	NTLA-2001	Phase I	Transthyretin gene knockout
Prothena Corporation plc	PRX004	Phase I	TTR protein binder
Proclara Biosciences	NPT189	Phase I	Fusion protein
Source: Biomedtracker