ADC specialist Solve raises $120m, and other biofinancings

Solve Therapeutics has completed a $120 million unlabelled round as it advances a pair of antibody-drug conjugates (ADCs) for cancer that use its proprietary linker technology.

San Diego-based Solve has welcomed some new investors in the financing, which was led by cancer-focused venture capitalist firm Yosemite and takes the total raised by the start-up to $321 million. Big pharma group MSD (known as Merck & Co in the US and Canada) was one new backer, along with Abingworth, Ally Bridge Group, B Capital, Balyasny Asset Management, and SymBiosis.

Solve is one of a number of new biotechs focusing on improving issues faced by current ADCs, including premature release of their cell-killing payload, which can lead to off-target side effects, and subpar pharmacokinetics.

Its platform revolves around its CloakLink linkers, which join the payload to the targeting antibody, which boosts the stability of their ADC candidates and reduces the hydrophobicity of the payload. This property can reduce stability, increase toxicity, and result in the drug being cleared from the body more quickly.

Solve's lead programmes, SLV-154 and SLV-324, are currently in phase 1 clinical trials in patients with solid tumours, and the company said the new cash will allow it to advance them through phase 1b proof-of-concept testing. The company is unusual among ADC specialists in that it is developing the therapeutics alongside diagnostics to identify patients most likely to respond to treatment.

Other private rounds this week

Personalised cell therapy developer Aspen Neuroscience added $115 million to its cash reserves with a Series C that included Gilead Sciences' cell therapy subsidiary Kite as a new investor and was led by OrbiMed, ARCH Venture, Frazier Life Sciences, and Revelation Partners.

The San Diego biotech will use the proceeds for clinical testing of ANPD001, its lead autologous cell therapy candidate for Parkinson's disease currently in a phase 1/2a trial, as well as to build up the manufacturing capabilities it will need for later-stage testing and potential commercial supply. The therapy has been fast-tracked by the FDA.

Aspen is developing cell therapies based on an induced pluripotent stem cell (iPSC) derived cell therapy platform that creates therapies that are based on a patient's own cells, eliminating the need for immunosuppressive therapy.

UK biotech Artios Pharma has raised $115 million in a fourth-round financing that will support its ongoing work in DNA damage response (DDR)-targeting cancer treatments, led by alnodesertib, an ATR inhibitor that is being tested for various forms of ATM-negative tumour types.

The new money will allow mid-stage testing to start in second-line pancreatic cancer and third-line colorectal cancer treatment settings, said the Cambridge company, and also fund the start of a phase 2 trial of PolTheta inhibitor ART6043 in BRCA-positive, HER2-negative breast cancer patients unable to tolerate standard PARP inhibitor therapy. Also, a lead candidate in Artios' DDR inhibitor-ADC programme is expected to be selected early next year.

The Series D was co-led by SV Health and new backer RA Capital Management, joined by Janus Henderson as a new investor and various existing supporters.

Turning to the world of AI in protein drug discovery, California start-up Profluent has taken the total financing it has raised to date to $150 million, with a $106 million co-led by Altimeter Capital and Bezos Expeditions, the investment vehicle for Amazon founder Jeff Bezos.

The company said the investment – which was also backed by existing investors including Spark Capital, Insight Partners, and Air Street Capital – will help to further its use of genome editors and large language models (LLMs) for protein design in what it calls "programmable biology."

Finally this week, California's Gate Bioscience raised $65 million in a Series B that has been earmarked for taking the first of its small-molecule 'molecular gate' programmes into clinical trials. Molecular gates are designed to eliminate a target protein by blocking an intracellular process that results in it being broken down before it can exert any activity.

The round was led by new investor Forbion and was joined by Eli Lilly, another new backer, as well as existing investors Versant Ventures, Andreessen Horowitz (a16z) Bio + Health, GV, and ARCH Venture Partners.