28 July 2021 - - US-based biopharmaceutical company Arena Pharmaceuticals, Inc. (NASDAQ: ARNA) and US-based immunology focused drug development company Aristea Therapeutics, Inc. have forged a strategic collaboration to advance the clinical development of RIST4721, an oral CXCR2 antagonist being developed by Aristea for the treatment of palmoplantar pustulosis and other neutrophil-mediated diseases, the companies said.

Under the terms of the agreement, Arena will provide a USD 60m upfront payment to Aristea and a USD 10m equity investment in Aristea's series B financing.

In return, Aristea has granted Arena an exclusive option to acquire Aristea, including rights to all CXCR2 programs, upon completion of the Phase 2b study of RIST4721 in PPP.

The agreement also provides a framework during the option period for the companies to jointly explore the development of additional neutrophil-mediated diseases, including hidradenitis suppurativa and inflammatory bowel disease, potentially generating multiple data readouts during the option period.

Separately, Aristea announced the closing of a USD 63m series B financing led by Fidelity Management and Research company, LLC, with participation by existing investor Novo Holdings A/S and new investors Arena Pharmaceuticals and funds managed by Tekla Capital Management, LLC.

RIST4721 is an oral CXCR2 antagonist being developed for the treatment of PPP with results reported from its Phase 2a clinical trial in 2020.

PPP is a debilitating condition that is characterized by repeated flares of sterile neutrophil-filled pustules that lead to redness and thickening on the palms of the hands and/or the soles of the feet and associated pain, itching and burning sensations.

CXCR2 plays important roles in neutrophil recruitment to inflammatory sites and represents a promising therapeutic target for the treatment of neutrophil-mediated inflammatory diseases.

Later this year, Aristea is initiating a Phase 2b study to investigate RIST4721 in PPP and plans to expand development into two additional orphan indications, familial Mediterranean fever and Behcet's disease.

Arena Pharmaceuticals is developing a portfolio of therapeutic candidates targeting gastroenterology, dermatology and cardiology. Its pipeline includes four investigational medicines in eight indications and eleven ongoing or planned clinical trials.

Arena's lead investigational compound in dermatology, etrasimod, is a highly selective, once-daily, oral sphingosine 1-phosphate receptor modulator intended to provide systemic and local effects on specific immune cell types with the potential to treat multiple immune-mediated inflammatory diseases, including ulcerative colitis, Crohn's disease, eosinophilic esophagitis, atopic dermatitis, and alopecia areata.

Aristea Therapeutics (Air-iss-tay-uh) is a clinical-stage immunology focused drug development company developing novel therapies to treat serious inflammatory orphan diseases.

The Aristea team is leveraging its broad industry expertise and proven success in drug development to form synergistic partnerships and build a pipeline of novel drugs. Aristea's lead program, RIST4721, is currently in Phase 2 clinical development.

Aristea is headquartered in San Diego, CA.