Scorpion secures $150M to expand PI3Kα program

Scorpion Therapeutics, a biotechnology company, aims to address the limitations of first-generation PI3Kα inhibitors, which have faced significant safety challenges. The firm believes its new allosteric, mutant-selective candidate, STX-478, has the potential to be best-in-class. To support the development of this experimental cancer treatment, Scorpion successfully secured a $150-million Series C funding round, co-led by Frazier Life Sciences and Lightspeed Venture Partners. This infusion of capital will facilitate the clinical advancement of STX-478.

Interestingly, Scorpion Therapeutics is the second company in recent times to focus on targeting the PI3K pathway. Just last month, iOnctera raised €80 million in a Series B round to advance its lead asset, roginolisib, an allosteric modulator of PI3Kδ, into Phase II clinical trials.

The PI3K class of inhibitors, though promising, has been plagued by toxic side effects, particularly when treating blood cancers. These challenges have led to several market withdrawals over the years due to poor tolerability and modest efficacy, compounded by competitive pressures. Scorpion Therapeutics aims to overcome these hurdles by targeting solid tumors driven by PI3Kα mutations. They are exploring STX-478 both as a monotherapy and in combination with other treatments like Faslodex (fulvestrant) and CDK4/6 inhibitors.

The company initiated a Phase I/II clinical trial last year for patients with locally advanced or metastatic HR+/HER2- breast cancer. This trial has since broadened to include gynecologic cancers and head and neck squamous cell carcinoma. Early PI3K inhibitors often affected the wild-type kinase, resulting in on-target toxicities. Scorpion Therapeutics believes their targeted approach may circumvent these selectivity issues, potentially offering improved outcomes in terms of both efficacy and safety.

Shelley Chu, a partner at Lightspeed, expressed optimism about Scorpion's targeted approach, suggesting that it may address the selectivity challenges that burden current treatment options and ultimately lead to better patient outcomes. The recent funding will also support the development of Scorpion’s EGFR inhibitors, STX-721 and STX-241, which are being developed in collaboration with Pierre Fabre.

The latest funding round saw participation from a broad range of investors including Willett Advisors, Omega Funds, Vida Ventures, Atlas Venture, Abingworth, Fidelity Management & Research Company, Boxer Capital, EcoR1 Capital, Surveyor Capital, Invus, Wellington Management, Nextech Invest, OrbiMed, Logos Capital, Woodline Partners, and Casdin Capital. This diverse backing underscores the confidence in Scorpion Therapeutics' innovative approach to cancer treatment.

In summary, Scorpion Therapeutics aims to overcome the limitations of first-generation PI3Kα inhibitors with its candidate STX-478. The recent $150-million Series C funding will bolster the clinical development of this promising treatment, potentially offering better efficacy and safety outcomes for patients. The company is also progressing its EGFR inhibitors in partnership with Pierre Fabre. The breadth of investor participation highlights significant confidence in Scorpion's potential to make a meaningful impact in the field of cancer therapy.