IDRx funding, valuation and investors

Latest tracked event: Acquired by GSK (January 2025). It is shown separately because it is not counted as disclosed equity funding.

Overview

IDRx, incubated by Borisy Labs and launched in August 2022, develops purpose-built precision combination therapies for cancer—starting with gastrointestinal stromal tumors (GIST) driven by KIT mutations. The Plymouth, Massachusetts company in-licensed IDRX-42 from Merck KGaA and IDRX-73 from Blueprint Medicines, initiating a Phase 1 trial at launch. Andreessen Horowitz co-led a $122M Series A with Casdin Capital; Nextech Invest and Forge Life Science Partners participated. In January 2025, GSK agreed to acquire IDRx for up to $1.15 billion ($1B upfront plus $150M regulatory milestone), completing the deal to gain IDRX-42—a selective TKI covering primary and resistance KIT mutations where treatment options are limited.

Why IDRx is interesting

Alexis Borisy's second act after EQRx: IDRx launched clinical-stage with $122M Series A and purpose-built TKIs for KIT mutations—GSK paid $1B upfront for lead asset IDRX-42.

Product & use cases

IDRx designs selective tyrosine kinase inhibitor combinations that hit driver mutations and anticipated resistance pathways in GIST—aiming for durable responses earlier in treatment versus sequential single-agent therapy.

• First-line and relapsed GIST where KIT resistance mutations limit existing TKIs
• Combination regimens engineered upfront vs. reactive sequencing after failure
• Precision oncology pipelines expandable beyond GIST with in-licensed assets

Key facts

• Series A (Aug 2022): $122M co-led by a16z and Casdin at clinical stage (Businesswire)
• Phase 1 IDRX-42 initiated at launch; licensed from Merck KGaA (Businesswire)
• GSK acquisition up to $1.15B announced Jan 2025, completed thereafter (GSK, Guardian)
• Co-founders include Alexis Borisy and CEO Ben Auspitz (CombinatoRx alumni)

Funding history (newest first)

Investors in our directory

Funds linked from IDRx's profile — open a fund page for stage focus and related deal articles.

Competitive landscape

Edge: Clinical-stage start with two licensed TKIs and world-class GIST advisors (George Demetri, Nicholas Lydon)—plus Borisy's combination-therapy thesis honed since CombinatoRx.

GIST treatment progresses from imatinib to sunitinib/regorafenib to Qinlock, but resistance mutations remain a gap. IDRX-42's preclinical/clinical profile against diverse KIT mutations attracted GSK's oncology build-out. Combination design is differentiated but unproven commercially until registrational data read out.

• Blueprint Medicines adjacent

  GIST/franchise competitor and licensor of IDRX-73; also sells avapritinib for PDGFRA-driven GIST.

• Novartis (Gleevec/generic imatinib) incumbent

  Standard first-line TKI; most patients develop secondary KIT mutations requiring next-gen agents.

• Deciphera (Qinlock) direct

  Approved for advanced GIST after prior TKIs; IDRX-42 targets broader mutation coverage.

Notable stories

• Marc Andreessen noted Borisy had pursued combination cancer therapy since CombinatoRx in 2000—"bad timing" then, different moment now (a16z announcement).
• Nicholas Lydon co-developed Gleevec—the baseline TKI IDRx aims to improve upon for resistant GIST (Inside Precision Medicine).
• GSK cited IDRX-42 activity against all clinically relevant primary and secondary KIT mutations as deal rationale (GSK press).

Industries

Related funding articles

Venture Capital Tracker pieces that cover IDRx's financing or category context.

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