Pharma, Startups

Genzyme spinout X4 Pharmaceuticals lays out clinical plan

The company’s CXCR4 inhibitors work to modulate the tumor microenvironment – improving the efficacy of the immune system in fighting cancer.

X4 Pharmaceuticals, a Cambridge startup with deep ties to Genzyme, has laid out its clinical development plans for its small molecule CXCR4 antagonists that help rev up the immune system and declutter the tumor microenvironment.

The company recently closed out a $37.5 million financing round, and will use the funding to push its lead candidate into the clinic next year for kidney cancer and another solid tumor cancer. It has licensed its core technology from Genzyme – and has several Genzyme alumni on its roster.

Genzyme has one CXCR4 antagonist under its belt – Mozobil, an immunostimulant used in one- or two-day bursts to prime patients for stem cell transplants. The creator of Mozobil is the cofounder of X4.

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Unsurprisingly, the company is backed by Henri Termeer, the former chairman, president and CEO of Genzyme.

“Like all companies, there was a prioritization list,” CEO Paula Ragan said in a phone interview. “Within the Genzyme/Sanofi world, this technology was not prioritized in a way that the company wanted – but they believed in the biology, and thought it best placed in a startup.”

Ragan, a Genzyme alum, says that X4 maintains a collegial relationship with its progenitor, but outside of the license has no formal agreements in place.

X4’s technology targets and inhibits CXCR4 – a receptor that’s over-expressed in several forms of cancer. It impacts the tumor microenvironment, modulating two different mechanisms in cancer – so as to reduce cancer growth and improve immune surveillance.

Specifically, inhibiting CXCR4 can stop a tumor from recruiting immunosuppressive and pro-angiogenic cells, allowing immune cells to attack the cancer and cut off its blood supply.

X4 is launching clinical trials next year for its lead drug candidate, X4P-001, in a number of advanced cancers, including refractory clear cell renal cell carcinoma. It’s also in preclinical development for a second drug program, X4P-002, which will be meant for brain cancers and expected to enter the clinic in 2017. The drug is meant to be taken orally.

X4’s drug is the only small molecule CXCR4 antagonist in the clinic.