Startup Ultragenyx snags PhII program for growing rare-disease pipeline


Flush from raising more than $100 million, Novato, CA-based startup Ultragenyx Pharmaceutical has stepped up with a new pact to partner on a rare bone-disease drug from Japan's Kyowa Hakko Kirin.

Under the guiding hand of BioMarin veteran Emil Kakkis, Ultragenyx will step in to co-develop KRN23, an antibody designed to treat X-linked hypophosphatemia which is now wrapping a Phase I/II study at KHK. Ultragenyx will now take over development responsibilities, while sharing costs with the Japanese pharma as they take aim at the U.S., Canadian and European markets.

"The collaboration combines KHK's broad antibody-based discovery, manufacturing and development capabilities with our expertise in the clinical development of novel therapeutics for rare genetic diseases," says Kakkis in a statement. "We look forward to working closely with the KHK team, investigators, and patients on continuing development of KRN23, a much-needed new therapy for XLH patients."

Launched only two years ago with a $45 million A round from TPG Biotech, Fidelity Biosciences, Europe's HealthCap and Pappas Ventures, Ultragenyx has been growing at a rapid pace. Its latest pipeline update now includes an impressive slate of four mid-stage programs for rare diseases, with one early-stage effort and more waiting in the preclinical wings.

XLH is a rare ailment triggered by inadequate mineralization of bone that can cause short stature and various abnormalities. The standard treatment today is oral phosphate replacement and vitamin D (calcitriol) therapy, which the biotech says is poorly tolerated and only partially effective at restoring bone physiology and growth.

KRN 23--which has completed several early-stage studies--works by binding to inhibiting fibroblast growth factor 23, a hormone that promotes phosphate excretion by the kidney and suppresses vitamin D production.