Daiichi Sankyo is to buy drug discovery and development firm Plexxikon for $805 million up front. The deal comes less than two months after Plexxikon reported positive interim data from a Phase III trial evaluating its lead oncology candidate, PLX4032, in patients with previously untreated BRAF-mutation-positive metastatic melanoma. As part of the acquisition deal, Daiichi Sankyo could pay another $130 million in near-term milestones, dependent on approval of PLX4032.
“With the acquisition of Plexxikon, we see an opportunity to accelerate the building of our oncology franchise, particularly with the opportunity to co-promote PLX4032,” comments Joji Nakayama, Daiichi Sankyo CEO. “We have been impressed by the productivity and quality of Plexxikon’s pipeline, as well as discovery and early development capabilities. We intend to provide a high degree of independence to the Plexxikon group to support their continuing success.”
Plexxikon is developing PLX4032 in partnership with Roche, and in January negotiated a co-promotion deal for the drug with the latter’s Genentech business. Under terms of this deal Plexxikon would provide a specialty sales force to co-promote PLX4032 in the U.S. The firm also agreed to reimburse Genentech for certain marketing and promotion costs related to the product in exchange for enhanced royalties on product sales.
In January Plexxikon reported positive interim data from the open-label, Phase III BRIM3 trial, which is comparing PLX4032 therapy with dacarbazine in 675 patients with previously untreated metastatic melanoma with the BRAF mutation. The interim results confirmed that in comparison with dacarbazine therapy, treatment using PLX4032 boosted overall survival and progression-free survival.
Plexxikon is exploiting its Scaffold-Based Drug Discovery Platform™ to design drugs against a range of drug-target families. Lead candidate PLX4032 is a small molecule targeting cancers that harbor the oncogenic BRAF mutation. The candidate was taken into clinical development against BRAF-mutated melanoma back in 2006, and is now separately undergoing Phase I evaluation for the treatment of colorectal cancer. A DNA-based companion diagnostic to identify patients whose tumors carry the BRAF mutation is being developed by Plexxikon and Roche Molecular Diagnostics in parallel with the therapeutic development of PLX4032.
Behind PLX4032, the firm’s clinical pipeline includes the Phase II type 2 diabetes candidate, PLX-204, which has been designed to target all three PPAR (peroxisome proliferator-activated receptor) receptors: alpha, gamma, and delta. Plexxikon claims that in contrast to currently marketed PPAR compounds, PLX-204's activity on all three receptors is expected to modulate lipids and cholesterol as well as lower glucose. Another of the firm’s anticancer compounds, PLX3397, is designed to target the kinases Fms, Kit, and Flt30lTD. This candidate is currently undergoing Phase I evaluation, and Plexxikon says it plans to initiate Phase II studies this year to evaluate PLX3397 against a number of cancers including Hodgkin lymphoma, AML, glioblastoma, and metastatic breast cancer. At the end of January the firm’s oral Fms kinase inhibitor, PLX5622, started in Phase I development as a potential treatment of rheumatoid arthritis.
Plexxikon’s preclinical pipeline includes a protease inhibitor candidate for the treatment of hypertension and kinase inhibitor programs targeting Alzheimer disease, multiple sclerosis, polycystic kidney disease, and systemic lupus erythematosus.