TG Therapeutics, Rhizen to collaborate on PI3K delta inhibitor

NEW YORK—Biopharmaceutical company TG Therapeutics andRhizen Pharmaceuticals S A (Rhizen), a company specializing in therapeutics forcancer and immune disorders, have announced an exclusive global agreement. Thecompanies will collaborate to develop and commercialize Rhizen's lead drugcandidate, TGR-1202 (previously known as RP5264), a novel PI3K delta inhibitor.TG Therapeutics and Rhizen will develop the product jointly worldwide, with theexclusion of India, and will initially focus on indications in hematologicmalignancies and autoimmune diseases. Beyond the candidate compound, Rhizenwould contribute backup molecules offering opportunities for TG Therapeutics todevelop therapies against the same indications.

"We are excited to enter into this collaboration withRhizen Pharmaceuticals, whose innovative pre-clinical development program hasyielded an impressive portfolio of PI3K delta inhibitors that we are eager toadvance into development," Michael S. Weiss, executive chairman andinterim CEO of TG Therapeutics, said in a press release. "TGR-1202 hasalready demonstrated encouraging pre-clinical activity, and will serve toexpand our pipeline as we seek to develop much needed therapies for patientssuffering from hematologic malignancies."

Per the terms of the agreement, TG Therapeutics will payRhizen both upfront licensing and milestone payments based on early clinicaldevelopment, and will handle clinical development costs for the productsthrough Phase II. Following Phase II, both companies will be jointlyresponsible for all development costs. TG Therapeutics and Rhizen will eachretain an exclusive option that can be exercised at specific times duringproduct development, for TG Therapeutics to license the rights to TGR-1202. ifTG Therapeutics exercises that option, Rhizen will be eligible for upfront,development and commercialization milestone payments in addition to milestonepayments and royalties based on net sales of the product, with all told couldtotal more than $250 million. Rhizen will maintain rights to manufacture andsupply the product to TG Therapeutics, who will be responsible for clinical andregulatory development for the compound worldwide.

TGR-1202 is a highly specific PI3K delta inhibitor whichtargets the delta isoform with nanomolar potency as well as several foldselectivity over the alpha, beta and gamma isoforms of PI3K. thephosphoinositide-3-kinases (PI3Ks) are a family of enzymes known to be involvedin a variety of cellular functions, including cell proliferation and survival,cell differentiation, intracellular trafficking and immunity. In particular,the delta isoform of PI3K is implicated in B-cell related lymphomas, andinhibitors of the PI3K delta pathway are presumed to be effective against theproliferation and survival of B-cell lymphocyes. Inhibition of PI3K deltasignaling by use of TGR-1202 has demonstrated significant activity inpreclinical xenograft models as well as primary cells from patients withhematologic cancers. It is expected that an Investigational New Drugapplication will be filed for the compound by the end of this year.

"The deep clinical and regulatory development knowledgeand experience of the team at TG Therapeutics, and the existing clinicalprogram focused on B-cell malignancies, makes TG an ideal partner with which tocollaborate on development of TGR-1202," Swaroop Vakkalanka, president ofRhizen, said in a press release regarding the deal.

SOURCE: TG Therapeutics press release