Idenix Pharmaceuticals has regained the rights to hepatitis C compounds that were partnered with Novartis and announced plans to raise $150 million.

The US firm and the Swiss major first teamed up in May 2003 when the latter purchased a 54% stake in Idenix and licensed the hepatitis B treatment Tyzeka/Sebivo (telbivudine). Under the original agreement, Novartis had the option to license any of Idenix' candidates after proof-of-concept, so long as it maintained at least a 30% stake.

Novartis currently has a 31% holding but the pact has now been restructured. The option to license Idenix's development-stage drug candidates in any therapeutic area has been terminated and Novartis will be entitled to royalties on future hepatitis C virus drugs.

Novartis will have a non-exclusive option to conduct trials evaluating a combination of any of its and Idenix' HCV drug candidates, and the latter firm will no longer receive royalty or milestone payments from Tyzeka/Sebivo sales. The Basel-headquartered group will retain the right to designate one member to Idenix's board, reduced from two, as long as it continues to own at least a 15% stake.

Ron Renaud, Idenix chief executive, said the new agreement gives the firm "increased flexibility to optimise the value of our pipeline". By regaining the worldwide rights to all its drug candidates, "we believe Idenix will be well-positioned to develop pan-genotypic all-oral direct-acting antiviral combination treatments with potential collaborators," he added.

As the restructured deal was being announced, Idenix noted that it has commenced an underwritten registered public offering of $150 million of its common stock.

The proceeds will be used to develop combination Phase IIb trials of its HCV drugs IDX184 and IDX719, and Phase IIa studies with IDX19368 in combination with ribavirin. The funds may also be used to "potential acquisitions of new businesses, technologies or products that Idenix believes complements or expands its business".