A federal judge has upheld a Takeda Pharmaceutical and Abbott Laboratories patent for the drugmakers’ jointly marketed heartburn drug Prevacid.

The ruling “will ease investor concerns regarding the pending split of the TAP joint venture between Abbott and Takeda,” analyst Lawrence Keusch of Goldman Sachs said in an investor note. “The ruling should also keep generic competition at bay and allow Abbott to collect royalties on an intact Prevacid franchise prior to the patent expiration in 2009.”

US District Judge Sue Robinson, in Wilmington, Delaware, ruled a patent on Prevcid is both valid and enforceable.

Generics drugmaker Teva, which sought to market a copycat version of the drug, has pledged to appeal.

Prevacid is made by TAP Pharmaceutical Products, a joint-venture between Takeda and Abbott.  Last month, the companies agreed to split the venture, with Takeda getting Prevacid. Analysts said in published reports that the court decision will ensure that agreement goes as planned since a loss would have required a renegotiation between Abbott and Takeda.