(Wraps details of two FDA advisory panel votes)
By Toni Clarke
WASHINGTON, March 31 (Reuters) - A panel of advisers to the U.S. Food and Drug Administration gave favorable reviews on Monday to two new medications to treat acute bacterial skin infections.
The panel voted unanimously that Cubist Pharmaceuticals Inc's tedizolid and Durata Therapeutics Inc's dalbavancin showed substantial evidence of safety and efficacy.
The votes pave the way for approval of the drugs. The FDA is not obliged to follow the advice of its expert panels but typically does so. Cubist's shares closed up 4.4 percent at $73.15. Durata's shares rose 1.4 percent to $13.65 in after-hours trading.
The drugs are designed to treat serious acute bacterial skin and skin structure infections, or ABSSSI. These are infections that involve deep tissue or are associated with an underlying disease such as diabetes. The drugs are aimed at serious Gram-positive infections, including methicillin-resistant Staphylococcus aureus, or MRSA.
Tedizolid, which would be sold under the brand name Sivextro if approved, would be given once daily either intravenously or orally. Dalbavancin, which would be sold under the brand name Dalvance if approved, would be given in two doses, the first on day one and the second on day eight.
Panelists said they would like to see both companies conduct further safety studies once the drugs reach the market, but they agreed that the drugs would be useful new treatments.
Cubist's tedizolid can be dosed less frequently, given for shorter periods of time, and may have fewer side effects than linezolid, a rival treatment marketed by Pfizer Inc in the United States under the brand name Zyvox, they said.
"This is clearly an effective drug which will add to our armamentarium," said Dr. Thomas Moore, a panelist and clinical professor at the University of Kansas School of Medicine.
If approved, the drug is expected to generate annual sales of $219 million by 2019, according to the average estimate of six analysts polled by Thomson Reuters.
Results from its clinical development program showed tedizolid was not inferior to linezolid in terms of efficacy and could be given once a day for six days compared with linezolid's dosage of twice a day for 10 to 14 days.
Trials of dalbavancin showed the drug was not inferior when compared with a control group that included vancomycin or vancomycin followed by linezolid.
One analyst polled by Thomson Reuters sees dalbavancin sales reaching $449 million by 2019.
The main treatment for MRSA today is vancomycin, which is given intravenously and available generically. Cubist also sells another anti-infective, Cubicin, which generated global sales of more than $1 billion in 2013.
Panelists said they had some concerns about the potential for dalbavancin to cause liver problems, especially in patients with underlying liver disease, and recommended the company be required to conduct additional safety studies once the drug is on the market.
They also urged the FDA to work with the company to develop guidelines for patient follow-up after the initial dose has been given to ensure patients receive the critical second dose.
"I'm wondering how many people will get a shot of this, go out the door and never come back," said Dr. Michael Neely, a panelist and associate professor of pediatrics at the University of Southern California.
The urged that Cubist's drug be studied for safety over a longer period than that studied in the trial.
Cubist, based in Lexington, Massachusetts, acquired tedizolid with its 2013 purchase of Trius Therapeutics for about $704 million. Durata is based in Chicago. (Reporting by Toni Clarke in Washington; Editing by Bill Trott, Paul Simao and Steve Orlofsky)