With Gilead Sciences Inc.'s planned $11.9 billion acquisition of Kite Pharma Inc., the Silicon Valley biotech is pivoting to an oncology focus, executives said on a conference call.

Kite Pharma is centered on immuno-oncology with KTE-C19, a chimeric antigen receptor T-cell treatment, or CAR-T therapy, leading its portfolio.

Gilead, meanwhile, has made a large part of its fortunes on hepatitis C and HIV treatments, but calls for an acquisition have grown louder since the company cut sales expectations earlier this year due to falling hepatitis C numbers in the U.S.

"Our oncology efforts have been fairly nascent and we've had few real successes in those areas. This is a pivot to cellular therapy as our main strategy going forward," Gilead CEO John Milligan said on the Aug. 28 conference call.

Milligan added that the company is going to review its own portfolio and that the business development group is still active.

"We're not going quiet after this deal, we'll continue to use the team to look for many opportunities," he said, adding that cellular therapy could be considered a "cornerstone" of the strategy now.

CAR-T therapy, which uses genetically engineered cells to fight blood cancer, is a relatively new treatment avenue that only Kite and Switzerland-based Novartis AG have made substantial progress on.

With Novartis' earlier filing and positive support from a U.S. Food and Drug Administration panel, it is likely to reach the market before Kite's own treatment. Analysts in the call wondered if this would factor into future pricing strategy.

Gilead executives said that while Novartis is further on the approval path, it is aiming for a pediatric blood cancer indication, bringing it a different and likely narrower market than what Kite is aiming for.

Gilead drew fire in 2014 when it launched cutting-edge hepatitis C medicines with price tags of roughly $1,000 per pill. Those treatments, Sovaldi and Harvoni, helped the company nearly triple its revenues from 2013 to 2015, but sales have plateaued recently, and competition is closing in on the space.