Roche snags another Perjeta combo nod, but will 'weak' data limit its use?

Perjeta
Roche's Perjeta racked up $1.08 billion in sales through the first half of 2017.

Analysts and investors think Perjeta’s end-of-the-year indication may not be as lucrative as they once hoped.

The FDA green-lighted the drug in tandem with giant Herceptin and chemo for HER2-positive, post-surgery breast cancer patients with a high risk of recurrence. Patients should receive up to 18 cycles of the regimen over the course of one year, according to the indication.

RELATED: How much does Perjeta add to Herceptin postsurgery? Depends how you slice it

Regulators based the go-ahead on data from a phase 3 trial that in June sent shares plunging and Roche scrambling for “damage control,” as one analyst put it. The reason? After a previous top-line announcement cued high hopes from industry watchers, the Swiss drugmaker revealed that adding Perjeta to the equation held off cancer in 94.1% of patients at the three-year markjust one percentage point more than the 93.2% of patients who achieved the same result on Herceptin and chemo alone.

Roche, for its part, pointed out that the difference translates to a 19% lower chance of developing invasive breast cancer. “The goal of treating breast cancer early is to provide people with the best chance for a cure. While we come closer to this goal with each advance, many people still have a recurrence and progress to the metastatic stage,” Roche CMO Sandra Horning said in a statement on the approval.

RELATED: ASCO fallout: Roche does 'damage control' after Perjeta combo disappoints investors

In June, though, Bernstein’s Tim Anderson called the data “weak” and predicted that they “very likely will confine use to higher-risk" patients, rather than the broader population.

Meanwhile, Rocheand Perjeta, specificallygot another regulatory boost alongside the post-surgery approval, with the FDA converting an accelerated approval for Perjeta-Herceptin-chemo trio in pre-surgery patients to a full approval. Pre-surgery use helped the medication rack up CHF 1.07 billion ($1.08 billion) in the first half of 2017 and push sales for Roche’s HER2 franchise up by 6% over the year-ago period.