Roche's Perjeta chalks up needed win in Herceptin combo trial, but questions remain

Perjeta's top-line victory in a new trial suggests it might nab sales growth in a new group of patients, but until full details are available, "some degree of hand-wringing will likely continue, in terms of just how big the clinical benefit is likely to be," Bernstein analyst Tim Anderson said.

Roche got its hoped-for win in a crucial breast cancer trial—at least in principle. The question is how big that win might be.

The Swiss-based drugmaker said Thursday that its next-gen HER2-positive cancer therapy, Perjeta, staved off cancer progression in patients at an early stage of the disease whose tumors had been surgically removed. The announcement didn’t include detailed data—those will be presented at a cancer meeting this year—but the bare fact of success suggests that a new FDA-approved use could be on the way for the Roche med.

The adjuvant trial, dubbed Aphinity, tested Perjeta alongside Herceptin, its gold standard treatment for HER2-positive breast cancer, and chemotherapy. The cocktail is already approved to treat metastatic breast cancer and early-stage disease before surgery, and the after-surgery treatment setting would be a sizable new market for Perjeta to tackle.

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That would be a welcome development for Roche as its top-selling drugs get ever closer to biosimilar competition. Herceptin’s turn could come as early as next year, some analysts say, with patent expiration set for 2019. That doesn’t give Roche much time to amp up sales of its other drugs to help absorb the blow—and a new Perjeta indication is one prospect investors have been watching very closely.

Compared with patients on Herceptin and chemo alone, patients in the Perjeta combo arm saw a “statistically significant reduction in the risk of recurrence of invasive disease or death,” Roche said in a release. The company says it will be taking the data to the FDA and European regulators.

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Bernstein analyst Tim Anderson said Thursday that the will-it-or-won’t-it question on Aphinity has been making Roche investors nervous, despite indications from previous trials that the Perjeta combo would work.

The fact that it did, in fact, work is likely to be a boost for Perjeta and could be a stabilizer for Herceptin down the road. The Perjeta combo uses have given Herceptin some help already, as the older drug is used for a longer time period in those indications. And importantly, the trial turned up no new safety signals for the combo. But Anderson figures that the new indication, if approved, won’t be an overwhelming driver of new sales.

“We have viewed the magnitude of the benefit as likely to be modest because Herceptin works pretty well,” Anderson wrote in a Thursday note, “yet good safety/tolerability would still drive meaningful sales growth.”

And until the specifics on the Aphinity results are presented—likely at the American Society of Clinical Oncology meeting in June—it’s unclear just how much the new data would change clinical practice. A breast cancer specialist told Bernstein analysts last year that the combo will need to deliver at least a 2% to 3% improvement over Herceptin and chemo alone.

“Without full details of the data … some degree of hand-wringing will likely continue, in terms of just how big the clinical benefit is likely to be,” Anderson noted. His firm now estimates that Perjeta sales would peak in 2022 at about 4.2 billion Swiss francs, or $4.16 billion, up from 1.85 billion francs last year (which itself marked 26% growth). For comparison’s sake, Herceptin brought in 6.78 billion francs in 2016.

Meanwhile, Herceptin biosims are marching forward. Mylan and Biocon have a Herceptin biosim under FDA review right now, Pfizer’s knockoff recently succeeded in a key trial, and Amgen and Allergan together have a version progressing toward the market.