When Roche and Blueprint Medicine’s Gavreto got the FDA go-ahead in September to challenge Eli Lilly’s first-to-market Retevmo, the newer entrant lacked an indication boasted by its rival. But now, a new FDA greenlight has leveled the playing field.
The FDA has approved Gavreto in advanced or metastatic RET-mutant medullary or RET fusion-positive thyroid cancer, Roche and Blueprint said Tuesday. The accelerated approval means the two companies may need to provide more clinical data in confirmatory trials.
Gavreto was already approved for non-small cell lung cancer that bears an abnormality in the RET gene. The addition of thyroid cancer to its label puts Gavreto head-to-head against Retevmo, which earned its marketing rights in May.
Roche estimates that around 10% to 20% of people with papillary thyroid cancer—the most common type of thyroid cancer—have RET fusion-positive tumors, and almost all people with the rare medullary form of the disease carry RET mutations.
Gavreto proved its worth in the phase 1/2 Arrow study. The drug shrank tumors in 60% of previously-treated medullary patients and 66% in previously untreated participants. In RET fusion-positive thyroid cancer patients, the drug triggered a response in 89% of patients.
Gavreto’s thyroid cancer showing looked roughly similar to that of Retevmo’s in its own trial. In the phase 1/2 Libretto-001 study, Retevmo shrank tumors in 69% of previously treated medullary patients and 73% of new patients. In RET fusion-positive cases, the Lilly drug induced a response in 79% of patients who were radioactive iodine-refractory and had previously been treated with Bayer’s Nexavar and/or Eisai’s Lenvima. In eight patients who had not, the drug’s overall response was 100%.
The two drugs also put up similar numbers in NSCLC. And in a recent interview with SVB Leerink, an expert who’s the chief of medical oncology at an academic hospital in the Northeast also labeled the two RET inhibitors as “relatively similar.”
“While he only uses Retevmo in his practice, he believed that the datasets were similar and implied that they were relatively interchangeable in his mind,” SVB Leerink analysts Andrew Berens and Daina Graybosch wrote in an October investor note.
Retevmo has a side-effect warning on its label that Gavreto does not—an increased risk of a heart rhythm abnormality known as QT interval prolongation—but the expert shrugged it off, saying he didn’t believe that would give Gavreto any significant advantage.
Gavreto also cleared signs of tumors in more NSCLC patients than Retevmo did in their separate trials. Cross-trial comparisons can be problematic given differing trial protocols, and the expert “didn’t seem to think that the benefit was large enough to warrant distinction,” according to Berens and Graybosch.
When it comes to thyroid cancer, the tumor eradication data appear to favor Retevmo. The complete response rates for the Lilly drug were 9% for previously treated RET-mutant medullary thyroid cancer and 11% for treatment naïve patients. In RET fusion-positive thyroid cancer, 5.3% of patients who'd been previously treated with systemic therapy showed a complete response, while 12.5% of the systemic therapy-naïve patients did. For Gavreto, the rates were 1.8% and 10%, respectively, for the two medullary cancer groups, and 0% for the entire RET fusion-positive arm.
Another advantage for Gavreto is that it’s given once daily, while Retevmo is taken twice daily.
Roche signed on to help develop and market Gavreto in July. The collaboration should “facilitate physician access and biomarker testing to identify RET patients,” Berens wrote in a separate note in October. Plus, the Swiss pharma also comes with a broad set of oncology drugs that might be used in tandem with Gavreto.
So far, Gavreto is getting “broad access” with payers, Christy Rossi, Blueprint’s commercial chief said during a call with investors in October. “The pricing strategy that we’ve taken, I think has been incredibly well-received,” she added.
In the third quarter, Retevmo brought in sales of $11.6 million for Lilly.