Seagen's Tukysa picks up FDA priority review after Merck buyout talks said to sputter

After a potential $40 billion merger between pharma giant Merck & Co. and antibody-drug conjugate (ADC) specialist Seagen reportedly stalled on pricing last month, Seagen is pushing ahead solo and has nabbed an FDA priority review for Tukysa.

Seagen’s Tukysa has snagged a priority review alongside Roche’s Herceptin for adults with previously treated HER2-positive colorectal cancer, the company said Monday. The speedy regulatory tag comes a little more than two months after Seagen unveiled full results on the Tukysa-Herceptin combo from its pivotal phase 2 Mountaineer trial at the European Society for Medical Oncology (ESMO) World Congress on Gastrointestinal Cancer.

Now, the FDA has said it will deliver its approval verdict on the combo in colorectal cancer by Jan. 19, 2023.

In Mountaineer, the Seagen-Roche combo helped colorectal cancer patients live a median of 24.1 months. The anti-cancer duo also helped patients live a median of 8.2 months without tumor progression.

An approval could be significant, given that “[t]here are currently no FDA-approved therapies for metastatic colorectal cancer that specifically target HER2,” Marjorie Green, M.D., SVP and head of late-stage development at Seagen, said in a statement. The protein in question—human epidermal growth factor receptor 2 (HER2)—is overexpressed in about 3% to 5% of patients with metastatic disease, the company explained.

“Precision medicine is key for patients with HER2-positive mCRC,” Sebastian Stintzing, a professor at Charité Universitätsmedizin in Berlin, Germany, told ESMO Daily Reporter earlier this month. “Although this is a phase II study that recruited a small number of patients, the findings are optimistic considering the rarity of HER2 positivity and provide support for HER2 testing in this setting,” he added.

Seagen estimates some 151,000 people will be diagnosed with colorectal cancer in the U.S. this year, noting that the rate of disease is ticking up in older adults.

The regulatory update comes as industry watchers wait with bated breath for news on Merck and Seagen’s potential tie-up. Back in early July, The Wall Street Journal reported Merck was in advanced talks to buy Seagen for $40 billion or more. Come late August, however, the deal had hit a roadblock over price, Bloomberg reported, citing sources close to the negotiations.

Still, the buyout remains on the table, Bloomberg noted last month.

Pipeline aside, Seagen is scanning the horizon for a new chief executive after former CEO Clay Siegall resigned in May. Siegall stepped aside in light of domestic violence allegations, which the ex-Seagen helmsman has denied, explaining that he’s in the midst of a divorce.

In the meantime, Seagen has slotted its four-year chief medical officer Roger Dansey, M.D., into the CEO seat.

Seagen boasts approvals for a quartet of cancer treatments and last year took home revenues of $1.6 billion.