More than two-thirds of patients responded to an experimental bladder cancer treatment from Merck and Seagen, according to a weekend update that bolstered Merck stock on Monday.
The test results could "rewrite textbooks," Marjorie Green, a Merck senior vice president, told Investor's Business Daily. Green is also head of late-stage oncology development for Merck.
Merck and Seagen studied a combination of blockbuster cancer drug Keytruda and Seagen's Astellas Pharma-partnered Padcev. Keytruda is an immuno-oncology drug while Padcev is an antibody drug conjugate, or ADC. Immuno-oncology drugs help the immune system uncover camouflaged cancer cells, while ADCs deliver a toxic load of chemotherapy directly to tumors.
After a median of 17.2 months, 67.7% of patients responded to the regimen compared to just 44.4% of chemotherapy recipients. The combination reduced the risk of disease progression or death by more than 50%.
"These results are just tremendous," Green said in an interview. "They rewrite textbooks. They're astonishingly good. It's the first I-O, ADC combination that's shown in a Phase 3 study what it can do."
On today's stock market, Merck stock rose 0.7% to close at 103.35. Seagen stock ended the day with a 0.7% gain, at 216.87. Pfizer is working to acquire Seagen for $43 billion. Pfizer stock inched 0.6% ahead, to 30.84. Astellas stock closed up 4.2% at 12.98.
Merck Stock Is Tied To Severe Cancer
Merck and Seagen studied the treatment in patients with metastatic or unresectable bladder cancer. This means their cancer has spread broadly and can't be surgically removed. This is a severe form of cancer in which just 5% of patients will survive for five years following their diagnosis.
Typically, bladder cancer patients will receive cisplatin-based chemotherapy. Cisplatin is a powerful drug, but it carries numerous side effects and some patients are too sick to receive it. For patients who can't get cisplatin, there are other chemotherapies. But some patients are also too sick for those treatments. Keytruda, alone, is an option for that subset of patients. But just 29% of patients respond to it.
"The majority of patients who receive Keytruda as a monotherapy don't have a major response," Green said. "That's why this data is so compelling."
Overall, 886 patients received either the Keytruda/Padcev combination or a chemotherapy regimen. Patients who received the experimental treatment lived for a median of 12.5 months before their cancer worsened — a measure known as progression-free survival — compared to just 6.3 months for the chemotherapy group. So, the test combination cut down on the risk of disease progression by 55%.
Notably, patients who received the Keytruda/Padcev regimen were 53% less likely to die than those given chemotherapy.
Leerink Partners analyst Daina Graybosch says the results in bladder cancer treatment "bested decades-old standards of care." The results also push Merck to the forefront of medical research, helping replace chemotherapy in their Keytruda regimens with antibody drug conjugates, she said.
"The (bladder cancer treatment) results bridge the Merck of the last decade to the Merck of the next decade — (Keytruda) combined with a targeted antibody drug conjugate toppled traditional platinum-based chemotherapy," she said in a report.
She has an outperform rating on Merck stock.
Side Effects In Line With Expectations
Bullishly for Merck stock, the combination yielded similar side effects to each drug individually.
Nearly 56% of patients who received Keytruda and Padcev experienced at least one severe, but not life-threatening, side effect. In comparison, 69.5% of chemotherapy recipients reported the same level of side effects. The most common among the Keytruda/Padcev group were rash and hyperglycemia.
"But these side effects are generally manageable," Green said.
The Food and Drug Administration has already granted the Keytruda and Padcev combination an accelerated approval in patients ineligible for cisplatin-based chemotherapy. The new test results could help Merck and Seagen seek a traditional approval, and expand treatment to patients who can receive cisplatin-based chemo, but might do better on the Keytruda and Padcev combo.
Green, an oncologist by training, says she tries not to be "overly bold" in her statement. But she called the results "fantastic," saying there hasn't been any major advance in previously untreated bladder cancer treatment in two decades.
"Having something like this where you double survival is something we don't see often in oncology," she said. "I hope people appreciate how special the data is."
Merck Stock Is Under Pressure
Still, Merck stock remains under pressure. Shares are far below their 50-day and 200-day moving averages, according to MarketSmith.com. This is reflected in the IBD Digital Relative Strength Rating of 56, putting Merck shares in the bottom 56% of all stocks when it comes to 12-month performance.
Seagen stock, on the other hand, is highly rated with an RS Rating of 96 out of a best-possible 99.
Follow Allison Gatlin on X, the platform formerly known as Twitter, at @IBD_AGatlin.
