Amgen’s Targeted Cancer Drug Shows Early Promise in New Areas

(Bloomberg) -- Amgen Inc.’s buzzed-about cancer treatment showed some promising signs that the experimental medicine might work in different tumor types.

In an early-stage study of 22 patients getting AMG 510 across a variety of cancers, three patients saw their tumors shrink and 13 didn’t have their cancer spread further while six showed signs of their disease progressing. The partial responders were patients with appendiceal and endometrial cancers and melanoma. The group didn’t include lung or colon cancer patients.

The most severe treatment-related side effects included diarrhea and pneumonia in two different patients.

The results build upon prior data looking at AMG 510 in lung and colon cancers. The medicine targets a tumor mutation known as KRAS G12C, once thought to be untreatable. The mutation is estimated to be present in roughly 13% of non-small cell lung tumors and as many as 5% of colon tumors. Greg Friberg, Amgen’s head of oncology, estimates it may be present in 1% to 2% of other tumor types.

A handful of companies are also racing to develop their own KRAS medicines.

Mirati Therapeutics Inc. is hot on Amgen’s heels, with therapies from Eli Lilly and Co., Johnson & Johnson and Revolution Medicines Inc. also in the running. Potential responses for AMG 510 in tumors outside of lung and colon cancers “would be a win for the entire class,” JPMorgan analyst Anupam Rama said in a note to clients before the results were published. He predicted Mirati, rated overweight at JPMorgan, could move as much as 15% higher if that happened.

The experimental cancer treatment has grabbed investors’ attention as Amgen looks to bolster its arsenal of new medicines to replace revenue from aging blockbusters including arthritis drug Enbrel and Neulasta, used by cancer patients to reduce infection. Bloomberg Intelligence analyst Marc Engelsgjerd said AMG 510 could drive more than $3 billion in annual sales in lung cancer alone. Colon and pancreatic cancers could add as much as another $500 million, he said via email.

Amgen also gave an updated look at results in colon cancer ahead of the American Society of Clinical Oncology meeting in late May, which is being held online this year due to Covid-19. In advanced colon cancer, three of 25 patients getting the target dose saw their tumors shrink, while another 20 didn’t see their cancer spread. Tumors also shrank to some degree among the 80% of patients who showed signs of stable disease, said Friberg, but not enough to meet the criteria to deem them partial responses.

“The challenge with colorectal cancer is even successful drugs, when you are on your fourth or fifth line of treatment typically don’t shrink tumors,” said Friberg. He views the 12% response rate as “encouraging” from the last update, so that “we think it compares favorably to what’s typical seen in this setting.”

Investors attending ASCO virtually will get a look at the medicine’s impact on survival and how long colon cancer patients live before their cancer gets worse.

Scientists have suggested such medicines may work best as part of a treatment cocktail, and Amgen has started testing the safety of AMG 510 in combination with other targeted therapies, including those that block proteins known as MEK and PD-1.

©2020 Bloomberg L.P.