On Thursday afternoon, the American Society of Clinical Oncology will release summaries of many of the nearly 3,000 studies set to be presented early next month at the medical association’s annual meeting.
These abstracts offer an early glimpse of the wide array of cancer research that will be featured at the conference, which is typically considered the field’s largest and most influential.
Details for some of the highest-profile studies won’t be released, as they’re held back for disclosure during the meeting as “late-breaking” abstracts. ASCO previously released titles of all abstracts, however, giving a hint of what’s to come at the conference, which is being held from June 3 to June 7 in Chicago and online.
Here’s a preview of three late-breaking studies and the context for why they’ll be closely tracked by doctors and investors.
Can Enhertu change how breast cancer is treated?
Over the past couple years, Enhertu, an antibody drug from Daiichi Sankyo and AstraZeneca, has become a go-to treatment option for breast cancer patients whose tumors overexpress a protein known as HER2. The drug was conditionally approved for third-line use in treating metastatic disease in 2019, but has since been shown to help in additional settings. Earlier this month, U.S. regulators cleared Enhertu for second-line care, where it could challenge long-dominant drugs from Roche.
A late-breaking presentation at ASCO could help support further expansion of its use and, depending on the details, might change the way breast cancer tumors are treated.
The data are from a study known as DESTINY-Breast04, which tested Enhertu in patients whose tumors express very little HER2. These “low expressors” are a large group, representing more than half of all breast cancer patients — including many with HR-positive tumors, the most common form of the disease. Their status makes them ineligible to receive widely used HER2-targeting medicines from Roche, Seagen and Macrogenics. Chemotherapy is the only option for HR-positive patients who have progressed after hormone therapy, as well as for people with HR-negative tumors.
Enhertu could be a new choice, though it’s unclear how much benefit it might offer. In March, AstraZeneca and Daiichi said, without offering any details, that their drug kept tumors from spreading and extended survival longer than doctors’ choice of chemotherapy. Specific data will be revealed at ASCO, and could show whether the drug helps all patients with low HER2 levels or only a more narrow group.
Safety, too, will be important, as Enhertu has been associated with a type of lung scarring that requires stringent monitoring to detect and manage.
AstraZeneca and Daiichi will present the study details at a plenary session on June 5.
Will Trodelvy live up to expectations?
Gilead has spent billions of dollars and more than a decade trying to build an oncology business, with mixed results. Its cancer drug sales, though growing, still make up only a fraction of its total revenue. Those numbers, along with some notable clinical and regulatory setbacks, have left investors and analysts questioning whether Gilead’s money was well spent.
Gilead is counting on its biggest investment, a $21 billion purchase of Immunomedics and its cancer drug Trodelvy, to help change the narrative.
So far, sales of Trodelvy, which is currently approved for advanced bladder cancer and triple-negative breast cancer, have been modest, totaling $380 million in 2021 and $146 million last quarter. To match Gilead’s blockbuster expectations, Trodelvy needed to succeed in a Phase 3 study known as TROPiCS-02, which enrolled patients with HR-positive, HER2-negative breast cancer — a form of the disease that accounts for 60% to 70% of all breast cancer cases.
In March, Gilead said Trodelvy met that trial’s goal, reducing the risk of cancer progression or death compared to physicians’ choice of chemotherapy. But it didn’t disclose any specific data and took the unusual step of publishing a “frequently asked questions” document to express its confidence in the study’s results.
The disclosure sent Gilead shares down to their lowest levels since late 2020 and heightened anticipation for further details, which will be presented at ASCO next week. Analysts and investors will be watching to see the magnitude of Trodelvy’s benefit, which will be important in convincing doctors to use it instead of cheaper chemotherapies.
What will Roche’s study results say about TIGIT?
Until recently, an emerging group of cancer medicines aimed at a cellular target called TIGIT were viewed as the next step forward for cancer immunotherapy. Promising results from early studies run by Roche and Merck & Co. helped catalyze a string of acquisitions and investments by Bristol Myers Squibb, GlaxoSmithKline and Gilead, while multiple treatments have now advanced into late-stage testing.
Yet TIGIT inhibitors face new questions. Since March, Roche’s TIGIT prospect, tiragolumab, has failed two Phase 3 trials in different forms of lung cancer. The results are the first two late-stage readouts for anti-TIGIT drugs and have led biotech analysts to wonder whether the treatments will become the latest immunotherapy partner to fall short of expectations. There have already been ripple effects. One TIGIT drug developer, iTeos, recently said it and partner GSK are evaluating “how best to proceed” in light of Roche’s findings.
Roche hasn’t disclosed the details of either study. Negative results for the first, a trial called SKYSCRAPER-02, will be unveiled at ASCO on June 5. Although the study was run in a particularly aggressive and tough-to-treat type of lung cancer, the data could still yield answers about TIGIT ahead of the next big readout: a Phase 2 study from Gilead and partner Arcus Biosciences, which is expected to deliver results in the second half of the year.