$21 Billion Bet On Cancer Drug Trodelvy: What Does It Mean for Patients?

The FDA gave accelerated approval to Trodelvy this past spring for people with advanced triple-negative breast cancer who had already tried, but hadn’t improved on at least two other treatments. The approval came after a study called ASCENT,  in which tumors shrank in over one-third of patients. Among people who improved on the drug, more than half maintained their response for six or more months, and nearly 17% maintained it for a year or more. This is really good news. In fact, Trodelvy was so effective that the study was halted early to give more people access to it.

Before this approval, these patients were usually treated with traditional chemotherapy which had poor response and survival rates or they were enrolled in a clinical trial. “Patients now have an option of a more targeted therapy with improved progression-free survival and overall response rates compared to standard chemotherapy,” Dr. Berger says. Studies are under way to see whether Trodelvy also improves overall survival.

Related: What is Triple-Negative Breast Cancer?

Gilead plans to launch several studies to see which patients will benefit most from Trodelvy, both on its own and combined with other drugs, Daniel O'Day, the company's chairman and chief executive officer, said in a company statement. Studies are currently investigating whether the treatment might also work against lung cancer and other types of solid (non-blood) cancers.

How Does Trodelvy Work?

Triple-negative breast cancer affects between 10 to 15% of people with breast cancer. It's called "triple-negative" because the cells don't have estrogen or progesterone receptors, and they don't make much of the protein human epidermal growth factor receptor 2 (HER2). That makes them tough to treat, on top of the fact that they grow faster than other breast cancers, which makes the approval of Trodelvy such an important milestone.

Related: Treatment Sequence for Triple-Negative Breast Cancer 

Trodelvy is a new type of targeted therapy called an antibody drug conjugate (ADC). It’s designed “to kill cancer cells while minimizing toxicity to healthy cells,” Dr. Berger says. It combines a man-made protein called a monoclonal antibody, which targets a specific protein called Trop-2 that’s on the surface of many triple-negative breast cancer cells. Once the ADC binds to the cancer cells, it releases a chemotherapy drug directly into the cancer cell that leads to the cell’s death. The drug is also released on the outside of cancer cells, so it can kill nearby cancer cells that may not contain Trop-2.

Medical oncologist Dr. Elizabeth Comen overviews the treatment options for those who've been diagnosed with triple-negative breast cancer

 

Possible Side Effects to Trodelvy

The most common side effects from Trodelvy include:

• Nausea
• Vomiting
• Diarrhea
• Constipation
• Fatigue
• Hair Loss
• Appetite loss
• Rash
• Belly pain

This drug carries a boxed warning about the risk of more serious side effects, such as low white blood cell counts and severe diarrhea. White blood cells are the immune system’s infection fighters, and a drop in these cells could increase your risk of getting sick. If you take this drug, your doctor has treatments to boost your white blood cell count and to relieve diarrhea. Your doctor should carefully monitor you for side effects while you take Trodelvy, and lower the dose or stop the drug entirely if your side effects are serious.

Related: 'This was the one thing we could control" A Young Mother Diagnosed with Triple-Negative Cancer Decides to Have Her Wedding Safely Amidst Treatment and the COVID-19 Pandemic

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