Nearly half of breast cancer patients (those with low level HER2 protein) targeted treatment options have always been limited. Palliative chemo has been (up ‘til now) “the gold standard.” Dr. Shanu Modi, who is the lead researcher of a groundbreaking trial, proved a drug that combines antibody with a chemotherapy—trastuzumab deruxtecan (T-DXd) can control cancer cells AND extend survival in Stage 4 HER2-low breast cancer patients. More good news is that the TDXd has been FDA approved to be tested on other cancers and morphing oncology treatment, in general.
There is a cancer treatment podcast called “Cancer Straight Talk” from Memorial Sloan Kettering that brings together patients and experts showing straightforward evidence-based conversations. Dr. Diane Reidy-Lagunes hosts for purposes of educating and empowering patients along with their family members. If any of you have questions, feedback or topic suggestions for upcoming episodes, please email: MSKPodcast@mskcc.org
HER2 status (in breast cancer) means that the cancer has a lot of this protein on the surface of its cells which makes the cancer behave more aggressively. Targeted therapies that are extremely active against the HER2 driven cancers haven’t been that effective.
HER2-negative cancers make up a large variety of cancers, many of which have a low level of HER2 protein, so we refer to them as HER2 low. To date, most excellent targeted therapies have NOT been effective against these HER2-low breast cancers and because of this they have taken on the name of HER2-negative, which means, basically, there have been no targeted therapy options.
HER2-low is expressed on nearly half of all breast cancers, so it is a large population of patients who now have the potential to benefit from T-DXd!
The reason the T-DXd works is because it can bind to very small amounts of HER2 expression on cancer cells. It is made up of an antibody trastuzumab or Herceptin (brand name) and its job is to findHER2 and attach to it on the surface of the cell. The T-DXd antibody is linked with six, seven or eight molecules of a very potent chemotherapy drug, deruxtecan. When trastuzumab or Herceptin binds to its HER2 target on the cells, the entire complex including the deruxtecan becomes internalized. It dumps the chemo right inside the breast cancer cell!
T-DXd can target and combine successfully with cancer cells with even the lowest levels of HER2. This is the first HER2 targeted therapy that works on HER2-low breast cancer!
Subsets of stomach, lung and colorectal cancer and other cancers are known to express the HER2, as well, and T-DXd is already approved for a subset of patients with advanced gastric cancer and is under testing for its benefits in other tumor types to treat people who have HER2-expressing or HER2-altered tumors.
TDXd has the potential to significantly improve treatment outcomes for a large population of patients with cancer. It opens up a whole new avenue of research which is great news for all cancer patients.
Now onto an even more important issue. How do regular people afford this treatment? The reason I’m so keen on this aspect is because a lady with breast cancer who lived in my mom’s condo had a treatment which worked very well (it may have been the drug touted in this column?), but cost her $30,000 per month. She easily afforded it, but this scenario won’t work for the masses, so what is available?
For those who cannot afford cancer drugs, access is often facilitated via a combination of public and private entities that offer financial assistance including PAPs (patient assistance programs) run by pharmaceutical companies, government health insurance plans like Medicare, nonprofit organizations and family foundations, charitable donations, allowing individuals to receive treatment even if they can’t fully cover the cost themselves. However, this system still faces challenges with affordability and access for many patients, so, until this part can be fully repaired, the bottom line and bad news are that only the rich can afford treatment. As always, the key is “prevention” and what ALL cancers need to thrive is “glucose and glutamine,” so if we can keep both of these to a minimum in our diets, we will have a great chance of escaping cancer!
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