Wow!! Thank you. This is far more information than I was able to find in my searches. Thank you so much for your willingness to share all this!🤗

You're welcome Cathy. I'm big on research and like to share what I learn 🤓

I have copied and pasted the below info from breastcancer.org. It gives a detailed and easy to understand explanation about CDK inhibitors. I've only copied the first 4 paragraphs, but if you go to their website you can read the rest of it if interested.

"HER2-negative breast cancer. These medicines interrupt the process through which breast cancer cells divide and multiply. To do this, they target specific proteins known as the cyclin-dependent kinases 4 and 6, abbreviated as CDK4/6. That's why you may hear them referred to as targeted therapies.

If a breast cancer is hormone receptor-positive, it means the cancer’s growth is fueled by the hormones estrogen, progesterone, or both. HER2-negative cancers have tested negative for a protein called human epidermal growth factor receptor 2, or HER2, which promotes cancer cell growth. So HER2-negative cancers don’t respond to treatments that target the HER2 protein (such as Herceptin). More than two out of every three breast cancers are both hormone receptor-positive and HER2-negative.

The CDK4/6 proteins, found both in healthy cells and cancer cells, control how quickly cells grow and divide. In breast cancer, these proteins can become overactive and cause the cells to grow and divide uncontrollably. CDK4/6 inhibitors interrupt these proteins in order to slow or even stop the cancer cells from growing.

All three CDK4/6 inhibitors are pills taken by mouth, but they are used a little bit differently. Verzenio is a pill that you take every day, either alone or with other treatments. It appears to affect the CDK4 protein more than the CDK6 protein. Ibrance and Kisqali affect both CDK4 and CDK6 and have to be taken along with hormonal therapy. They are also given in four-week cycles that include a week-long break — so you would take the medicine for three weeks and then take one week off."

Here is the link 🤓

https://www.breastcancer.org/treatment/targeted...

What Are CDK4/6 Inhibitors?
What Are CDK4/6 Inhibitors?
https://www.breastcancer.org/treatment/targeted...

What Are CDK4/6 Inhibitors?

https://www.breastcancer.org/treatment/targeted-therapy/what-are-cdk46-inhibitors

I just made a couple of posts regarding Kisqali in the Side Effects group. I am copying them to this post. Here is the first post. Second post to follow on separate reply.

Kisqali does offer payment assistance, but only if you are on a "Commercial" insurance plan. That means your insurance is not Medicare or Medicaid. The info is on their website. I am in the process of making a spreadsheet with all the side effects of the 3 CDK inhibitors which are Kisqali/Ribociclib, Ibrance/Palbociclib, and Verzenio/Abemaciclib. On the same spreadsheet I have the AIs which are Letrozole/Femara, Arimidex/Anastrozole, and Aromasin/Exemestane. I made the spreadsheet so I can compare all the side effects of the AIs and CDKs together since doctors don't give you an accurate, detailed assessment of these drugs. I have an appt today, 9/25/25 with a cardiologist and on Friday, 9/26/25 with my oncologist about which ones of these drugs I want to take. They are all horrible and have multiple scary side effects that you need to take into account with all your non cancer related health issues. Kisquali has over 150 side effects. Some of those side effects are blood clots, liver damage/failure, heart attack/heart damage, diahrrhea, hair loss/thinning, headaches, strokes, joint pain, low white & red blood cell counts, low platelet counts, nausea, neuropathy, neutropenia, edema, lung/breathing issues, QT prolongation, kidney damage, Stevens-Johnson syndrome (SJS), Toxic Epidermal Necrosis (TEN), and the list goes on. My former oncologist told me Kisqali would be best for me because I've had blood clots and Kisqali doesn't put you at risk of blood clots. That was pure poppycock. All three AIs and CDKs put you at risk of multiple types of blood clots. Kisqali, in my opinion, has the worst side effects of the 3 CDKs. I don't know if I can post my spreadsheet once it is completed so anyone who's interested could take a look. Does anyone know if we can upload a Word document? I could try to copy/paste, but I don't know if it would get skewed and illegible if I try that technique.

I'm taking Kisqali along with Letrozol. The biggest issues that I have with Kisqali is that it interferes with my heart medicine (I have Afib). I've had to stop my BP meds and cholesterol meds for the foreseeable future. My cardiologist and my oncologist are working closely. I have to get EKG's every 3-4 weeks.

The Kisqali, like Chemo wrecks my blood numbers.
My white blood cells have been running from 1.9 - 3.2.
My red blood cells have been running in the mid 3.0's
Platelets have been rising since July
Absolute Neutrophils have been in the mid 1's to low 2's.
Primary and Oncologist are keeping an eye on my kidney and liver due to the Kisqali as well.

I talked to my oncologist about what other options there are. This is the best option, and I really want to stick with it, as I'm praying for the best outcome possible.

Hope this helps.