Anyone taking cyclin-dependent kinase (CDK) 4/6 inhibitors?

I did have some joint stiffness from anastrazole but walking daily for about 20-30 minutes seem to really make a huge difference in the side effects. I made it 10 years on this drug. There is some things that I didn’t love and some I still don’t like, but I am still here.
Are you able to get up and walk a bit?

Yes, I do daily walking and lots of stretching. The stiffness is increasing, but still tolerable.
I am more concerned with taking CDK 4/6 inhibitors, such as palbociclib, abemaciclib, and ribociclib. They suggest adding that to anastrozole to mitigate recurrance.
Does anyone have experience with any of these drugs? I would really appreciate hearing about your experience and rationale for taking.

@llthomson, you were asking about others who have experience with CDK4/6 inhibitors, a class of medicines used to treat certain types of hormone receptor-positive, HER2-negative breast cancer, like Ibrance (palbociclib), Kisqali (ribociclib), and Verzenio (abemaciclib).

I pulled your posts into a new discussion to invite conversation among members with experience with these drugs like @ampeltekian @californiazebra @sallymayo22 @eku @hockeymom25 @elizm @trivia @pampurr @meme5 @canderson5 @slapshotmary @lynelyn @mjwhearts22 @jbp and many others here.

@llthomson, has a CDK4/6 inhibitor been added to your treatment plan? How are you doing?

Thank you for replying.
I will be meeting with my oncologist next Monday at which time we will decide on whether to add Verzenia. I read comments on the "Deciding wether to go on abemaciclib" thread and at this time, I think I will decline it. At 72, I am not sure that the benefit is worth risking the sever side effects noted(eye infection-vicsmit, hair loss-lynelyn, diarrhea/vomiting...). I am waiting to hear from my doctor as to what she thinks the benefit will be for my case. I have stage III cancer, but low Ki-67 and only 1 node micrometastases. What is the risk of recurrence in the first 2-3years for me? What is the reduction benefit by adding Verzenio?

I am 65. Was diagnosed in 2016. Stage 2A IDC ER PR positive and HER2 negative. Another primary tumor was detected on the same breast ( invasive lobular carcinoma) so my oncologist decided to have a neo adjuvant treatment plan for me. For 6 months I took 3 tablets of Ribociclib for 21 days rest for 7 days and then resume. I also take Letrozole continuously. The combines pills shrunk my tumor from 2.9 cm to 1 cm. I just had a mastectomy three weeks ago. I will continue to take these medicines for 6 more months. Then Letrozole alone for 2 years. In between I will have to undergo blood tests, Denosumab injections ( once a year) and PET Scans.

Thank you for sharing. What side effects if any did you experience? Was the shrinkage on the ILC tumor or the IDC? What was the dosage of Ribociclib? Ribociclib was the other drug option that is on the table for me...

Using brand names for ease. I’ve been taking Kisqali 400 mg for 4 years for recurrent breast cancer IDC ER/PR+ HER2- BRCA2+ CHEK2+ Ki-67 50%. Had a double mastectomy the first time around, stage 1 but genetic mutations. 7 years later recurrent BC in chest wall. Removed tumor, positive margin. 37 radiation treatments then started Kisqali and Letrozole at the same time. Can’t do chemo because of pre-x neuropathy. Because the BC is so aggressive my oncologist felt some cells likely got away before surgery. Once the tumor was removed, nothing large enough to show on CT scan. 4 years later still nothing showing except the non-related lung NETs neuroendocrine cancer — 50+ slow growing tumors.

Originally took 600 mg Kisqali but immediately had the dangerous heart rhythm QT prolongation. Lowered dose to 400 and it stopped. I have had paroxysmal afib since 5 days after starting Kisqali. My worst side effect. Ongoing issue. First year or two extreme fatigue and trouble staying awake. The fatigue is less severe now than the first two years. I still run out of energy quickly. I now have serious insomnia issues rather than sleepiness but that could be the Letrozole. Hair thinning. Lower BP. Aggravates my neuropathy. Some joint pain probably from Letrozole. It lowers immunity. I wash my hands a lot and avoid sick people but am not overly concerned about lower immunity. When I catch a bug, I’m sicker and for longer than in the past. It sounds awful when I list it out but I will stay with the treatment as long as it’s effective. I still enjoy life and am still here.

Everyone reacts so differently to meds. One person has severe side effects and another has none and everything in between. I’m typically prone to adverse side effects with most meds.

Why Kisqali? My oncologist chose that over Ibrance and Verzenio because the clinical trials showed all 3 meds extended progression free survival time but only Kisqali showed an increase in overall survival. Ask your oncologist to show you the latest clinical data for each.

I do not like the heart rhythm issues from Kisqali but want the most effective med. Verzenio commonly causes severe diarrhea and that’s a quality of life dealbreaker for me. Just my preference. I would love to take a break from meds but don’t want to risk it. Lastly, I started octreotide for my lung NETs 2 months after the Kisqali and that compounded the original side effects. Hard to know how much fatigue and hair thinning (not bald) each med is causing.

Hope this helps. Prayers for your decisions and successful outcome.

The shrinkage was on the ILC tumor. From 2.9 cm to 1 cm. Initial dosage was 3 tablets of Ribociclib for 21 days then rest for 7 days. After that you have to resume the dosage. This is taken with 2.5 mg of Letrozole. But three months after I had a nasty case of diarrhea, some hair loss and fatigue. I experienced itchiness in my arms and legs too. My oncologist reduced the dosage to two tablets of Ribo per day. The diarrhea, fatigue and the itchiness stopped but the mild hair loss is still there. I have been taking it since May and will continue until April 2025.

Jan 2022, age 72, Stage 4 BC spread to a few bones and C3 vertebrae. 5 sessions radiation took care of the bones. Then I took Ribociclib 600 for 19 days and nearly collapsed in a train station due to neutropenia. 2-3 weeks later tried 400. After 9 days sharp pain in head so I quit it but not soon enough. My liver enzymes AST and ALT shot up near 1200. I was hospitalized for 10 days for 24/7 infusions. The only drug that brought the numbers down was a steroid which left me with side effects I’m still dealing with today. I deeply regret taking the Ribociclib. I took letrole from Feb - June 2022. Now I’m supposed to take it everyday but I don’t want the effects of not enough estrogen to brain and bones etc. Eventually I learned about the Metabolic Therapy for cancer which makes more sense to me. So I’m focused on that.
These are hard decisions and all the oncologists are not on the same page when they discuss these dangerous drugs.

Thank you for your reply. This was helpful to me because it shows efficacy of this drug for ILC. Your cancer was first diagnosed in 2016 and you just had a mastectomy 3 weeks ago. You did not have any surgery for 8 years, only drug therapy? Is this correct?