Does Ibrance Dosage Affect Its Effectiveness?

I am on 75 mg due to side effects. I am told that the 3 different dors work about the same.

Hello I was 1st place on 125mg dose of Ibrance and was on it for at least 8 to 9 months and I was having really bad cases of diarrhea and my Oncologist lowered my dosage to 100mg...so far its still working for me. I'm not sure if effectiveness mg dosage determines the effects.

Joyce B, I was on 125mg. of Ibrance for 3 years and it worked for me until my red and white blood counts got to low ( I also had diarrhea). My oncologist also lowered my dosage to 100mg and it is still working for me also with letrozole. So, Dee W Glenda D, I am told by my oncologist that we still get effective results with lower doses as well. I pray 🙏 that our meds work well for all of us for many, many years and they keep coming up with better and better research. They have come a long way with treatments in the years! Best of good luck to all of you during this crazy journey ❤️

Denise O, I have been on Ibrance along with Anastrazole not quite 2 years yet but every scan I've had my Oncologist says they look good and the Ibrance is working. Also having to keep up with lab work every 6 weeks to monitor my red/white blood counts as well because the numbers are going down. She has me to get MRI SCANS every 5/6 months since my bilateral mastectomy metasized to my lungs afterwards. It's crazy and leaves me constantly with many questions. I will pray for us all that we overcome this horrible disease and we will not let it defeat us. WE ARE WARRIORS! BLESSINGS & PRAYERS TO ALL!

Joyce B, This is a constant journey of scans and bloodwork and tests. It gets on our nerves and physiologically it worries us waiting for the results. We are thrilled when our Dr. says that the Ibrance (or whatever med) is working. You are right, we get used to doing what we have to do,and we are WARRIORS, we will keep fighting forever 💙. We all understand each other going through this! You are so right, Blessings and Prayers to all of us 🙏 🙏

My oncology pharmacist told me that the size of the Ibrance dose doesn’t impact the effectiveness. I think people metabolize it differently, depending on our genetics, so some people can handle the higher dose while others get more toxic side effects and need a lower dose. But I agree with you, I wonder why they started you at 75mg? It might be worth asking your doctor 1) why they started you on the lowest dose, 2) could you try a different CDK4/6 inhibitor, 3) can you get a second opinion from a different doctor. I wish you luck and I hope you find the support you need. Hugs to you ❤️

Also, I don’t know what your treatment has included so far, but if they haven’t done molecular testing, be sure to ask for that. It looks for tumor mutations that might respond to different medications. There are several different brand names for these tests, like Guardant360, some are covered by insurance others aren’t, hopefully your doctor can help (or has already helped) get this testing done. ❤️

I was on 125mg of Ibrance but hospitalized for a week. My blood counts dropped too fast. I completed 1 round of treatment with alot of side effects. At times it's better to start at level you can increase too. More not always better.

Amen to that, Kate M. I need a lesser dose of 2nd line med Enhertu, its been too toxic on me- for past 3mos...time to titrate dosage <down> or look at other options...

I was also started on the 75 mg dose of Ibrance plus Aromasin; it worked well for almost 2 years and then I went up to 100 mg, which was effective for another year. Last April I was tested for the ESR1 mutation, which I do have, so I am now only taking Orserdu.

In 2021 my cancer came back in my sacrum. I was having back pain seeing A back specialist along with my oncologist for a year. Woke up from a nap in 10+ pain and could not walk. My husband put me the back of the Subaru station wagon because I could not sit. Emergency took a scan and a tumor size of a grapefruit. Now I was stageIV metastatic breast cancer. Started radiation to shrink the tumor to help with pain. 2 weeks radiation,lestrozole 2.5mg, ibrance 125mg and Zometa infusions every 3 months. I have PET scans every 3 months. No tumors detected for the last 2 1/2 years. My oncologist felt comfortable with taking me off ibrance. I am going to request my ERS1 just worried about mutation. Lestrozole is my main defense. Is anyone else on 2.5 mg of Lestrozole?

I just took my first pill of lestozole. Do you have any side affects from it?

I had severe joint pain several months in on letrozole. Switched to exemestane and it got worse incoming bilateral trigger thumbs. Now on Fulvestrant which is definitely more tolerable. Still stiff but not nearly as much as the AIs caused.

Well I have pretty bad back pain . Just started Letrozole. What do you take for the back pain?

I take Tylenol and CBD. Occasionally an Aleve. Allergic to most opioids.

Also just had CBC done on 75mg Ibrance 7 days on and 7 off and my ANC was 0.76

Treatment doses can vary significantly from person to person based on many individual factors that oncologists carefully consider when creating treatment plans. It's completely understandable to have questions about dosing decisions, especially when treatment outcomes aren't what was hoped for. Many factors beyond dose can influence how well a treatment works, and oncologists often have specific medical reasons for their dosing choices that may not always be immediately apparent. Consider discussing these concerns with the care team to better understand the reasoning behind the dosing decision and explore what options might be available moving forward.