How often should CDK 4/6 inhibitors like Ibrance be monitored?

I had very good results with Ibrance cdk4/6. First with letrozole and then, with fluvestrant. It killed most of my bone mets over 7.5 years. I had them in most of my bones except below my elbows and knees and head. However, since then nothing has helped. We tested for genome and I have PTEN & PIK3 genetic mutations which are hard to treat.

Thank you for sharing such thoughtful questions about CDK 4/6 inhibitor monitoring - this information could be really helpful for others navigating similar treatment paths. The monitoring approach can vary based on individual factors, so it's encouraging to hear that your oncology team has established a regular schedule that aligns with standard practices. Others in the community may have valuable insights to share about their own monitoring experiences and any discussions they've had with their medical teams about emerging biomarker options.

Virginia M - I too have Pik3CA and have been on Truqap and Fulvestrant for 12 months.

I have CTDNA blood work every 3 months along with my PET scan. With clean blood work and clear scans I was able to go off ibrance.After 3 years. I have stage lV metastatic ER+ with primary immunoglobulin disease. I now take letrozole 2.5mg daily and Xembify sub-que (plasma) infusion x1 at home. I am very grateful for my care team.

I’m on Ibrance, monthly fulvesterant injections, and quarterly Zometa infusions. Quarterly CT scans, monthly Signatera blood tests, and quarterly CBC tests. All this since last February. So far, good results. We also tried Itovebi but my PCP added jardiance to that (because Itovebi raises blood sugar). Not sure whether it was the Itovebi or the Jardiance that caused problems but I finally stopped them both. I’m willing to try Itovebi again but without the Jardiance (I’m already on Metformin for the increase in blood sugar so maybe that and the Itovebi will work well together).