Real-world study of overall survival with palbociclib plus aromatase inhibitor in HR+/HER2− metastatic breast cancer

[Hazelgreen]

npj Breast Cancer volume 8, Article number: 114 (2022)

The Flatiron Health Analytic Database was used to assess overall survival (OS) in patients with hormone receptor–positive/human epidermal growth factor receptor 2–negative (HR+/HER2−) metastatic breast cancer (MBC) treated with first-line palbociclib plus an aromatase inhibitor (AI) versus an AI alone in routine US clinical practice. In total, 2888 patients initiated treatment during February 3, 2015–March 31, 2020, with a potential ≥6-month follow-up (cutoff date, September 30, 2020). After stabilized inverse probability treatment weighting, median OS (95% CI) is significantly longer among palbociclib versus AI recipients (49.1 [45.2–57.7] versus 43.2 [37.6–48.0] months; hazard ratio, 0.76 [95% CI, 0.65–0.87]; P < 0.0001). Progression-free survival (95% CI) is 19.3 (17.5–20.7) versus 13.9 (12.5–15.2) months, respectively (hazard ratio, 0.70 [95% CI, 0.62–0.78]; P < 0.0001). These data support first-line palbociclib plus an AI treatment for HR+/HER2− MBC.

[Susan1953]

Thanks for sharing. 5 years 7 months for me.

[Merma]

Good to know…5 yrs for me.

[TE53_67]

thanks for the upload of this data. Do I read it right that the longest overall survival was 57 months for those on Pal. Albeit I see on this platform lots of ladies on this and longer. Sorry I may be reading this incorrectly.

[Hazelgreen in reply to TE53_67]

Hello,

The range around the median (49.1 mos) for those on Pal is indeed 45.2 to 57.7mos. That range gives the 95% probability that the true median falls within that range. Statisticians always consider the fact that they are sampling data from a limited number of patients so need to consider whether their sample could be biased. As patients, we don't have to care about the range around the median. Instead, what we need to know is that 50% of the patients taking Pal lived at least 49 months (and were continuing to live now that the study was over). It would take a much longer follow-up study to determine which patient lived the longest.

Please let me know if my explanation doesn't make this clearer.

Regards,

Cindy

[TE53_67 in reply to Hazelgreen]

hi Cindy this completely makes sense. A light bulb moment, of course this is the end of the study and not the patients life as they are still under treatment currently! Thank you so much for explaining it further. All good feedback overall then.

[diamags]

To all our friends out there, remember these are statistics and although we make up statistics, individually we're not. I have been on AIs alone for 9 years with no progression!!!

[Hazelgreen]

Aww, diamags, that's terrific to read! Thanks for sharing. It is clear that the median for the AI control group is also only talking about those at the 50th percentile. In this study, half the AI only group were still alive after 43 months of treatment.

Hugs, Cindy

[Guitarbella]

Dear Hazelgreen, thank you as always for sharing this encouraging information. I am a bit confused about overall survival and PFs. For example I had 21 months PFS on Palbo & Letrazole, so has this now meant I could have a longer chance of median Overall Survival of 49.1 months as opposed to the 3 years from previous statistics,

Or am I getting ahead of myself?

Many thanks for your help with this.

I hope you are doing well?

Guitarbella

[Hazelgreen in reply to Guitarbella]

Hi Bev,

I looked at your earlier posts, and understand that you are now on Paclitaxel for liver mets. I hope that will restore your liver enzymes to their normal ranges.

Since you had progression when you were taking palbociclib and letrozole, this suggests that this combo did not work as well for you as it did for the majority of the patients in the study I mentioned above. If you were just starting the combo now, the best guess would be that you would get at least 49.1 months from it. However, in your case, we know how long it worked for you (21 months) so no one needs to guess. I do not think your oncologist will want you to take this same combo in the future.

I'm in Canada which also has socialized medicine so I don't have to pay for the ribociclib I am taking for my extensive mets. I am very grateful for our system! My oncologist has already mentioned that patients are only given one of these very expensive CDK4/6 inhibitors most of us on this site are taking. (Even with the Canadian government's negotiating, these CDK4/6 inhibitors cost over $6600 per month per patient!)

Thanks for asking about my health. I soon will have been taking ribociclib (Kisqali) for a year. My cancer markers have shrunk from 125 to 38 so it seems to be working so far. I continue to have extensive mets (bones, lungs, liver, lymph system, spleen, skin, etc.) but I feel lucky that, at my age (77 yrs.), the mets tend to be slow-growing so have not reached my brain, and my liver enzymes continue to be in the normal range.

From my liver biopsy, my oncologist knows that I have the PIK3CA mutation so has said that I will be switched to Piqray once Kisqali quits working. I have found the side effects from Kisqali bad enough that I certainly am not looking forward to the side effects from Piqray! I may choose to take nothing if it comes down to that.

Hugs, Cindy