HR+ MBC: Palbociclib Plus Endocrine Therapy on Time to Chemotherapy

Sara A. Hurvitz, MD: Time to chemotherapy has become a more popular end point to be reported in clinical trials of endocrine-based therapy. I think all of us would agree that it’s meaningful to patients to delay the initiation of chemotherapy. The longer we can give them an endocrine-based approach, probably the better their lifestyle or quality of life will be. The investigators from the PALOMA-2 and PALOMA-3 trials provided a pooled analysis, looking at the subgroup of patients who were treated on these 2 studies with palbociclib [Ibrance] plus endocrine therapy and what their time to chemotherapy was as their next subsequent post-progression therapy and compared that to patients who were treated in the placebo arms of these clinical trials. In this analysis, more patients who were treated with endocrine therapy alone were noted to receive chemotherapy as their first treatment after being off of the study compared to those patients who were treated with palbociclib plus endocrine therapy. Palbociclib treatment was associated with a prolonged time to chemotherapy, as well as progression-free survival across all subgroups that were analyzed. Those on palbociclib who were being treated as a first-line therapy with no prior endocrine therapy had a greater delay to chemotherapy than those patients who were being treated with palbociclib plus endocrine therapy as a second-line approach. These data, of course, aren’t very surprising. But in all, I think these data support the use of a CDK4/6 inhibitor as not only benefiting patients in terms of an improvement in progression-free survival but also importantly delaying a time to the patient needing to move on to chemotherapy.

Transcript edited for clarity.