Breast Cancer: PROMISE Study

A Prospective Study to Evaluate the Role of Tumor Sequencing in Women Receiving Palbociclib for Advanced Hormone Receptor (HR)-Positive Breast Cancer (PROMISE; NCT03281902) is ongoing at all three Mayo Clinic campuses, but closed to new participants.

PROMISE is designed to further individualize treatment for patients with metastatic breast cancer. The PROMISE study combines drug treatment, blood and tumor sequencing, and the development of patient-derived xenografts (PDX) for women with HR-positive, HER2-negative metastatic breast cancer.

Endocrine resistance is common in patients with breast cancer, and while the drug palbociclib (Ibrance) in combination with endocrine therapy has provided substantial improvements in progression-free survival in women with metastatic breast cancer, the majority of patients will experience disease progression.

The PROMISE study uses participants' biopsies to obtain detailed information regarding their genetic makeup (germline) as well as the genetic makeup of their tumors, with the goal of developing personalized treatment approaches to improve patient outcomes.

The PROMISE study:

  • Obtains biopsies from participants prior to the beginning of treatment, after two months of treatment and at disease progression
  • Extracts DNA and RNA from biopsies of participants' tumors for sequencing by TEMPUS
  • Identifies genetic alterations in germline and tumor DNA
  • Collects participants' blood samples ("liquid biopsies") prior to, during and at discontinuation of treatment to identify circulating tumor DNA
  • Develops PDX that will be used by Mayo Clinic investigators to study new drug therapies designed to overcome resistance to palbociclib
  • Studies drug response phenotypes by creation of fresh tumor 3D microcancer models
  • Identifies metabolite biomarkers of response among participants receiving first line or second line palbociclib for HR-positive, HER2-negative metastatic breast cancer


PROMISE study investigators will recruit 250 subjects to be enrolled over 36 months and followed for at least 12 months after the close of enrollment.

Eligible participants:

  • Are at least 18 years of age
  • Female
  • Have been recommended first line endocrine treatment with palbociclib and letrozole (Femara) for HR-positive, HER2-negative metastatic breast cancer or second line therapy with palbociclib and fulvestrant (Faslodex) for women whose cancer progressed after first line endocrine treatment
  • Willing to undergo a standard of care core biopsy of recurrent or metastatic breast cancer at baseline to document that the tumor is HR-positive and HER2-negative
  • Willing to undergo a mandatory research biopsy after two months of therapy and at disease progression (optional)

The results of participants' tumor and blood sequencing will be made available to patients and their doctors. This information may assist in treatment decisions going forward.


Contact the PROMISE study chairs for more information:

Ciara C. O'Sullivan, M.B., B.Ch.

Matthew P. Goetz, M.D.

You can also contact the Center for Individualized Medicine for information on clinical studies and trials.