Trial · NCT02764541

Palbociclib and Endocrine Therapy for LObular Breast Cancer Preoperative Study (PELOPS)

NCT02764541, Phase 2, Active not recruiting, Dana-Farber Cancer Institute; results first posted 2023-08-31

3 sourcestrials-2026-11-12-0.5.0

Cite this record

ConductScience Library. Palbociclib and Endocrine Therapy for LObular Breast Cancer Preoperative Study (PELOPS). Trials, record NCT02764541. Release trials-2026-11-12-0.5.0, 12 Nov 2026. https://conductscience.org/library/trials/NCT02764541

On this page

Trial

As registered on ClinicalTrials.gov, in the graph's capture of the registry.

Title: Palbociclib and Endocrine Therapy for LObular Breast Cancer Preoperative Study (PELOPS)
NCT number: NCT02764541
Status: Active not recruiting
Phases: Phase 2
Enrollment: 195 participants, actual
Lead sponsor: Dana-Farber Cancer Institute
Conditions: Breast Cancer
Interventions: Letrozole, Tamoxifen, Palbociclib, Endocrine Therapy
First posted: 2016-05-06
Last updated: 2026-06-23
Results first posted: 2023-08-31

Source ClinicalTrials.gov

Registered outcomes6

Each outcome the trial registered, primary first, in ClinicalTrials.gov's words.

List	Outcome	Time frame	Description
Primary	Difference in Anti-proliferative Activity of Patients Given Letrozole Versus Tamoxifen During the Window Phase	baseline to day 15	Log fold change in anti-proliferative activity of Letrozole versus Tamoxifen within cohorts of hormone receptor positive breast cancer for patients with invasive lobular and ductal carcinoma during the window phase. Higher absolute value indicates larger change in the anti-proliferative activity
Primary	Pathologic Complete Response (pCR) of Patients Given Endocrine Therapy Plus Palbociclib and of Endocrine Therapy Alone During the Treatment Phase	day 15 to 24 weeks	Residual Cancer Burden index (RCB) between hormone receptor positive invasive breast cancer patients given endocrine therapy plus palbociclib (Arm C) and endocrine therapy alone (Arm D). RCB score is used to assess the response to neoadjuvant chemotherapy in breast cancer patients and is in a scale of 0 to infinity. Higher RCB score indicates more tumor burden remaining, thus worse outcome.
Secondary	Odds Ratio of Achieving Cell Cycle Arrest at the End of Window Phase	baseline to day 15	Odds Ratio of Achieving Cell Cycle Arrest at the end of Window Phase in hormone receptor positive invasive breast cancer patients given Tamoxifen vs Letrozole. Cell cycle arrest is defined to be percentage of Ki67\<2.7
Secondary	Change in RCB Index Between Arm C and Arm D During the Treatment Phase	day 15 to 24 weeks	The estimate of RCB index change for patients who receive both endocrine and Palbociclib instead of endocrine alone, but have the same lymph node status, tumor size and menopausal status. RCB score is used to assess the response to neoadjuvant chemotherapy in breast cancer patients and is in a scale of 0 to infinity. Higher RCB score indicates more tumor burden remaining, thus worse outcome.
Secondary	Number of Participants With RCB Response in Arm C and Arm D During the Treatment Phase	day 15 to 24 weeks	RCB response is defined as RCB-0 or RCB-I; RCB not response is defined as RCB-II or RCB-III Residual Cancer Burden (RCB) considers residual disease in the tumor bed and lymph nodes after NAC, generating a continuous score which is then grouped into four categories: RCB-0, RCB-I, RCB-II and RCB-III. Higher RCB group reflects more tumor burden remaining, thus worse outcome
Secondary	Percentage of Participants With Clinical Response in Arm C and Arm D in the Treatment Phase	day 15 to 24 weeks	Percentage of Participants with Clinical Response in Arm C and Arm D in Breast cancer patients diagnosed with hormone receptor positive invasive breast cancer; Clinical response rate is defined as the number of partial and complete responses after preoperative endocrine therapy plus palbociclib (Arm C) and of endocrine therapy alone (Arm D)

Source ClinicalTrials.gov

Outcomes6

Each outcome the trial posted results for, in ClinicalTrials.gov's words.

Type	Outcome	Time frame	Population	Units	Measured as
PRIMARY	Difference in Anti-proliferative Activity of Patients Given Letrozole Versus Tamoxifen During the Window Phase	baseline to day 15	Patients both not missing baseline and day15 Ki67 were included into the analysis population	log fold-change	MEAN
PRIMARY	Pathologic Complete Response (pCR) of Patients Given Endocrine Therapy Plus Palbociclib and of Endocrine Therapy Alone During the Treatment Phase	day 15 to 24 weeks	Patients with treatment and surgery are included into the analysis population	score on a scale	MEAN
SECONDARY	Odds Ratio of Achieving Cell Cycle Arrest at the End of Window Phase	baseline to day 15	Patients both not missing baseline and day15 Ki67 were included into the analysis population	odds ratio	NUMBER
SECONDARY	Change in RCB Index Between Arm C and Arm D During the Treatment Phase	day 15 to 24 weeks	Patients with treatment and surgery are included into the analysis population	units on a scale	MEAN
SECONDARY	Number of Participants With RCB Response in Arm C and Arm D During the Treatment Phase	day 15 to 24 weeks	Patients with treatment and surgery are included into the analysis population	Participants	COUNT_OF_PARTICIPANTS
SECONDARY	Percentage of Participants With Clinical Response in Arm C and Arm D in the Treatment Phase	day 15 to 24 weeks	Patients with treatment and surgery are included into the analysis population	percentage of participants	NUMBER

Source ClinicalTrials.gov

Results by group14

Each measurement the trial posted, group by group, in the words and numbers it posted.

Outcome	Group	Value	Spread	Units
Difference in Anti-proliferative Activity of Patients Given Letrozole Versus Tamoxifen During the Window Phase	Tamoxifen With Invasive Ductal	-0.180	Standard Deviation 2.5	log fold-change
Difference in Anti-proliferative Activity of Patients Given Letrozole Versus Tamoxifen During the Window Phase	Letrozole With Invasive Ductal	-1.304	Standard Deviation 2.2	log fold-change
Difference in Anti-proliferative Activity of Patients Given Letrozole Versus Tamoxifen During the Window Phase	Tamoxifen With Invasive Lobular	-0.635	Standard Deviation 2.5	log fold-change
Difference in Anti-proliferative Activity of Patients Given Letrozole Versus Tamoxifen During the Window Phase	Letrozole With Invasive Lobular	-1.944	Standard Deviation 2.6	log fold-change
Pathologic Complete Response (pCR) of Patients Given Endocrine Therapy Plus Palbociclib and of Endocrine Therapy Alone During the Treatment Phase	Arm C Endocrine With Palbociclib	2.88	Full Range 0.00 to 4.83	score on a scale
Pathologic Complete Response (pCR) of Patients Given Endocrine Therapy Plus Palbociclib and of Endocrine Therapy Alone During the Treatment Phase	Arm D Endocrine Therapy Alone	2.88	Full Range 0.03 to 4.71	score on a scale
Odds Ratio of Achieving Cell Cycle Arrest at the End of Window Phase	Tamoxifen vs Letrozole in Invasive Ductal Patients	0.26	95% Confidence Interval 0.08 to 0.89	odds ratio
Odds Ratio of Achieving Cell Cycle Arrest at the End of Window Phase	Tamoxifen vs Letrozole in Invasive Lobular Patients	0.60	95% Confidence Interval 0.19 to 1.9	odds ratio
Change in RCB Index Between Arm C and Arm D During the Treatment Phase	Endocrine With Palbociclib	2.88	Full Range 0.00 to 4.83	units on a scale
Change in RCB Index Between Arm C and Arm D During the Treatment Phase	Endocrine Alone	2.88	Full Range 0.03 to 4.71	units on a scale

1 to 10 of 14Source ClinicalTrials.gov

See all 14 results by group

Participant flow24

How many started, completed or left each group, period by period.

Period	Milestone	Group	Participants
Overall Study	STARTED	Arm A Tamoxifen First, Then Arm C Endocrine With Palbociclib	36
Overall Study	STARTED	Arm A Tamoxifen First, Then Arm D Endocrine Alone	21
Overall Study	STARTED	Arm B Letrozole First, Then Arm C Endocrine With Palbociclib	37
Overall Study	STARTED	Arm B Letrozole First, Then Arm D Endocrine Alone	19
Overall Study	STARTED	Arm A Tamoxifen Only	1
Overall Study	STARTED	Arm B Letrozole Only	2
Overall Study	STARTED	Arm C Endocrine With Palbociclib Only	55
Overall Study	STARTED	Arm D Endocrine Alone Only	21
Overall Study	COMPLETED	Arm A Tamoxifen First, Then Arm C Endocrine With Palbociclib	33
Overall Study	COMPLETED	Arm A Tamoxifen First, Then Arm D Endocrine Alone	20

1 to 10 of 24Source ClinicalTrials.gov

See all 24 participant flow

Adverse events928

Each adverse event the trial posted, group by group: the participants affected out of those at risk.

Type	Event	Organ system	Group	Affected	At risk
other	Anemia	Blood and lymphatic system disorders	Arm A Tamoxifen First, Then Arm C Endocrine With Palbociclib	6	36
other	Anemia	Blood and lymphatic system disorders	Arm A Tamoxifen First, Then Arm D Endocrine Alone	0	21
other	Anemia	Blood and lymphatic system disorders	Arm B Letrozole First, Then Arm C Endocrine With Palbociclib	4	37
other	Anemia	Blood and lymphatic system disorders	Arm B Letrozole First, Then Arm D Endocrine Alone	0	19
other	Anemia	Blood and lymphatic system disorders	Arm A Tamoxifen Only	0	1
other	Anemia	Blood and lymphatic system disorders	Arm B Letrozole Only	0	2
other	Anemia	Blood and lymphatic system disorders	Arm C Endocrine With Palbociclib Only	6	55
other	Anemia	Blood and lymphatic system disorders	Arm D Endocrine Alone Only	0	21
other	Hypothyroidism	Endocrine disorders	Arm A Tamoxifen First, Then Arm C Endocrine With Palbociclib	5	36
other	Hypothyroidism	Endocrine disorders	Arm A Tamoxifen First, Then Arm D Endocrine Alone	2	21

1 to 10 of 928Source ClinicalTrials.gov

See all 928 adverse events

Adverse event totals24

The totals the trial posted for each group.

Total	Group	Affected	At risk
Total, all-cause mortality	Arm A Tamoxifen First, Then Arm C Endocrine With Palbociclib	1	36
Total, all-cause mortality	Arm A Tamoxifen First, Then Arm D Endocrine Alone	2	21
Total, all-cause mortality	Arm B Letrozole First, Then Arm C Endocrine With Palbociclib	0	37
Total, all-cause mortality	Arm B Letrozole First, Then Arm D Endocrine Alone	1	19
Total, all-cause mortality	Arm A Tamoxifen Only	0	1
Total, all-cause mortality	Arm B Letrozole Only	0	2
Total, all-cause mortality	Arm C Endocrine With Palbociclib Only	3	55
Total, all-cause mortality	Arm D Endocrine Alone Only	1	21
Total, other adverse events	Arm A Tamoxifen First, Then Arm C Endocrine With Palbociclib	36	36
Total, other adverse events	Arm A Tamoxifen First, Then Arm D Endocrine Alone	21	21

1 to 10 of 24Source ClinicalTrials.gov

See all 24 adverse event totals

Papers4

The papers the trial lists on ClinicalTrials.gov.

PMID	Listed as	Source
37450351	DERIVED	PubMed
41272386	DERIVED	PubMed
41276768	DERIVED	PubMed
41672025	DERIVED	PubMed

Grants0

The grants NIH RePORTER links to the trial, newest funded first: NIH's, and some of AHRQ's, CDC's, FDA's and VA's. Each shows its title, principal investigators, organization and funder in its newest year.

None in this release.

Trial comparisons1

Comparisons of the trial's two groups, calculated by ConductScience from the counts it posted.

Comparison
Arm C Endocrine With Palbociclib vs Arm D Endocrine Therapy Alone: Number of Participants With RCB Response in Arm C and Arm D During the Treatment Phase

Source Trial comparisons

Tests0

The ConductCognition tests this trial's registered outcomes name, as ScienceGraph matched them in trial-tests-2026-11-12-0.2.1.

None in this release.

Data dates

The day each source was copied for this release.

ClinicalTrials.gov: 2026-11-12; ClinicalTrials.gov
Results, from AACT: 2026-03-23; AACT
NIH grant links: 2026-11-13; NIH RePORTER

Sources 3

ClinicalTrials.gov's posted results, through CTTI's AACTFreely available. Acknowledgement requested
ClinicalTrials.govNo license stated
NIH RePORTER's clinical studies and project filesPublic domain

Each source's terms

ClinicalTrials.gov's posted results, through CTTI's AACTClinicalTrials.gov data via Aggregate Analysis of ClinicalTrials.gov (AACT), CTTI. CTTI makes its materials freely available and requests acknowledgement. https://aact.ctti-clinicaltrials.org/documentation/299
ClinicalTrials.govnone stated
NIH RePORTER's clinical studies and project filesPublic domain (NIH RePORTER)

ClinicalTrials.gov's data carry an international copyright outside the United States: https://clinicaltrials.gov/about-site/terms-conditions.

For software

Read this trial from software.

The record and each of its lists are JSON, twenty rows a page. No key.

GET https://conductscience.org/api/trials/v1/NCT02764541

GET https://conductscience.org/api/trials/v1/NCT02764541/flow?page=2

API reference For AI assistants