A Phase 2 interventional study of Abemaciclib and Tersolisib in Breast Neoplasms, sponsored by Eli Lilly and Company. Not yet recruiting at 9 sites in United States. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-11-13.
Sponsored by Eli Lilly and Company · Phase 2, Interventional, and Treatment
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Among 56 studies testing abemaciclib in Breast Neoplasms — 23 open to participants now, 35 under way, 10 of them phase 3. abemaciclib · Breast Neoplasms.
Among the 56 studies testing abemaciclib in Breast Neoplasms, this one is the 28th largest by planned enrollment, is one of 8 that started in 2026, is one of 28 in phase 2, reaches primary completion later than 18 of the 34 other live ones, and was the 56th registered.
14,832 studies on the registry are indexed under Breast Neoplasms; 3,318 are open to participants now.
Browse Breast Neoplasms studies →23 of the 56 studies testing abemaciclib in Breast Neoplasms are open now, in 6 countries. Recruiting first, the newest first:
Jonsson Comprehensive Cancer Center · Sites in United States
Ages 18+
UNC Lineberger Comprehensive Cancer Center · Sites in United States
Ages 18+
Japanese Foundation for Cancer Research · Sites in Japan
Ages 18+
Memorial Sloan Kettering Cancer Center · Sites in United States
Ages 18+
Mridula George, MD · Sites in United States
Ages 60+ · Women only
By country, each count listing its studies:
abemaciclib: first FDA approval 2017 (VERZENIO), first EMA approval 2018. What it is approved for, and how studies give it, is on its page →
Of the 2,398 Breast Neoplasms studies recruiting now, 1,569 (65%) set no upper age limit and 592 (25%) stop at 75 or younger; 103 take children under 18; 215 take healthy volunteers.
This study: 18 Years and older · all sexes · no healthy volunteers.
The full table on the hub →This tab as a report to print or save as PDF → With an account.
On this site’s reading of the record, abemaciclib is the treatment under test here. Read study by study →
56 studies; the count open now beside each. This study's row is marked.
A study in two phases is counted once above. Listed by phase, each with its combined phases: Phase 1 8 · Phase 2 30 · Phase 3 11 · Phase 4 8
First in 2014; this study’s year is marked. 8 started in 2026.
By drug class, each counting the studies that test any of its medicines:
This study's planned enrollment of 120 is above the median of 72 across 10,900 interventional studies indexed under Breast Neoplasms.
Median enrollment 120 across the 56 interventional studies. Of the 17 that completed or were terminated, 12 (71%) have results posted.
This tab as a report to print or save as PDF → With an account.
19 of 56 have an industry lead sponsor. The 10 most frequent:
Eli Lilly and Company is the lead sponsor of 2,108 studies on the registry; 153 are open to participants now.
Of its 536 completed or terminated interventional studies of FDA-regulated products, 358 (67%) have results posted.
88 studies in Breast Neoplasms by Eli Lilly and Company: 7 open now, 22 under way, 8 of them phase 3. Of 61 finished, 40 (66%) have results posted.
Among the 88 studies in Breast Neoplasms by Eli Lilly and Company, this one is the 43rd largest by planned enrollment of the 80 interventional ones that give a count, is one of 2 that started in 2026, is one of 41 in phase 2, reaches primary completion later than 15 of the 21 other live ones, and was the 88th registered.
Eli Lilly and Company’s Breast Neoplasms studies by the year they started, since 1998.
6 of the studies testing abemaciclib in Breast Neoplasms that are under way reach primary completion within a year, 1 of them phase 3. Phase 3 first, then by date:
| Study | Primary completion |
|---|---|
| NCT06341621Phase 3Fudan UniversityChemotherapy Omission in ER+/HER2- Breast Cancer With 1-3 Positive Lymph Nodes Receiving Extended Adjuvant Abemaciclib | 2027-02-25 |
| NCT05305924The Methodist Hospital Research InstituteFulvestrant+Abemaciclib With Run-In of Fulvestrant in Er-Positive, Her2-Negative Metastatic Breast Cancer | 2026-12-01 |
| NCT06207734Institut für Klinische Krebsforschung IKF GmbH at Krankenhaus NordwestDiscontinuation of CDK4/6 Inhibitors in Patients With Metastatic HR Positive, HER2 Negative Breast Cancer | 2027-01-10 |
| NCT04614194University of Texas Southwestern Medical CenterSingle Cell Immune and Non-immune Correlates of Response to Neoadjuvant Abemaciclib | 2027-04-15 |
| NCT04305834City of Hope Medical CenterAbemaciclib and Endocrine Therapy in Older Patients With Breast Cancer. | 2027-05-21 |
Add all 6 to your calendar (.ics) → With an account.
Among the 56 studies testing abemaciclib in Breast Neoplasms, from their registry updates:
Among Eli Lilly and Company’s 88 in Breast Neoplasms:
This tab as a report to print or save as PDF → With an account.
The main purpose of this study is to compare two ways of giving the anti-cancer medicines abemaciclib and hormone therapy with tersolisib in participants with early breast cancer that has a genetic mutation (PIK3CA mutation).
For each participant, the study will last up to 56 weeks and include 12 visits.
Go through the criteria one by one — yes, no or not sure — and take the list to your doctor or the study team. Kept in this browser only.
Have or cytologically confirmed breast cancer, defined as individuals with:
have confirmed hormone receptor positive (HR+), human epidermal growth factor receptor 2 negative (-) status defined by
Tumor involvement in at least 1 axillary lymph node (ALN).
1 to 3 ipsilateral positive ALN and either:
Exclusion Criteria:
Have evidence of
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Histologically or cytologically confirmed
The diagnosis was confirmed by looking at a sample under a microscope: tissue from a biopsy or surgery (histology), or cells from a fluid or needle sample (cytology).
Your pathology report is the document that shows this.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Metastases
Cancer that has spread from where it began to other parts of the body. “Metastatic” cancer is cancer that has spread this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HER2
HER2 is a protein, made from the ERBB2 gene, that drives the growth of some cancers. A study may look for a level of the protein, extra copies of the gene, or a particular change in it.
In breast cancer, protein tests are read as HER2-positive, HER2-low or HER2-negative; other cancers use their own rules. Check which test result the study requires.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Adjuvant and neoadjuvant
Neoadjuvant treatment is given before the main treatment (usually surgery), often to shrink a tumour. Adjuvant treatment is given after it, to lower the chance of the cancer coming back.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Contraception
Ways of preventing pregnancy. “Highly effective” methods fail less than 1% of the time a year when used correctly — for example an IUD or an implant.
Criteria usually say which methods count and how long to keep using them after the last dose, sometimes for male participants too. Some studies accept a partner’s vasectomy if it was confirmed successful and that person is the participant’s only sexual partner.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HbA1c
A blood test of average blood sugar over the past two to three months, given as a percentage or in mmol/mol. 6.5% (48 mmol/mol) or more is the usual threshold for diabetes, normally confirmed by a second test.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Cancer (malignancy)
Malignancy means cancer. Criteria about another or earlier malignancy ask whether you have had a different cancer, usually within a set number of years.
Some are commonly allowed, such as treated skin cancers other than melanoma and early cancers removed completely — check the exceptions this study lists.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis B tests
Hepatitis B is a virus that infects the liver. These are separate tests: HBsAg positive usually means a current infection (a recent vaccination can briefly cause it too); total anti-HBc (HBcAb) positive means an infection now or in the past; HBV DNA measures how much virus is in the blood.
Some studies accept a past infection if HBV DNA is undetectable, sometimes with antiviral medicine during the study. Check what this study allows.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Hepatitis C tests
Hepatitis C is a virus that infects the liver. An HCV antibody test can stay positive after an infection has cleared (and is occasionally positive without one); an HCV RNA test shows whether the virus is there now.
After treatment, hepatitis C counts as cured when HCV RNA is still undetectable 12 weeks or more after the treatment ended. Studies often accept people cured this way.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
HIV
The human immunodeficiency virus, which weakens the immune system.
Many studies now accept people whose HIV is controlled on treatment, judged by the viral load and the CD4 count. Check the limits this study sets.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Abemaciclib in combination with physician's choice of endocrine therapy (ET). Tersolisib will be added in a staggered approach after 2 cycles of abemaciclib and ET. All drugs will be administered orally.
Drug: Abemaciclib · Drug: Tersolisib · Drug: Letrozole · Drug: Anastrozole · Drug: Exemestane
Abemaciclib and tersolisib will be administered concurrently in combination with physician's choice of ET. All drugs will be administered orally.
Drug: Abemaciclib · Drug: Tersolisib · Drug: Letrozole · Drug: Anastrozole · Drug: Exemestane
Administered orally
Administered orally
Also known as: LY4064809
Administered orally
Administered orally
Administered orally
Rate of Participants who Discontinue Tersolisib Due to Treatment Emergent Adverse Events (TEAEs).
Time frame: Cycle 1 through study completion (estimated as 56 weeks)
Duration of Exposure to Study Intervention
Study intervention start is defined as Cycle -1 for Arm A and Cycle 1 for Arm B. Arm A includes an additional 8 weeks.
Time frame: Start of study intervention through study completion (estimated as 56 weeks)
Number of Study Intervention Dose Adjustments
Study intervention start is defined as Cycle -1 for Arm A and Cycle 1 for Arm B. Arm A includes an additional 8 weeks.
Time frame: Start of study intervention through study completion (estimated as 56 weeks)
Pharmacokinetics (PK): Predose Plasma Concentrations (Cmax) of Tersolisib
Time frame: Day 15 through study completion (estimated as 56 weeks)
Change from Baseline in Side-Effect Burden as Measured by Functional Assessment of Cancer Therapy - General Item GP5 (FACT-GP5)
Time frame: Baseline to end of study completion (estimated as 56 weeks)
Plan to share: Yes — Anonymized individual patient level data will be provided in a secure access environment upon approval of a research proposal and a signed data sharing agreement.
Supporting information: Study protocol, Statistical analysis plan, Clinical study report
Time frame: Data are available 6 months after the primary publication or approval of the indication studied in the US and EU, whichever is later. Data will be indefinitely available for requesting.
Access criteria: A research proposal should be approved by an independent review panel and researchers should sign a data sharing agreement.
Data sharing details ↗ · vivli.org
No publications or documents are linked to this record.
Start is estimated for Dec 2026; primary completion for Dec 2027, 12 months later.
Of 232 industry-sponsored phase 2 interventional studies under Breast Neoplasms, half reached primary completion within 34 months of starting (the median), counting those still running; a quarter within 22 and three quarters within 53. This study's planned 12 months is below that.
Counting every sponsor, half of 1,302 studies reached it within 51 months; a quarter within 30 and three quarters within 82.
How these figures are worked out, and which studies are left out of them.
From the registry record's own update history. This site started tracking changes on Sep 25, 2026; for anything earlier, see the record history on ClinicalTrials.gov ↗
This study is not yet recruiting, as verified in Nov 2026. You cannot join it, but the record below documents what was studied.
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Studies of the drugs tested here: Abemaciclib · STX-478