Tests tersolisib alone and combined with other cancer drugs in advanced solid tumors
Tests tersolisib, alone or with other drugs, in adults with advanced solid tumors.
Key facts
- Who runs it
- Eli Lilly and Company
- Where
- Alexandria, Brescia, Milan, Monza, Pisa, Ravenna, Rome, and Verona, ItalySee the 9 sitesAlso in 8 other countries, 56 sites
- Registry title
- First-in-Human Study of Tersolisib (STX-478) as Monotherapy and in Combination With Other Antineoplastic Agents in Participants With Advanced Solid Tumors
- Status
- Recruiting
- Phase
- Phase 1/2
- People taking part
- 880 people, planned
- Started
- 17 Apr 2023
- Expected to end
- Jul 2030
- Type of study
- Interventional, 5 groups
- Treatments tested
- STX-478
- Fulvestrant
- Ribociclib
- Palbociclib
- Letrozole
- Anastrozole
- Exemestane
- Tamoxifen
- Abemaciclib
- Imlunestrant
- Metformin
- Record updated
- 7 July 2026
Who can take part
AI summary
From the trial's eligibility criteria. Machine-read from the registry text on this page, so it can be wrong. The registry text below and the trial team decide who can take part.
The trial is looking for adults with an advanced solid tumor, such as breast cancer, whose tumor has a documented PI3Kα mutation.
- Age
- 18 years or older.
- Sex
- All sexes can join.
- Disease stage
- Advanced or refractory solid tumor that has spread (metastatic) or is locally advanced and cannot be removed by surgery. Some parts look at hormone receptor positive (HR+) breast cancer.
- Earlier treatment
- People who had earlier treatment with PI3K/AKT/mTOR inhibitors cannot join, except in certain circumstances. Other cancer treatment or investigational drugs must stop at least 14 days (or 4 half-lives, whichever is longer, up to 28 days) before the trial treatment starts.
- Biomarker or test result
- The tumor must have a documented PI3Kα mutation. The mutation type depends on the cohort.
Main reasons for not taking part
- Another solid tumor or blood cancer within the last 2 years that is different from the cancers studied
- Brain or spinal metastases that cause symptoms
- Uncontrolled diabetes
- Earlier treatment with PI3K/AKT/mTOR inhibitors, except in certain circumstances
- Side effects of earlier cancer treatment that have not improved to grade 1 or lower (except hair loss and peripheral neuropathy)
The registry criteria, word for word
Show all 13 criteriaShow less
Who can take part
- Has an advanced or refractory solid tumor malignancy that is metastatic or locally advanced and unresectable (as specified by Cohort)
- Has a new or recent tumor biopsy (collected at screening, if feasible) or will provide an adequate tissue sample prior to screening
- Has a tumor that harbors a documented PI3Kα mutation (cohort specific criterion for cohort-specific mutation types)
- Is ≥18 years of age at the time of signing the ICF
- Has an ECOG performance status score of 0 or 1 at screening
- Has adequate organ function as defined per protocol
Who cannot take part
- Has had prior treatment with PI3K/AKT/mTOR inhibitor(s), except in certain circumstances
- Has had treatment with any local or systemic antineoplastic therapy or investigational anticancer agent within 14 days or 4 half-lives, whichever is longer, prior to the initiation of study treatment up to a maximum washout period of 28 days. Endocrine therapy does not require a washout period if the patient is enrolling in a cohort with the same combination endocrine therapy
- Has toxicities from previous anticancer therapies that have not resolved to baseline levels or CTCAE grade ≤1, with the exception of alopecia and peripheral neuropathy
- Has had radiotherapy within 14 days before the initiation of study treatment
- Has an established diagnosis of uncontrolled diabetes mellitus (defined as HbA1c ≥8% and/or FBG ≥140 mg/dL [7.7 mmol/L] and/or requiring or required insulin)
- Has history (within ≤2 years before screening) of a solid tumor or hematological malignancy that is histologically distinct from the cancers being studied
- Has symptomatic brain or spinal metastases
Where in Italy
Also in 8 other countries, 56 sites
- Azienda Ospedaliero-Universitaria Ss.Antonio E Biagio E C.Arrigo AlessandriaAlexandria, ItalyTaking people
- Azienda Socio Sanitaria Territoriale degli Spedali Civili di BresciaBrescia, ItalyTaking people
- European Institute Of Oncology S.r.l.Milan, ItalyTaking people
- Fondazione IRCCS - Istituto Nazionale dei TumoriMilan, ItalyTaking people
- Fondazione IRCCS San Gerardo dei TintoriMonza, ItalyTaking people
- Azienda Ospedaliero Universitaria PisanaPisa, ItalyTaking people
- Azienda Unità Sanitaria Locale della RomagnaRavenna, ItalyTaking people
- Fondazione Policlinico Universitario Agostino Gemelli IRCCSRome, ItalyTaking people
- Centro Ricerche Cliniche di Verona s.r.l.Verona, ItalyTaking people
About the trial
What the trial wants to find out
Study STX-478-101 (LY4064809) is a multipart, open-label, phase 1/2 study evaluating the safety, tolerability, pharmacokinetics (PK), and preliminary antitumor activity of STX-478 (LY4064809) in participants with advanced solid tumors with P13Ka mutations.
Read full original descriptionShow less
Part 1 will evaluate STX-478 as monotherapy in participants with advanced solid tumors. Part 2 will evaluate STX-478 therapy as combination therapy with fulvestrant in participants with hormone receptor positive (HR+) breast cancer. Part 3 will evaluate STX-478 as combination therapy with endocrine therapy (aromatase inhibitors, fulvestrant, tamoxifen, or imlunestrant) and a CDK4/6 Inhibitor (either Ribociclib, Palbociclib or Abemaciclib) in participants with HR+ breast cancer.
Each study part will include a 28-day screening period, followed by treatment with STX-478 monotherapy or combination therapy.
The 5 groups in the trial
- Dose Escalation (Advanced Solid Tumors)Treatment being tested
* Cohort A0: Advanced Solid tumors expressing PI3Kα mutations * Cohort A1: HR+ breast cancer expressing PI3Kα mutations
Treatment: STX-478
- Dose ExpansionTreatment being tested
* Cohort A2: Gynecologic cancers * Cohort A3: Head and Neck Squamous Cell Carcinoma * Cohorts A4/A5: Other solid tumors not included in Cohorts A1, A2, A3 expressing PI3Kα mutations * Cohort A6: Endometrial cancer * Cohort A7: Non-gastrointestinal solid tumors
Treatment: STX-478
- Dose Selection/Expansion: Combination STX-478 + fulvestrantTreatment being tested
Cohort B: HR+/HER2- or HR+/HER2low breast cancer expressing PI3Kα mutations
Treatment: STX-478 and Fulvestrant
- Dose Selection/Expansion CombinationTreatment being tested
STX-478 + Endocrine therapy + CDK4/6 inhibitor Cohort C/D/E: HR+/HER2- or HR+/HER2low breast cancer expressing PI3Ka mutations
Treatment: STX-478, Fulvestrant, Ribociclib, Palbociclib, Letrozole, Anastrozole, Exemestane, Tamoxifen, Abemaciclib, and Imlunestrant
- Experimental: Drug to Drug Interaction (DDI) Metformin STX-478 +/- ET ([AIs or fulvestrant]Treatment being tested
CDK4/6 inhibitor therapy in Cohort A8: all solid tumors Cohort B2 and Cohort F: HR+/HER2- or HR+/HER2 low breast cancer expressing PI3Kα mutations
Treatment: STX-478, Fulvestrant, Ribociclib, Palbociclib, Letrozole, Anastrozole, Exemestane, Abemaciclib, and Metformin
Questions to ask the study team
- How often do I need to come in, and for how long each time?
- Are travel costs paid?
- Can I keep my own doctor?
- What happens if I want to stop?
Contact the study team: see the registry record → Contacts and Locations
Print a page for my doctorData and sources
- Registry record
- Listed on ClinicalTrials.gov and on the EU's official list of trials (CTIS).
- Official title
- First-in-Human Study of STX-478, a Mutant-Selective PI3Kα Inhibitor as Monotherapy and in Combination With Other Antineoplastic Agents in Participants With Advanced Solid Tumors
- Plain-language title
- Tests tersolisib alone and combined with other cancer drugs in advanced solid tumorsGenerated from the registry record. The registry title is the official one.
- AI summary
- From the trial's eligibility criteria. Read by machine on 12 November 2026.
- Record updated
- 7 July 2026