for people ages 18 years and up (full criteria)
at San Francisco, California and other locations
study started
completion around



Study STX-478-101 is a multipart, open-label, phase 1/2 study evaluating the safety, tolerability, pharmacokinetics (PK), and preliminary antitumor activity of STX-478 in participants with advanced solid tumors with certain mutations.

Part 1 will evaluate STX-478 as monotherapy in participants with advanced solid tumors and breast cancer; Part 2 will evaluate STX-478 therapy as combination therapy with fulvestrant in participants with breast cancer.

Each study part will include a 28-day screening period, followed by treatment with STX-478 monotherapy or combination therapy.

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


Breast Cancer, Gynecologic Cancer, HNSCC, Solid Tumors, Adult, Breast Neoplasms, Neoplasms by Site, Neoplasms, Breast Diseases, HER2-negative breast cancer, HR-positive breast cancer, Endometrial cancer, Ovarian cancer, Cervical cancer, Head and neck cancer, Head and neck squamous cell carcinoma, Fulvestrant, Antineoplastic Agents, PI3Kα, PI3K alpha, PI3Kα mutation, Alpelisib, STX-478, PI3Kα inhibitor, Estrogen Receptor Antagonists, Estrogen Antagonists, Hormone Receptor Antagonists, Hormone Antagonists, Hormones, Hormone Substitutes, and Hormone Antagonists, Physiological Effects of Drugs


You can join if…

Open to people ages 18 years and up

  1. Has an advanced or refractory solid tumor malignancy that is metastatic or locally advanced and unresectable (as specified by Cohort)
  2. Has a new or recent tumor biopsy (collected at screening, if feasible) or archival tumor specimen within 10 years prior to screening
  3. Has a tumor that harbors a documented PI3Kα mutation (cohort specific criterion for cohort-specific mutation types) obtained either from tumor or plasma samples, determined by PCR or NGS-based assay as an FDA-approved test in US, CE marked in EU, or obtained as part of normal clinical care in a CLIA certified or similarly certified laboratory.
  4. Is ≥18 years of age at the time of signing the ICF
  5. Has an ECOG performance status score of 0 or 1 at screening

You CAN'T join if...

  1. Has history (within ≤2 years before screening) of a solid tumor or hematological malignancy that is histologically distinct from the cancers being studied
  2. Has symptomatic brain or spinal metastases
  3. Has a tumor with known mutations/deletions in PTEN and activating mutations in AKT (E17K) confirmed by a CLIA-certified or similarly certified laboratory
  4. Has an established diagnosis of diabetes mellitus type 1 or has uncontrolled diabetes mellitus type 2 (based on FPG and HbA1c thresholds defined in the inclusion criteria) requiring antihyperglycemic medication
  5. Cohorts A0, A1, A2, A3, A4, A5 and B: Has had prior treatment with PI3K/AKT/mTOR inhibitor(s), except in certain circumstances
  6. 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
  7. 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
  8. Has had radiotherapy within 14 days before the initiation of study treatment


  • UCSF accepting new patients
    San Francisco California 94158 United States
  • Angeles Clinic and Research Institute accepting new patients
    Los Angeles California 90025-6602 United States


accepting new patients
Start Date
Completion Date
Scorpion Therapeutics, Inc.
Phase 1/2 research study
Study Type
Expecting 400 study participants
Last Updated