This is an open label Phase 1, first-in-human (FIH) study of TST005, a bi-specific antibody
consisting of a PD-L1 monoclonal antibody (mAb) and a transforming growth factor beta (TGF-β)
trap in subjects with locally advanced or metastatic cancers
The study has 2 parts. Part A is a dose escalation portion where the patients will be doses
every three weeks following an accelerated 3+3 design. This portion will enroll approximately
25 patients with locally advanced or metastatic cancers.
Part B is an expansion portion where approximately 30 additional patients will be dosed at
the recommended dose level every 3 weeks. This part will include patients with locally
advanced or metastatic HPV related malignancies.
The trial will last approximately 2 years, with assessments including safety labs, ECGs, PKs
and PDs and CT/MRI tumor assessments, based on the Q3W dosing schedule.
1. Willing and able to provide signed and dated informed consent
2. Patients with histologically or cytologically confirmed, locally advanced or
metastatic solid tumors, evaluable by RECIST v1.1. (Part B includes metastatic HPV+
3. Subject who has tumor progression during or after prior therapy and for whom no
standard therapy exists that would confer clinical benefit.
4. At least one measurable lesion per RECIST 1.1 (Part B only).
5. Eastern Cooperative Oncology Group Performance Status (ECOG PS)0~1.
6. Provide archived tumor tissue samples
7. Adequate organ function
1. Concurrent malignancy within 3 years prior to entry other than adequately treated
cervical carcinoma-in-situ, localized squamous cell cancer of the skin, basal cell
carcinoma, prostate cancer not requiring treatment (with or without resection), ductal
carcinoma in situ of the breast, or ≤ T1 urothelial carcinoma.
2. Untreated or symptomatic central nervous system (CNS) metastases.
3. Any unresolved Grade 2 or greater toxicity from previous anticancer therapy except
4. Active leptomeningeal disease.
5. Active autoimmune diseases or history of autoimmune diseases that may relapse, with
the following exceptions:
- Controlled type 1 diabetes
- Hypothyroidism (provided it is managed with hormone-replacement therapy only)
- Controlled celiac disease
- Skin diseases not requiring systemic treatment (eg, vitiligo, psoriasis, or
- Any other disease that is not expected to recur in the absence of external
6. Any condition that required systemic treatment with either corticosteroids (> 10 mg
daily of prednisone or equivalent) or other immunosuppressive medication ≤ 14 days
before the first dose of investigational product, with the following exceptions:
- Adrenal replacement steroid (dose ≤ 10 mg daily of prednisone or equivalent)
- Topical, ocular, intra-articular, intranasal, or inhalational corticosteroid with
minimal systemic absorption
- Short course (≤ 7 days) of corticosteroid prescribed prophylactically (eg, for
contrast dye allergy) or for the treatment of a non-autoimmune condition (eg,
delayed-type hypersensitivity reaction caused by contact allergen)
7. History of interstitial lung disease, noninfectious pneumonitis, or uncontrolled lung
diseases, including but not limited to pulmonary fibrosis, active pneumonitis.
8. Severe cardiovascular disease, including cerebrovascular accident, transient ischemic
attack, myocardial infarction, or unstable angina, New York Heart Association class
III or IV heart failure or uncontrolled arrhythmia within 6 months of first dose.
9. Active, uncontrolled bacterial, viral, or fungal infections, requiring systemic
therapy within 2 weeks of screening.
10. Clinically significant bleeding within three months of the first dose.
11. Uncontrolled hypertension, defined as systolic ≥150 mm Hg or diastolic ≥90 mm Hg
maintained over time and despite antihypertensive treatment.
12. Patients with QTcF > 480 ms on screening ECG or with a history of additional risk
factors for TdP (e.g., heart failure, hypokalemia，family history of Long QT Syndrome)
13. Pregnant or nursing.
14. Known human immunodeficiency virus (HIV) or known acquired immunodeficiency syndrome.
15. A serious nonmalignant disease (e.g., psychiatric, substance abuse, uncontrolled
intercurrent illness, etc.) that could compromise protocol objectives in the opinion
of the Investigator and/or the Sponsor.
16. Any other condition that, in the opinion of the Investigator, would prohibit the
subject from participating in the study.
17. Active autoimmune disease requiring systemic therapy in the last 2 years prior to the
first dose (i.e., with use of disease modifying agents, systemic corticosteroids or
• Subjects with Type 1 diabetes mellitus (TD1M), hypothyroidism requiring only hormone
replacement, or skin disorders not requiring systemic treatment are permitted to
18. A history of (non-infectious) pneumonitis that required steroids or has current
19. < 4 weeks after any major procedures/surgery; clinically significant unhealed wound;
any unhealed ulceration in GI prior to first dose of TST005.
20. History of severe immune-related adverse effects from checkpoint inhibitor (CPI)
therapy (NCI CTCAE Grade 3 or 4) with the exception of endocrinopathy managed with
replacement therapy or subjects who discontinued CPI therapy for CPI-associated
toxicity or intolerability.