A Study of ASP388B Given by Itself and With Standard Therapies in Participants With Solid Tumors
A Phase 1b/2 Study of ASP388B as Monotherapy and in Combination With Standard Therapies in Participants With Locally Advanced Unresectable or Metastatic Solid Tumors
2 other identifiers
interventional
392
0 countries
N/A
Brief Summary
This is an early development study of ASP388B in people with solid tumors. In this study, ASP388B will be given to people for the first time. It will be given by itself or together with standard cancer therapies. The main aims of the study are to check the safety of ASP388B and find the most suitable dose. This study will be in 2 parts. In Part 1, different small groups of people with solid tumors will receive lower to higher doses of ASP388B. Some groups will receive ASP388B by itself, and other groups will receive ASP388B with standard cancer therapies. Any medical problems will be recorded for each dose. This is to find suitable doses of ASP388B to use in Part 2 of the study, and to include the tumor types that responded well to ASP388B. In Part 2, other different small groups of people with the specific tumor types (from Part 1) will receive the most suitable doses worked out from Part 1. Some groups will receive ASP388B by itself, and other groups will receive ASP388B with standard cancer therapies. In both parts of the study, ASP388B will be given once in 3-week cycles. The standard cancer therapies will be given according to their approved label. ASP388B and the standard cancer therapies will be given slowly through a tube into a vein. This is called an infusion. In both parts of the study, safety checks will be done at each visit, and the doctors will continue to check for medical problems throughout the study.
Trial Health
Trial Health Score
Automated assessment based on enrollment pace, timeline, and geographic reach
participants targeted
Target at P75+ for phase_1
Started Aug 2026
Typical duration for phase_1
Health score is calculated from publicly available data and should be used for screening purposes only.
Trial Relationships
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Study Timeline
Key milestones and dates
First Submitted
Initial submission to the registry
July 23, 2026
CompletedFirst Posted
Study publicly available on registry
July 28, 2026
CompletedStudy Start
First participant enrolled
August 31, 2026
ExpectedPrimary Completion
Last participant's last visit for primary outcome
February 28, 2030
Study Completion
Last participant's last visit for all outcomes
May 31, 2030
July 28, 2026
July 1, 2026
3.5 years
July 23, 2026
July 23, 2026
Conditions
Keywords
Outcome Measures
Primary Outcomes (7)
Number of Participants with Dose Limiting Toxicities (DLTs)
A DLT is defined as any event meeting the DLT criteria occurring within 21 days of first dose on Cycle 1 Day 1 (C1D1) that cannot clearly be attributed to a cause other than ASP388B administered in monotherapy or in combination with standard treatments.
Up to 21 days after C1D1
Number of Participants with Treatment-Emergent Adverse Events (TEAEs)
An AE is any untoward medical occurrence in a patient or clinical study participant, temporally associated with the use of study intervention, whether or not considered related to the study intervention. NOTE: An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom or disease (new or exacerbated) temporally associated with the use of study intervention. This includes events related to the comparator, if applicable, and events related to the (study) procedures. A TEAE is an AE with onset at any time from first dosing until last scheduled procedure.
Up to 45 months
Number of participants with laboratory value abnormalities and/or adverse events (AEs)
Number of participants with potentially clinically significant laboratory values.
Up to 45 months
Number of participants with vital sign abnormalities and/or AEs
Number of participants with potentially clinically significant vital sign values.
Up to 45 months
Number of participants with electrocardiogram (ECG) abnormalities and/or AEs
Number of participants with potentially clinically significant ECG values.
Up to 45 months
Number of Participants with Physical Examination (PE) abnormalities and/or AEs
Number of participants with potentially clinically significant PE values.
Up to 45 months
Number of Participants at each grade of Eastern Cooperative Oncology Group (ECOG) performance status score
The ECOG scale will be used to assess performance status. Scores range from 0 (fully active) to 5 (dead). Negative change scores represent an improvement. Positive scores represent a decline in performance.
Up to 45 months
Secondary Outcomes (12)
Objective Response Rate (ORR) of ASP388B per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1
Up to 45 months
Objective Response Rate (ORR) of ASP388B per Prostate Cancer Working Group 3 (PCWG3)
Up to 45 months
Duration of Response (DOR) of ASP388B per RECIST v1.1
Up to 45 months
Duration of Response (DOR) of ASP388B per Prostate Cancer Working Group (PCWG3)
Up to 45 months
Disease Control Rate (DCR) of ASP388B per RECIST v1.1
Up to 45 months
- +7 more secondary outcomes
Study Arms (7)
ASP388B Monotherapy Dose Escalation
EXPERIMENTALParticipants with head and neck squamous cell carcinoma (HNSCC) \[including nasopharyngeal cancer (NPC)\], esophageal squamous cell carcinoma (ESCC), metastatic castration-resistant prostate cancer(mCRPC), squamous non-small cell lung cancer (sqNSCLC) or small cell lung cancer (SCLC) will receive the dose based on the assigned dose level of ASP388B in 21-day cycles.
ASP388B Monotherapy Dose Expansion (HNSCC)
EXPERIMENTALParticipants with HNSCC excluding NPC, will receive ASP388B in 21-day cycles with dose level(s) selected from dose escalation.
ASP388B Monotherapy Dose Expansion (ESCC)
EXPERIMENTALParticipants with ESCC will receive ASP388B in 21-day cycles with dose level(s) selected from dose escalation.
ASP388B Combination Therapy Dose Escalation (HNSCC)
EXPERIMENTALParticipants with HNSCC excluding NPC and salivary gland tumors will receive ASP388B in 21-day cycles at dose level(s) based on emerging data.
ASP388B Combination Therapy Dose Escalation (ESCC)
EXPERIMENTALParticipants with ESCC will receive ASP388B in 21-day cycles at dose level(s) based on emerging data.
ASP388B Combination Therapy Dose Expansion (HNSCC)
EXPERIMENTALParticipants with HNSCC excluding NPC and salivary gland tumors will receive ASP388B in 21-day cycles at dose level(s) based on emerging data.
ASP388B Combination Therapy Dose Expansion (ESCC)
EXPERIMENTALParticipants with ESCC will receive ASP388B in 21-day cycles at dose level(s) based on emerging data.
Interventions
Intravenous infusion
Intravenous infusion
Intravenous infusion
Intravenous infusion
Intravenous infusion
Eligibility Criteria
You may qualify if:
- For the ASP388B monotherapy dose escalation (excluding the tumor-specific backfill participants), the following criteria apply:
- Participant has a confirmed diagnosis of locally advanced unresectable or metastatic solid tumors.
- Participant has progressed on, is ineligible for, or has refused all available standard therapies (no limit to the number of prior treatment regimens).
- Prior exposure to B7-H3, STING agonist or TopI directed therapy is allowed.
- Participant must have one of the following malignancies (for all tumor types, any compounds of neuroendocrine histology is ineligible): HNSCC, ESCC, mCRPC, sqNSCLC, SCLC
- mCRPC
- Participants with histologically or cytologically confirmed mCRPC who are refractory to a novel antiandrogen therapy (including but not limited to abiraterone, enzalutamide and/or apalutamide) and have failed at least 1 (but not more than 2) taxane regimens (or who are deemed medically unsuitable to be treated with a taxane regimen or have actively refused treatment with a taxane regimen).
- Participants must have undergone bilateral orchiectomy or must be on continuous ADT with a GnRH agonist or antagonist.
- Total serum testosterone ≤ 50 ng/dL or 1.7 nmol/L
- Evidence of progressive disease, defined as ≥ 1 PCWG3 criteria: PSA level ≥ 1 ng/mL that has increased on at least 2 successive occasions at least 1 week apart; Nodal or visceral progression as defined by RECIST v1.1 with PCWG3 modifications; Appearance of ≥ 2 new lesions in bone scan
- Participants with mCRPC can be enrolled without measurable disease.
- For sqNSCLC
- Participants with known EGFR, ALK, ROS, BRAF or other actionable mutations are eligible if treated with mutation targeted therapy and have progressed, relapsed or discontinued treatment due to toxicity.
- For SCLC
- Metastatic or extensive stage (EC-SCLC)
- +37 more criteria
You may not qualify if:
- Participant weighs \< 40 kg during screening.
- Participant has known active central nervous system (CNS) metastases. NOTE: A participant with CNS metastases that have been treated with surgery and/or radiation therapy, who is no longer taking pharmacologic doses of glucocorticoids and is neurologically stable, is eligible. Prophylactic use of anticonvulsants is permitted.
- Participant has any of the following:
- Any history of recurrent Grade 3 AEs/ immune-related AEs (irAEs) or history of Grade 4 irAEs related to prior anticancer therapy.
- Participant has active or prior autoimmune or inflammatory disorders requiring systemic therapy within the past 2 years including inflammatory skin conditions, inflammatory bowel disease (e.g., ulcerative colitis or Crohn's disease), diverticulitis (with the exception of diverticulosis), celiac disease, systemic lupus erythematosus, Sarcoidosis syndrome, Wegener syndrome (granulomatosis with polyangiitis), Graves' disease, rheumatoid arthritis, hypophysitis or uveitis. The following are exceptions to this criterion:
- Participant with type 1 diabetes mellitus
- Participant with vitiligo or alopecia
- Participant with endocrinopathies stably maintained on appropriate replacement therapy
- Participant with any chronic skin condition that does not require systemic therapy
- Participant has leptomeningeal disease as a manifestation of the current malignancy.
- Participant has a known additional malignancy that requires active treatment, with the exception of any of the following:
- Adequately treated basal or squamous cell skin cancer, superficial bladder cancer or carcinoma in situ of the cervix or breast
- Adequately treated stage I cancer from which the participant is currently in remission and has been in remission for ≥ 2 years
- Any other cancer from which the participant has been disease-free for ≥ 5 years
- Participant has a known history of HIV infection with AIDS-related complications. HIV testing will be conducted per local requirements.
- +25 more criteria
Contact the study team to confirm eligibility.
Sponsors & Collaborators
MeSH Terms
Conditions
Interventions
Condition Hierarchy (Ancestors)
Intervention Hierarchy (Ancestors)
Study Officials
- STUDY DIRECTOR
Medical Monitor
Astellas Pharma Global Development, Inc.
Central Study Contacts
Study Design
- Study Type
- interventional
- Phase
- phase 1
- Allocation
- NON RANDOMIZED
- Masking
- NONE
- Purpose
- TREATMENT
- Intervention Model
- SEQUENTIAL
- Sponsor Type
- INDUSTRY
- Responsible Party
- SPONSOR
Study Record Dates
First Submitted
July 23, 2026
First Posted
July 28, 2026
Study Start (Estimated)
August 31, 2026
Primary Completion (Estimated)
February 28, 2030
Study Completion (Estimated)
May 31, 2030
Last Updated
July 28, 2026
Record last verified: 2026-07
Data Sharing
- IPD Sharing
- Will share
- Shared Documents
- STUDY PROTOCOL, SAP, CSR
- Time Frame
- Access to participant level data is offered to researchers after publication of the primary manuscript (if applicable) and is available as long as Astellas has legal authority to provide the data.
- Access Criteria
- Researchers must submit a proposal to conduct a scientifically relevant analysis of the study data. The research proposal is reviewed by an Independent Research Panel. If the proposal is approved, access to the study data is provided in a secure data sharing environment after receipt of a signed Data Sharing Agreement.
Access to anonymized individual participant level data collected during the study, in addition to study-related supporting documentation, is planned for studies conducted with approved product indications and formulations, as well as products terminated during development. Studies conducted with product indications or formulations that remain active in development are assessed after study completion to determine if Individual Participant Data can be shared. Further details on Astellas' data sharing policy can be found at https://www.clinicaltrials.astellas.com/transparency/.