To Evaluate the Safety, Tolerability, Pharmacokinetics and Antitumor Activity of DAY301 in Participants With Locally Advanced or Metastatic Solid Tumors

A Phase 1, Open Label, Multiple Dose, Dose Escalation and Expansion Study to Investigate the Safety, Tolerability, Pharmacokinetics and Antitumor Activity of the PTK7-Targeted Antibody-drug Conjugate DAY301 in Patients With Locally Advanced or Metastatic Solid Tumors

This is a Phase 1a/1b, open-label, dose escalation and expansion study to evaluate the safety and anti-tumor activity of DAY301, a PTK7-directed antibody-drug conjugate in participants with advanced or metastatic solid tumors. The study comprises of 2 phases: Phase 1a dose escalation where participants will be administered DAY301 at escalating dose levels to assess safety and tolerability, and to determine the maximum tolerated dose (MTD) and/or the recommended dose (RD); In Phase 1b dose expansion, DAY301 will be evaluated in dose expansion cohorts.

Study Overview

• Status: Recruiting
• Conditions: Advanced or Metastatic Solid Tumors
• Intervention / Treatment: Drug: DAY301

• Study Type: Interventional
• Enrollment (Estimated): 254
• Phase: Phase 1

Contacts and Locations

• Study Contact: Name: Day One Clinical Trials Information; Phone Number: 650-484-0899; Email: clinicaltrials@dayonebio.com

Study Locations

• Canada
  • British Columbia
    • Vancouver, British Columbia, Canada, V5Z 4E6
      • Recruiting
      • Site: 011-013
  • Ontario
    • Toronto, Ontario, Canada, M5G 2M9
      • Recruiting
      • Site: 011-005
• United States
  • Connecticut
    • New Haven, Connecticut, United States, 06510
      • Recruiting
      • Site: 001-058
  • Florida
    • Lake Mary, Florida, United States, 32746
      • Recruiting
      • Site: 001-063
    • Sarasota, Florida, United States, 34232
      • Recruiting
      • Site: 001-064
  • Indiana
    • Indianapolis, Indiana, United States, 46202
      • Recruiting
      • Site: 001-060
  • Michigan
    • Grand Rapids, Michigan, United States, 49546
      • Recruiting
      • Site: 001-059
  • New York
    • New York, New York, United States, 10021
      • Recruiting
      • Site: 001-039
  • Oklahoma
    • Oklahoma City, Oklahoma, United States, 73104
      • Recruiting
      • Site: 001-073
  • Tennessee
    • Nashville, Tennessee, United States, 37203
      • Recruiting
      • Site: 001-065
  • Texas
    • Houston, Texas, United States, 77030
      • Recruiting
      • Site: 001-069
    • San Antonio, Texas, United States, 78229
      • Recruiting
      • Site: 001-057

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Histologically or cytologically confirmed diagnosis of advanced or metastatic solid tumors of the following histologies:
• Ovarian cancer
• Esophageal squamous cell carcinoma
• Triple-negative breast cancer
• Non-small cell lung cancer
• Small cell lung cancer
• Head and neck squamous cell carcinoma
• Gastric/gastroesophageal junction adenocarcinoma
• Cervical squamous cell carcinoma
• Endometrial cancers

(Participants must have been previously treated with standard of care systemic therapy, or for whom no standard therapy is available).

• Availability of tumor tissue sample (either an archival specimen or a fresh biopsy) at screening
• Measurable disease per Response Evaluation Criteria in Solid Tumors, Version 1.1 (RECIST v1.1).
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
• Adequate organ function.

Exclusion Criteria:

• Prior use of PTK7 targeting treatment (Phase 1a) or prior use of PTK7 targeting treatments and/or topoisomerase 1 (TOP1) inhibitor-based antibody-drug conjugate (ADC) (Phase 1b).

• Phase 1b disease-specific exclusion criteria:

  1. Cohort 1: Neuroendocrine tumors or endometrial sarcoma (eg, stromal sarcoma, leiomyosarcoma, or other types of pure sarcomas)
  2. Cohort 2: Ovarian cancer that progressed >6 months after the last dose of platinum-based chemotherapy (platinum-sensitive disease), or disease that did not respond (partial response [PR] or complete response [CR]) to or progressed ≤91 days after the last dose of first-line platinum-based chemotherapy (primary platinum-refractory disease)
  3. Cohort 3: nasopharyngeal primary tumors.
• History of small bowel obstruction requiring hospitalization within 3 months prior to the first dose of study treatment.
• Ascites requiring frequent paracentesis (more often than approximately every 4 weeks) for symptomatic management, or new onset within 4 weeks prior to the first dose of study treatment. Patients with an indwelling catheter may be considered eligible, after consultation with the medical monitor.
• Active or progressing brain metastases or evidence of leptomeningeal disease.
• Persistent toxicities from previous systemic antineoplastic treatments of Grade >1, excluding alopecia and vitiligo.
• Systemic antineoplastic therapy within five half-lives or 4 weeks, whichever is shorter, prior to first dose of study treatment, including investigational agents.

Note: Other protocol defined Inclusion/Exclusion criteria may apply.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: DAY301 intravenous (IV) infusion; DAY301 will be administered at different dose levels in dose escalation and at the RD in dose expansion cohorts.	Drug: DAY301; DAY301 will be administered as IV infusion

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Phase 1a: Dose Escalation: Number of participants with reported Dose Limiting Toxicities (DLTs)	To evaluate adverse events (AEs) considered dose limiting toxicities that occur in the first cycle of treatment (within a DLT observation period).	Within 21 days of first infusion (Day 1)
Phase 1a: Dose Escalation: Number of participants with reported adverse events (AEs) or serious AEs (SAEs)	The type, incidence, and severity of AEs and SAEs will be determined using the National Cancer Institute (NCI) Common Terminology Criteria for Adverse Events (CTCAE) v5.0.	through the duration of treatment, up to approximately 12 months
Phase 1a: Dose Escalation: Frequency of dose interruptions	The frequency at which dose interruptions occur during dose-escalation	through the duration of treatment, up to approximately 12 months
Phase 1a: Dose Escalation: Duration of dose interruptions	The duration of dose interruptions that occur during dose-escalation.	through the duration of treatment, up to approximately 12 months
Phase 1a: Dose Escalation: Frequency of dose reductions	The frequency at which dose reductions occur during dose-escalation.	through the duration of treatment, up to approximately 12 months
Phase 1a: Dose Escalation: Duration of dose reductions	The duration of dose reductions that occur during dose-escalation.	through the duration of treatment, up to approximately 12 months
Phase 1b: Dose Expansion: Number of participants reporting AEs and SAEs	The type, incidence, and severity of AEs and SAEs will be determined using the NCI CTCAE v5.0.	through the duration of treatment, up to approximately 12 months
Phase 1b: Dose Expansion: Frequency of dose interruptions	The frequency at which dose interruptions occur during dose-expansion.	through the duration of treatment, up to approximately 12 months
Phase 1b: Dose Expansion: Duration of dose interruption	The duration of dose interruptions that occur during dose-expansion.	through the duration of treatment, up to approximately 12 months
Phase 1b: Dose Expansion: Frequency of dose reductions	The frequency at which dose reductions occur during dose-expansion.	through the duration of treatment, up to approximately 12 months
Phase 1b: Dose Expansion: Duration of dose reductions	The duration of dose reductions that occur during dose-expansion.	through the duration of treatment, up to approximately 12 months
Phase 1b: Dose Expansion: Objective response rate	Objective response rate based on best overall response (BOR) will be assessed by investigators according to Response Evaluation Criteria in Solid Tumors (RECIST v1.1).	through the duration of treatment, up to approximately 12 months-up

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Phase 1a and Phase 1b: Maximum concentration (Cmax) of DAY301	Blood samples will be collected at indicated time points for the analysis of pharmacokinetic parameters.	Varying timepoints through the duration of treatment, up to approximately 12 months
Phase 1a and Phase 1b: time to Cmax (Tmax) of DAY301	Blood samples will be collected at indicated time points for the analysis of pharmacokinetic parameters.	Varying timepoints through the duration of treatment, up to approximately 12 months
Phase 1a and Phase 1b: area under the curve (AUC) of DAY301	Blood samples will be collected at indicated time points for the analysis of pharmacokinetic parameters.	Varying timepoints through the duration of treatment, up to approximately 12 months
Phase 1a and Phase 1b: terminal half-life (t1/2) of DAY301	Blood samples will be collected at indicated time points for the analysis of pharmacokinetic parameters.	Varying timepoints through the duration of treatment, up to approximately 12 months
Phase 1a and 1b: Clinical Benefit rate (CBR)	Clinical Benefit rate will be assessed by investigators according to RECIST v1.1.	through the duration of treatment, up to approximately 12 months
Phase 1a and 1b: duration of response (DOR)	Duration of response will be assessed by investigators according to RECIST v1.1.	through the duration of treatment, up to approximately 12 months
Phase 1a and 1b: time to response (TTR)	Time to response will be assessed by investigators according to RECIST v1.1.	through the duration of treatment, up to approximately 12 months
Phase 1a and 1b: Progression-free survival	Progression-free survival will be assessed by investigators according to RECIST v1.1.	through the duration of treatment, up to approximately 12 months
Phase 1a and 1b: Number of participants with positive antidrug antibodies (ADAs)	Assessed by the measure of anti-drug antibodies in serum.	varying timepoints through the duration of treatment, up to approximately 12 months
Phase 1a Dose Escalation: Objective response rate	Objective response rate based on BOR will be assessed by investigators according to RECIST v1.1.	through the duration of treatment, up to approximately 12 months
Phase 1b: Overall survival	Overall survival will be assessed by investigators.	through the duration of treatment, up to approximately 12 months

Collaborators and Investigators

• Sponsor: Day One Biopharmaceuticals, Inc.

Study record dates

Study Major Dates

• Study Start (Actual): November 18, 2024
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 1, 2028

Study Registration Dates

• First Submitted: December 23, 2024
• First Submitted That Met QC Criteria: December 23, 2024
• First Posted (Actual): December 31, 2024

Study Record Updates

• Last Update Posted (Estimated): October 10, 2025
• Last Update Submitted That Met QC Criteria: October 8, 2025
• Last Verified: October 1, 2025

More Information

Terms related to this study

• Keywords: Dose Escalation; Dose Expansion; Advanced or metastatic solid tumors; DAY301; PTK7-Targeted Antibody-drug Conjugate
• Additional Relevant MeSH Terms: Neoplasms
• Other Study ID Numbers: DAY301-001

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: Yes
• Studies a U.S. FDA-regulated device product: No