Eligible patients (18-75 years) must have recurrent/metastatic solid tumors (HNSCC prioritized) with measurable lesions (RECIST 1.1), ECOG 0-1, adequate organ function, archived/fresh tumor tissue, and resolved prior treatment toxicities (≤Grade 1), with reproductive safeguards (contraception for 6 months post-treatment).

Administration by intravenous infusion for a cycle of 3 weeks.

A Phase I Clinical Study to Evaluate the Safety, Tolerability, Pharmacokinetics and Preliminary Efficacy of BL-B16D1 in Patients With Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma and Other Solid Tumors

Phase Ia assesses DLTs (NCI-CTCAE v5.0) and MTD within 21 days post-first dose, while Phase Ib determines RP2D (within 24 months) based on integrated safety, efficacy, PK, and PD data of BL-B16D1.

Key measures include TEAE monitoring, PK parameters (Cmax/Tmax/T1/2/AUC0-t/CL/Ctrough), ADA incidence, and efficacy outcomes (ORR/DCR/DOR per RECIST 1.1) over 24 months, evaluating both safety and antitumor activity of BL-B16D1.

Eligible patients (18-75) must have advanced/metastatic solid tumors (breast cancer prioritized) with measurable lesions (RECIST 1.1), ECOG 0-1, adequate organ function, available tumor tissue, resolved prior toxicities (≤Grade 1), and use contraception for 6 months post-treatment.

Administration by intravenous infusion for a cycle of 3 weeks.

A Phase I Clinical Study to Evaluate the Safety, Tolerability, Pharmacokinetics Characteristics and Preliminary Efficacy of BL-B16D1 in Patients With Unresectable Locally Advanced or Metastatic Breast Cancer and Other Solid Tumor

Phase Ia evaluates DLTs (NCI-CTCAE v5.0) and MTD within 21 days post-dose, while Phase Ib determines RP2D (24 months) based on integrated safety, efficacy, PK/PD data of BL-B16D1.

Key measures include TEAE monitoring, PK parameters (Cmax/Tmax/T1/2/AUC0-t/CL/Ctrough), ADA incidence, and efficacy outcomes (ORR/DCR/DOR per RECIST 1.1) over 24 months.

Eligible patients (18-75) must have advanced/metastatic solid tumors with measurable lesions (RECIST 1.1), ECOG 0-1, adequate organ function, available tumor tissue, resolved prior toxicities (≤Grade 1), and use contraception for 6 months post-treatment.

Administration by intravenous infusion for a cycle of 3 weeks.

A Phase I Clinical Study to Evaluate the Safety, Tolerability, Pharmacokinetics Characteristics and Preliminary Efficacy of BL-B16D1 in Patients With Locally Advanced or Metastatic Solid Tumors

Phase Ia evaluates DLTs (NCI-CTCAE v5.0) and determines MTD within 21 days post-dose, while Phase Ib establishes RP2D (24 months) based on comprehensive safety, efficacy, PK/PD data of BL-B16D1.

Key assessments include TEAE monitoring, PK parameters (Cmax/Tmax/T1/2/AUC0-t/CL/Ctrough), ADA incidence, and efficacy outcomes (ORR/DCR/DOR per RECIST 1.1) over 24 months of BL-B16D1 treatment.

Inclusion: Signed consent, age 18-75 (Ia) or ≥18 (Ib), HER2+/- solid tumors, measurable lesions (RECIST 1.1), ECOG 0-1, adequate organ function. Exclusion: Recent antitumor therapy, uncontrolled comorbidities (cardiac, autoimmune, infections), CNS metastases, allergies to BL-M17D1, pregnancy, or investigator-assessed ineligibility.

Participants receive BL-M17D1 as intravenous infusion for the first cycle (3 weeks). Participants with clinical benefit could receive additional treatment for more cycles. The administration will be terminated because of disease progression or intolerable toxicity occurring or other reasons.

A Phase I Study to Evaluate the Safety, Tolerability, Pharmacokinetic Characteristics and Preliminary Efficacy of BL-M17D1 in Patients With Locally Advanced or Metastatic HER2 Positive/Lower Expression Gastrointestinal Cancer and Other Solid Tumors

Phase Ia assesses DLTs (NCI-CTCAE v5.0) and MTD (highest dose with ≤1/6 DLTs) within 21 days post-first dose. Phase Ib determines RP2D (within ~24 months) based on integrated safety, efficacy, PK, and PD data.

TEAEs (type/frequency/severity) and PK parameters (Cmax, Tmax, T1/2, AUC0-t, CL, Ctrough) are monitored for ~24 months. Immunogenicity (ADA) and efficacy (ORR, DCR per RECIST 1.1; DOR) are evaluated in Phase Ib.

Inclusion: Signed consent, age ≥18, HER2+/- solid tumors, measurable lesions (RECIST 1.1), ECOG 0-1, adequate organ function. Exclusion: Recent antitumor therapy, uncontrolled comorbidities (cardiac, autoimmune, infections), CNS metastases, allergies to BL-M17D1, pregnancy, or investigator-assessed ineligibility.

The study includes 3 parts: Part 1 Dose escalation. Part 2 Dose Finding non-randomized and Part 3 Dose expansion randomized. BL-M17D1 will be administered on Day 1 via by intravenous infusion every 3 weeks.

A Phase 1 Open-Label Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Efficacy of BL-M17D1 in Subjects with HER2-Expressing or HER2-Mutant Advanced or Metastatic Solid Tumors

The study evaluates dose-limiting toxicities (DLTs) including hematologic (Grade 4 neutropenia >7 days, febrile neutropenia ≥Grade 3) and nonhematologic toxicities (Grade ≥3 events, Hy's law cases) over 1 year. MTD, MAD, and RDEs of BL-M17D1 will be determined, alongside monitoring of SAEs and TEAEs.

Inclusion: Signed consent, age 18-75 (Ia) or ≥18 (Ib), HER2+/- solid tumors, measurable lesions (RECIST 1.1), ECOG 0-1, adequate organ function. Exclusion: Recent antitumor therapy, uncontrolled comorbidities (cardiac, autoimmune, infections), CNS metastases, allergies to BL-M17D1, pregnancy, or investigator-assessed ineligibility.

Participants receive BL-M17D1 as intravenous infusion for the first cycle (3 weeks). Participants with clinical benefit could receive additional treatment for more cycles. The administration will be terminated because of disease progression or intolerable toxicity occurring or other reasons.

A Phase I Study to Evaluate the Safety, Tolerability, Pharmacokinetic Characteristics and Preliminary Efficacy of BL-M17D1 in Patients With Locally Advanced or Metastatic HER2 Positive/Negative Breast Cancer and Other Solid Tumors

Phase Ia evaluates DLTs (NCI-CTCAE v5.0) and MTD (highest dose with ≤1/6 DLTs) within 21 days post-first dose. Phase Ib determines RP2D (up to 24 months) based on integrated safety, efficacy, PK, and PD data.

TEAEs (type/frequency/severity) and PK parameters (Cmax, Tmax, T1/2, AUC0-t, CL, Ctrough) are monitored for 24 months. Immunogenicity (ADA) and efficacy (ORR/DCR per RECIST 1.1, DOR) are assessed in Phase Ib.