A Study of SGN-B6A in Chinese Participants With Advanced Solid Tumors

Inclusion Criteria: * Subjects must have histologically or cytologically confirmed metastatic or unresectable locally advanced solid malignancy within one of the tumor types listed below. * NSCLC * HNSCC * ESCC * GAC * EAC * GEJ adenocarcinoma * Subjects must have disease that is relapsed or refractory, or be intolerant to systemic standard-of-care therapies, and in the judgement of the investigator, should have no appropriate standard-of-care therapeutic option. If a standard-of-care therapy is available that has not been administered, the reason that the therapy is not appropriate must be documented. * Adequate organ function as defined by the baseline laboratory criteria obtained within 7 days prior to SGN-B6A initiation (Cycle 1 Day 1) * Measurable or non-measurable disease per RECIST v1.1 at baseline. * An Eastern Cooperative Oncology Group (ECOG) Performance Status score of 0 or 1. Exclusion Criteria: * History of another malignancy within 3 years before the first dose of study intervention, or any evidence of residual disease from a previously diagnosed malignancy. Exceptions are malignancies with a negligible risk of metastasis or death. * Participants with any of the following respiratory conditions: * Evidence of noninfectious interstitial lung disease (ILD) or pneumonitis that: * \* Was previous diagnosed and required systemic steroids, or * \* Is currently diagnosed and managed, or * \* Is suspected on radiologic imaging at screening * Known diffusing capacity of the lung for carbon monoxide (DLCO) \< 50% * Any Grade greater than or equal to (≥) 3 pulmonary disease unrelated to underlying malignancy * Prior radiation therapy to the lung that is \>30 gray (Gy) within 6 months of the first dose of sigvotatug vedotin. * Pre-existing peripheral neuropathy Grade greater than or equal to (≥) 2 * Uncontrolled diabetes mellitus * Known active central nervous system metastases. Participants with previously treated brain metastases may participate provided they: * are clinically stable for at least 4 weeks prior to study entry after brain metastasis treatment, * have no new or enlarging brain metastases, and * are off of corticosteroids prescribed for symptoms associated with brain metastases for at least 7 days prior to first dose of study drug. * Known history or current diagnosis of carcinomatous meningitis * Previous treatment with an MMAE-containing agent or an agent targeting integrin beta-6 * Prior anticancer therapies: * Chemotherapy within 21 days prior to first administration of sigvotatug vedotin * Targeted small molecule agents within 14 days or 5 half-lives (whichever is longer) prior to first administration of sigvotatug vedotin * Antibody-based anticancer or other investigational antitumor therapy within 28 days prior to first administration of sigvotatug vedotin * Focal radiotherapy or major surgery that is not completed 14 days prior to the first dose of sigvotatug vedotin * Traditional or herbal medicines: * Anti-cancer traditional or herbal medicines within 28 days prior to first administration of sigvotatug vedotin * Traditional or herbal medicines for other purposes (such as supportive care) within 7 days prior to first administration of sigvotatug vedotin