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