A Study of ZL-1310 Versus Investigator's Choice of Therapy in Participants With Relapsed Small Cell Lung Cancer (DLLEVATE)

Inclusion Criteria:

* Age \>/= 18 years, or considered an adult by local regulations, at the time of consent
* Signed informed consent
* Histologically or cytologically confirmed SCLC. Received 1L platinum-based systemic therapy and had documented disease progression during or after the most recent systemic therapy. Or received 2L tarlatamab is allowed.
* Measurable disease according to RECIST v1.1 as assessed by the investigator.
* Participants with a history of treated and stable or untreated and asymptomatic CNS metastases based on criteria per protocol.
* Adequate organ and marrow function
* Eastern Cooperative Group (ECOG) performance status of 0 or 1
* Life expectancy of at least 3 months
* Participants must be willing to undergo a tumor biopsy or provide archived tumor tissue sample at Screening
* Participants must be willing and able to comply with protocol for the duration of the study

Exclusion Criteria:

* Received more than one line of systemic therapy for Extensive-Stage SCLC.
* Received any prior ADC with topoisomerase 1 inhibitor payload
* Participants with another known malignancy with exceptions defined in the protocol.
* History or suspected ILD/pneumonitis based on criteria per protocol
* Clinically severe pulmonary compromise resulting from intercurrent pulmonary illnesses.
* Receipt of anti-cancer treatment known to treat cancers within 3 weeks before the first dose of study treatment.
* Prior radiotherapy before study treatment based on criteria per protocol
* Unresolved toxicity of Grade \>/= 2 from previous anti-cancer treatment, except for alopecia and skin pigmentation.
* Known infection or active infection defined in the protocol.
* Clinically significant active cardiovascular disease or history of arterial thromboembolic event within 6 months prior to the first dose of study treatment based on criteria per protocol.