Small cell lung cancer (SCLC) is known as the "small lung killer" due to its high invasiveness and malignancy. Statistics show that about 80% of small cell lung cancer patients are diagnosed at an extensive stage (ES-SCLC), with an extremely poor prognosis. The median overall survival time is only 7 to 10 months, and the 2-year overall survival rate is only 10% to 20%.

On April 18 , 2026 , Zai Lab officially announced that it will present the latest clinical data of its antibody-drug conjugate (ADC) zocilurtatug pelitecan (Zoci, formerly known as ZL-1310) targeting DLL3 at the 2026 American Association for Cancer Research (AACR) Annual Meeting. The study showed that the drug achieved rapid and significant intracranial remission in previously treated patients with brain metastases from extensive-stage small cell lung cancer (ES-SCLC), and also demonstrated encouraging antitumor activity in patients with extrapulmonary neuroendocrine carcinoma (epNEC).

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According to publicly available information, Zoci is a potential first-in-class DLL3-targeting antibody-drug conjugate (ADC). DLL3 is a validated therapeutic target for small cell lung cancer (SCLC) and is also overexpressed in various neuroendocrine tumors, often associated with poor clinical outcomes. Zoci is expected to become Zai Lab's first globally marketed anti-tumor product, with plans to conduct three registration studies by the end of 2026, involving second-line and above SCLC, first-line SCLC, and extrapulmonary neuroendocrine carcinoma.

Zoci has a potentially best-in-class safety profile, as well as well-established systemic and intracranial efficacy, supporting its potential as a new standard of care for previously treated extensive-stage small cell lung cancer (ES-SCLC) and as a cornerstone of antibody-drug conjugates (ADCs) targeting DLL3 for first-line combination therapy, including regimens to reduce the toxic burden of chemotherapy, such as combinations with immune checkpoint inhibitors and T-cell connectors.

Results from an ongoing global phase 1 study (NCT06179069) indicate that zoci treatment can significantly reduce intracranial lesions in patients with ES-SCLC whose tumors have metastasized to the brain, a patient population with low survival rates and a lack of effective treatment options.

Of the 136 patients who received treatment, 36% had brain metastases at baseline before entering the study.

Among all patients with brain metastases who had the opportunity to complete at least two post-baseline scans, the intracranial objective response rate (iORR) was 53.7% (22/41) in patients treated with zoci, including 7 complete responses. At a dose of 1.6 mg/kg, the confirmed iORR was 62.5% (10/16), including 4 complete responses.

Intracranial tumor shrinkage was observed in multiple dose levels, and remissions were observed in both patients who had previously received radiotherapy (50%, 13/26) and those who had not received radiotherapy (60%, 9/15).

Zoci demonstrated a manageable safety profile, with most treatment-emergent adverse events (TEAEs) reported being low-grade and discontinuation of treatment being extremely rare. No intracranial metastatic complications or treatment-related serious neurological adverse events were reported.

In addition to SCLC, zoci has also shown therapeutic potential in extrapulmonary neuroendocrine carcinoma (epNEC). In a multicenter phase 1b/2 study (NCT06885281) involving patients with epNEC and other selected solid tumors, 46 patients who had previously received platinum-based chemotherapy and other systemic therapies received zoci at a dose of 1.6 mg/kg, administered intravenously every three weeks. The data cutoff date was February 18, 2026, and the median follow-up time for the phase 1b portion of the study was 3.7 months.

In 46 patients who had previously received platinum-based chemotherapy and other systemic therapies, zoci treatment reduced tumor volume in multiple extrapulmonary neuroendocrine carcinoma (epNEC) subtypes, and confirmed remissions were observed in previously treated patients.

Among patients with evaluable remission, the overall objective response rate across all study cohorts was 38.2% (13/34), and the overall disease control rate was 55.9% (19/34).

Zoci demonstrated a manageable safety profile; the decrease in neutrophil count (5.2%, 3/58) was the only ≥ grade 3 TRAE to date to occur in more than one patient.

In addition, researchers will share preliminary data from a phase 1b/2 clinical trial (NCT06885281) of zoci in patients with extrapulmonary neuroendocrine carcinoma (epNEC) and other selected solid tumors. These data demonstrate that zoci has antitumor activity in this population of highly aggressive, poorly prognostic patients with limited treatment options, achieving an objective response rate (ORR) of 38.2%. It is noteworthy that there is currently no approved standard treatment for previously treated epNEC. There are also no targeted therapies available for this type of cancer.

In summary, these findings highlight the broad potential of zoci in various neuroendocrine carcinomas expressing DLL3. Zoci has reportedly received Orphan Drug Designation and Fast Track Designation from the FDA for the treatment of SCLC, which is expected to accelerate its market launch.

https://mp.weixin.qq.com/s/wo_kvNw_vPbYgM2AvqyCgg