Neoadjuvant socazolimab shows promise for locally advanced oesophageal squamous cell cancer

24th March 2023

Neoadjuvant socazolimab combined with chemotherapy showed promising outcomes in locally advanced oesophageal squamous cell carcinoma

The use of neoadjuvant socazolimab with cisplatin chemotherapy appears to be a promising approach to the treatment of locally advanced oesophageal squamous cell carcinoma (OSCC) according to the findings of a phase 2, randomised trial by Chinese researchers.

Data from 2020 show that globally, there were 604,000 new cases of oesophageal cancer and which gave rise to 544,000 deaths. Survival from advanced oesophageal cancer is poor and following surgery, one study identified how 1-year survival was 29% and 5-year survival only 6%. Although programmed cell death protein 1 inhibitors such as pembrolizumab with chemotherapy significantly prolonged overall survival compared to placebo as a first-line treatment for advanced OSCC, much less is known about the value of programmed cell death ligand 1 (PD-L1) inhibitors for this cancer. Evidence to date, shows that one such PD-L1 inhibitor, socazolimab, demonstrated a durable safety and efficacy for the treatment of recurrent or metastatic cervical cancer. But whether neoadjuvant socazolimab in combination with nab-paclitaxel and cisplatin chemotherapy is of benefit to patients with locally advanced OSCC is uncertain and was examined in the current randomised, phase 2 trial.

The Chinese team randomised participants 1:1 to socazolimab plus nab-paclitaxel and cisplatin or the same regimen without PD-L1 inhibitor and which formed the placebo arm. The primary endpoint was a major pathological response (MPR) whereas the secondary endpoints were a pathological complete response (pCR), R0 resection rate, event-free survival (EFS), overall survival (OS), and safety.

Neoadjuvant socazolimab associated outcomes

A total of 64 patients with a median age of 62 years (79.7% male) were enrolled and equally randomised between the two groups.

There were 29 patients in each arm who subsequently underwent surgery. The MPR rate was 69% in the socazolimab group and 62.1% in the placebo arm although this difference was not significant (p = 0.509). Similarly, whilst the pCR rate was higher with socazolimab (41.4%) than in the placebo group (27.6%), again this was not significant (p = 0.311).

However, there was a significantly higher incidence rate of ypT0 for socazolimab (37.9%) compared to placebo (3.5%, p = 0.001) and the rate of T down-staging was also higher (65.5% vs 62.1%). At the time of publication, the EFS and OS outcomes were not mature.

The authors concluded that neoadjuvant socazolimab combined with chemotherapy demonstrated promising MPR and pCR rates and significant T down-staging in locally advanced OSCC and without increasing surgical complication rates.

Citation
Li Y et al. Comparing a PD-L1 inhibitor plus chemotherapy to chemotherapy alone in neoadjuvant therapy for locally advanced ESCC: a randomized Phase II clinical trial : A randomized clinical trial of neoadjuvant therapy for ESCC. BMC Med 2023