Advances in antibody therapeutics targeting small-cell lung cancer.

The proportion of small-cell lung cancer (SCLC) among all lung cancers decreased from 17.26% in 1986 to 12.95% in 2002. Chemotherapy is the key mode of treatment. However, novel therapeutic strategies and drugs are imperative, as the prognosis remains poor. In recent years, antibody therapies have shown promising prospects against malignancy. This review focuses on the advances in antibody therapies in SCLC. Although the results of pembrolizumab, nivolumab, ipilimumab, and rovalpituzumab tesirine are inspiring, all of the clinical trials on these drugs are phase I/II and have been verified for further phase III clinical trials. It was demonstrated that chemotherapy in combination with bevacizumab can improve the progression-free survival (PFS) in phase III trials. The insulin-like growth factor-1 receptor (IGF-1R) is associated with a poor prognosis in SCLC, while the anti-IGF-1R monoclonal antibody figitumumab has a potential therapeutic value. Tarextumab, an antibody that blocks both Notch2 and Notch3 signaling, in combination with etoposide and platinum (EP) in patients with untreated extensive-stage SCLC, proved to be well-tolerated and showed dosedependent anti-tumor activity. The therapeutic effect of sacituzumab govitecan, BW-2 and lorvotuzumab mertansine in SCLC warranted further evaluation. Bec2/BCG as an adjuvant vaccination in patients with limited-disease SCLC could not improve the survival, PFS, or quality of life. Thus, clinical studies are essential to confirm the anti-tumor efficacy of trastuzumab in SCLC.