Cervical cancer – State of the science: From angiogenesis blockade to checkpoint inhibition

Vascular endothelial growth factor (VEGF) has emerged as a therapeutic target in several malignancies, including cervical cancer. Chemotherapy doublets combined with the fully humanized monoclonal antibody, bevacizumab, now constitute first-line therapy for women struggling with recurrent/metastatic cervical carcinoma. Regulatory approval for this indication was based on the phase III randomized trial, GOG 240, which demonstrated a statistically significant and clinically meaningful improvement in overall survival when bevacizumab was added to chemotherapy: 17.0 vs 13.3 months; HR 0.71; 98% CI, 0.54-0.95; p = .004. Incorporation of bevacizumab resulted in significant improvements in progression-free survival and response. These benefits were not accompanied by deterioration in quality of life. GOG 240 identified vaginal fistula as a new adverse event associated with bevacizumab use. All fistulas occurred in women who had received prior pelvic radiotherapy, and none resulted in emergency surgery, sepsis, or death. Final protocol-specified analysis demonstrated continued separation of the survival curves favoring VEGF inhibition: 16.8 vs 13.3 months; HR 0.77; 95% CI, 0.62-9.95; p = .007. Post-progression survival was not significantly different between the arms in GOG 240. Moving forward, immunotherapy has now entered the clinical trial arena to address the high unmet clinical need for effective and tolerable second line therapies in this patient population. Targeting the programmed cell death 1/programmed death ligand 1 (PD-1/PD-L1) pathway using checkpoint inhibitors to break immunologic tolerance is promising. The immunologic landscape involving human papillomavirus-positive head and neck carcinoma and cutaneous squamous cell carcinoma can be informative when considering feasibility of checkpoint blockade in advanced cervical cancer. Phase II studies using anti-PD-1 molecules, nivolumab and pembrolizumab are ongoing, and GOG 3016, the first phase III randomized trial of a checkpoint inhibitor (cemiplimab) in cervical cancer, recently activated. Important considerations in attempts to inhibit the inhibitors include pseudoprogression and post-progression survival, abscopal effects, and immune-related adverse events, including endocrinopathies

Quantitative assessment of DNA replication to monitor microgametogenesis in Plasmodium berghei

Targeting the crucial step of Plasmodium transition from vertebrate host to mosquito vector is a promising approach to eliminate malaria. Uptake by the mosquito activates gametocytes within seconds, and in the case of male (micro) gametocytes leads to rapid DNA replication and the release of eight flagellated gametes. We developed a sensitive assay to monitor P. berghei microgametocyte activation based on [3H]hypoxanthine incorporation into DNA. Optimal pH range and xanthurenic acid concentrations for gametocyte activation were established and the kinetics of DNA replication investigated. Significance of the method was confirmed using P. berghei mutants and the assay was applied to analyse the effect of protease inhibitors, which revealed differences regarding their inhibitory action. The developed method thus appears suitable for reproducible determination of microgametocyte activation, medium-throughput drug screenings and deeper investigation of early blocks in gametogenesis and will facilitate the analysis of compounds for transmission blocking activities