Drug monographs: afatinib and obinutuzumab

Kinome scale profiling of venom effects on cancer cells reveals potential new venom activities

The search for novel and relevant cancer therapeutics is continuous and ongoing. Cancer adaptations, resulting in therapeutic treatment failures, fuel this continuous necessity for new drugs to novel targets. Recently, researchers have started to investigate the effect of venoms and venom components on different types of cancer, investigating their mechanisms of action. Receptor tyrosine kinases (RTKs) comprise a family of highly conserved and functionally important druggable targets for cancer therapy. This research exploits the novelty of complex venom mixtures to affect phosphorylation of the epidermal growth factor receptor (EGFR) and related RTK family members, dually identifying new activities and unexplored avenues for future cancer and venom research. Six whole venoms from diverse species taxa, were evaluated for their ability to illicit changes in the phosphorylated expression of a panel of 49 commonly expressed RTKs. The triple negative breast cancer cell line MDA-MB-468 was treated with optimised venom doses, pre-determined by SDS PAGE and Western blot analysis. The phosphorylated expression levels of 49 RTKs in response to the venoms were assessed with the use of Human Phospho-RTK Arrays and analysed using ImageLab 5.2.1 analysis software (BioRad). Inhibition of EGFR phosphorylation occurred with treatment of venom from Acanthoscurria geniculata (Theraphosidae), Heterometrus swammerdami (Scorpionidae), Crotalus durissus vegrandis (Crotalidae) and Naja naja (Elapidae). Western green mamba Dendroaspis viridis venom increased EGFR phosphorylation. Eph, HGFR and HER were the most affected receptor families by venoms. Whilst the importance of these changes in terms of effect on MDA-MB-468 cells' long-term viability and functionality are still unclear, the findings present exciting opportunities for further investigation as potential drug targets in cancer and as tools to understand better how these pathways interact.

Obinutuzumab: a novel anti-CD20 monoclonal antibody for previously untreated chronic lymphocytic leukemia

OBJECTIVE

To review and summarize data on obinutuzumab, which was approved by the Food and Drug Administration (FDA) in November 2013 for use in combination with chlorambucil for previously untreated chronic lymphocytic leukemia (CLL).

DATA SOURCES

A PubMed literature search (August 2002 to March 2014) was conducted using the terms obinutuzumab, GA101, anti-CD20 antibody, and CLL. Data were also obtained through the FDA briefing documents and American Society of Hematology abstracts.

STUDY SELECTION AND DATA EXTRACTION

The literature search was limited to human studies published in English. Priority was placed on trials of obinutuzumab in previously untreated CLL.

DATA SYNTHESIS

Obinutuzumab is a novel glycoengineered type II anti-CD20 monoclonal antibody, with a higher affinity for CD20 epitope, leading to superior cytotoxicity compared with rituximab. The FDA approval was based on a phase III, randomized trial of chlorambucil monotherapy (n = 118), chlorambucil plus obinutuzumab (n = 333), or rituximab (n =330) in previously untreated elderly CLL patients. Obinutuzumab was administered intravenously as 1000 mg on days 1, 8, and 15 of cycle 1 and day 1 for subsequent cycles. Median progression-free survival was 26.7 months in the chlorambucil plus obinutuzumab arm. The incidence of grade 3 or higher adverse events in the obinutuzumab plus chlorambucil arm was as follows: neutropenia (33%), infusion-related reactions (20%), thrombocytopenia (10%), and infections (7%).

CONCLUSION

Obinutuzumab in combination with chlorambucil is a safe and effective new treatment option for previously untreated elderly CLL patients. It should become the new preferred therapy for these patients with significant comorbidities who are not candidates for fludarabine-based therapy.