Osimertinib is an oral, third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) drug developed by AstraZeneca Pharmaceuticals. Its use is indicated for the treatment of metastatic non-small cell lung cancer (NSCLC) in cases where tumour EGFR expression is positive for the T790M mutation as detected by FDA-approved testing and which has progressed following therapy with a first-generation EGFR tyrosine kinase inhibitor. Approximately 10% of patients with NSCLC have a rapid and clinically effective response to EGFR-TKIs due to the presence of specific activating EGFR mutations within the tumour cells. More specifically, deletions around the LREA motif in exon 19 and exon 21 L858R point mutations are correlated with response to therapy. Osimertinib is an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI) that binds to certain mutant forms of EGFR (T790M, L858R, and exon 19 deletion) that predominate in non-small cell lung cancer (NSCLC) tumours following treatment with first-line EGFR-TKIs. As a third-generation tyrosine kinase inhibitor, osimertinib is specific for the gate-keeper T790M mutation which increases ATP binding activity to EGFR and results in poor prognosis for late-stage disease. Furthermore, osimertinib has been shown to spare wild-type EGFR during therapy, thereby reducing non-specific binding and limiting toxicity. Osimertinib is marketed under the brand name Tagrisso.

Alectinib is a second generation oral drug that selectively inhibits the activity of anaplastic lymphoma kinase (ALK) tyrosine kinase. It was developed by Chugai Pharmaceutical Co. Japan, which is part of the Hoffmann-La Roche group. Alectinib is specifically used in the treatment of non-small cell lung cancer (NSCLC) expressing the ALK-EML4 (echinoderm microtubule-associated protein-like 4) fusion protein that causes proliferation of NSCLC cells. Inhibition of ALK prevents phosphorylation and subsequent downstream activation of STAT3 and AKT resulting in reduced tumour cell viability. Approved under accelerated approval in 2015, alectinib is indicated for use in patients who have progressed on or were not tolerant of crizotinib, which is associated with the development of resistance. Alectinib is marketed as Alecensa.

Cobimetinib is an orally active, potent and highly selective small molecule inhibiting mitogen-activated protein kinase kinase 1 (MAP2K1 or MEK1), and central components of the RAS/RAF/MEK/ERK signal transduction pathway. It has been approved in Switzerland and the US, in combination with vemurafenib for the treatment of patients with unresectable or metastatic BRAF V600 mutation-positive melanoma. Preclinical studies have demonstrated that Cobimetinib is effective in inhibiting the growth of tumor cells bearing a BRAF mutation, which has been found to be associated with many tumor types. A threonine-tyrosine kinase and a key component of the RAS/RAF/MEK/ERK signalling pathway that is frequently activated in human tumors, MEK1 is required for the transmission of growth-promoting signals from numerous receptor tyrosine kinases. Cobimetinib is used in combination with vemurafenib because the clinical benefit of a BRAF inhibitor is limited by intrinsic and acquired resistance. Reactivation of the MAPK pathway is a major contributor to treatment failure in BRAF-mutant melanomas, approximately ~80% of melanoma tumors becomes BRAF-inhibitor resistant due to reactivation of MAPK signalling. BRAF-inhibitor resistant tumor cells are sensitive to MEK inhibition, therefore cobimetinib and vemurafenib will result in dual inhibition of BRAF and its downstream target, MEK. Cobimetinib specifically binds to and inhibits the catalytic activity of MEK1, resulting in inhibition of extracellular signal-related kinase 2 (ERK2) phosphorylation and activation and decreased tumor cell proliferation. Cobimetinib and vemurafenib target two different kinases in the RAS/RAF/MEK/ERK pathway. Cobimetinib is used for the treatment of patients with unresectable or metastatic melanoma with a BRAF V600E or V600K mutation. Cobimetinib is used in combination with vemurafenib, a BRAF inhibitor. Cobimetinib is marketed under the trade name Cotellic.

Idelalisib is a first-in-class selective inhibitor of adenosine-5'-triphosphate (ATP) binding to PI3Kdelta kinase, resulting in inhibition of the P13K signalling pathway in malignant B cells. The compound is approved for the treatment of several types of blood cancer. Idelalisib is intended to be used in combination with rituximab as second or subsequent line therapy for the treatment of chronic lymphocytic leukaemia. The drug may cause fatal and/or severe diarrhea or colitis, hepatotoxicity, pneumonitis and intestinal perforation.