Prinomastat is a synthetic hydroxamic acid derivative with potential antineoplastic activity. Prinomastat inhibits matrix metalloproteinases (MMPs) (specifically, MMP-2, 9, 13, and 14), thereby inducing extracellular matrix degradation, and inhibiting angiogenesis, tumor growth and invasion, and metastasis. As a lipophilic agent, prinomastat crosses the blood-brain barrier. Pfizer conducted multicenter, randomized, double-bind, placebo-controlled trials to evaluate the safety and efficacy of prinomastat in combination with standard chemotherapy in patients with advanced hormone refractory prostate cancer and non-small cell lung cancer. However, this study has been terminated for the reason that Prinomastat did not improve the outcome of chemotherapy in non-small cell Lung cancer patients.

Carboxyamidotriazole (L651582) is a carboxyamide-amino-imidazole compound originally developed as a coccidiostat, an antiprotozoal agent that acts upon Coccidia parasites. Carboxyamidotriazole (L651582) is an orally-active agent with potential antineoplastic activity. Carboxyamidotriazole binds to and inhibits non-voltage-operated Ca2 channels, blocking both Ca2 influx into cells and Ca2 release from intracellular stores and resulting in the disruption of calcium channel-mediated signal transduction and inhibition of vascular endothelial growth factor (VEGF) signaling, endothelial proliferation, and angiogenesis. This agent may also inhibit tumor cell growth, invasion, and metastasis.

Dactolisib is a dual inhibitor of phosphatidylinositol 3-kinase (P13K) and the downstream mammalian target of rapamycin (mTOR) by binding to the ATP-binding cleft of these enzymes (inhibitor of PI3K/Akt/mTOR cascade). It is being investigated as a possible anti-cancer cancer agent and drug against Influenza virus infections. Frequently reported adverse events included nausea, vomiting, diarrhoea, fatigue/asthenia, anaemia, and anorexia.

Rebimastat (BMS-275291) is a broad-spectrum matrix metalloproteinase (MMP) inhibitor free from toxicity-related inhibition of sheddases (cleaving membrane proteins at the cell surface). This MMP2 and MMP9 inhibitor may stop the growth of cancers by stopping blood flow to the tumor (stopping them from dividing). It might also block the enzymes necessary for growth of the tumor cell. Multiple phase II trials and a phase III clinical trial have been completed, testing the efficacy and safety of the compound in prostate cancer, HIV-related Kaposi’s Sarcoma, non-small cell lung cancer (phase II and III) and breast cancer.

Apricoxib, (CS-706, 1) 2-(4-ethoxyphenyl)-4-methyl-1-(4-sulfamoylphenyl)-pyrrole, a small-molecule, orally active, selective COX-2 inhibitor was discovered by investigators at Daiichi Sankyo in 1996. Apricoxib binds to and inhibits the enzyme cyclooxygenase-2 (COX-2), thereby inhibiting the conversion of arachidonic acid into prostaglandins. Apricoxib-mediated inhibition of COX-2 may induce tumor cell apoptosis and inhibit tumor cell proliferation and tumor angiogenesis. COX-related metabolic pathways may represent crucial regulators of cellular proliferation and angiogenesis. Clinical studies demonstrated potent analgesic activity and preclinical studies demonstrated good pharmacokinetics, pharmacodynamics and gastrointestinal tolerability. As an anticancer agent, preclinical studies demonstrated efficacy in biliary tract cancer models and colorectal carcinoma. Phase IIa trial data indicated that apricoxib was a potent analgesic in the treatment of pain in postoperative dental surgery. Apricoxib, a novel once-daily selective cyclooxygenase-2 inhibitor, was investigated in combination with erlotinib for recurrent stage IIIB/IV nonsmall cell lung cancer. Apricoxib plus erlotinib was well tolerated and yielded a 60% disease control rate. A phase II trial was investigating 400 mg/day apricoxib plus 150 mg/day erlotinib in patients selected based on change in urinary PGE-M. However, in 2015 development was abandoned due to poor clinical trial results.

Pilaralisib (XL147, SAR245408) is a potent and highly selective inhibitor of class I phosphatidylinositol 3-kinase (PI3K) (α, β, γ, and δ). In cellular assays, XL147 inhibits the formation of PIP3 in the membrane, and inhibits phosphorylation of AKT, p70S6K, and S6 in multiple tumor cell lines with diverse genetic alterations affecting the PI3K pathway. In a panel of tumor cell lines, XL147 inhibits proliferation with a wide range of potencies, with evidence of an impact of genotype on sensitivity. Repeat-dose administration of XL147 results in significant tumor growth inhibition in multiple human xenograft models in nude mice. Pilaralisib, was being developed by Exelixis and its licensee, Sanofi (formerly sanofi-aventis), for the treatment of solid tumours. However, the product was not listed on Sanofi's early stage pipeline as of end of July 2015 and there have been no recent reports on development identified.

Wortmannin is a fungal metabolite that so far has been shown to act as a selective inhibitor of phosphoinositide 3-kinase. Wortmannin inhibits cancer cell growth and has shown activity against mouse and human tumor xenografts in mice. Wortmannin is the first described PI3K inhibitor with IC50 of 3 nM in a cell-free assay, with little selectivity within the PI3K family. Also blocks autophagosome formation and potently inhibits DNA-PK/ATM with IC50 of 16 nM and 150 nM in cell-free assays.

Umbralisib (Ukoniq, TG Therapeutics) is an orally available PI3K delta inhibitor, targeting the delta isoform with nanomolar potency and several fold selectivity over the alpha, beta, and gamma isoforms of PI3K. The delta isoform of PI3K is strongly expressed in cells of hematopoietic origin and is believed to be important in the proliferation and survival of B-cell lymphocytes. On February 5, 2021, the Food and Drug Administration granted accelerated approval to umbralisib for the following indications: adult patients with relapsed or refractory marginal zone lymphoma (MZL) who have received at least one prior anti-CD20-based regimen; adult patients with relapsed or refractory follicular lymphoma (FL) who have received at least three prior lines of systemic therapy. However, on June 1, 2022, the FDA withdrew its approval for the cancer medicine Ukoniq due to safety concerns.