Carnosol is an ortho-diphenolic diterpene with an abietane carbon skeleton with hydroxyl groups at positions C-11 and C-12 and a lactone moiety across the B ring. Carnosol is the product of oxidative degradation of carnosic acid. Carnosol is a naturally occurring phytopolyphenol found in rosemary that functions as an antioxidant, antimicrobial, and anticarcinogen. Carnosol has been shown to inhibit inductions of COX-2 by blocking PKC signaling. Carnosol is an inhibitor of AR and ER α. Several pre-clinical studies have suggested that carnosol selectively targets tumorigenic cell as opposed to non-tumorigenic cells and is safe and tolerable in animals. Carnosol has been shown to elicit chemopreventive effects by (1) blocking the bioactivation of carcinogens, (2) enhancing antioxidant and/or detoxification enzyme activities, (3) suppressing tumor-promoting inflammation, (4) inhibiting cell proliferation and inducing apoptosis selectively in cancer cells, and (5) blocking tumor angiogenesis and invasion.

SAR-405838 is an inhibitor of the interaction between the oncoprotein murine double minute 2 (MDM2) and p53. SAR-405838 was investigated in phase I clinical trials in patients with locally advanced/metastatic solid tumor with wild-type TP53 or with TP53 mutation prevalence below 40%. SAR-405838 had an acceptable safety profile with limited activity in patients with advanced solid tumors.

AZD-8186 is a potent and selective inhibitor of PI3Kβ and PI3Kδ with IC50 of 4 nM and 12 nM, respectively. AZD-8186 is currently in phase 1 clinical trials. Combination therapy using AZD-8186 with androgen deprivation results in long-lasting tumor regression, which persisted after treatment cessation.

CUDC-305, is a novel heat shock protein 90 (HSP90) inhibitor with strong affinity for HSP90 alpha/beta, high oral bioavailability and potent anti-proliferative activity against a broad range of cancer cell lines (with a mean IC50 of 220 nmol/L), including many non-small cell lung cancer (NSCLC) cell lines which are resistant to standard-of-care (SOC) agents. In both laboratory and animal testing, CUDC-305 demonstrated high potency in vitro and/or in vivo across a wide range of cancers. Most notably, Curis scientists observed complete tumor regression following oral administration of CUDC-305 in a mouse xenograft model of acute myelogenous leukemia (AML). Tumor regression has also been observed after treatment of CUDC-305 in mouse xenograft models of breast, non-small cell lung, gastric cancer and glioblastoma brain cancers. In this preclinical testing, the compound also demonstrated an ability to effectively cross the blood brain barrier, and demonstrated an ability to extend survival in an intracranial glioblastoma model. Early stage toxicity studies suggest that CUDC-305 appears to have a better therapeutic window than several leading Hsp90 inhibitors in clinical development.

Cinobufotalin, the bufadienolide isolated from toad venom, has displayed antitumor activities in many in vitro systems. It has been shown that cinobufotalin induced significant apoptosis in cultured human lymphoma U-937 cells. It induced DNA fragmentation, mitochondrial membrane potential decrease, and reactive oxygen species (ROS) production in U-937 cells. Cinobufotalin induces cytotoxic effect in cultured lung cancer cells. Cinobufotalin (1/5 mg/kg, i.p. twice daily, for 7 days) significantly inhibited A549 xenograft growth in mice. Further, same cinobufotalin administration improved mice survival at week five. Cinobufotalin administration didn’t significantly affect mice body weight, indicating the relative safety of this regimen. Thus, cinobufotalin inhibits A549 xenograft growth in vivo and improves mice survival.

Amcasertib is an orally administered investigational agent designed to inhibit cancer stemness pathways, including Nanog, by targeting stemness kinases. Amcasertib is undergoing multiple Phase I and Phase II studies as monotherapy and combination therapy for treating a range of tumor types.

Voruciclib (also known as P1446A-05) is a flavone-based, potent and selective CDK 4/6 inhibitor with activity in multiple BRAF-mutant and wild type cell lines. It is currently in clinical trials in combination with BRAF inhibitor (PLX4032) to treat advanced BRAF-mutant melanoma. Voruciclib has significant inhibitory activity against cutaneous and uveal melanoma. Mechanistic studies revealed that P1446A-05 inhibits phosphorylation targets of CDK members, and induces cell cycle arrest and apoptosis irrespective of melanoma genotype or phenotype. Voruciclib Hydrochloride is in phase I clinical trials by Piramal Life Sciences for the treatment of chronic lymphocytic leukaemia and malignant melanoma.

LTX-315 is a cationic amphipathic peptide that preferentially permeabilizes mitochondrial membranes, thereby causing partially BAX/BAK1-regulated, caspase-independent necrosis. The oncolytic effect of LTX-315 involves a unique immunogenic cell death targeting the mitochondria with subsequent release of danger-associated molecular pattern molecules. This initial targeting of the mitochondria is followed by disintegration of other cytoplasmic organelles resulting ineffective release of additional danger signals and a broad repertoire of tumour antigens and finally lysis of plasma membrane (necrosis). Preclinical and clinical studies have demonstrated LTX-315`s unique ability to reshape the tumour microenvironment by inducing the effective release of danger signals, chemokines and a broad repertoire of tumour antigens. These properties of LTX-315 results in enhanced infiltration of activated CD 8 T cells and Th1 responses. This ability to convert non-T cell inflamed tumours to T cell inflamed tumours makes LTX-315 an ideal combination partner with other types of immunotherapy, including immune checkpoint inhibitors/agonists, vaccines, and T cell-based therapies. Both preclinical and clinical studies have confirmed LTX-315s ability to induce a systemic anticancer immune response when injected locally into tumours resulting in complete or partial regression of injected and non-injected tumours (i.e. abscopal effect). Preclinical studies have demonstrated strong synergy with immune-checkpoint blockade which have given the scientific rationale for initiating combinations studies with Ipilimumab and Pembrolizumab in melanoma and TNB cancer patients respectively. Phase Ib study combining LTX-315 with ipilimumab (anti-CTLA4) in malignant melanoma patients, as well as LTX-315 with pembrolizumab (anti-PD-1) in metastatic breast cancer patients, is ongoing.

BMS-906024 is a lead candidate of a series of inhibitors of gamma secretase-mediated Notch signalling. BMS-906024 is an orally bioavailable, small-molecule gamma secretase (GS) and pan-Notch inhibitor, with potential antineoplastic activity. Upon administration, GS/pan-Notch inhibitor BMS-906024 binds to GS and blocks activation of Notch receptors, which may inhibit the proliferation of tumor cells with an overly-active Notch pathway. The integral membrane protein GS is a multi-subunit protease complex that cleaves single-pass transmembrane proteins, such as Notch receptors, at residues within their transmembrane domains that lead to their activation. Overexpression of the Notch signaling pathway has been correlated with increased tumor cell growth. BMS-906024 is currently in Phase 1 clinical trials for patients with T-cell acute lymphoblastic leukemia and metastatic solid tumors, including lung cancer.

BGT 226 is an orally available, small molecule, the dual inhibitor of mammalian target of rapamycin (mTOR) and phosphatidylinositol 3'kinase (PI3K), developed by Novartis for the treatment of solid tumors, including advanced breast cancer. A phase I/II trial was completed in the US, Canada, and Spain, and a phase I trial was completed in Japan. However, development appears to have been discontinued.