RO4929097

RO4929097 is a small-molecule inhibitor of γ secretase with IC50 of 4 nM and EC50 of 5 nM [1]. It shows no in vitro inhibitory activity on the closely related proteases. It also has greater than 100-fold selectivity with respect to 75 other proteins of various types [1]. RO4929097 binds to γ secretase and inhibits its protease activity, therefore blocking the cleavage of Notch and reducing Notch signaling. Up-regulaton of this signaling pathway promotes tumorigenesis of multiple cancers.

RO4929097 has shown potential antitumor activity both in vitro and in vivo. It impaired the growth of melanoma cell lines and tumor formation of human primary melanoma xenograft [2]. It slowed proliferation and reduces colony formation of breast cancer cell lines[1]. In addition, RO4929097 decreased tumor formation in xenograft models of colorectal, pancreatic, lung cancer and melanoma[1, 2]. RO4929097 has been tested in multiple phase I/II clinical trials in patients with advanced solid tumors, either as monotherapy or in combination with other anti-tumor agents[3-8].

References:
1. Luistro L, He W, Smith M et al. Preclinical profile of a potent gamma-secretase inhibitor targeting notch signaling with in vivo efficacy and pharmacodynamic properties. Cancer Res 2009; 69: 7672-7680.
2. Huynh C, Poliseno L, Segura MF et al. The novel gamma secretase inhibitor RO4929097 reduces the tumor initiating potential of melanoma. PLoS One 2011; 6: e25264.
3. Richter S, Bedard PL, Chen EX et al. A phase I study of the oral gamma secretase inhibitor R04929097 in combination with gemcitabine in patients with advanced solid tumors (PHL-078/CTEP 8575). Invest New Drugs 2014; 32: 243-249.
4. Sahebjam S, Bedard PL, Castonguay V et al. A phase I study of the combination of ro4929097 and cediranib in patients with advanced solid tumours (PJC-004/NCI 8503). Br J Cancer 2013; 109: 943-949.
5. Diaz-Padilla I, Hirte H, Oza AM et al. A phase Ib combination study of RO4929097, a gamma-secretase inhibitor, and temsirolimus in patients with advanced solid tumors. Invest New Drugs 2013; 31: 1182-1191.
6. Tolcher AW, Messersmith WA, Mikulski SM et al. Phase I study of RO4929097, a gamma secretase inhibitor of Notch signaling, in patients with refractory metastatic or locally advanced solid tumors. J Clin Oncol 2012; 30: 2348-2353.
7. Strosberg JR, Yeatman T, Weber J et al. A phase II study of RO4929097 in metastatic colorectal cancer. Eur J Cancer 2012; 48: 997-1003.
8. Kolb EA, Gorlick R, Keir ST et al. Initial testing (stage 1) by the pediatric preclinical testing program of RO4929097, a gamma-secretase inhibitor targeting notch signaling. Pediatr Blood Cancer 2012; 58: 815-818.

Inhibition of the NOTCH pathway using gamma-secretase inhibitor RO4929097 has limited antitumor activity in established glial tumors.[Pubmed:25486598]

Anticancer Drugs. 2015 Mar;26(3):272-83.

Notch signaling is altered in many cancers. Our previous findings in primary pediatric ependymoma support a role for NOTCH in glial oncogenesis. The present study evaluates the gamma-secretase inhibitor RO4929097 in glial tumor models. The expression of Notch pathway genes was evaluated using real-time RT-PCR in 21 ependymoma and glioma models. NOTCH1 mutations were analyzed by DNA sequencing. RO4929097 activity was evaluated in vitro and in vivo, as a single agent and in combination, in glioma and ependymoma models. Notch pathway genes are overexpressed in ependymomas and gliomas along with FBXW7 downregulation. NOTCH1 mutations in the TAD domain were observed in 20% (2/10) of ependymoma primary cultures. Blocking the Notch pathway with the gamma-secretase inhibitor RO4929097 reduced cell density and viability in ependymoma short-term cultures. When combined with chemotherapeutic agents, RO4929097 enhanced temozolomide effects in ependymoma short-term cultures and potentiated the cytotoxicity of etoposide, cisplatinum, and temozolomide in glioma cells. RO4929097, in combined treatment with mTOR inhibition, potentiated cytotoxicity in vitro, but did not enhance antitumor effects in vivo. In contrast, RO4929097 enhanced irradiation effects in glioma and ependymoma xenografts and showed tumor growth inhibition in advanced-stage IGRG121 glioblastoma xenografts. RO4929097-mediated effects were independent of NOTCH1 mutation status or expression levels, but associated with low IL-6 levels. In established glial tumor models, NOTCH inhibition had limited effects as a single agent, but enhanced efficacy when combined with DNA-interfering agents. These preclinical data need to be considered for further clinical development of NOTCH inhibitors in glial tumors.

Phase I study of RO4929097 with bevacizumab in patients with recurrent malignant glioma.[Pubmed:27826680]

J Neurooncol. 2016 Dec;130(3):571-579.

Antiangiogenic therapies for malignant gliomas often result in transient response, and recurrent disease is characterized by adoption of invasive and hypoxic phenotype. The notch signaling pathway is activated in gliomas, and augments cell migration and hypoxic response. Here we report a clinical study of the combination of bevacizumab and RO4929097, an inhibitor of the notch signaling cascade. A phase I clinical trial was conducted through the Adult Brain Tumor Consortium in subjects with recurrent malignant glioma. Primary objectives were to assess safety and to define the maximum tolerated dose of RO4929097 in combination with bevacizumab. Secondary objectives were to determine overall survival, progression free survival, radiographic response, pharmacokinetic evaluation, and tissue biomarker analysis. Thirteen subjects were enrolled. Of the three subjects treated with the highest dose of RO4929097, one grade 3 toxicity and one grade 2 toxicity were observed. Definitive maximum tolerated dose of RO4929097 in combination with bevacizumab was not identified due to manufacturer's decision to halt drug production. 2 of 12 evaluable subjects demonstrated radiographic response; one subject experienced CR and the second PR. The median overall survival was 10.9 months with a median progression-free survival of 3.7 months. Two subjects remained free of disease progression at 6 months from treatment initiation. PK evaluation did not identify clinically significant drug-drug interactions. All analyzed tissue specimens revealed activation of notch signaling. Combination of RO4929097 and bevacizumab was well-tolerated. Given the compelling scientific rationale, additional studies of antiangiogenic and notch signaling inhibitors should be considered.

Anti-myeloma effect of pharmacological inhibition of Notch/gamma-secretase with RO4929097 is mediated by modulation of tumor microenvironment.[Pubmed:26934342]

Cancer Biol Ther. 2016 May 3;17(5):477-85.

Multiple myeloma (MM), a blood cancer characterized by the uncontrolled proliferation of plasma cells, remains incurable by current therapy. Notch signaling has been implicated in the growth and chemoresistance of various cancer types including MM, and therefore we hypothesized that targeting the Notch pathway could be beneficial for the treatment of this disease. Here, we report an anti-tumor effect of Notch/gamma-secretase inhibitor RO4929097 in a pre-clinical model of MM. We demonstrate that this effect was associated with decreased angiogenesis and significant down-regulation of TGF-beta1. In addition, we also show that treatment with RO4929097 results in decreased number and functional activity of osteoclasts. Taken together, our data indicate that targeting Notch may be considered as a new strategy to be tested for MM therapy.

A phase II study of single-agent RO4929097, a gamma-secretase inhibitor of Notch signaling, in patients with recurrent platinum-resistant epithelial ovarian cancer: A study of the Princess Margaret, Chicago and California phase II consortia.[Pubmed:25769658]

Gynecol Oncol. 2015 May;137(2):216-22.

PURPOSE: A phase II study was performed to evaluate the efficacy and safety of single-agent RO4929097 (a gamma-secretase inhibitor) in patients with recurrent platinum-resistant ovarian cancer. EXPERIMENTAL DESIGN: Women with progressive platinum-resistant ovarian cancer treated with RO4929097 at 20 mg once daily, 3 days on/4 days off each week in a three week cycle. The primary endpoint was progression-free survival (PFS) rate at the end of 4 cycles. Secondary objectives included assessment of the safety of RO4929097 and exploration of molecular correlates of outcome in archival tumor tissue and serum. RESULTS: Of 45 patients enrolled, 40 were evaluable for response. Thirty-seven (82%) patients had high-grade ovarian cancer. No objective responses were observed. Fifteen patients (33%) had stable disease as their best response, with a median duration of 3.1 months. The median PFS for the whole group was 1.3 months (1.2-2.5). Treatment was generally well tolerated with 10% of patients discontinuing treatment due to an adverse event. In high grade serous ovarian cancer patients, the median PFS trended higher when the expression of intracellular Notch (NICD) protein by immunohistochemistry was high versus low (3.3 versus 1.3 months, p=0.09). No clear relationship between circulating angiogenic factors and PFS was found despite a suggestion of an improved outcome with higher baseline VEGFA levels. CONCLUSIONS: RO4929097 has insufficient activity as a single-agent in platinum-resistant ovarian cancer to warrant further study as monotherapy. Future studies are needed to explore the potential for cohort enrichment using NICD expression.