ALAMEDA - Exelixis, Inc. (Nasdaq: EXEL) today announced results from the dose-escalation stage of STELLAR-001, an ongoing phase 1b trial evaluating XL092 as a single-agent and in combination with atezolizumab in patients with locally advanced or metastatic solid tumors.
The data are being presented on Monday, September 12 during the Poster Session (481P) at 12:00 p.m. CEST at the 2022 European Society of Medical Oncology (ESMO) Congress.
'We are pleased to present these findings from the dose-escalation stage of STELLAR-001 at ESMO, which show XL092 demonstrated preliminary clinical activity similar to that observed with cabozantinib in phase 1 across a range of solid tumors and dose levels, with a manageable safety profile,' said Vicki L. Goodman, M.D., Executive Vice President, Product Development & Medical Affairs, and Chief Medical Officer, Exelixis. 'We are particularly encouraged by the activity of XL092 in heavily pretreated renal cell carcinoma patients who have received prior treatment with immunotherapy and/or VEGF-targeting tyrosine kinase inhibitors, including approximately 70% of patients who received cabozantinib as a prior treatment. As we continue to enroll in the cohort-expansion stage across multiple solid tumors, we look forward to gaining additional insight into the potential of XL092 alone and in combination with immune checkpoint inhibitors as a potential new therapy for people with cancer in need of new treatment options.'
STELLAR-001 enrolled patients with advanced solid tumors for which standard of care did not exist or was not effective. For this analysis, patients received XL092 either as a single-agent (n=47) or in combination with atezolizumab (n=40). The most common types of cancer for patients enrolled in the single-agent XL092 cohort were clear cell renal cell carcinoma (RCC), metastatic castration-resistant prostate cancer (CRPC) and breast cancer. The most common types of cancer for patients enrolled in the XL092 in combination with atezolizumab cohort were colorectal cancer, metastatic CRPC and sarcoma. The median duration of follow-up was 17.9 months and 6.0 months for those receiving single-agent XL092 and XL092 in combination with atezolizumab, respectively. Median age was 61 years for those receiving single-agent XL092 and 59 years for those receiving XL092 in combination with atezolizumab; 62% and 55% of patients, respectively, had an Eastern Cooperative Oncology Group score of 1. In each arm, 68% of patients had at least three prior lines of therapy.
The maximum tolerated dose was determined to be 120 mg, and the recommended dose for the expansion phase is 100 mg for both single-agent XL092 and XL092 in combination with atezolizumab. Tumor reduction was seen in 71% of patients receiving single-agent XL092 and in 56% of patients receiving XL092 in combination with atezolizumab. The objective response rate (ORR) was 10% for single-agent XL092 and 4% for XL092 in combination with atezolizumab; disease control rate (DCR) (complete response + partial response + stable disease) was 90% and 74%, respectively. Confirmed partial responses were observed in four patients treated with single-agent XL092 and one patient treated with XL092 in combination with atezolizumab.
In the 19 patients with clear cell RCC who were heavily pretreated with immunotherapy and/or VEGF-targeting tyrosine kinase inhibitors (TKIs), including 68% who received prior cabozantinib, ORR was 11%, and DCR was 95% with single-agent XL092.
The activity of single-agent XL092, as measured by the percent of patients with reduction in tumor size (RTS), was similar to that observed with cabozantinib in phase 1 (trial identifier: XL184-011): XL092 demonstrated a 71% RTS versus a 74% RTS with cabozantinib; a greater than 30% RTS was seen in 15% of patients treated with XL092 versus 18% of those treated with cabozantinib.
Grade 3/4 treatment-emergent adverse events (AEs) occurred in 60% of those receiving single-agent XL092 and 38% of those receiving XL092 in combination with atezolizumab. The most common (5%) grade 3/4 treatment-emergent AEs for those receiving single-agent XL092 were hypertension (19%), diarrhea (9%) and fatigue (6%); for those receiving XL092 in combination with atezolizumab, they were hypertension (13%), abdominal pain (5%), fatigue (5%) and thrombocytopenia (5%). There were no grade 5 treatment-related AEs.
'These results show manageable tolerability along with promising early indications of activity for XL092, alone and in combination with atezolizumab, even in this heavily pretreated population of patients with a broad range of advanced tumors,' said Manish R. Sharma, M.D., Associate Director of Clinical Research at START Midwest and lead author of the study. 'We will continue enrolling for the expansion stage of this trial as we look to identify potential new therapies and combinations for our cancer patients.'
About STELLAR-001
STELLAR-001 is a global, open-label phase 1b study of Exelixis' novel TKI XL092 as a single agent or in combination with atezolizumab or avelumab in patients with inoperable locally advanced or metastatic solid tumors. The trial plans to enroll 800 patients and is divided into two parts: a dose-escalation stage and an expansion cohort stage.
The expansion cohorts evaluating XL092 as a single agent or in combination with atezolizumab include patients with: RCC with clear cell histology, RCC with non-clear cell histology, breast cancer that is hormone receptor-positive and HER-2 negative, CRPC and CRC. The expansion cohorts evaluating XL092 in combination with avelumab will enroll patients with urothelial carcinoma.
About XL092
XL092 is a next-generation oral TKI that inhibits the activity of receptor tyrosine kinases implicated in cancer growth and spread, including VEGF receptors, MET, AXL and MER. These receptor tyrosine kinases are involved in both normal cellular function and in pathologic processes such as oncogenesis, metastasis, tumor angiogenesis, and resistance to multiple therapies, including immune checkpoint inhibitors. In designing XL092, Exelixis sought to build upon its extensive experience with and the target profile of cabozantinib, the company's flagship medicine, while improving key characteristics, including pharmacokinetic half-life. XL092 is currently being developed for the treatment of advanced solid tumors, including genitourinary cancers, as a monotherapy and in combination with immune checkpoint inhibitors. XL092 is the first internally discovered Exelixis compound to enter the clinic following the company's reinitiation of drug-discovery activities.
About CABOMETYX (cabozantinib)
In the U.S., CABOMETYX tablets are approved for the treatment of patients with advanced RCC; for the treatment of patients with hepatocellular carcinoma (HCC) who have been previously treated with sorafenib; for patients with advanced RCC as a first-line treatment in combination with nivolumab and for adult and pediatric patients 12 years of age and older with locally advanced or metastatic differentiated thyroid cancer (DTC) that has progressed following prior VEGFR-targeted therapy and who are radioactive iodine-refractory or ineligible. CABOMETYX tablets have also received regulatory approvals in the European Union and additional countries and regions worldwide. In 2016, Exelixis granted Ipsen Pharma SAS exclusive rights for the commercialization and further clinical development of cabozantinib outside of the U.S. and Japan. In 2017, Exelixis granted exclusive rights to Takeda Pharmaceutical Company Limited for the commercialization and further clinical development of cabozantinib for all future indications in Japan. Exelixis holds the exclusive rights to develop and commercialize cabozantinib in the U.S.
About Exelixis
Founded in 1994, Exelixis, Inc. (Nasdaq: EXEL) is a commercially successful, oncology-focused biotechnology company that strives to accelerate the discovery, development and commercialization of new medicines for difficult-to-treat cancers. Following early work in model system genetics, we established a broad drug discovery and development platform that has served as the foundation for our continued efforts to bring new cancer therapies to patients in need. Our discovery efforts have resulted in four commercially available products, CABOMETYX (cabozantinib), COMETRIQ (cabozantinib), COTELLIC (cobimetinib) and MINNEBRO (esaxerenone), and we have entered into partnerships with leading pharmaceutical companies to bring these important medicines to patients worldwide. Supported by revenues from our marketed products and collaborations, we are committed to prudently reinvesting in our business to maximize the potential of our pipeline. We are supplementing our existing therapeutic assets with targeted business development activities and internal drug discovery - all to deliver the next generation of Exelixis medicines and help patients recover stronger and live longer. Exelixis is a member of the Standard & Poor's (S&P) MidCap 400 index, which measures the performance of profitable mid-sized companies.
Forward-Looking Statements
This press release contains forward-looking statements, including, without limitation, statements related to: the presentation of data from STELLAR-001 during the Poster Session at the 2022 ESMO Congress; the therapeutic potential of XL092, both alone and in combination with immune checkpoint inhibitors, as a therapy for cancer patients in need of new treatment options and Exelixis' plans to reinvest in its business to maximize the potential of the company's pipeline, including through targeted business development activities and internal drug discovery. Any statements that refer to expectations, projections or other characterizations of future events or circumstances are forward-looking statements and are based upon Exelixis' current plans, assumptions, beliefs, expectations, estimates and projections. Forward-looking statements involve risks and uncertainties. Actual results and the timing of events could differ materially from those anticipated in the forward-looking statements as a result of these risks and uncertainties, which include, without limitation: the availability of data at the referenced times; complexities and the unpredictability of the regulatory review and approval processes in the U.S. and elsewhere; Exelixis' continuing compliance with applicable legal and regulatory requirements; the potential failure of XL092 as a single agent or in combination with atezolizumab to demonstrate safety and/or efficacy in STELLAR-001 and in future clinical testing; unexpected concerns that may arise as a result of the occurrence of adverse safety events or additional data analyses of clinical trials evaluating XL092; the costs of conducting clinical trials; Exelixis' dependence on third-party vendors for the development, manufacture and supply of XL092; Exelixis' ability to protect its intellectual property rights; market competition; changes in economic and business conditions, including as a result of the COVID-19 pandemic and other global events and other factors affecting Exelixis and its development programs discussed under the caption 'Risk Factors' in Exelixis' Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission (SEC) on August 9, 2022, and in Exelixis' future filings with the SEC. All forward-looking statements in this press release are based on information available to Exelixis as of the date of this press release, and Exelixis undertakes no obligation to update or revise any forward-looking statements contained herein, except as required by law.
Contact:
Susan Hubbard
Tel: (650) 837-8194
Email: shubbard@exelixis.com
EXELIXIS, INC. 
