Exelixis unveils phase 1 trial results for cabozantinib in combination with nivolumab in advanced genitourinary tumors

The findings will be presented during a poster discussion session (Abstract #774PD) on October 9 at the European Society for Medical Oncology (ESMO) 2016 Congress, which is being held in Copenhagen, October 7 – 11, 2016.

Andrea Apolo, M.D., Genitourinary Malignancies Branch, Center for Cancer Research, National Cancer Institute, the principal investigator of the trial, said: “The treatment landscape for advanced, intractable cancers such as metastatic urothelial carcinoma is continuously evolving and the use of combination therapies may improve outcomes for patients in need of new options.

“Our previous correlative studies have demonstrated that cabozantinib has immunomodulatory properties that may counteract tumor-induced immunosuppression, providing the rationale for this trial.1,2 These promising early stage clinical findings support further investigation of cabozantinib in combination with nivolumab in a number of genitourinary tumors.”

Between July 2015 and September 2016, 24 patients were accrued with metastatic urothelial carcinoma (n=7), urachal adenocarcinoma (n=4), squamous cell carcinoma of the bladder or urethra (n=3), germ cell tumor (n=4), castration-resistant prostate cancer (n=4), renal cell carcinoma (n=1), or trophoblastic tumor (n=1) and were treated in Part I of the study, which evaluated the combination of cabozantinib and nivolumab at four dose levels.

The median number of prior systemic therapies was 3, and 10 patients had received 4 or more prior therapies. The objective response rate was 43 percent among the 23 patients who were evaluable for response, with one complete response and nine partial responses.

Four of six patients (67 percent) with urothelial cancer achieved a response. The recommended doses for the ongoing expansion cohorts were determined to be cabozantinib at 40 mg daily and nivolumab at 3 mg/kg once every 2 weeks. Part II of the phase 1 trial examining the use of the triplet combination of cabozantinib, nivolumab, and ipilimumab is also ongoing.

Exelixis president and CEO Michael Morrissey said: “Cabozantinib has demonstrated clinical activity as a single agent in several tumors, and we are interested in further examining its potential in combination with immunotherapies to treat a variety of genitourinary and other cancers.

“We are encouraged by these preliminary phase 1 data and look forward to results from the ongoing expansion cohorts in this trial in patients with metastatic urothelial carcinoma and renal cell carcinoma.”

Common grade 1/2 adverse events observed in more than 30 percent of patients were fatigue, diarrhea, anorexia, dysgeusia, hoarseness, and oral mucositis.

Grade 3 adverse events observed in more than 10 percent of patients, included neutropenia, fatigue, and thromboembolic events. There was one grade 4 adverse event of lipase elevation. No grade 5 toxicities were observed.

In addition to Part I, the study also has enrolled 15 patients in Part II, which is evaluating the triplet combination of cabozantinib, nivolumab, and ipilimumab.

Expansion cohorts assessing cabozantinib and nivolumab are currently being accrued with bladder, renal and rare genitourinary cancer patients. Data from these patients will be reported at a later date.

About Genitourinary Cancers

Genitourinary cancers are those that affect the urinary tract, bladder, kidneys, ureter, prostate, testicles, penis or adrenal glands — parts of the body involved in reproduction and excretion — and include renal cell carcinoma and urothelial carcinoma.

Kidney cancer is among the top ten most commonly diagnosed forms of cancer among both men and women in the U.S., according to the American Cancer Society’s 2016 statistics. Clear cell renal cell carcinoma is the most common type of kidney cancer in adults.

If detected in its early stages, the five-year survival rate for RCC is high; for patients with advanced or late-stage metastatic RCC, however, the five-year survival rate is only 12 percent, with no identified cure for the disease.

Approximately 30,000 patients in the U.S. and 68,000 globally require treatment.

Prostate cancer is the second most common cause of cancer death in men, behind only skin cancer. There is a high survival rate for patients when prostate cancer is detected early, but once the disease has spread to other parts of the body the five-year survival rate is just 28 percent.

Approximately 2,850,000 men were living with prostate cancer in the U.S. in 2013,9 and 180,000 new cases are diagnosed each year.

Urothelial cancers encompass carcinomas of the bladder, ureter and renal pelvis at a ratio of 50:3:1, respectively.10 Urothelial carcinoma occurs mainly in older people, with 90 percent of patients aged 55 or older.

Bladder cancer is the fourth most common cancer in men and accounts for about five percent of all new cases of cancer in the U.S. each year.11 In 2013, an estimated 587,426 people were living with bladder cancer in the U.S.

About CABOMETYX (cabozantinib)

CABOMETYX is the tablet formulation of cabozantinib. Its targets include MET, AXL and VEGFR-1, -2 and -3. In preclinical models, cabozantinib has been shown to inhibit the activity of these receptors, which are involved in normal cellular function and pathologic processes such as tumor angiogenesis, invasiveness, metastasis and drug resistance.

CABOMETYX is available in 20 mg, 40 mg or 60 mg doses. The recommended dose is 60 mg orally, once daily.

On April 25, 2016, the FDA approved CABOMETYX tablets for the treatment of patients with advanced renal cell carcinoma who have received prior anti-angiogenic therapy.

On September 9, 2016, the European Commission approved CABOMETYX tablets for the treatment of advanced renal cell carcinoma in adults who have received prior vascular endothelial growth factor (VEGF)-targeted therapy in the European Union, Norway and Iceland.

On February 29, 2016, Exelixis and Ipsen jointly announced an exclusive licensing agreement for the commercialization and further development of cabozantinib indications outside of the United States, Canada and Japan.