Study of Cabozantinib (XL184) Versus Mitoxantrone Plus Prednisone in Men With Previously Treated Symptomatic Castration-resistant Prostate Cancer (COMET-2)
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ClinicalTrials.gov Identifier: NCT01522443 |
Recruitment Status :
Terminated
(Stopped after the outcome of cabozantinib Phase 3 CRPC study XL184-307.)
First Posted : January 31, 2012
Results First Posted : May 23, 2018
Last Update Posted : May 23, 2018
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Bone metastases and associated pain are a major cause of morbidity and mortality in castration-resistant prostate cancer (CRPC). Most approved therapies have shown some ability to reduce soft tissue lesions but none meaningfully impacts bone metastases (as demonstrated by lack of resolution of lesions on bone scan with these agents) or the pain associated with these metastases.
This study will evaluate the effect of cabozantinib versus mitoxantrone plus prednisone on pain response and bone scan response in men with CRPC.
Condition or disease | Intervention/treatment | Phase |
---|---|---|
Prostate Cancer Castration Resistant Prostate Cancer Pain Prostatic Neoplasms | Drug: cabozantinib Drug: mitoxantrone Drug: prednisone | Phase 3 |
Study Type : | Interventional (Clinical Trial) |
Actual Enrollment : | 119 participants |
Allocation: | Randomized |
Intervention Model: | Parallel Assignment |
Masking: | Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor) |
Primary Purpose: | Treatment |
Official Title: | A Phase 3, Randomized, Double-blind, Controlled Trial of Cabozantinib (XL184) Versus Mitoxantrone Plus Prednisone in Men With Previously Treated Symptomatic Castration-resistant Prostate Cancer |
Study Start Date : | March 2012 |
Actual Primary Completion Date : | October 2014 |
Actual Study Completion Date : | January 13, 2015 |

Arm | Intervention/treatment |
---|---|
Experimental: Cabozantinib
Subjects randomized to the cabozantinib arm will also receive placebo mitoxantrone injections (color-matched with methylene blue) and placebo prednisone capsules. There will be a maximum of 10 infusions for mitoxantrone placebo. |
Drug: cabozantinib
Tablets taken orally once daily. |
Active Comparator: Mitoxantrone/prednisone
Subjects randomized to the mitoxantrone + prednisone arm will also receive placebo cabozantinib tablets. There will be a maximum of 10 infusions for mitoxantrone. |
Drug: mitoxantrone
Given by IV once every 3 weeks. Drug: prednisone Taken twice a day orally by mouth. Commercially-obtained prednisone tablets will be over-encapsulated in order to blind identity. |
- Pain Response at Week 6 Confirmed at Week 12, Week 12 Reported [ Time Frame: Pain response was measured at Week 6 and Week 12 by self-reports of subjects ]The pre-specified primary analysis of Pain Response at Week 6 confirmed at Week 12 was defined as ≥ 30% from baseline in the average daily worst pain intensity score during a 7-day reporting period, with neither a concomitant increase in average daily use of any opioid narcotic type, nor addition of any new opioid narcotic type, relative to baseline. Pain Progression at a given time point is defined as ≥ 30% increase compared with baseline in the average daily worst pain intensity score during a 7-day reporting period or either an increase in the average daily use of any type of opioid narcotic or addition of a new opioid narcotic type compared with baseline.
- Bone Scan Response (BSR) [ Time Frame: BSR was measured at the end of Week 12 as determined by the IRF ]BSR is defined as >=30% in the bone scan lesion area (BSLA) compared with baseline. Bones scans were evaluated by an independent radiology facility (IRF) for response.
- Overall Survival (OS) [ Time Frame: OS was measured at the time of randomization until 78 deaths ]OS was defined as the time from randomization to the date of death (due to any cause). Participants that had not died were censored at last known date alive. The analyses for OS occurred after 78/196 deaths (40% of the total required for the pre-specified primary analysis of OS). The data cut-off date was 06 October 2014. Median OS was calculated using Kaplan-Meier estimates.

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Ages Eligible for Study: | 18 Years and older (Adult, Older Adult) |
Sexes Eligible for Study: | Male |
Accepts Healthy Volunteers: | No |
Inclusion Criteria:
- Histological or cytological diagnosis of castration resistant prostate cancer (serum testosterone less than 50 ng/dL).
- Evidence of bone metastasis related to prostate cancer on bone scans.
- Documented pain from bone metastases that requires opioid narcotic intervention.
- Adopted a narcotic regimen that consists of one sustained release opioid agent taken daily for chronic pain and one immediate release opioid agent for breakthrough pain.
- Received prior docetaxel and either abiraterone or MDV3100 treatment and has evidence of investigator assessed prostate cancer progression on each agent independently.
- Maintenance of LHRH agonist or antagonist unless treated with orchiectomy.
- Recovered from toxicities related to any prior treatments, unless the toxicities are clinically non significant or easily manageable.
- Adequate organ and marrow function.
- A left-ventricular ejection fraction (LVEF) of >/= 50% assessed by echocardiogram or MUGA (multigated acquisition scan).
- Capable of understanding and complying with the protocol requirements (including having the ability to access an interactive voice recognition system and self-report pain and narcotic use) and signed the informed consent form.
- Sexually active fertile patients and their partners must agree to use medically accepted methods of contraception (eg, barrier methods, including male condom, female condom, or diaphragm with spermicidal gel) during the course of the study and for 3 months after the last dose of study treatment.
Exclusion Criteria:
- Prior treatment with cabozantinib or mitoxantrone.
- Treatment with docetaxel, abiraterone, or MDV3100 in the last 2 weeks; or with any other type of cytotoxic or investigational anticancer agent in the last 2 weeks.
- Radiation therapy in the last 4 weeks (includes radiation targeting bone metastases), radionuclide treatment in the last 6 weeks, or radiation therapy to the thoracic cavity (unless radiation targets bone metastases) in the past 3 months.
- Treatment with serotonergic psychiatric medication(s) in the last 2 weeks (5 weeks for fluoxetine).
- Known brain metastases or uncontrolled epidural disease.
- Requires concomitant treatment, in therapeutic doses, with anticoagulants such as warfarin or warfarin-related agents, heparin, thrombin or FXa (coagulation factor X) inhibitors, or antiplatelet agents (eg, clopidogrel). Low dose aspirin (above low dose levels for cardioprotection per local applicable guidelines), low-dose warfarin (≤ 1 mg/day), and prophylactic low molecular weight heparin are permitted.
- Uncontrolled, significant intercurrent illness including, but not limited to, cardiovascular disorders, gastrointestinal disorders, active infections, non-healing wounds, recent surgery.
- Clinically significant hematemesis or hemoptysis of > 0.5 teaspoon of red blood, or other signs indicative of pulmonary hemorrhage in the last 3 months, or history of other significant bleeding in the past 6 months.
- Cavitating pulmonary lesion(s) or a lesion invading or encasing a major blood vessel.
- Corrected QT interval (QTc) > 500 ms in the last 4 weeks.
- Unable to swallow capsules or tablets or tolerate infusions.
- Previously-identified allergy or hypersensitivity to components of the study treatment formulations investigator or designee.
- History of another malignancy (except non-melanoma skin cancer, adequately treated stage I colon cancer, superficial transitional carcinoma of the bladder) in the past 2 years.

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.
Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01522443

Responsible Party: | Exelixis |
ClinicalTrials.gov Identifier: | NCT01522443 |
Other Study ID Numbers: |
XL184-306 |
First Posted: | January 31, 2012 Key Record Dates |
Results First Posted: | May 23, 2018 |
Last Update Posted: | May 23, 2018 |
Last Verified: | April 2018 |
prostate cancer castration resistant prostate cancer bone pain CRPC |
Prostatic Neoplasms Genital Neoplasms, Male Urogenital Neoplasms Neoplasms by Site Neoplasms Genital Diseases, Male Genital Diseases Urogenital Diseases Prostatic Diseases Male Urogenital Diseases Prednisone Mitoxantrone Anti-Inflammatory Agents |
Glucocorticoids Hormones Hormones, Hormone Substitutes, and Hormone Antagonists Physiological Effects of Drugs Antineoplastic Agents, Hormonal Antineoplastic Agents Analgesics Sensory System Agents Peripheral Nervous System Agents Topoisomerase II Inhibitors Topoisomerase Inhibitors Enzyme Inhibitors Molecular Mechanisms of Pharmacological Action |