Development and Validation of a Clinic Machine Learning Classifier for the Prediction of Risk Stratifications of Prostate Cancer Bone Metastasis Progression to Castration Resistance

Objective

To explore the predictive factors and predictive model construction for the progression of prostate cancer bone metastasis to castration resistance.

Methods

Clinical data of 286 patients diagnosed with prostate cancer with bone metastasis, initially treated with endocrine therapy, and progressing to metastatic castration resistant prostate cancer (mCRPC) were collected. By comparing the differences in various factors between different groups with fast and slow occurrence of castration-resistant prostate cancer (CRPC). Kaplan-Meier survival analysis and COX multivariate risk proportional regression model were used to compare the differences in the time to progression to CRPC in different groups. The COX multivariate risk proportional regression model was used to evaluate the impact of candidate factors on the time to progression to CRPC and establish a predictive model. The accuracy of the model was then tested using receiver operating characteristic (ROC) curves and decision curve analysis (DCA).

Results

The median time for 286 mCRPC patients to progress to CRPC was 17 (9.5-28.0) months. Multivariate analysis showed that the lowest value of PSA (PSA nadir), the time when PSA dropped to its lowest value (timePSA), and the number of BM, and LDH were independent risk factors for rapid progression to CRPC. Based on the four independent risk factors mentioned above, a prediction model was established, with the optimal prediction model being a random forest with area under curve (AUC) of 0.946[95% CI: 0.901-0.991] and 0.927[95% CI: 0.864-0.990] in the training and validation cohort, respectively.

Conclusion

After endocrine therapy, the PSA nadir, timePSA, the number of BM, and LDH are the main risk factors for rapid progression to mCRPC in patients with prostate cancer bone metastases. Establishing a CRPC prediction model is helpful for early clinical intervention decision-making.

Health-related quality of life and pain outcomes with [177Lu]Lu-PSMA-617 plus standard of care versus standard of care in patients with metastatic castration-resistant prostate cancer (VISION): a multicentre, open-label, randomised, phase 3 trial

BACKGROUND

In VISION, the prostate-specific membrane antigen (PSMA)-targeted radioligand therapy lutetium-177 [177Lu]Lu-PSMA-617 (vipivotide tetraxetan) improved radiographic progression-free survival and overall survival when added to protocol-permitted standard of care in patients with metastatic castration-resistant prostate cancer. Here, we report additional health-related quality of life (HRQOL), pain, and symptomatic skeletal event results.

METHODS

This multicentre, open-label, randomised, phase 3 trial was conducted at 84 cancer centres in nine countries in North America and Europe. Eligible patients were aged 18 years or older; had progressive PSMA-positive metastatic castration-resistant prostate cancer; an Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2; and had previously received of at least one androgen receptor pathway inhibitor and one or two taxane-containing regimens. Patients were randomly assigned (2:1) to receive either [177Lu]Lu-PSMA-617 plus protocol-permitted standard of care ([177Lu]Lu-PSMA-617 group) or standard of care alone (control group) using permuted blocks. Randomisation was stratified by baseline lactate dehydrogenase concentration, liver metastases, ECOG performance status, and androgen receptor pathway inhibitor inclusion in standard of care. Patients in the [177Lu]Lu-PSMA-617 group received intravenous infusions of 7·4 gigabecquerel (GBq; 200 millicurie [mCi]) [177Lu]Lu-PSMA-617 every 6 weeks for four cycles plus two optional additional cycles. Standard of care included approved hormonal treatments, bisphosphonates, and radiotherapy. The alternate primary endpoints were radiographic progression-free survival and overall survival, which have been reported. Here we report the key secondary endpoint of time to first symptomatic skeletal event, and other secondary endpoints of HRQOL assessed with the Functional Assessment of Cancer Therapy-Prostate (FACT-P) and EQ-5D-5L, and pain assessed with the Brief Pain Inventory-Short Form (BPI-SF). Patient-reported outcomes and symptomatic skeletal events were analysed in all patients who were randomly assigned after implementation of measures designed to reduce the dropout rate in the control group (on or after March 5, 2019), and safety was analysed according to treatment received in all patients who received at least one dose of treatment. This trial is registered with ClinicalTrials.gov, NCT03511664, and is active but not recruiting.

FINDINGS

Between June 4, 2018, and Oct 23, 2019, 831 patients were enrolled, of whom 581 were randomly assigned to the [177Lu]Lu-PSMA-617 group (n=385) or control group (n=196) on or after March 5, 2019, and were included in analyses of HRQOL, pain, and time to first symptomatic skeletal event. The median age of patients was 71 years (IQR 65-75) in the [177Lu]Lu-PSMA-617 group and 72·0 years (66-76) in the control group. Median time to first symptomatic skeletal event or death was 11·5 months (95% CI 10·3-13·2) in the [177Lu]Lu-PSMA-617 group and 6·8 months (5·2-8·5) in the control group (hazard ratio [HR] 0·50, 95% CI 0·40-0·62). Time to worsening was delayed in the [177Lu]Lu-PSMA-617 group versus the control group for FACT-P score (HR 0·54, 0·45-0·66) and subdomains, BPI-SF pain intensity score (0·52, 0·42-0·63), and EQ-5D-5L utility score (0·65, 0·54-0·78). Grade 3 or 4 haematological adverse events included decreased haemoglobin (80 [15%] of 529 assessable patients who received [177Lu]Lu-PSMA-617 plus standard of care vs 13 [6%] of 205 who received standard of care only), lymphocyte concentrations (269 [51%] vs 39 [19%]), and platelet counts (49 [9%] vs five [2%]). Treatment-related adverse events leading to death occurred in five (1%) patients who received [177Lu]Lu-PSMA-617 plus standard of care (pancytopenia [n=2], bone marrow failure [n=1], subdural haematoma [n=1], and intracranial haemorrhage [n=1]) and no patients who received standard of care only.

INTERPRETATION

[177Lu]Lu-PSMA-617 plus standard of care delayed time to worsening in HRQOL and time to skeletal events compared with standard of care alone. These findings support the use of [177Lu]Lu-PSMA-617 in patients with metastatic castration-resistant prostate cancer who received previous androgen receptor pathway inhibitor and taxane treatment.

FUNDING

Advanced Accelerator Applications (Novartis).

Pharmacological Efficacy of Repurposing Drugs in the Treatment of Prostate Cancer

Worldwide, prostate cancer (PC) is the second most frequent cancer among men and the fifth leading cause of death; moreover, standard treatments for PC have several issues, such as side effects and mechanisms of resistance. Thus, it is urgent to find drugs that can fill these gaps, and instead of developing new molecules requiring high financial and time investments, it would be useful to select non-cancer approved drugs that have mechanisms of action that could help in PC treatment, a process known as repurposing drugs. In this review article, drugs that have potential pharmacological efficacy are compiled to be repurposed for PC treatment. Thus, these drugs will be presented in the form of pharmacotherapeutic groups, such as antidyslipidemic drugs, antidiabetic drugs, antiparasitic drugs, antiarrhythmic drugs, anti-inflammatory drugs, antibacterial drugs, antiviral drugs, antidepressant drugs, antihypertensive drugs, antifungal drugs, immunosuppressant drugs, antipsychotic drugs, antiepileptic and anticonvulsant drugs, bisphosphonates and drugs for alcoholism, among others, and we will discuss their mechanisms of action in PC treatment.

Spine Pain and Metastatic Prostate Cancer: Defining the Contribution of Nonmalignant Etiologies

PURPOSE

In patients with metastatic prostate cancer (MPC), the contribution of nonmalignant etiologies to morbidity is often overlooked.

METHODS

We retrospectively reviewed the documented specialist assessments of back pain in men with MPC in a joint medical oncology and physiatry clinic at our tertiary cancer care center. Data on cancer disease extent, hormonal status, sites of spread, pain characteristics, physiatric examination findings, imaging, and recommended management were reviewed, extracted, and codified. For those with back pain at a site of known disease, pain etiology was classified as malignant, nonmalignant, or mixed.

RESULTS

Ninety-three men were collaboratively assessed for back pain, 24 (26%) with a biochemical recurrence and 69 (74%) with MPC of whom 53 (77%) reported pain in an area of known spinal metastases including 35 (66%) metastatic castration-resistant disease and 34 (64%) a precancer history of back pain. The presenting pain symptoms of the 53 patients were activity-related in 22 (42%), radicular in eight (15%), transitional movement-related in seven (13%), biologic in five (9%), and multifactorial in 11 (21%). Overall, pain was deemed malignant in 20 (38%; five castration-sensitive, 15 metastatic castration resistant prostate cancer), nonmalignant in 12 (23%; four castration-sensitive, eight CRPC), and of mixed etiology in 21 (40%; nine castration-sensitive, 12 CRPC).

CONCLUSION

Nonmalignant etiologies contributed significantly to back pain at sites of metastatic spread for 33/53 (62%) patients with MPC assessed by medical oncology and physiatry. We recommend multidisciplinary care for patients with MPC and back pain to address nonmalignant etiologies that contribute to functional compromise.

Initiation of bone-targeted agents in patients with bone metastases and breast or castrate-resistant prostate cancer actively treated in routine clinical practice in Europe

BACKGROUND

Guidelines recommend starting bone-targeted agents (BTA), such as zoledronic acid and denosumab, as soon as bone metastases (BMs) are definitively diagnosed in all patients with breast cancer (BC) or castration-resistant prostate cancer (CRPC) whether they are symptomatic or not.

METHODS

Data were analyzed from 1364 patients with BC and 1161 patients with CRPC who had BMs and were receiving anti-cancer therapy in hospitals across six European countries (Belgium, France, Germany, Italy, Spain and the UK). The 731 physicians (medical oncologists or urologists) provided insights in the decision-making factors driving their management of bone health for these patients, and the patient medical records indicated how these decisions were reflected in routine clinical practice.

RESULTS

Within three months of a BM diagnosis, 74% of BC and 51% of CRPC patients had initiated treatment with a BTA. Around 12% of BC and 23% of CRPC patients did not receive a BTA following BM diagnosis. Irrespective of the tumour type (BC or CRPC), most physicians prescribed either denosumab or zoledronic acid as first BTA therapy. Physicians reported bone pain as a major decision-making factor to initiate a BTA. The presence of bone complications at BM diagnosis and bone pain at BM diagnosis were found to be significant predictive factors for a BTA initiation, irrespective of tumour type.

CONCLUSIONS

Despite European Society for Medical Oncology (ESMO) guidance on bone protection irrespective of symptomatic disease, not all patients with BMs received a BTA following a BM diagnosis. This suggests that clinical judgements and patients' communication of their pain to their physicians contributed to the decision to prescribe bone protection therapy in cancer patients.

Imaging features of the evolving patterns of metastatic prostate cancer

The pattern of metastases in prostate cancer (PC) is evolving. Increased use of imaging, newer imaging techniques with higher sensitivity for disease detection and patients receiving multiple lines of novel therapies with increased life expectancy are likely to be contributory. Awareness of metastatic disease patterns improves early diagnosis, accurate staging, and initiation of appropriate therapy, and can inform prognostic information and anticipate potential disease complications. The aim of this review is to document the spectrum of metastases in PC including emerging and unusual patterns, and to highlight the role of novel imaging including prostate-specific membrane antigen (PSMA)-positron-emission tomography (PET) and whole-body magnetic resonance imaging (WB-MRI) to improve diagnostic and response assessment accuracy.

Management of cancer pain with analgetic adjuvant and weak opioid in prostate cancer bone metastases: A case series

BACKGROUND

In cancer patients, cancer pain is the most common cancer complication. About 60-90% of patients with advanced stage cancer experience various levels of pain, and about 30% of patients have been suffering from persistent severe pain. Bones are the most frequent targets of metastases in patients with cancer such as breast, prostate, lung, kidney, and thyroid. In advanced prostate cancer, bone metastasis leads to bone pain, skeletal fracture, and increased mortality. At least 75% of patients with bone metastasis experience bone pain.

CASE DESCRIPTION

We report three cases of cancer pain, treated with primary cancer from the prostate metastasis to the spine. All three patients had lower back pain that radiated to the left and right limbs, with mixed pain and bone pain, where early hospital admission shows the Numeric Rating Scale (NRS) pain scale 9-10. Treated with administration of adjuvant therapy (Gabapentin) and weak opioids (injections of Tramadol) as well as injections of Metylprednisolone (for 3 days), the patient's pain scale was evaluated, and the average NRS obtained on days 2-4 was 5-6. On day 5-8, treatment continued with Gabapentin and Tramadol injections, and the pain scale (NRS) decreased to 2-3. All patients on the 8-9th day of treatment also received Biphosphonates to reduce pain, bone damage, fracture risk, and blood calcium levels. Patients can be discharged with an oral Gabapentin prescription only.

CONCLUSION

A pain scale (NRS) reduction of >50% is obtained from the initial pain scale in cancer pain patients treated using a combination of adjuvant therapy and weak opioids.

Epidemiology of spinal cord and column tumors

The spine is a frequent location for metastatic disease. As local control of primary tumor pathology continues to improve, survival rates improve and, by extension, the opportunity for metastasis increases. Breast, lung, and prostate cancer are the leading contributors to spinal metastases. Spinal metastases can manifest as bone pain, pathologic fractures, spinal instability, nerve root compression, and, in its most severe form, spinal cord compression. The global extent of disease, the spinal burden, neurologic status, and life expectancy help to categorize patients as to their candidacy for treatment options. Efficient identification and workup of those with spinal metastases will expedite the treatment cascade and improve quality of life.

Three-Dimensional Cell Cultures as an In Vitro Tool for Prostate Cancer Modeling and Drug Discovery

In the last decade, three-dimensional (3D) cell culture technology has gained a lot of interest due to its ability to better recapitulate the in vivo organization and microenvironment of in vitro cultured cancer cells. In particular, 3D tumor models have demonstrated several different characteristics compared with traditional two-dimensional (2D) cultures and have provided an interesting link between the latter and animal experiments. Indeed, 3D cell cultures represent a useful platform for the identification of the biological features of cancer cells as well as for the screening of novel antitumor agents. The present review is aimed at summarizing the most common 3D cell culture methods and applications, with a focus on prostate cancer modeling and drug discovery.

Targeting of radioactive platinum-bisphosphonate anticancer drugs to bone of high metabolic activity

Platinum-based chemotherapeutics exhibit excellent antitumor properties. However, these drugs cause severe side effects including toxicity, drug resistance, and lack of tumor selectivity. Tumor-targeted drug delivery has demonstrated great potential to overcome these drawbacks. Herein, we aimed to design radioactive bisphosphonate-functionalized platinum (^195mPt-BP) complexes to confirm preferential accumulation of these Pt-based drugs in metabolically active bone. In vitro NMR studies revealed that release of Pt from Pt BP complexes increased with decreasing pH. Upon systemic administration to mice, Pt-BP exhibited a 4.5-fold higher affinity to bone compared to platinum complexes lacking the bone-seeking bisphosphonate moiety. These Pt-BP complexes formed less Pt-DNA adducts compared to bisphosphonate-free platinum complexes, indicating that in vivo release of Pt from Pt-BP complexes proceeded relatively slow. Subsequently, radioactive ^195mPt-BP complexes were synthesized using ^195mPt(NO₃)₂(en) as precursor and injected intravenously into mice. Specific accumulation of ^195mPt-BP was observed at skeletal sites with high metabolic activity using micro-SPECT/CT imaging. Furthermore, laser ablation-ICP-MS imaging of proximal tibia sections confirmed that ^195mPt BP co-localized with calcium in the trabeculae of mice tibia.

Natural Compounds in Prostate Cancer Prevention and Treatment: Mechanisms of Action and Molecular Targets

Prostate cancer (PCa) represents a major cause of cancer mortality among men in developed countries. Patients with recurrent disease initially respond to androgen-deprivation therapy, but the tumor eventually progresses into castration-resistant PCa; in this condition, tumor cells acquire the ability to escape cell death and develop resistance to current therapies. Thus, new therapeutic approaches for PCa management are urgently needed. In this setting, natural products have been extensively studied for their anti-PCa activities, such as tumor growth suppression, cell death induction, and inhibition of metastasis and angiogenesis. Additionally, numerous studies have shown that phytochemicals can specifically target the androgen receptor (AR) signaling, as well as the PCa stem cells (PCSCs). Interestingly, many clinical trials have been conducted to test the efficacy of nutraceuticals in human subjects, and they have partially confirmed the promising results obtained in vitro and in preclinical models. This article summarizes the anti-cancer mechanisms and therapeutic potentials of different natural compounds in the context of PCa prevention and treatment.

A review on osteoclast diseases and osteoclastogenesis inhibitors recently developed from natural resources

Natural products have been investigated as potential candidates of novel therapeutics and play a crucial role in advanced medicinal drugs. Natural resources, including local medicinal plants (especially folk medicinal plants), animals, bacteria, and fungi have been used for more than a century, and are precious gifts from nature, providing potential medicines with high safety. Osteoclast-related diseases, such as osteoporosis, rheumatoid arthritis, Paget's disease, osteoclastoma, and periprosthetic osteolysis, are currently the most common reasons for bone inflammation, pain and fractures, resulting in low quality of life. However, the curative effects of current therapeutic drugs for these osteoclast-related diseases are limited, and long-term treatment is needed. Further, in severe cases, surgical treatments are necessary, which may cause unaffordable expenses and subsequent influences such as neuralgia, mental stress, and even development of cancer. Thus, safer inhibitors and potential drugs with enhanced curative effects and quick relief are needed to treat patients with osteoclast diseases. This review aims to introduce the main osteoclast-related diseases and some of the recently developed naturally sourced inhibitors against osteoclastogenesis, also it is desired to attract people's attention on using widely available natural resources for the evolution of new types of osteoclast inhibitors with minimal or no side-effects upon long-term treatments.

The Current Role of Osteoclast Inhibitors in Patients with Prostate Cancer

Purpose

Prostate cancer (PCa) is one of the most frequently diagnosed malignancies worldwide. Hormonal deprivation therapy is a well-established treatment for locally advanced or metastatic diseases but exposes patients to the risk of osteoporosis and fragility fractures. Furthermore, the tropism of the PCa cells to osseous metastases increases the incidence of skeletal-related events (SREs).

Methods

A nonsystematic review of the international literature was performed in respect to the use of osteoclast inhibitors zoledronic acid (ZA) and denosumab (DEN) in PCa patients.

Results

DEN and ZA have proved their efficacy in preventing osteoporosis and bone mass loss in patients treated with hormonal therapy with no proven superiority of one agent over the other. However, the effectiveness in reducing fragility fractures has been proved only for DEN so far. In metastatic-free castrate-sensitive high-risk PCa patients, ZA has not shown any efficacy in preventing osseous metastasis, and evidence is lacking in favor or against the use of DEN. The use of osteoclasts inhibitors had no evident positive effect in overall and disease-specific survival in this group of patients. In advanced castrate-refractory malignancy, DEN has shown clinical superiority over ZA in preventing new SRE but not in overall survival.

Conclusion

Superiority of DEN over ZA has been proved only in advanced castrate refractory disease in terms of preventing new SRE. In the rest of the cases, the selection of either agent should be based on the clinical condition of each patient and the cost of the treatment.

Symptom assessment to guide treatment selection and determine progression in metastatic castration-resistant prostate cancer: Expert opinion and review of the evidence

Multiple new agents to treat metastatic castration-resistant prostate cancer (mCRPC) have become available in recent years; however, the appropriate timing and sequencing of these agents have yet to be elucidated. Until accurate biomarkers become available to allow more focused therapeutic targeting for this population, treatment selection for men with mCRPC will continue to be driven largely by close assessment of patient-related factors and symptoms. Pain, as the predominant symptom of mCRPC, is often the focus when assessing progression and the need for a change in treatment. A myriad of other symptoms, including fatigue, impact on activities of daily living, sleep, and lower urinary tract symptoms, also affect men with mCRPC, and assessment of the composite of these symptoms provides an earlier signal for the need to adjust treatment. A number of tools are available for assessing symptoms in patients with advanced prostate cancer, but they are not routinely used, given their complexity and length. A new simplified questionnaire is proposed for the assessment of symptoms, beyond pain, to inform treatment decisions for men with mCRPC.

Treatment dynamics of bone-targeting agents among men with bone metastases from prostate cancer in the United States

PURPOSE

To examine the dynamics of treatment with 2 bone-targeting agents (BTAs)-denosumab and zoledronic acid-among men with bone metastases from prostate cancer.

METHODS

Using electronic health record data from oncology practices across the US, we identified prostate cancer patients diagnosed with bone metastasis in 2012/2013 without evidence of BTA use within 6 months prior to diagnosis. We examined the risk and predictors of BTA initiation, interruption, and re-initiation.

RESULTS

Among 897 men diagnosed with prostate cancer, the cumulative incidence of BTA initiation after bone metastasis diagnosis was 34% (95% confidence interval [CI], 31-37%) at 30 days, 64% (95% CI, 61-68%) at 180 days, and 88% (95% CI, 85-91%) at 2 years. Denosumab was initiated more frequently than zoledronic acid. Men with diabetes, more bone lesions, history of androgen deprivation therapy, or no hospice enrollment were more likely to initiate treatment. Following initiation, the cumulative incidence of treatment interruption was 17% (95% CI, 14-19%) at 60 days and 70% (95% CI, 66-74%) at 2 years, with interruption more likely among patients receiving emerging therapies for prostate cancer or enrolling in hospice. The cumulative incidence of re-initiation following interruption was 36.3% (95% CI, 32.7-40.2%) at 15 days, 49.8% (95% CI, 45.9-54.1%) at 30 days, and 81.0% (95% CI, 77.5-84.7%) at 1 year.

CONCLUSIONS

Bone-targeting agent therapy is initiated by the majority of men living with bone metastases following a prostate cancer diagnosis; however, the timing of initiation is highly variable. Once on treatment, gaps or interruptions in therapy are common.

Recognizing Symptom Burden in Advanced Prostate Cancer: A Global Patient and Caregiver Survey

BACKGROUND

Bone metastases in men with prostate cancer are often initially asymptomatic, resulting in delayed identification, diagnosis, and appropriate treatment. To assess how patients with advanced prostate cancer (aPC) communicate symptoms to health care providers, an international patient survey was conducted.

METHODS

An online and phone survey was conducted by Harris Poll in 11 countries (Brazil, France, Germany, Japan, Italy, Netherlands, Singapore, Spain, Taiwan, United Kingdom, United States) from February 12 to October 27, 2015, in men with aPC (ie, those who reported as having PC beyond the prostate [metastatic]) and their caregivers. Cell weighting was used to ensure equal weight of data across countries. Percentages are based on weighted n values.

RESULTS

A total of 927 men with aPC (weighted n = 664) and 400 caregivers completed the survey. Most commonly reported symptoms were fatigue (73%), urinary symptoms (63%), sexual function symptoms (62%), and bone pain (52%). Of 568 patients with bone metastases (weighted n = 421), most (73%) noticed pain before receiving a diagnosis of metastatic PC. Most patients with aPC (56%) were uncertain if their pain was cancer related, 55% felt they had to live with daily pain, 45% sometimes ignored pain, and 39% had difficulty talking about pain. Patients who had a caregiver were more likely than those without to discuss pain at every visit (45% vs. 32%, P < .05).

CONCLUSIONS

Disease symptoms in aPC are often underrecognized. Tools encouraging effective communication among patients, caregivers, and health care providers on early symptom reporting may lead to enhanced symptom and disease management.

Skeletal-related events significantly impact health-related quality of life in metastatic castration-resistant prostate cancer: data from PREVAIL and AFFIRM trials

Background:

We investigated the impact of skeletal-related events (SREs) on health-related quality of life (HRQoL) in patients with metastatic castration-resistant prostate cancer (mCRPC) in phase III trials of enzalutamide versus placebo.

Methods:

Patients with mCRPC experiencing at least one SRE during AFFIRM and PREVAIL were assessed for trajectory-adjusted mean change in HRQoL by first SRE using Functional Assessment of Cancer Therapy-Prostate (FACT-P; AFFIRM, three domains, and PREVAIL, nine domains) and EQ-5D (PREVAIL) instruments.

Results:

First SREs caused HRQoL deterioration in both trials. Spinal cord compression had the largest impact, with clinically meaningful reductions in seven of nine FACT-P domains in PREVAIL and all three in AFFIRM (mean (95% confidence interval (CI)) change in FACT-P total score –16.95 (–26.47, –7.44) and –9.69 (–16.10, –3.27), respectively). In PREVAIL, first SREs caused clinically meaningful declines in EQ-5D utility index, irrespective of category; spinal cord compression had the largest impact (mean (95% CI) change –0.24 (–0.39, –0.08)). In AFFIRM, FACT-P and FACT-General total scores showed clinically meaningful declines after radiation/surgery to bone.

Conclusions:

SREs were associated with clinically meaningful functional declines in the daily lives of patients with mCRPC. Spinal cord compression had the largest impact on HRQoL.

Differential Effect on Bone Lesions of Targeting Integrins: Randomized Phase II Trial of Abituzumab in Patients with Metastatic Castration-Resistant Prostate Cancer

PURPOSE

Integrins play a critical role in the progression of prostate cancer and its bone metastases. We investigated the use of the pan-αv integrin inhibitor abituzumab in chemotherapy-naïve patients with asymptomatic or mildly symptomatic metastatic castration-resistant prostate cancer.

EXPERIMENTAL DESIGN

PERSEUS (NCT01360840) was a randomized, double-blind phase II study. Men with pathologically confirmed prostate cancer and radiologic progression of bone lesions in the 28 days prior to randomization were assigned to receive abituzumab 750 mg or 1,500 mg or placebo (1:1:1) every 3 weeks in combination with luteinizing hormone-releasing hormone agonist/antagonist therapy. The primary endpoint was progression-free survival (PFS).

RESULTS

The intent-to-treat population comprised 180 patients, 60 in each arm. The primary endpoint of PFS was not significantly different with abituzumab-based therapy compared with placebo [abituzumab 750 mg, 3.4 months, HR = 0.89; 95% confidence interval (CI), 0.57-1.39; abituzumab 1,500 mg, 4.3 months, HR = 0.81; 95% CI, 0.52-1.26; placebo, 3.3 months], but the cumulative incidence of bone lesion progression was lower with abituzumab than with placebo for up to 24 months (cumulative incidence 23.6% vs. 41.1% at 6 months, 26.1% vs. 45.4% at 12 months). Two partial tumor responses were observed (1 abituzumab 1,500 mg and 1 placebo). Approximately 85% to 90% of patients experienced at least one treatment-emergent adverse event (TEAE) in the different arms, but the incidences of serious TEAEs and TEAEs with fatal outcome were similar in the three arms.

CONCLUSIONS

Although PFS was not significantly extended, abituzumab appears to have specific activity in prostate cancer-associated bone lesions that warrants further investigation. Clin Cancer Res; 22(13); 3192-200. ©2016 AACR.