Atypical Presentation of Metastatic Castrate-resistant Prostate Cancer in a Middle Aged African Male with Good Response to Radioligand Therapy

Prostate cancer typically follows a characteristic pattern of metastatic spread to the pelvic lymph nodes and bone. Atypical patterns of metastasis are rare but have been documented. In African men, this disease tends to follow a more aggressive course, with the possibility of an atypical site of metastatic spread. We present a case of a 58-year- old African male with metastatic castrate-resistant prostate cancer who presented with both typical and atypical patterns of metastatic disease detected by a fluorine 18 prostate-specific membrane antigen positron emission tomography/computed tomography scan. This patient also had a good response to radioligand therapy.

Circulating Tumour DNA Biomarkers Associated with Outcomes in Metastatic Prostate Cancer Treated with Lutetium-177-PSMA-617

Background

Lutetium-177-prostate-specific membrane antigen- 617 (Lu-PSMA) is an effective therapy for metastatic castration-resistant prostate cancer (mCRPC). However, treatment responses are heterogeneous despite stringent positron emission tomography (PET)-based imaging selection criteria. Molecularly based biomarkers have potential to refine patient selection and optimise outcomes.

Objective

To identify circulating tumour DNA (ctDNA) features associated with treatment outcomes for men treated with Lu-PSMA.

Design setting and participants

ctDNA from men treated with Lu-PSMA in combination with idronoxil for progressive mCRPC were analysed using an 85-gene customised sequencing assay. ctDNA fractions, molecular profiles, and the presence of alterations in aggressive-variant prostate cancer (AVPC) genes were analysed at baseline, cycle 3 and at disease progression.

Intervention

Men received Lu-PSMA with idronoxil every 6 wk for up to six cycles.

Outcome measurements and statistical analysis

Baseline and exit PSMA and fluorodeoxyglucose PET/computed tomography (CT) imaging was conducted at baseline and study exit. Single-photon emission CT (SPECT) scans were performed 24 h after Lu-PSMA. Blood samples were collected at baseline,cycle 3 and at disease progression. Cox proportional-hazards models were used to assess associations and derive hazard ratios (HRs) and confidence intervals (CIs) for associations between molecular factors, imaging features, and clinical outcomes.

Results and limitations

Sixty samples from 32 men were sequenced (32 at baseline, 24 at cycle 3, four from patients with disease progression); two samples (baseline, on-treatment) from one individual were excluded from analysis owing to poor quality of the baseline sequencing data. Alterations in AVPC genes were associated with shorter prostate-specific antigen (PSA) progression-free survival (PFS) and overall survival (OS) in univariate (HR 3.4, 95% CI 1.5-7.7; p = 0.0036; and HR 3.3, 95% CI 1.4-7.7; p = 0.0063, respectively) and multivariate analyses (HR 4.8, 95% CI 1.8-13; p = 0.0014; and HR 4.1, 95% CI 1.6-11; p = 0.004).

Conclusions

ctDNA alterations in AVPC genes were associated with shorter PSA PFS and OS among men treated with Lu-PSMA and intermittent idronoxil. These candidate molecular biomarkers warrant further study to determine whether they have predictive value and potential to guide synergistic combination strategies to enhance outcomes for men treated with Lu-PSMA for mCRPC.

Patient summary

Certain DNA/gene changes detected in the blood of men with advanced prostate cancer were associated with shorter benefit from lutetium PSMA, a targeted radioactive therapy. This information may be useful in determining which men may benefit most from this treatment, but additional research is needed.

Effect of Prior Local Therapy on Response to First-line Androgen Receptor Axis Targeted Therapy in Metastatic Castrate-resistant Prostate Cancer: A Secondary Analysis of the COU-AA-302 Trial

BACKGROUND

Men with localized prostate cancer are often treated with local therapy (LT). However, a proportion of these patients will eventually develop recurrence and progression requiring systemic therapy. Whether primary LT affects the response to this subsequent systemic treatment is unclear.

OBJECTIVE

We investigated whether the receipt of prior prostate-directed LT influenced the response to first-line systemic therapy and survival in docetaxel-naïve metastatic castrate-resistant prostate cancer (mCRPC) patients.

DESIGN, SETTING, AND PARTICIPANTS

This is an exploratory analysis of the COU-AA-302 trial, a multicentric double-blinded phase 3 randomized controlled trial in which mCRPC patients with no to mild symptoms were randomized to receive abiraterone plus prednisone or placebo plus prednisone.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

We compared the time-varying effects of first-line abiraterone in patients with and without prior LT using a Cox proportional hazard model. The cut points were chosen using grid search, and were 6 and 36 mo for radiographic progression-free survival (rPFS) and overall survival (OS), respectively. We also investigated whether there was any difference in treatment effect on score change (relative to baseline) in various patient-reported outcomes (measured by Functional Assessment of Cancer Therapy-Prostate [FACT-P]) over time depending on the receipt of prior LT. The adjusted association of prior LT with survival was determined using weighted Cox regression models.

RESULTS AND LIMITATIONS

Among 1053 eligible patients, 64% (n = 669) received prior LT. We did not find any statistically significant heterogeneity of time-dependent treatment effect from abiraterone on rPFS in patients with (hazard ratio [HR]: 0.36 [95% confidence interval: 0.27-0.49] at ≤6 mo; 0.64 [0.49-0.83] at >6 mo) or without (HR: 0.37 [0.26-0.55] at ≤6 mo; 0.72 [0.50-1.03] at >6 mo) prior LT. Similarly, there was no significant heterogeneity in time-dependent treatment effect on OS with (HR: 0.88 [0.71-1.10] at ≤36 mo; 0.76 [0.52-1.11] at >36 mo) or without (0.78 [0.60-1.01] at ≤36 mo; 0.55 [0.30-0.99] at >36 mo) prior LT. We did not find sufficient evidence of a difference in treatment effect from abiraterone on score change over time in prostate cancer subscale (interaction p = 0.4), trial outcome index (interaction p = 0.8), and FACT-P total score (interaction p = 0.6) depending on the receipt of prior LT. Receipt of prior LT was associated with a significant improvement in OS (average HR: 0.72 [0.59-0.89]).

CONCLUSIONS

This study demonstrates that the efficacy of first-line abiraterone and prednisone in docetaxel-naïve mCRPC do not vary significantly based on the receipt of prior prostate-directed LT. Further studies are needed to explore the plausible mechanisms of the association of prior LT with superior OS.

PATIENT SUMMARY

This secondary analysis of the COU-AA-302 trial suggests that survival benefits and temporal changes in quality of life with first-line abiraterone in docetaxel-naïve mCRPC do not differ significantly among patients who received versus those who did not receive prior prostate-directed local therapy.

A Rare Case of Castrate-Resistant Prostate Adenocarcinoma with a Unilateral Testicular Metastasis Mimicking a Primary Testicular Tumour

Prostate adenocarcinoma with testicular metastasis is rare, present in up to 4% of autopsy diagnoses, and presents symptomatically in less than 0.5% of cases. We report an unusual case of a 55-year-old male who developed a symptomatic testicular metastasis from primary prostate cancer 4 years after initial diagnosis of metastatic castrate-sensitive prostate cancer with nodal and bone-only involvement. The patient had orchidectomy, histologically confirming the metastasis and revealing sparing of the spermatic cord. Prior treatment for his metastatic castrate-sensitive prostate cancer had included androgen deprivation therapy and upfront docetaxel chemotherapy. He had received palliative radiotherapy for symptomatic bone metastasis and managed on enzalutamide for castrate-resistant disease for the preceding 22 months with ongoing PSA response at the time of diagnosis of new testicular metastasis, with a further significant PSA response following his "testicular metastasectomy." At the time of diagnosis of testicular metastasis, he did not have any evidence of other visceral metastases, and his metastatic disease otherwise remained radiologically stable. We describe his disease course, treatment and outline the rare nature of his case of testicular metastasis from prostate cancer.

Feasibility of Different Tumor Delineation Approaches for 18F-PSMA-1007 PET/CT Imaging in Prostate Cancer Patients

Background

Delineation of PSMA-positive tumor volume on PET using PSMA-ligands is of highest clinical interest as changes of PSMA-PET/CT-derived whole tumor volume (WTV) have shown to correlate with treatment response in metastatic prostate cancer patients. So far, WTV estimation was performed on PET using ⁶⁸Ga-labeled ligands; nonetheless, ¹⁸F-labeled PET ligands are gaining increasing importance due to advantages over ⁶⁸Ga-labeled compounds. However, standardized tumor delineation methods for ¹⁸F-labeled PET ligands have not been established so far. As correlation of PET-based information and morphological extent in osseous and visceral metastases is hampered by morphological delineation, low contrast in liver tissue and movement artefacts, we correlated CT-based volume of lymph node metastases (LNM) and different PET-based delineation approaches for thresholding on ¹⁸F-PSMA-1007 PET.

Methods

Fifty patients with metastatic prostate cancer, ¹⁸F-PSMA-1007 PET/CT and non-bulky LNM (short-axis diameter ≥10mm) were included. Fifty LNM were volumetrically assessed on contrast-enhanced CT (volumetric reference standard). Different approaches for tumor volume delineation were applied and correlated with the reference standard: I) fixed SUV threshold, II) isocontour thresholding relative to SUV_max (SUV%), and thresholds relative to III) liver (SUV_liver), IV) parotis (SUV_parotis) and V) spleen (SUV_spleen).

Results

A fixed SUV of 4.0 (r=0.807, r² = 0.651, p<0.001) showed the best overall association with the volumetric reference. 55% SUV_max (r=0.627, r² = 0.393, p<0.001) showed highest association using an isocontour-based threshold. Best background-based approaches were 60% SUV_liver (r=0.715, r² = 0.511, p<0.001), 80% SUV_parotis (r=0.762, r² = 0.581, p<0.001) and 60% SUV_spleen (r=0.645, r² = 0.416, p<0.001). Background tissues SUV_liver, SUV_parotis & SUV_spleen did not correlate (p>0.05 each). Recently reported cut-offs for intraprostatic tumor delineation (isocontour 44% SUV_max, 42% SUV_max and 20% SUV_max) revealed inferior association for LNM delineation.

Conclusions

A threshold of SUV 4.0 for tumor delineation showed highest association with volumetric reference standard irrespective of potential changes in PSMA-avidity of background tissues (e. g. parotis). This approach is easily applicable in clinical routine without specific software requirements. Further studies applying this approach for total tumor volume delineation are initiated.

FDA Approval Summary: Rucaparib for the Treatment of Patients with Deleterious BRCA-Mutated Metastatic Castrate-Resistant Prostate Cancer

The U.S. Food and Drug Administration (FDA) granted accelerated approval to rucaparib in May 2020 for the treatment of adult patients with deleterious BRCA mutation (germline and/or somatic)-associated metastatic castrate-resistant prostate cancer (mCRPC) who have been treated with androgen receptor-directed therapy and a taxane. This approval was based on data from the ongoing multicenter, open-label single-arm trial TRITON2. The primary endpoint, confirmed objective response rate, in the 62 patients who met the above criteria, was 44% (95% confidence interval [CI]: 31%-57%). The median duration of response was not estimable (95% CI: 6.4 to not estimable). Fifty-six percent of patients had a response duration of >6 months and 15% >12 months. The safety profile of rucaparib was generally consistent with that of the class of poly-(ADP-ribose) polymerase enzyme inhibitors and other trials of rucaparib in the treatment of ovarian cancer. Deaths due to adverse events (AEs) occurred in 1.7% of patients, and 8% discontinued rucaparib because of an AE. Grade 3-4 AEs occurred in 59% of patients. No patients with prostate cancer developed myelodysplastic syndrome or acute myeloid leukemia. The trial TRITON3 in patients with mCRPC is ongoing and is planned to verify the clinical benefit of rucaparib in mCRPC. This article summarizes the FDA thought process and data supporting this accelerated approval. IMPLICATIONS FOR PRACTICE: The accelerated approval of rucaparib for the treatment of adult patients with deleterious BRCA mutation (germline and/or somatic)-associated metastatic castrate-resistant prostate cancer who have been treated with androgen receptor-directed therapy and a taxane represents the first approved therapy for this selected patient population. This approval was based on a single-arm trial demonstrating a confirmed objective response rate greater than that of available therapy with a favorable duration of response and an acceptable toxicity profile. The ongoing trial TRITON3 is verifying the clinical benefit of this drug.

Circulating cell-free nucleic acids as prognostic and therapy predictive tools for metastatic castrate-resistant prostate cancer

Metastatic castrate-resistant prostate cancer remains a disease hard to cure, and for this reason predictive tools to monitor disease progression and therapy response are an urgent need. In this respect, liquid biopsy on circulating cell-free nucleic acids represents an interesting strategy based on robust data. The low invasiveness and the possibility to target circulating cell-free tumor deoxyribonucleic acid underline the high specificity, sensitivity and clinical usability of the technique. Moreover, it has been observed that the cell-free tumor deoxyribonucleic acid of metastatic castrate-resistant prostate cancer patients can be representative of the tumor heterogeneity. Cell-free tumor deoxyribonucleic acids express the same behaviors as mutations: Variation in gene copy number or the methylation rate of the tumor tissue. Recently, circulating cell-free ribonucleic acid molecules have emerged as interesting markers to stratify the disease. Due to high-throughput technologies, liquid biopsy on circulating cell-free nucleic acids will soon be utilized in the clinical management of metastatic castrate-resistant prostate cancer patients.

Randomized phase 2 therapeutic equivalence study of abiraterone acetate fine particle formulation vs. originator abiraterone acetate in patients with metastatic castration-resistant prostate cancer: The STAAR study

BACKGROUND

This multicenter, randomized, open-label, active-controlled study evaluated therapeutic equivalence, steady-state pharmacokinetics, and safety of a novel abiraterone acetate fine particle formulation (AAFP) 500mg plus methylprednisolone vs. the originator AA (OAA) 1000mg plus prednisone in men with metastatic castrate-resistant prostate cancer (mCRPC). The primary endpoint was a comparison of average of serum testosterone levels on treatment days 9 and 10 between groups.

METHODS

Men with progressive mCRPC, receiving gonadotropin-releasing hormone agonist or antagonist therapy, and with a serum testosterone level of <50ng/dl were randomized 1:1 to either AAFP 500mg daily plus 4mg methylprednisolone orally twice daily (BID), or OAA 1000mg daily plus 5mg prednisone BID for 84 days. Serum testosterone, serum prostate-specific antigen (PSA), steady-state (trough) abiraterone pharmacokinetics, and safety were evaluated.

RESULTS

Fifty-three patients were enrolled (n = 24, AAFP; n = 29, OAA). Mean age was 75.1 years and 54.7% had Gleason>7. Over 90% of patients in each group achieved absolute testosterone levels of ≤1ng/dl during the study. The averaged absolute testosterone levels ≤0.1ng/dl were achieved in 25% of AAFP-treated patients and 17% of OAA-treated patients. A PSA-50 response was observed in>65% of patients in both groups on days 28, 56, and 84 (P = NS, all timepoints). Days 9 and 10 averaged rounded-up least squares (LS) mean (SE) serum testosterone levels were comparable (1.05ng/dl [0.04], AAFP; 1.02ng/dl [0.03], OAA; P = 0.4703 for LS mean difference). The geometric mean ratio between groups was 1.021 (90% CI: 0.965-1.081); the 90% CI fell within 80.0% to 125.0% equivalence limits. The LS mean differences in abiraterone trough plasma concentrations were not statistically significant at any visit. Adverse event frequency was comparable between arms (75.0%, AAFP; 82.8%, OAA). Musculoskeletal events were more common among OAA-treated patients (37.9% vs. 12.5%).

CONCLUSION

Therapeutic equivalence between AAFP 500mg daily and OAA 1000mg daily based on serum testosterone levels was confirmed in mCRPC patients. Both agents led to similar PSA-50 response rates. Abiraterone trough levels were similar between treatments. No new safety concerns were observed.

Predictive value of stathmin-1 and osteopontin expression for taxan resistance in metastatic castrate-resistant prostate cancer

Objective:

Several pathways are known to be activated during metastasis and treatment of cancer. We investigated the role of osteopontin (OPN) and stathmin-1 (STHMN1) in metastatic castrate-resistant (mCRPC).

Methods:

We included 30 patients who received at least 6 cycles of taxane regimen for metastatic mPC in the present study. For this study retrospective data was taken from Firat University, Faculty of Medicine, Medical Oncology Department between 2009 and 2015. OPN expression and STHMN1 expression were retrospectively evaluated by immunohistochemical staining in biopsy specimens. The relationship between the expression levels of OPN and STMN1 and the response to taxane based regimen and survival was analyzed.

Results:

There was mild or strong overexpression of OPN and STHMN1 in all the patients. STHMN1 expression was mildly positive (+2) in four of the cases (13.2%) while it was strongly positive (+3) in 25 (83.4%) cases. Similarly, OPN expression was mildly positive (+2) and strongly positive (+3) in five (16.6%) and 25 (87.4%) patients, respectively. There was no significant correlation between the expression levels of STHMN1 and OPN, survival, and response to taxane based regimen (p>0.05); however, OPN overexpression showed a significant correlation with lower Gleason scores (GS) (p:0.032).

Conclusions:

STHMN1 and OPN may be prognostic markers although they are not predictive markers of response to treatment in mCRPC. The overexpression of OPN may help identifying patients with lower GS.

Long-term complete remission with Ipilimumab in metastatic castrate-resistant prostate cancer: case report of two patients

BACKGROUND

Prostate cancer is one of the most common cancers in men and the fourth leading cause of cancer mortality worldwide. Although major progress has been achieved in the last years for patients with metastatic castrate-resistant prostate cancer (mCRPC), thanks to next-generation androgen receptor axis targeted drugs, taxanes, and bone-targeted agents, immunotherapy has not been widely approved and used for the treatment of prostate cancer. Two large studies with ipilimumab, an anti-CTLA-4 (cytotoxic T-lymphocyte antigen 4) antibody reported improved progression-free survival, but not statistically improved overall survival at the primary analysis (CA184 043 and CA184 095).

CASE PRESENTATION

Here, we report on two patients who received ipilimumab in these trials and are still in long-term complete remission with a follow-up of 64 and 52 months respectively after the initiation of ipilimumab. Immunohistochemical staining for hMLH1, hMSH2, hMSH6 and PMS2 was performed on archival prostate biopsy samples from one of the two patients; they exhibited normal protein expression. Interestingly for this patient, a high CD3+ and CD8+ T cell infiltration was observed on archival prostate biopsies as well as Treg FoxP3+ T cells.

CONCLUSION

Ipilimumab produces clinical activity in patients with CRPC, including very long responders with no detectable residual disease.

Rationale for Modernising Imaging in Advanced Prostate Cancer

CONTEXT

To effectively manage patients with advanced prostate cancer (APC), it is essential to have accurate, reproducible, and validated methods for detecting and quantifying the burden of bone and soft tissue metastases and for assessing their response to therapy. Current standard of care imaging with bone and computed tomography (CT) scans have significant limitations for the assessment of bone metastases in particular.

OBJECTIVE

We aimed to undertake a critical comparative review of imaging methods used for diagnosis and disease monitoring of metastatic APC from the perspective of their availability and ability to assess disease presence, extent, and response of bone and soft tissue disease.

EVIDENCE ACQUISITION

An expert panel of radiologists, nuclear medicine physicians, and medical physicists with the greatest experience of imaging in advanced prostate cancer prepared a review of the practicalities, performance, merits, and limitations of currently available imaging methods.

EVIDENCE SYNTHESIS

Meta-analyses showed that positron emission tomography (PET)/CT with different radiotracers and whole-body magnetic resonance imaging (WB-MRI) are more accurate for bone lesion detection than CT and bone scans (BSs). At a patient level, the pooled sensitivities for bone disease by using choline (CH)-PET/CT, WB-MRI, and BS were 91% (95% confidence interval [CI], 83-96%), 97% (95% CI, 91-99%), and 79% (95% CI, 73-83%), respectively. The pooled specificities for bone metastases detection using CH-PET/CT, WB-MRI, and BS were 99% (95% CI, 93-100%), 95% (95% CI, 90-97%), and 82% (95% CI, 78-85%), respectively. The ability of PET/CT and WB-MRI to assess therapeutic benefits is promising but has not been comprehensively evaluated. There is variability in the cost, availability, and quality of PET/CT and WB-MRI.

CONCLUSIONS

Standardisation of acquisition, interpretation, and reporting of WB-MRI and PET/CT scans is required to assess the performance of these techniques in clinical trials of treatment approaches in APC.

PATIENT SUMMARY

PET/CT and whole-body MRI scans have the potential to improve detection and to assess response to treatment of all states of advanced prostate cancer. Consensus recommendations on quality standards, interpretation, and reporting are needed but will require validation in clinical trials of established and new treatment approaches.

Treatment landscape of metastatic prostate cancer: the role of radium-223

The landscape of metastatic prostate cancer has changed recently with the availability of six new molecules showing an overall survival benefit. The development of compounds able to decrease the rate of complications from bone metastasis has also led to improvements in overall morbidity associated with this disease. In this paper, we briefly review the currently available drugs indicated in the treatment of metastatic prostate cancer, focusing on the place of the radiopharmaceutical agent radium-223 and its very unique mechanism of action and safety profile.

METastasis Reporting and Data System for Prostate Cancer: Practical Guidelines for Acquisition, Interpretation, and Reporting of Whole-body Magnetic Resonance Imaging-based Evaluations of Multiorgan Involvement in Advanced Prostate Cancer

CONTEXT

Comparative reviews of whole-body magnetic resonance imaging (WB-MRI) and positron emission tomography/computed tomography (CT; with different radiotracers) have shown that metastasis detection in advanced cancers is more accurate than with currently used CT and bone scans. However, the ability of WB-MRI and positron emission tomography/CT to assess therapeutic benefits has not been comprehensively evaluated. There is also considerable variability in the availability and quality of WB-MRI, which is an impediment to clinical development. Expert recommendations for standardising WB-MRI scans are needed, in order to assess its performance in advanced prostate cancer (APC) clinical trials.

OBJECTIVE

To design recommendations that promote standardisation and diminish variations in the acquisition, interpretation, and reporting of WB-MRI scans for use in APC.

EVIDENCE ACQUISITION

An international expert panel of oncologic imagers and oncologists with clinical and research interests in APC management assessed biomarker requirements for clinical care and clinical trials. Key requirements for a workable WB-MRI protocol, achievable quality standards, and interpretation criteria were identified and synthesised in a white paper.

EVIDENCE SYNTHESIS

The METastasis Reporting and Data System for Prostate Cancer guidelines were formulated for use in all oncologic manifestations of APC.

CONCLUSIONS

Uniformity in imaging data acquisition, quality, and interpretation of WB-MRI are essential for assessing the test performance of WB-MRI. The METastasis Reporting and Data System for Prostate Cancer standard requires validation in clinical trials of treatment approaches in APC.

PATIENT SUMMARY

METastasis Reporting and Data System for Prostate Cancer represents the consensus recommendations on the performance, quality standards, and reporting of whole-body magnetic resonance imaging, for use in all oncologic manifestations of advanced prostate cancer. These new criteria require validation in clinical trials of established and new treatment approaches in advanced prostate cancer.

Sipuleucel-T for the Treatment of Patients With Metastatic Castrate-resistant Prostate Cancer: Considerations for Clinical Practice

Sipuleucel-T treatment is associated with a significant and consistent survival benefit in patients with metastatic castrate-resistant prostate cancer. Most adverse events are infusion related, manageable, and of short duration. Early screening and diagnosis of metastatic disease is important, as the greatest survival benefit may occur in patients with a lower disease burden. The short duration of sipuleucel-T treatment facilitates the use of subsequent therapies. Sipuleucel-T is now being used in the clinic for patients with a lower disease burden. We present our own experience with the use of sipuleucel-T in the setting of a large urology practice.

Emerging Therapeutic for the Treatment of Skeletal-related Events Associated With Metastatic Castrate-resistant Prostate Cancer

Prostate cancer is the most prevalent cancer in US and European men and the second leading cause of cancer death in those populations. It is somewhat unique in that nearly all patients who succumb to the disease will ultimately develop bone metastasis. Morbidity from bone metastasis-referred to as skeletal-related events, which include fractures, cord compression, radiation to bone, and surgery to bone-leads to significant costs and impaired quality of life. This article reviews three agents and the roles they play in the ever-changing armamentarium of treatments for metastatic castrate-resistant prostate cancer (mCRPC). The potential benefits of these agents are discussed, as well as the continuing use of these agents and their earlier introduction in the patient with progressive mCRPC with bone metastasis.

Cabazitaxel in patients with metastatic castration-resistant prostate cancer: results of a compassionate use program in the Netherlands

BACKGROUND

Cabazitaxel has been reimbursed as a second-line therapy for patients with metastatic castrate-resistant prostate cancer (mCRPC) in the Netherlands since 2011. Before reimbursement was available, cabazitaxel was provided through a Compassionate Use Program (CUP). We report the results of the Dutch CUP, detailing the safety and efficacy of cabazitaxel in a routine clinical practice setting.

PATIENTS AND METHODS

Safety and efficacy data of all 5 Dutch centers participating in the cabazitaxel CUP were collected. Safety data were collected prospectively using the National Cancer Institute Common Toxicity Criteria for Adverse Events, version 3.0. Overall survival (OS) and progression-free survival (PFS), time to PSA progression (TTPP), and best clinical response were evaluated retrospectively.

RESULTS

Fifty-one patients were registered in the CUP; 49 received cabazitaxel. Forty-two of 49 patients [85.7%], 42 patients had ≥ 2 metastatic sites. Patients received on average 6 cabazitaxel cycles (range, 1-21). A dose reduction or dose delay occurred in 13 and 20 patients [26.5% and 40.9%] respectively. Prophylactic granulocyte colony-stimulating factor (G-CSF) was used in 8 patients [16.3%]. Grade ≥ 3 adverse events were observed in 25 patients [51.0%]; 16 patients [32.7%] discontinued treatment because of treatment-emergent adverse events (TEAEs). Serious adverse events (SAEs) occurred in 16 (32.7%) patients; the most frequent SAEs were hematuria (4 patients [8.3%]) and urosepsis (3 patients [6.3%]). Febrile neutropenia occurred twice; no patient had grade ≥ 3 neuropathy. No toxicity-related mortality occurred. Median follow-up was 24.1 months. Median OS was 8.7 months (interquartile range [IQR], 6.0-15.9 months); median TTPP was 2.8 months (IQR, 1.7-5.9 months).

CONCLUSION

In the Dutch CUP, patients with advanced mCRPC had delayed tumor progression with acceptable toxicities using cabazitaxel treatment.