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`Amerigen Exhibit 1140
`Amerigen v. Janssen IPR2016-00286
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`Publisher: Taylor & Francis
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`Journal: Expert Review of Anticancer Therapy
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`DOI: 10.1080/14737140.2016.1241148
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`Review
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`Therapeutic management of bone metastasis in prostate cancer: an update
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`Fable Zustovich1 and Davide Pastorelli2
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`1Oncologia Medica, ULSS 1 Belluno, Italy
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`2Oncologia Medica, ULSS 2 Feltre, Italy
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`Corresponding author
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`Fable Zustovich
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`Oncologia Medica ULSS 1,
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`Belluno, Italy
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`E-mail: fable.zustovich@ulss.belluno.it
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`Phone: +39043751615
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`Fax: ++390437516522
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`

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`Abstract
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`Introduction: Bone metastases affect the majority of patients with castration-resistant prostate
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`cancer (CRPC), resulting in significant morbidity and mortality. This review describes the current
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`therapies available for the management of CRPC patients with bone metastases.
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`Areas covered: Studies on the use of currently available therapeutic approaches for palliating pain,
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`delaying skeletal-related events (SREs) and prolonging survival in CRPC patients with bone metastases
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`have been examined. PubMed database was searched in May 2016 starting with the following
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`keywords: ("castration-resistant prostate cancer" OR "CRPC") AND "bone metastases", and
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`approximately 270 results were retrieved. More specific searches were then performed on the
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`epidemiology and molecular pathogenesis (in particular, "vicious cycle" was used as a keyword), the
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`management of pain, SREs and survival. The following keywords were also used individually:
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`abiraterone, cabazitaxel, denosumab, docetaxel, enzalutamide, radium-223, sipuleucel-T, samarium-
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`153, strontium-89, zoledronate. Randomized-controlled trials, observational studies, reviews,
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`systematic reviews and meta-analyses were selected and articles were excluded if not in English.
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`Expert Commentary: Currently, clear recommendations on the optimal use of the agents available to
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`treat mCRPC are lacking. Therefore, to ensure patients the best treatment, both their clinical
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`characteristics and the features of each product have to be considered.
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`
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`Keywords: Abiraterone; bone metastases; cabazitaxel; castration-resistant prostate cancer;
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`denosumab; docetaxel; enzalutamide; radium-223; zoledronate.
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`

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`1. Introduction
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`
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`Prostate cancer (PCa) is the second most common type of cancer in men and accounts for nearly 20%
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`of all newly diagnosed male tumors. In the US, 180,890 new cases have been estimated to be
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`diagnosed in 2016 and 26,120 men to die of this disease [1].
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`At diagnosis, approximately 80% of patients present with localized PCa and 4% with distant
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`metastases, the 5-year relative survival rate being 100% and 28% respectively [1].
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`Due to PCa cell growth dependance on androgens, recurrent or metastatic disease is managed with
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`surgical or pharmaceutical castration. Indeed, androgen deprivation therapy (ADT) is the mainstay
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`therapy in metastatic PCa, with response observed in 80-90% of cases. However, nearly all men
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`eventually progress within one to three years leading to castration-resistant PCa (CRPC) [2]. The
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`majority of patients with metastatic CRPC (mCRPC) develop bone metastases [3] resulting in a
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`significant increase in morbidity and mortality [4,5]. Morbidity and impact on quality of life (QoL) are
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`due to the increased risk of bone fractures, bone pain, nervous tissue compressions and
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`hypercalcemia [5,6]. These complications, collectively referred to as skeletal-related events (SREs),
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`are associated with impaired mobility, general suffering, reduced self-sufficiency, poor QoL,
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`increased mortality, and increased health care costs [7–9].
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`Greater insight into the pathophysiology of bone metastases has led to the development of new
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`bone-targeted agents aimed at reducing the rate of SREs and prolonging survival. While the number
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`of available treatments that yield significant benefit in these patients has increased in recent years
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`[10], initial survival benefit was observed only with docetaxel-based chemotherapy [11,12].
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`Therefore, it was approved by FDA in 2004. Since 2010, five new agents have emerged following
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`phase III studies that have also gained FDA approval. These therapies include the CYP17 lyase
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`inhibitor abiraterone acetate, the antiandrogen enzalutamide, the microtubule stabilizer cabazitaxel,
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`and the radiopharmaceutical radium(cid:1086)223 [13,14]. Although these drugs act through different
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`mechanisms on different targets, they have been shown to be able to further prolong survival in
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`chemo-naïve patients treated previously with docetaxel [15].
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`The aim of this review is to describe the current therapies available for patients with CRPC and bone
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`metastases.
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`2. CRPC and mCRPC: epidemiology, natural history and prognosis
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`Two phase III randomized trials investigated the natural history of nonmetastatic CRPC patients
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`included in the respective placebo arms [16,17]. Results showed that 33% [16] and 46% of [17] men
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`had developed bone metastasis and 21% [16] and 20% [17] had died within 2 years from study entry.
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`Also, a systematic review analyzing data from 71,179 patients observed for up to 12 years reported
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`that 10-20% of PCa patients had experienced progression to CRPC within approximately 5 years and,
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`at the time of CRPC diagnosis, (cid:1096)84% already presented with bone metastases and 33% of those
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`without developed them within 2 years [18]. mCRCP patients had a shorter survival than CRPC cases
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`(9-13 months vs. 9-30 months, respectively) and suffered from a rapid deterioration of QoL, with
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`frequently reported pain and SREs such as bone fractures and spinal cord compression [18].
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`Pain can occur in each stage of PCa, although its incidence increases up to 90% during the terminal
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`phase of disease [19]. SREs occur in 44% to 80% of PCa men with bone metastases [20–22], but their
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`incidence and severity have been also linked to endocrine therapy [23] and ADT [24]. SREs and bone
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`metastases negatively affect overall survival (OS). Indeed, it has been reported that the 1- and 5-year
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`survival rate in PCa patients without bone metastasis is 87% and 56%, respectively, vs. 47% and 3% in
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`those with bone metastasis and 40% and <1% in those with bone metastasis and SREs [20]. The
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`presence of bone metastases increased the risk of death (hazard ratio [HR]=6.6, 95% confidence
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`interval [CI] 6.4-6.9 [21]), which was further worsened by concomitant SREs (HR=10.2, 95% CI 9.8-
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`10.7) [21]). Moreover, the site (axial vs appendicular) [25] and number of sites of bone metastases
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`[26], together with the time from initial diagnosis to first bone metastasis [27], pain intensity, SREs
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`and bone turnover markers [26,28,29] (the latter being predictors also of the risk of SREs
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`development [28,30]) have been shown to be predictors of survival in mCRPC patients.
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`Since men with or without bone metastases have distinct therapeutic options, especially if receiving
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`ADT, the correct, early detection of bone metastasis is important to promptly ensure the most
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`adequate treatment [31]. However, metastatic disease can be misdiagnosed as a result of the
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`insufficient detection limit of standard radiologic imaging [32,33]. Hence, new molecular imaging
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`techniques have been developed, such as magnetic resonance imaging (MRI) of the axial skeleton,
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`PET imaging, and whole-body MRI [32–35]. It is worth noting that in 2015 the Prostate Cancer Clinical
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`Trials Working Group 3 (PCWG3) has advised to increase, in clinical trials conducted in mCRPC
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`patients, the frequency of imaging assessment (by bone scans or CT/MRI) from every 12 weeks to
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`every 8-9 weeks for the first 24 weeks and then every 12 weeks [36].
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`3. Pathogenesis of bone metastases
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`
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`Bone metastases display areas of both osteoblastic and osteoclastic (i.e. osteolysis) activity [37],
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`which result in bone frailty, weakened structural integrity and SREs. Hence, understanding the
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`pathogenesis of metastatic disease is of the utmost importance for treatment. In this process, the
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`complex interaction between tumor cells and bone microenvironment plays a central role. Under
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`normal conditions, skeletal integrity is maintained through the dynamic interplay of osteoclasts,
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`deriving from hematopoetic stem cells (HSC) and osteoblasts, from stromal stem cells [38]. After
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`adhering to the bone, osteoclasts form a resorption cavity and release chemotactic cytokines that
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`

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`
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`attract osteoblasts. Once in the resorprion cavity, osteoblasts produce bone matrix and express the
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`receptor activator of nuclear factor-kB ligand (RANKL), which is a key mediator of
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`osteoclasteogenesis. Indeed, upon binding to the RANK transmembrane receptor on osteoclast
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`surface, osteoclasts express mediators of differentiation and survival (e.g. Src), bone adherence and
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`bone catabolism (e.g. cathepsin K). The balance between bone formation and resorption is
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`maintained by the decoy receptor osteoprotegerin (OPG), expressed by osteoblasts, that blocks
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`RANKL, preventing osteoclast activation. In the metastatic cascade (Figure 1), tumor cells home to
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`the bone and adhere to the bone matrix via the interaction between chemokine receptor-4 (CXCR4)
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`on their surface and stromal cell-derived factor 1 (SDF-1) secreted by osteoblasts, competing with
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`HSCs for the place in the bone marrow niche (i.e. onco-niche) [39]. Once established within the bone
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`microenvironment, tumor cells may remain dormant or proliferate. In the latter case, they secrete
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`paracrine mediators that stimulate osteoblasts and stromal cells to proliferate, differentiate, and
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`produce growth factors (e.g. parathyroid hormone-related peptide that induces RANKL expression,
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`interleukin-1 [IL-1] and IL-6). Abnormal levels of RANKL promote excessive activity of osteoclasts that
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`degrade the bone matrix and release, among others, fibroblast growth factor, transforming growth
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`factor-(cid:628) and tumor necrosis factor-(cid:626), which promote the growth and survival of tumor cells, thus
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`completing the so-called “vicious circle” [40]. In this process, the expression levels of RANKL, RANK
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`and OPG correlate with aggressive, metastatic PCa. Besides, recent in vitro and in vivo studies have
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`highlighted the role of different miRNAs [41,42], osteogenic transcription factor Runx2 [43], cyclin A1,
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`P450 aromatase [44] and contactin 1 [45] in CRPC progression and metastasization.
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`4. Pain palliation
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`Standard treatment of symptomatic metastatic bone pain relies on external beam radiation therapy
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`(EBRT) [46], localized at the painful area at risk of fracture, and radiopharmaceuticals combined with
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`analgesics (opioids or nonsteroidal anti-inflammatory drugs [NSAIDs]) [47]. Although EBRT is effective
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`in relieving pain and improving QoL in most patients, pain progression often occurs and retreatment
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`may be required [48,49]. Men with multifocal bone disease not eligible for EBRT are managed with
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`the radiopharmaceuticals strontium-89 chloride (Sr-89) and samarium-153 (Sm-153). Sr-89 is a pure
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`(cid:628)-emitter calcium-mimetic, with a half-life of 50.5 days and a penetration energy of 2.4 mm, while
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`Sm-153 is a chelating agent that emits also (cid:630)-particles, with a half-life of 1.9 days and a penetration
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`energy of 0.6 mm [50]. Both agents are incorporated into areas of high bone turnover (i.e. metastatic
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`sites with high osteoblastic activity) where (cid:628)-particles induce cancer cell death by DNA single-strand
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`breaks. Both radiopharmaceuticals are indicated for pain palliation in mCRPC patients with bone
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`metastases [50]. Symptom improvement has been reported in 55-80% of patients, with response
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`duration of 2-17 weeks [51,52]. However, despite a reduction in pain and analgesis needed, severe
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`adverse effects (AEs, mostly transient myelosuppression) are common [53]. For this reason, and
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`because they did not provide OS and PFS prolongation, nor SREs or QoL improvement, their use in
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`clinical practice is actually limited [54,55]. Finally, despite, in 2005, a qualitative systematic review
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`reported the increased effectiveness of NSAIDs, alone or combined with opioids, for the treatment of
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`cancer pain [47], it was recently withdrawn by the authors because, although correct at the time of
`
`publication, it is out of date and new reports are awaited [56].
`
`

`
`
`
`
`
` 5. Prevention of skeletal complications
`
`
`
`5.1 Zoledronic acid
`
`Zoledronic acid is a third-generation bisphosphonate and the first agent approved for the
`
`management of bone metastases in patients with CRPC [57]. Bisphosphonates show a chemical
`
`structure similar to the normal component of bone matrix pyrophosphate, are absorbed and bind to
`
`hydroxyapatite crystals causing inhibition of bone reabsorption by osteoclasts [58]. Zoledronic acid is
`
`the only bisphosphonate that has demonstrated significant efficacy and long-term clinical benefit by
`
`preventing SREs in PCa patients [59,60]. The administration of zoledronic acid (4 mg every 3 weeks)
`
`versus placebo in 643 mCRPC patients resulted in a reduction of the rate of patients having at least 1
`
`SRE (33% vs. 44%; P=0.021). It also displayed consistent efficacy across all secondary endpoints (time
`
`to the first SRE, skeletal morbidity rate, proportion of patients with individual SRE events, time to
`
`disease progression, objective bone lesion response, bone biochemical markers, and QoL) and
`
`improvements of pain and analgesia scores [61]. Pain scores and the use of analgesic drugs favored
`
`zoledronic acid, but there were no differences in disease progression or OS [22]. Based on the
`
`findings from this study, zoledronic acid was subsequently approved by the US and European
`
`regulatory authorities for the prevention of SREs in patients with prostate, breast, and lung cancer.
`
`In the past few years, several other trials have examined the use of zoledronic acid in CRPC patients
`
`with varying degrees of success. The TRAPEZE trial assessed the efficacy of zoledronic acid or Sr-89 on
`
`top of docetaxel in 757 patients [62]. Sr-89 combined with docetaxel improved clinical progression-
`
`free survival (PFS) but did not improve OS, SRE-free interval, or total SREs. Furthermore, zoledronic
`
`acid did not prolong PFS or OS but did significantly improve median SRE-free interval and reduced
`
`total SREs by about 30%.
`
`

`
`
`
`
`
`Other trials have also examined the benefit afforded by zoledronic acid in patients with earlier stages
`
`of CRPC. The CALGB90202 phase III trial compared the effect of zoledronic acid vs. placebo in
`
`castration-sensitive PCa patients with the aim of detecting a reduction in the risk of first SRE [63].
`
`Zoledronic acid was not associated with increased time to first SRE, the median time to first SRE being
`
`31.9 months in the zoledronic acid group and 29.8 months in the placebo group. OS and rates of AEs
`
`were similar between the two groups. In the STAMPEDE trial, a randomized controlled multiarm,
`
`multistage trial, the addition of zoledronic acid to ADT in hormone-naïve patients did show no
`
`significant benefit in time to first SRE, in the entire population or in the subgroup of patients with
`
`bone metastases [64]. The authors concluded that zoledronic acid showed no evidence of survival
`
`improvement and should therefore not be part of standard of care for this population [64]. Finally,
`
`the ZEUS study investigated the efficacy of zoledronic acid for the prevention of bone metastasis in
`
`high-risk non-metastatic PCa patients receiving ADT [65]. Zoledronic acid administered every 3
`
`months was found to be ineffective for the prevention of bone metastases in high-risk localized PCa
`
`patients at 4 years (proportion of bone metastasis was 14.7% with zoledronic acid vs. 13.2% in the
`
`control group). On the basis of evidence from these trials, CRPC is the only setting where zoledronic
`
`acid has been shown to have proven efficacy in the management of bone metastases.
`
`
`
`5.2 Denosumab
`
`RANKL is the main driver of osteoclast formation, function, and survival [66]. Denosumab is a fully
`
`human monoclonal antibody directed against RANKL inhibiting osteoclast-mediated bone
`
`destruction, decreasing bone reabsorption and increasing bone mass [67]. This agent is administered
`
`quickly via subcutaneous injection compared to zoledronic acid, which is administered intravenously
`
`over a period of 30 minutes.
`
`

`
`
`
`
`
`The HALT prostate cancer trial was undertaken in patients undergoing ADT and demonstrated the
`
`ability of denosumab (60 mg every 6 months) to avoid bone tissue density depletion and to reduce
`
`the incidence of new spine fractures compared with placebo. This study did not demonstrate any
`
`significant benefit in OS with denosumab [67].
`
`Another second phase III trial enrolled 1,904 patients with mCRPC, compared denosumab (120 mg
`
`administered subcutaneously every 4 weeks) with zoledronic acid (4 mg intravenously every 3 weeks)
`
`[68]. Denosumab improved the median delay in time to first SRE by 3.6 months (20.7 months vs 17.1
`
`months; HR=0.82; P<0.001 for noninferiority, P=0.008 for superiority). The two groups had similar OS
`
`and time to disease progression. OS, disease progression, and rates of AEs and serious AEs were
`
`similar in the 2 groups. However, an increased incidence of hypocalcemia (13% in the denosumab
`
`group vs 6% in the zoledronic acid group(cid:673) P<0.0001) was observed. Based on results from this trial,
`
`denosumab gained FDA approval for the treatment of mCRPC patients with bone metastases. A post-
`
`hoc analysis of this phase III trial [68] subsequently showed that denosumab reduced the risk of
`
`symptomatic skeletal-related events (SSEs) compared to zoledronic acid [69]. Denosumab therapy
`
`significantly reduced the risk of developing the first SSE [HR=0.78; 95% CI, 0.66–0.93; P=0.005] and
`
`first and subsequent SSEs (rate ratio=0.78; 95% CI, 0.65–0.92; P=0.004) compared to zoledronic acid.
`
`Another phase III trial examined the effect of denosumab (120 mg subcutaneously, every 4 weeks) or
`
`placebo in bone-metastasis-free survival in 1,432 men at high risk of developing bone metastasis
`
`(defined as elevated PSA of (cid:1096)8.0 ng/mL or those with short PSA doubling time [PSADT] of (cid:1095)10.0
`
`months or both) [70]. Although no difference in OS or PFS was seen between groups, denosumab
`
`significantly increased bone-metastases-free survival by 4.2 months (29.5 vs. 25.2 months, HR=0.85;
`
`95% CI, 0.73–0.98; P=0.028).
`
`More recently, a post-hoc analysis of 3 phase III randomized trials compared the effect of zoledronic
`
`acid to denosumab in preventing SREs in patients with bone metastases [71]. This analysis included a
`
`

`
`
`
`
`
`total of 5,543 patients, of which 1901 had PCa. This analysis demonstrated that denosumab
`
`administered every 4 weeks was superior to zoledronic acid in preventing SREs in all patients with
`
`metastatic bone disease, regardless of their baseline characteristics of ECOG performance status,
`
`number of bone metastases, presence or absence of visceral metastases, and urinary N-telopeptide
`
`(uNTx) level [71].
`
`Another post-hoc analysis by the same authors of 3 identical phase III trials demonstrated that uNTx
`
`and serum bone-specific alkaline phosphatase (sBSAP) levels ((cid:1096)median levels, compared with
`
`<median levels), after 3 months of treatment with denosumab or zoledronic acid were associated
`
`with reduced OS (HR for death=1.85, P<0.0001 and HR=2.44, P<0.0001, respectively), increased risk
`
`of disease progression (HR=1.31, P<0.0001 and HR=1.71, P<0.0001, respectively) and disease
`
`progression in bone (HR=1.11, P=0.041 and HR=1.27, P<0.0001, respectively) [72]. These recent
`
`findings suggest that uNTx and sBSAP may be considered as noninvasive, early predictors for
`
`response and survival in patients with advanced cancer and bone metastases receiving bone
`
`antiresorptive agents.
`
`
`
`6. Survival benefit
`
`
`
`6.1 Docetaxel
`
`Docetaxel is a taxane (i.e. mitotic inhibitor) approved by the FDA in 2004 for the treatment of mCRPC
`
`in combination with prednisone. Indeed, the TAX 327 randomized phase III trial compared the
`
`efficacy and safety of docetaxel (every 3 weeks or weekly) plus prednisone (n=335 and 334,
`
`respectively) to mitoxantrone plus prednisone (n=337) [11]. Docetaxel every 3 weeks yielded longer
`
`median OS compared to weekly docetaxel and control treatment (18.9, 17.4 and 16.5 months,
`
`respectively), and these results were subsequently confirmed in an updated analysis of median OS
`
`

`
`
`
`
`
`[73]. The HR for death was 0.76 (95% CI 0.62-0.94; P=0.009) upon docetaxel every 3 weeks and 0.91
`
`(95% CI 0.75-1.11; P=0.36) upon weekly docetaxel [11]. A significantly better response in terms of
`
`pain, serum PSA level and QoL was observed in docetaxel-treated men compared to those given
`
`mitoxantrone plus prednisone. However, they also experienced more AEs. In particular, despite the
`
`rate of grade 3-4 anemia and thrombocytopenia was low (range: 0-5%) and similar among treatment
`
`groups, the frequency of grade 3-4 neutropenia was significantly higher among patients treated with
`
`docetaxel every 3 weeks compared to those receiving mitoxantrone (32% vs. 22%, respectively;
`
`P<0.05). On the contrary, the latter group experienced significantly more frequently grade 3-4
`
`neutropenia than patients receiving weekly docetaxel (22% vs. 2%, P<0.0015) [11]. In the SWOG 9916
`
`randomized phase III trial, survival prolongation was observed in mCRPC patients treated with
`
`docetaxel (every 3 weeks) plus estramustine (n=338) versus mitoxantrone plus prednisone (n=336)
`
`(17.5 vs. 15.6 months, P=0.02; death HR=0.80; 95 % CI 0.67-0.97) [12]. In the docetaxel arm, time to
`
`progression was significantly longer than in the control arm (6.3 vs 3.2 months, P<0.001) but pain
`
`relief was similar and bone marrow toxicity more severe [12].
`
`Finally, the impact of early docetaxel treatment in association with hormone-therapy was recently
`
`examined in three randomized phase III trials [64,74,75]. The GETUG-AFU 15 study randomized 385
`
`men with metastatic, hormone-sensitive PCa (mHSPC) to receive ADT plus docetaxel (n=192) or ADT
`
`alone (n=193). Median OS was not significantly improved upon docetaxel (58.9 vs 54.2 months,
`
`HR=1.01; 95% CI 0.75-1.36), not even with long-term follow-up (60.9 vs 46.5 months; HR=0.9; 95% CI
`
`0.7-1.2; P=0.44). However, results from the CHAARTED trial, that randomized 790 mHSPC men to
`
`receive either ADT plus docetaxel or ADT alone, showed that, in the combination-treated group, the
`
`median OS was 13.6 months longer than in the ADT group (57.6 months vs. 44.0 months; HR for
`
`death in the combination group =0.61; 95% CI 0.47-0.80; P<0.001) [75]. Moreover, the STAMPEDE
`
`trial randomized 2,962 men with either high-risk localized (24%), node-positive (15%), or mHSPC
`
`

`
`
`
`
`
`(61%) to receive ADT alone, ADT plus docetaxel, ADT plus zoledronic acid or ADT plus zoledronic acid
`
`and docetaxel. Unlike zoledronic acid, the addition of docetaxel significantly prolonged OS compared
`
`to ADT only (81 vs 71 months, HR=0.78; 95% CI 0.66-0.93; P=0.006) [64].
`
`Therefore, while the benefit provived by docetaxel in terms of OS is well documented, no clear
`
`evidence exists on its effect on pain and the delay or prevention of SREs in bony mCRPC. In this
`
`regard, a recent phase III trial demonstrated that docetaxel in combination with zoledronic acid
`
`improved median SRE-free interval and reduced total SREs by approximately 30% [62], but further
`
`results are warranted.
`
`
`
`6.2 Cabazitaxel
`
`Cabazitaxel is a semi-synthetic taxane that received FDA approval in 2010 to be used in combination
`
`with prednisone for the treatment of mCRPC men previously on docetaxel. Approval was based on
`
`results from an open-label phase III study (TROPIC) conducted in mCRPC patients (25% with visceral
`
`and 84% with bone metastases) relapsed after first-line docetaxel and randomized to cabazitaxel plus
`
`prednisone (n=378) or mitoxantrone plus prednisone (n=377) [76]. Cabazitaxel yielded a significantly
`
`prolonged median survival compared to control treatment (15.1 vs 12.7 months, P<0.0001), with a
`
`death HR=0.70 (95% CI 0.59-0.83, P<0.0001) that was similar to that of patients suffering from pain at
`
`baseline (45%) (HR=0.76; 95% CI 0.59-0.98). Median PFS was also significantly improved in the
`
`experimental arm, being 2.8 vs 1.4 months (HR=0.74; 95% CI 0.64-0.86; P<0.0001). No improvement
`
`in pain relief was observed by either treatments. The most common clinically significant grade (cid:1096)3 AEs
`
`were neutropenia and diarrhea; 7 deaths (2% of the total) were recorded for septic neutropenia in
`
`the cabazitaxel arm [76]. A subsequent update of this trial demonstrated that, compared to
`
`mitoxantrone, this taxane could prolong OS at 2 years (odds ratio=2.11; 95% CI 1.33-3.33) but
`
`provided similar palliation benefits [77]. In line with these results, a recent review of randomized
`
`

`
`
`
`
`
`trials evaluating mCRPC patient-reported outcomes since 2010 found no meaningful impact of
`
`cabazitaxel on pain and QoL [78]. Analysis of the QoL and safety data from 112 mCRPC patients
`
`treated with cabazitaxel and progressed during or after docetaxel in the UK Early Access Programme
`
`showed a trend towards improved QoL; major toxicities were neutropenic sepsis (6.3%) and diarrhea
`
`(4.5%) [79].
`
`Despite the fact that cabazitaxel is able to prolong survival in the setting of mCRPC patients with bone
`
`metastases, to date no clinical benefit has been reported in term of pain palliation [76,78] and no
`
`clear evidence exists on its effect on the delay or prevention of SREs.
`
`
`
`6.3 Abiraterone
`
`Abiraterone acetate is a potent selective and irreversible inhibitor of the enzyme 17a-
`
`hydroxylase/C17.20-lyase (CYP17A1), therefore inhibiting androgen synthesis in adrenal glands,
`
`testicles, and prostate cancer, th