PARP inhibitors in prostate cancers, is it time for combinations?

Despite several improvements in outcomes, metastatic prostate cancer remains deadly. Alterations in the homologous recombination repair (HRR) pathway are associated with more aggressive disease. Olaparib and rucaparib, two poly-ADP-ribose polymerase (PARP) inhibitors, have received approval from the authorities of several countries for their anti-tumoral effects in patients with metastatic castration-resistant prostate cancers harboring HRR gene alterations, in particular BRCA2. More recently, it has been hypothesized that new hormonal therapies (NHTs) and PARP inhibitors (PARPi) could have synergistic actions and act independently of HRR deficiency. This review proposes to discuss the advantages and disadvantages of PARPi used as monotherapy or in combination with NHTs and whether there is a need for molecular selection.

Short-term Darolutamide (ODM-201) Concomitant to Radiation Therapy for Patients with Unfavorable Intermediate-risk Prostate Cancer: The Darius (AFU-GETUG P15) Phase 2 Trial Protocol.

BACKGROUND: Combination of androgen deprivation therapy (ADT) with external beam radiation therapy (EBRT) is a standard of care for patients with intermediate-risk prostate cancer (PCa). However, 6 months of ADT generates multiple side effects impacting quality of life (QoL). Darolutamide (an androgen receptor targeting agent [ARTA]) is associated with low blood-brain barrier penetrance and less drug-drug interaction. OBJECTIVE: To assess the efficacy of a combination of 6 months of darolutamide with EBRT to treat patients with unfavorable intermediate-risk PCa. DESIGN, SETTING, AND PARTICIPANTS: The DARIUS trial is a multicenter randomized non comparative phase 2 trial, randomizing the 6-months darolutamide + EBRT arm versus 6-months ADT + EBRT in patients with unfavorable intermediate-risk PCa. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: The primary endpoint is a biological response defined as prostate-specific antigen ≤0.1 ng/ml at month six of darolutamide or ADT. The key secondary endpoints are biochemical recurrence-free survival, disease-free survival, safety, and QoL. Ancillary studies using radiomics and genomic classifier are planned. Sixty-two patients will be included. RESULTS AND LIMITATIONS: In this population of patients requiring ADT combined with EBRT, the use of an ARTA alone, such as darolutamide, may demonstrate antitumoral efficacy while minimizing toxicity and maintaining QoL. Limitations are mainly inherent to the open-label design of this study. CONCLUSIONS: Six months of darolutamide + EBRT compared with 6 months of ADT + EBRT may be efficient in terms of a biological response, avoiding toxicity and altered QoL attributable to ADT in patients with unfavorable intermediate-risk PCa. PATIENT SUMMARY: The ongoing DARIUS clinical trial assesses short-term (6 months) darolutamide treatment in association with external beam radiation therapy in men with localized prostate cancer. The trial investigates whether single-agent darolutamide can improve the biological response while maintaining a favorable tolerability profile.

PARP Inhibitors as Monotherapy in Daily Practice for Advanced Prostate Cancers.

Despite recent improvements in survival, metastatic castration-resistant prostate cancers (mCRPCs) remain lethal. Alterations in genes involved in the homologous recombination repair (HRR) pathway are associated with poor prognosis. Poly-ADP-ribose polymerase (PARP) inhibitors (PARPis) have demonstrated anti-tumoral effects by synthetic lethality in patients with mCRPCs harboring HRR gene alterations, in particular BRCA2. While both olaparib and rucaparib have obtained government approvals for use, the selection of eligible patients as well as the prescription of these treatments within the clinical urology community are challenging. This review proposes a brief review of the rationale and outcomes of PARPi treatment, then a pragmatic vision of PARPi use in terms of prescription and the selection of patients based on molecular screening, which can involve potential genetic counseling in the case of associated germinal alterations.

Cabazitaxel multiple rechallenges in metastatic castration-resistant prostate cancer.

INTRODUCTION: Cabazitaxel multiple rechallenges may be a treatment option in heavily pretreated patients with metastatic castration-resistant prostate cancer (mCRPC) who had a good initial response to cabazitaxel and who are still fit to receive it. Our objective was to assess the efficacy and toxicity of multiple rechallenges. PATIENTS AND METHODS: We retrospectively identified 22 mCRPC patients previously treated with docetaxel and/or androgen receptor-targeted agents who received multiple cabazitaxel rechallenges in 9 French centers. Cabazitaxel was initiated at a dose of 25 mg/m2 q3week. A reduced dose (20 mg/m2 q3w) or an alternative schedule (mainly 16 mg/m2 q2w) was increasingly used for subsequent rechallenges. Progression-free survival, prostate-specific antigen (PSA) response, best clinical response, and grade ≥3 toxicities were collected. Overall survival was calculated from various time points. RESULTS: Twenty-two patients with an initial response to cabazitaxel were rechallenged at least twice. The median number of cabazitaxel cycles was 7 at first cabazitaxel treatment, 6 at first rechallenge, and 5 at subsequent rechallenges. Median progression-free survival at first rechallenge was 9.6 months and 5.6 months at second rechallenge. Median overall survival was 50.9 months from the first cabazitaxel dose, 114.9 months from first life-extending therapy initiation in mCRPC, and 105 months from mCRPC diagnosis. There was no cumulative grade ≥3 neuropathy or nail disorder and one case of febrile neutropenia. CONCLUSION: Cabazitaxel multiple rechallenges may be a treatment option without cumulative toxicity in heavily pretreated patients having a good response to first cabazitaxel use and still fit to receive it. NOVELTY & IMPACT STATEMENTS: Patients with metastatic castration-resistant prostate cancer can be treated with Cabazitaxel after docetaxel and androgen receptor-targeted agent. This chemotherapy can be used multiple times with efficacy and manageable toxicity.

Prostate cancer and PARP inhibitors: progress and challenges.

Despite survival improvements achieved over the last two decades, prostate cancer remains lethal at the metastatic castration-resistant stage (mCRPC) and new therapeutic approaches are needed. Germinal and/or somatic alterations of DNA-damage response pathway genes are found in a substantial number of patients with advanced prostate cancers, mainly of poor prognosis. Such alterations induce a dependency for single strand break reparation through the poly(adenosine diphosphate-ribose) polymerase (PARP) system, providing the rationale to develop PARP inhibitors. In solid tumors, the first demonstration of an improvement in overall survival was provided by olaparib in patients with mCRPC harboring homologous recombination repair deficiencies. Although this represents a major milestone, a number of issues relating to PARP inhibitors remain. This timely review synthesizes and discusses the rationale and development of PARP inhibitors, biomarker-based approaches associated and the future challenges related to their prescription as well as patient pathways.

Treatment of spinal metastases in renal cell carcinoma: A critical review.

Kidney cancer is the 9th most common cancer in men and the 14th most common in women worldwide. Renal cell carcinoma (RCC) constitutes 90% of all malignancies of the kidney. RCC, is known to be highly vascular and relatively radioresistant. Bone metastases are one of the most common metastatic sites and occur in around 30% of RCCs. They significantly impact the quality of life of patients causing pain and pathological fractures. Spinal metastases represent a particular case with regard to symptoms and treatment. Indeed, neurological pain is often added to the nociceptive pain caused by metastases. More importantly, neurological impairment can be seen, caused by spinal cord or nerve root compression (MSCC). Due to close contact with the spinal cord, the treatment of spinal bone metastases is challenging and requires a multidisciplinary approach. Specific treatment is currently focused on 4 main avenues which are surgery, radiotherapy, interventional radiology and systemic treatment. In June 2017 we carried out an extensive search on PubMed, Web of Science, and Cochrane Library to review the various treatment options and to establish a treatment strategy. This article presents the result of our critical review of the literature, given our expertise in the field.

Olaratumab for soft tissue sarcoma.

INTRODUCTION: Soft tissue sarcomas (STS) are rare malignant tumors. Unfortunately, the first-line doxorubicin-based treatment has not been improved since the 1970s. Platelet-derived growth factor (PDGF) receptor alpha (PDGFR-α) and its ligands are co-expressed in many types of cancer, including sarcomas. They are involved in stimulating growth and regulating stromal-derived fibroblasts and angiogenesis. PDGFR-α and its ligand may play an important role in tumorigenesis and be a potential target in the treatment of sarcomas. Olaratumab is a fully human IgG1-type anti-PDGFR-α monoclonal antibody with a high affinity and a low 50% inhibitory concentration (IC50). Areas covered: The authors review the role of olaratumab in the treatment of STS by focusing on the recent, randomized Phase II JDGD trial that challenged patients with unresectable or metastatic STS with doxorubicin in the presence or absence of olaratumab. This trial showed a great improvement in overall survival (OS), with an increase in survival from 14.7 months to 26.5 months for patients in the experimental arm and showed acceptable toxicity. Expert opinion: Results seem promising. However, it must be qualified, as the study includes several uncertainties. These uncertainties should be addressed by the ongoing Phase 3 JGDJ confirmatory trial, for which the final efficacy analysis is expected by 2019.

Metastatic non-muscle invasive bladder cancer with meningeal carcinomatosis: case report of an unexpected response.

BACKGROUND: Non-muscle invasive bladder cancer (NMIBC) is usually treated with local therapy including transurethral resection of the bladder tumor and intravesical therapy depending on the stage of the tumor. NMIBC is a rarely a metastatic diseases with lymph node invasion in less of 10%. In the other hand meningeal carcinomatosis is a rare location for metastases with extremely poor outcomes. We described a case report of a patient presenting a metastatic disease to bones and meninges, several years after the treatment of NMIBC, which had been in complete response (CR) for 4 years after chemotherapy treatment. CASE PRESENTATION: A 63-years old men was treated by TURBT in 2008 for a high grade NMIBC, pT1b. Three years later he presented an acute binocular diplopy with right trochlear nerve paralysis, and labial hypoesthesia. Brain scan and MRI were performed finding a clivus infiltration and a pachymeningitis. A vertebral biopsy was performed finding an invasive carcinoma, CK7+/CK20+, TTF1-, PSA-, Thyroglobulin- and GATA3+. The metastatic event was in relation to the high grade NMIBC treated 3 years previously. Palliative chemotherapy was started with cisplatin gemcitabine. After 6 cycles and to date, 4 years later, the patient is therefore considered in complete response. CONCLUSION: Metastasis in non-muscle invasive urothelial carcinoma is rare. Meningeal carcinomatosis outcome is poor, usually appearing in widely metastatic and progressive cancers but also because most systemic agents fail to pass the blood-brain barrier and penetrate into the cerebrospinal fluid. We described an unexpected response with complete response after chemotherapy for meningeal carcinomatosis of non muscle invasive urothelial carcinoma.