Androgen receptor pathway inhibitors (ARPI) and polyadenosine diphosphate-ribose inhibitors (PARPi) are part of the standard of care in patients with metastatic castration-resistant prostate cancer (mCRPC). There is biological evidence that the association of ARPI and PARPi could have a synergistic effect; therefore, several ongoing clinical trials are investigating the efficacy of this combination with preliminary results that are not perfectly concordant in identifying patients who can obtain the most benefit from this therapeutic option. The purpose of this review is to describe the PARPi mechanisms of action and to analyze the biological mechanisms behind the interplay between the androgen receptor and the PARPi system to better understand the rationale of the ARPI + PARPi combinations. Furthermore, we will summarize the preliminary results of the ongoing studies on these combinations, trying to understand in which patients to apply. Finally, we will discuss the clinical implications of this combination and its possible future perspectives.

Neuroendocrine differentiation (NED) represents a possible androgen receptor pathway inhibitors (ARPI) resistance mechanism in metastatic castration resistance prostate cancer (mCRPC). As mCRPC with NED has been excluded from clinical trials evaluating ARPI efficacy, this study investigates the prognostic impact of NED in mCRPC patients treated with ARPIs. Methods: We retrospectively analyzed 327 mCRPC patient data treated with Enzalutamide or Abiraterone in the first and second or successive lines of treatment. NED was assessed using prostate biopsy samples through immunohistochemical staining. Results: NED was confirmed in 32/327 (9.8%) mCRPC patients. In the overall population, mCRPC with NED showed worse PFS (4.38 vs. 11.48 months HR 2.505 [1.71–3.68] p < 0.05), disease control rate (DCR), and PSA response. In the first line setting, mCRPC with NED demonstrated worse PFS (8.5 vs. 14.9 months HR 2.13 [1.18–3.88], p < 0.05). Similarly, in the second or successive lines, mCRPC with NED showed worse PFS (4.0 vs. 7.5 months HR 2.43 [1.45–4.05] p < 0.05), DCR, PSA response and OS (12.53 vs. 18.03 months HR 1.86 [1.12–3.10] p < 0.05). The adverse impact of NED on PFS was consistence across all subgroups; we also noted a trend of worse PFS in patients with high vs. low NED. Conclusions: In our study, mCRPC with NED treated with Enzalutamide or Abiraterone showed worse clinical outcomes. NED assessment should be considered to optimize treatment decisions in the mCRPC setting.

The use of immune checkpoint inhibitors (ICIs) in combination with tyrosine kinase inhibitors or other ICIs has significantly improved the prognosis for patients with mccRCC. This marks a major milestone in the treatment of mccRCC. Nonetheless, most patients will discontinue first-line therapy. In this narrative review, we analyze the different patterns of treatment discontinuation in the four pivotal phase III trials that have shown an improvement in overall survival in mccRCC first-line therapy, starting from 1 January 2017 to 1 June 2023. We highlight the different discontinuation scenarios and their influences on subsequent treatment options, aiming to provide more data to clinicians to navigate a complex decision-making process through a narrative review approach. We have identified several causes for discontinuations for patients treated with ICI-based combinations, such as interruption for drug-related adverse events, ICI treatment completion, treatment discontinuation due to complete response or maximum clinical benefit, or due to progression (pseudoprogression, systemic progression, and oligoprogression); for each case, an extensive analysis of the trials and current medical review has been conducted.

Background: The timing of immune checkpoint inhibitor (ICI) administration may influence clinical outcomes, incidence, and severity of immune-related adverse events (irAEs), but evidence remains limited. Methods: We conducted a retrospective analysis of 41 patients with advanced melanoma treated with combined ipilimumab and nivolumab at the Istituto Oncologico della Svizzera Italiana between 2018 and 2024. Infusions completed before 2:00 p.m. were classified as morning (AM). Patients receiving ≥50% of doses in the morning were assigned to the AM group; the remaining patients comprised the afternoon (PM) group. Results: Twenty-one patients were included in the AM group and twenty in the PM group. Median progression-free survival (PFS) was not reached in the AM group, compared with 7.8 months in the PM group (univariate HR 0.29, 95% CI 0.12–0.70; p = 0.006). Overall survival (OS) was also significantly improved in the AM group (univariate HR 0.25, 95% CI 0.08–0.80; p = 0.019). The overall incidence of irAEs was similar between groups. However, systemic immunosuppression for grade ≥ 2 toxicities was more frequently required in the PM group (80% vs. 52%, p = 0.06). Conclusions: In this retrospective cohort, morning administration of ICIs was associated with improved PFS and OS in patients with advanced melanoma. While irAE incidence was comparable between groups, patients treated in the afternoon more often required systemic immunosuppression.

Background: Although the relationship between androgen deprivation therapy (ADT) for prostate cancer (PC) and the biological mechanisms of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection remains unequivocally unclear, it is possible that exposure to the virus may influence PC evolution by altering TMPRSS2 expression. This study aims to evaluate the long-term oncological outcomes of patients with metastatic PC who were undergoing medical therapy at the time of contracting SARS-CoV-2 and who resumed/continued anticancer treatment after recovery. Methods: We retrospectively evaluated a consecutive series of 151 metastatic PC patients who developed SARS-CoV-2 infection while receiving one active systemic anticancer therapy (125 metastatic castration-resistant PC (mCRPC) patients and 26 metastatic hormone-sensitive PC (mHSPC) patients). We evaluated variables that influence the ability to maintain or resume the ongoing therapy. For the maintained/resumed therapies, we calculated the post-infection overall survival (piOS) and the overall survival (OS). Results: Of the patients, 12.6% died due to SARS-CoV-2 infection, 10.6% recovered from the infection but failed to maintain/resume the ongoing anticancer treatment, and the remaining 76.8% maintained/resumed the treatment after recovery. Hospitalization, duration of infection, and the type of ongoing anticancer agent influenced these treatment changes. In the cohort of mCRPC patients, the median piOS was 32 months, and the median OS was 67.8 months. The median piOS was not achieved in the cohort of mHSPC patients, while the median OS was 122 months. The outcomes of single anticancer agents were in line with those of pivotal trials. Conclusions: Although observed in a highly selected population of PC patients who survived SARS-CoV-2 infection and were able to resume/maintain anticancer therapy, the survival outcomes of this study appear to be in line with those reported in pivotal studies, and SARS-CoV-2 infection does not seem to have adversely affected long-term oncological outcomes.