Efficacy and safety of rechallenge [177Lu]Lu-PSMA-617 RLT after initial partial remission in patients with mCRPC: evaluation of a prospective registry (REALITY study)

AIM

Rechallenge of [177Lu]Lu-PSMA-617 radioligand therapy (RLT) was proposed for patients who initially responded to PSMA-RLT experiencing partial remission, but relapsed into progression after a certain period of remission. However, only limited data is available regarding this approach. In this study, we analyzed the efficacy and safety profile of one or more series of [177Lu]Lu-PSMA-617 RLT rechallenge in patients from a prospective registry (REALITY Study, NCT04833517) after they initially benefited from PSMA-RLT.

METHODS

Forty-seven patients with metastatic castration-resistant prostate cancer (mCRPC) who had biochemical response to initial [177Lu]Lu-PSMA-617 RLT followed by disease progression received at least one (up to three) series of [177Lu]Lu-PSMA-617 RLT rechallenge. Biochemical response rates based on prostate-specific antigen (PSA) serum value, PSA-based progression-free survival (PFS) and overall survival (OS) were calculated. Adverse events of the treatment were assessed according to 'common terminology criteria for adverse events' (CTCAE).

RESULTS

After one series of RLT rechallenge, a PSA decline of at least 50% was achieved in 27/47 patients (57.4%). The median PFS of all patients was 8.7 mo and the median OS was 22.7 mo, each calculated from the administration of the first rechallenge series. Patients who responded (PSA decline > 50%) to the rechallenge showed a median OS of 27.3 mo. Regarding PFS, a significant correlation (r = 0.4128, p = 0.0323) was found for these patients comparing initial and rechallenge RLT. Ten patients received a second and 3 patients received a third rechallenge series with 8/10 and 3/3 patients responding to repeated RLT rechallenge. No severe deterioration of adverse events rated by CTCAE criteria was observed.

CONCLUSION

[177Lu]Lu-PSMA-617 RLT rechallenge is associated with significant PSA response and encouraging survival outcome as well as a very favourable safety profile and should therefore be considered as a straight-forward treatment option in mCRPC patients, who previously benefited from PSMA-RLT.

EGFR-Tyrosine Kinase Inhibitor Retreatment in Non-Small-Cell Lung Cancer Patients Previously Exposed to EGFR-TKI: A Systematic Review and Meta-Analysis

We performed a systematic review and meta-analysis to assess the efficacy of EGFR-tyrosine kinase inhibitors (TKI) retreatment in advanced/metastatic non-small-cell lung cancer (NSCLC) patients. We systematically searched PubMed, Embase, Cochrane databases, ASCO, and ESMO websites for studies evaluating EGFR-TKI retreatment in advanced/metastatic NSCLC patients. All analyses were performed using R software (v.4.2.2). We included 19 studies (9 CTs and 10 retrospective cohorts) with a total of 886 patients. In a pooled analysis of all patients during retreatment with TKI, median OS was 11.7 months (95% confidence interval [CI] 10.2-13.4 months) and PFS was 3.2 months (95% CI 2.5-3.9 months). ORR was 15% (95% CI 10-21%) and DCR was 61% (95% CI 53-67%). The subanalysis by generation of TKI in the rechallenge period revealed a slightly better ORR for patients on 3rd generation TKI (p = 0.05). Some limitations include the high heterogeneity of some of the analyses and inability to perform certain subanalyses. Our results unequivocally support the benefit of EGFR-TKI rechallenge in EGFR-mutated NSCLC patients progressing on TKI treatment after a TKI-free interval. These findings may be especially valuable in areas where access to novel therapeutic drugs and clinical trials is limited.

Different Targeting Ligands-Mediated Drug Delivery Systems for Tumor Therapy

Traditional tumor treatments have the drawback of harming both tumor cells and normal cells, leading to significant systemic toxic side effects. As a result, there is a pressing need for targeted drug delivery methods that can specifically target cells or tissues. Currently, researchers have made significant progress in developing targeted drug delivery systems for tumor therapy using various targeting ligands. This review aims to summarize recent advancements in targeted drug delivery systems for tumor therapy, focusing on different targeting ligands such as folic acid, carbohydrates, peptides, aptamers, and antibodies. The review also discusses the advantages, challenges, and future prospects of these targeted drug delivery systems.

Efficacy and safety of immune checkpoint inhibitor rechallenge in non-small cell lung cancer: A systematic review and meta-analysis

BACKGROUND

The aim of the study was to explore the efficacy and safety of immune checkpoint inhibitor (ICI) rechallenge in patients with non-small cell lung cancer (NSCLC).

METHODS

Studies that enrolled NSCLC patients treated with two lines of ICIs were included using four databases. The initial line (1L-) and subsequent lines (2L-) of ICIs were defined as 1L-ICI and 2L-ICI, respectively.

RESULTS

A total of 17 studies involving 2100 patients were included. The pooled objective response rate (ORR), disease control rate (DCR), median progression-free survival (mPFS), and median overall survival (mOS) for 2L-ICIs were 10%, 50%, 3.0 months, and 13.1 months, respectively. The 2L-ICI discontinuation rates caused by toxicities ranged from 0% to 23.5%. Original data were extracted from six studies, covering 89 patients. Patients in whom 1L-ICIs were discontinued following clinical decision (the mPFS of 2L-ICIs was not reach) achieved a more prolonged mPFS of 2L-ICIs than those due to toxicity (5.2 months) and progressive disease (2.1 months) (p < 0.0001). Patients' 1L-PFS for more than 2-years had preferable 2L-ORR (35.0% vs. 9.8%, p = 0.03), 2L-DCR (85.0% vs. 49.0%, p = 0.007), and 2L-mPFS (12.4 vs. 3.0 months, p < 0.0001) than those less than 1-year. Patients administered the same drugs achieved a significantly prolonged mPFS compared with the remaining patients (5.4 vs. 2.3 months, p = 0.0004), and those who did not accept antitumor treatments during the intervals of two lines of ICIs achieved a prolonged mPFS compared to those patients who did accept treatments (7.6 vs. 1.9 months, p < 0.0001).

CONCLUSIONS

ICI rechallenge is a useful therapeutic strategy for NSCLC patients, especially suitable for those who achieve long-term tumor remission for more than 2-years under 1L-ICIs.

Progress of Research in In Situ Smart Hydrogels for Local Antitumor Therapy: A Review

Cancer seriously threatens human health. Surgery, radiotherapy and chemotherapy are the three pillars of traditional cancer treatment, with targeted therapy and immunotherapy emerging over recent decades. Standard drug regimens are mostly executed via intravenous injection (IV), especially for chemotherapy agents. However, these treatments pose severe risks, including off-target toxic side effects, low drug accumulation and penetration at the tumor site, repeated administration, etc., leading to inadequate treatment and failure to meet patients’ needs. Arising from these challenges, a local regional anticancer strategy has been proposed to enhance therapeutic efficacy and concomitantly reduce systemic toxicity. With the advances in biomaterials and our understanding of the tumor microenvironment, in situ stimulus-responsive hydrogels, also called smart hydrogels, have been extensively investigated for local anticancer therapy due to their injectability, compatibility and responsiveness to various stimuli (pH, enzyme, heat, light, magnetic fields, electric fields etc.). Herein, we focus on the latest progress regarding various stimuli that cause phase transition and drug release from smart hydrogels in local regional anticancer therapy. Additionally, the challenges and future trends of the reviewed in situ smart hydrogels for local drug delivery are summarized and proposed.

Rechallenge of immunotherapy beyond progression in patients with extensive-stage small-cell lung cancer

Background: Rechallenge of immunotherapy beyond progression (RIBP) has been demonstrably effective in a variety of cancers. Our study aims to investigate the efficacy of RIBP in small-cell lung cancer (SCLC) patients under real-world conditions.

Methods: SCLC patients who experienced progressive disease after receiving programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) inhibitors combined with chemotherapy from January 2017 to October 2021 were enrolled. The study population was divided into two groups: the RIBP group and the discontinuation of immunotherapy beyond progression (DIBP) group. Inverse propensity score weighting (IPSW) method was used to balance the clinical baseline characteristics. The short-term and long-term efficacy of the two groups was compared.

Results: 100 SCLC patients were included in this study. There were 45 patients in the RIBP group and 55 patients in the DIBP group. The disease control rate (DCR) and the proportion of durable clinical benefit (DCB) were significantly higher in the RIBP group (DCR: 79.7% vs. 55.7%, p = 0.027; DCB: 40.7 vs. 20.7%, p = 0.025) after weighting. The median progressive-free survival (PFS) in the RIBP group was significantly longer than the DIBP group in the total population (mPFS: 4.8 vs. 2.4 months, p = 0.002), while there was no significant difference in overall survival (OS) of the two groups (mOS: 17.4 vs. 8.0 months, p = 0.098). In the weighted first-line initial immunotherapy subgroup, PFS and OS were significantly improved in the RIBP group (mPFS: 4.5 vs. 2.8 months, p = 0.017; mOS: 11.6 vs. 5.4 months, p = 0.028). After weighting, the RIBP group had a significantly longer PFS than the DIBP group in the SD/PD response to the initial immunotherapy subgroup (mPFS: 6.8 vs. 1.8 months, p = 0.026).

Conclusion: Rechallenge of PD-1/PD-L1 inhibitors could bring benefits to SCLC patients, especially in the first-line initial immunotherapy subgroup or SD/PD response to the initial immunotherapy subgroup.

Coadministration with bendamustine restores the antitumor activity of obinutuzumab in obinutuzumab-resistant tumors

BACKGROUND

The glycoengineered, humanized anti-CD20 antibody obinutuzumab is indicated for previously untreated or relapsed/refractory CD20-positive follicular lymphoma (FL). However, the effectiveness of obinutuzumab retreatment in relapsed/refractory FL after prior obinutuzumab-containing therapy is unclear. To address this issue, we investigated the antitumor activity of obinutuzumab plus bendamustine in obinutuzumab-resistant tumors established from a human non-Hodgkin lymphoma xenograft model.

MATERIALS AND METHODS

Obinutuzumab-resistant tumors (SU-DHL-4-OR-18-8) were established from an SU-DHL-4 xenograft model by repeated administration of obinutuzumab. Antitumor activity was evaluated based on tumor volume after treatment with obinutuzumab on Day 1, 8, and 15 and/or bendamustine on Day 1 and 2. Intratumoral natural killer (NK) cells/macrophages were evaluated by immunohistochemistry and flow cytometry.

RESULTS

In SU-DHL-4-OR-18-8 xenografted tumors, intratumoral NK cells/macrophages after obinutuzumab treatment were significantly decreased compared with parent tumors on Day 4. The endoplasmic reticulum stress sensor phospho-IRE1 was also decreased. In SU-DHL-4-OR-18-8 tumors, bendamustine treatment increased phospho-IRE1 on Day 4 and intratumor NK cells/macrophages on Day 10. Obinutuzumab combined with bendamustine significantly increased antitumor activity compared with each single agent on Day 29, with an increase in chemoattractant CCL6 expression on Day 10.

CONCLUSIONS

Coadministration of bendamustine in obinutuzumab retreatment may be effective against obinutuzumab-resistant tumors.

Treatment Following Progression in Metastatic Melanoma: the State of the Art from Scientific Literature to Clinical Need

INTRODUCTION

In the last few years, the advent of targeted therapy and immunotherapy has improved the management and the prognosis of metastatic melanoma, but the spread of resistance mechanisms can lead to disease progression. The clinical management in this setting can be challenging because the oncologist has to decide what is the best treatment strategy among therapy beyond progression (TBP), therapy change, and the rechallenge approach. This review of the relevant scientific literature is intended to clarify which patients with progressing metastatic melanoma will benefit from continuation of ongoing therapy and which ones will not. The data are based on a total of about 4300 patients coming from the main retrospective studies in the chosen field. The article body is divided into four sections which analyze respectively the targeted therapy beyond progression, the immunotherapy beyond progression, the possible treatment sequences, and finally the rechallenge strategy.

RECENT FINDINGS

Despite the possible approaches of TBP or rechallenge, the patient may not have an optimal response and may need new therapy, which is currently missing. To broaden the pharmacological offer in the fight against melanoma, cancer research is studying new disease targets, like the NRAS, PI3K, and cKIT pathways or combination treatment of targeted therapy plus immunotherapy. Despite the limitations of this work, mainly due to the limited number of studies, their retrospective nature and the lack of comparative studies, the analysis performed allows us to draw some important conclusions: therapy beyond progression, both targeted therapy and immunotherapy, represents a valid treatment option with positive effects on disease control and survival outcomes for patients with low clinical risk, expressed as low disease burden, normal LDH levels, and good performance status; moreover, the prognosis and quality of life of these patients improve when TBP is associated with locoregional treatments. In patients with progressive metastatic melanoma and high clinical risk (high disease burden, high LDH levels, and poor performance status), it is recommended to change therapy, without ever forgetting the possibility of enrolling the patient in a clinical trial. Finally, an efficacious treatment alternative is the rechallenge strategy; this approach consists in a re-treatment with the same drug after a variable interval of discontinuation. Preliminary studies seem to have demonstrated that patients retreated with targeted therapy achieved a greater benefit if they had a low clinical risk and if the drug doublet (BRAF + MEK inhibitors) was used. On the side of immunotherapy, the rechallenge strategy produced a major benefit in patients who prior experienced a severe toxic episode.

Immunotherapy retreatment: case report, review of the literature and proposal for the definition of different scenarios

Immune checkpoint inhibitors have improved the treatment landscape of different tumors and one of the emerging issues is the reintroduction of immunotherapy after discontinuation. Scarce evidence is currently available and different definitions have been used. The case of a patient with pretreated advanced urothelial cancer, who responded to immunotherapy retreatment after long-term benefit from the previous course, is reported. Based on a review of the different clinical scenarios, a definition of immunotherapy retreatment was proposed, as rechallenge or reintroduction, based on the reasons of discontinuation of the previous course. Clinical factors potentially associated with clinical benefit from immunotherapy retreatment are discussed, even though ad hoc studies are needed to assess the efficacy and safety of the different immunotherapy retreatment strategies.