Novel Treatment with Intraperitoneal MOC31PE Immunotoxin in Colorectal Peritoneal Metastasis: Results From the ImmunoPeCa Phase 1 Trial

Advances in pharmacotherapy for the treatment of peritoneal metastases from colorectal cancer

INTRODUCTION

Patients with peritoneal metastasis (PM) from colorectal cancer (CRC) typically have a poor prognosis with historically few treatment options. Cytoreductive surgery (CRS) is the mainstay of treatment to remove macrometastases into the peritoneum, but residual micrometastases are often left behind. Systemic chemotherapy remains a cornerstone of treatment for micrometastases, but intraperitoneal therapy offers advantages including higher local dose concentration with fewer systemic side effects from treatment.

AREAS COVERED

This review covers advancements in the routes and types of pharmacotherapies for PM in CRC.

EXPERT OPINION

More evidence is needed to justify HIPEC with CRS as the standard of care treatment modality for patients with resectable PM in CRC. New therapies such as oncolytic viruses, biologics, and small-molecule inhibitors may become additional treatment modalities for PM.

Progress in Biological Research and Treatment of Pseudomyxoma Peritonei

Pseudomyxoma peritonei (PMP) is a rare disease characterized by extensive peritoneal implantation and mass secretion of mucus after primary mucinous tumors of the appendix or other organ ruptures. Cytoreductive surgery (CRS) combined with hyperthermic intraperitoneal chemotherapy (HIPEC) is currently the preferred treatment, with excellent efficacy and safety, and is associated with breakthrough progress in long-term disease control and prolonged survival. However, the high recurrence rate of PMP is the key challenge in its treatment, which limits the clinical application of multiple rounds of CRS-HIPEC and does not benefit from conventional systemic chemotherapy. Therefore, the development of alternative therapies for patients with refractory or relapsing PMP is critical. The literature related to PMP research progress and treatment was searched in the Web of Science, PubMed, and Google Scholar databases, and a literature review was conducted. The overview of the biological research, treatment status, potential therapeutic strategies, current research limitations, and future directions associated with PMP are presented, focuses on CRS-HIPEC therapy and alternative or combination therapy strategies, and emphasizes the clinical transformation prospects of potential therapeutic strategies such as mucolytic agents and targeted therapy. It provides a theoretical reference for the treatment of PMP and the main directions for future research.

Peritoneal Metastasis: A Dilemma and Challenge in the Treatment of Metastatic Colorectal Cancer

Peritoneal metastasis (PM) is a common mode of distant metastasis in colorectal cancer (CRC) and has a poorer prognosis compared to other metastatic sites. The formation of PM foci depends on the synergistic effect of multiple molecules and the modulation of various components of the tumor microenvironment. The current treatment of CRC-PM is based on systemic chemotherapy. However, recent developments in local therapeutic modalities, such as cytoreductive surgery (CRS) and intraperitoneal chemotherapy (IPC), have improved the survival of these patients. This article reviews the research progress on the mechanism, characteristics, diagnosis, and treatment strategies of CRC-PM, and discusses the current challenges, so as to deepen the understanding of CRC-PM among clinicians.

Immunotherapy for Peritoneal Carcinomatosis: Challenges and Prospective Outcomes

Peritoneal metastasis, also known as peritoneal carcinomatosis (PC), is a refractory cancer that is typically resistant to conventional therapies. The typical treatment for PC is a combination of cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). Recently, research in this area has seen significant advances, particularly in immunotherapy as an alternative therapy for PC, which is very encouraging. Catumaxomab is a trifunctional antibody intraperitoneal (IP) immunotherapy authorized in Europe that can be used to diminish malignant ascites by targeting EpCAM. Intraperitoneal (IP) immunotherapy breaks immunological tolerance to treat peritoneal illness. Increasing T-cell responses and vaccination against tumor-associated antigens are two methods of treatment. CAR-T cells, vaccine-based therapeutics, dendritic cells (DCs) in combination with pro-inflammatory cytokines and NKs, adoptive cell transfer, and immune checkpoint inhibitors are promising treatments for PC. Carcinoembryonic antigen-expressing tumors are suppressed by IP administration of CAR-T cells. This reaction was strengthened by anti-PD-L1 or anti-Gr1. When paired with CD137 co-stimulatory signaling, CAR-T cells for folate receptor cancers made it easier for T-cell tumors to find their way to and stay alive in the body.

A Multicenter Phase 1 Trial Evaluating Nanoliposomal Irinotecan for Heated Intraperitoneal Chemotherapy Combined with Cytoreductive Surgery for Patients with Peritoneal Surface Disease

BACKGROUND

Nanoliposomal irinotecan (nal-IRI) is a promising novel hyperthermic intraperitoneal chemotherapy (HIPEC) agent given its enhanced efficacy against gastrointestinal tumors, safety profile, thermo-synergy, and heat stability. This report describes the first in-human phase 1 clinical trial of nal-IRI during cytoreductive surgery (CRS) and HIPEC.

METHODS

Patients with peritoneal surface disease (PSD) from appendiceal and colorectal neoplasms were enrolled in a 3 + 3 dose-escalation trial using nal-IRI (70-280 mg/m²) during HIPEC for 30 min at 41 ± 1 °C. The primary outcome was safety. The secondary outcomes were pharmacokinetics (PK) and disease-free survival. Adverse events (AEs) categorized as grade 2 or higher were recorded. The serious AEs (SAEs) were mortality, grade ≥ 3 AEs, and dose-limiting toxicity (DLT). Irinotecan and active metabolite SN38 were measured in plasma and peritoneal washings.

RESULTS

The study enrolled 18 patients, who received nal-IRI during HIPEC at 70 mg/m² (n = 3), 140 mg/m² (n = 6), 210 mg/m² (n = 3), and 280 mg/m² (n = 6). No DLT or mortality occurred. The overall morbidity for CRS/HIPEC was 39% (n = 7). Although one patient experienced neutropenia, no AE (n = 131) or SAE (n = 3) was definitively attributable to nal-IRI. At 280 mg/m², plasma irinotecan and SN38 measurements showed maximum concentrations of 0.4 ± 0.6 µg/mL and 3.0 ± 2.4 ng/mL, a median time to maximum concentration of 24.5 and 26 h, and areas under the curve of 22.6 h*µg/mL and 168 h*ng/mL, respectively. At the 6-month follow-up visit, 83% (n = 15) of the patients remained disease-free.

CONCLUSIONS

In this phase 1 HIPEC trial (NCT04088786), nal-IRI was observed to be safe, and PK profiling showed low systemic absorption overall. These data support future studies testing the efficacy of nal-IRI in CRS/HIPEC.

First experience with 224Radium-labeled microparticles (Radspherin®) after CRS-HIPEC for peritoneal metastasis in colorectal cancer (a phase 1 study)

Background

Peritoneal metastasis (PM) from colorectal cancer carries a dismal prognosis despite extensive cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC). With a median time to recurrence of 11-12 months, there is a need for novel therapies. Radspherin® consists of the α-emitting radionuclide radium-224 (²²⁴Ra), which has a half-life of 3.6 days and is adsorbed to a suspension of biodegradable calcium carbonate microparticles that are designed to give short-range radiation to the serosal peritoneal surface linings, killing free-floating and/or tumor cell clusters that remain after CRS-HIPEC.

Methods

A first-in-human phase 1 study (EudraCT 2018-002803-33) was conducted at two specialized CRS-HIPEC centers. Radspherin® was administered intraperitoneally 2 days after CRS-HIPEC. Dose escalation at increasing activity dose levels of 1-2-4-7-MBq, a split-dose repeated injection, and expansion cohorts were used to evaluate the safety and tolerability of Radspherin®. The aim was to explore the recommended dose and biodistribution using gamma-camera imaging. The results from the planned safety interim analysis after the completion of the dose-limiting toxicity (DLT) period of 30 days are presented.

Results

Twenty-three patients were enrolled: 14 in the dose escalation cohort, three in the repeated cohort, and six in the expansion cohort. Of the 23 enrolled patients, seven were men and 16 were women with a median age of 64 years (28-78). Twelve patients had synchronous PM stage IV and 11 patients had metachronous PM [primary stage II; (6) and stage III; (5)], with a disease-free interval of 15 months (3-30). The peritoneal cancer index was median 7 (3-19), operation time was 395 min (194-515), and hospital stay was 12 days (7-37). A total of 68 grade 2 adverse events were reported for 17 patients during the first 30 days; most were considered related to CRS and/or HIPEC. Only six of the TEAEs were evaluated as related to Radspherin®. One TEAE, anastomotic leakage, was reported as grade 3. Accordion ≥3 grade events occurred in a total of four of the 23 patients: reoperation due to anastomotic leaks (two) and drained abscesses (two). No DLT was documented at the 7 MBq dose level that was then defined as the recommended dose. The biodistribution of Radspherin® showed a relatively even peritoneal distribution.

Conclusion

All dose levels of Radspherin® were well tolerated, and DLT was not reached. No deaths occurred, and no serious adverse events were considered related to Radspherin®.Clinical Trial Registration: Clinicaltrials.gov, NCT03732781.

The Development of Investigator-Initiated Clinical Trials in Surgical Oncology

Investigator-initiated trials (IITs) are designed by principal investigators who identify important, unaddressed clinical gaps and opportunities to answer these questions through clinical trials. Surgical oncologists are poised to lead IITs due to their multidisciplinary clinical practice and substantial research background. The process of developing, organizing, and implementing IITs is multifaceted and involves important steps including (but not limited to) navigating regulatory requirements, obtaining funding, and meeting enrollment targets. Here, the authors explore the steps, methodology, and barriers of IIT development by surgical oncologists and highlight the importance of IITs in oncology.

Peritoneal carcinomatosis with intraperitoneal immunotherapy: current treatment options and perspectives

INTRODUCTION

Peritoneal carcinomatosis (PC) is an advanced malignancy that is not sensitive to systemic conventional chemotherapy. Treatment options for PC are usually palliative rather than curative. Cytoreductive surgery and hyperthermic intraperitoneal (IP) chemotherapy are associated with limited efficacy in patients with PC. However, the peritoneum can produce effective immunity by inducing T-lymphocyte recruitment and proliferation, and the unique immune environment of the peritoneum provides the rationale for IP immunotherapy in PC.

AREAS COVERED

The authors retrieved relevant documents of IP immunotherapy for PC from PubMed and Medline. This review elaborates on the knowledge of the peritoneal immune microenvironment and IP immunotherapy for PC covering immune stimulators, radioimmunotherapy, catumaxomab, cancer vaccines, chimeric antigen receptor (CAR)-T cells, and immune checkpoint inhibitors.

EXPERT OPINION

The prognosis of PC is poor. However, the peritoneal cavity is a unique immune compartment with abundant immune cells which can produce effective immunity. IP immunotherapy may be a promising strategy in patients with PC.

Immune response and locoregional treatments for peritoneal carcinomatosis

Peritoneal Carcinomatosis (PC) is considered as a terminal disease with short survival. It is treated with palliative therapies, consisting of repeated drainages and sometimes instillation of chemotherapy. Since the nineties, surgery has been combined with more effective systemic chemotherapy, intraperitoneal chemotherapy and hyperthermic intraperitoneal chemotherapy (HIPEC) for the treatment of PC. This combination therapy significantly increases the overall survival of selected PC patients. The understanding of how intraperitoneal chemotherapy and HIPEC can cure patients is still unclear. Experts hypothesized that the efficacy is obtained by the ability of high peritoneal drug exposure and hyperthermia to directly kill cancer cells. Several studies indicate that cancer cells death directly influences the response of the immune system. For this reason, the protective effect of intraperitoneal chemotherapy and HIPEC could be mediated by its ability to kill cancer cells in an immuno-genic way, causing an efficient anticancer immune response. In this review, we investigate the role of the innate peritoneal or locoregional therapy-induced immune response in PC therapy.

Current Trends in Cytoreductive Surgery (CRS) and Hyperthermic Intraperitoneal Chemotherapy (HIPEC) for Peritoneal Disease from Appendiceal and Colorectal Malignancies

Peritoneal carcinomatosis (PC) is a poor prognostic factor for all malignancies. This extent of metastatic disease progression remains difficult to treat with systemic therapies due to poor peritoneal vascularization resulting in limited drug delivery and penetration into tissues. Cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC) are surgical interventions that directly target peritoneal tumors and have improved outcomes for PC resulting from appendiceal and colorectal cancer (CRC). Despite these radical therapies, long-term survival remains infrequent, and recurrence is common. The reasons for these outcomes are multifactorial and signal the need for the continued development of novel therapeutics, techniques, and approaches to improve outcomes for these patients. Here, we review landmark historical studies that serve as the foundation for current recommendations, recent discoveries, clinical trials, active research, and areas of future interest in CRS/HIPEC to treat PC originating from appendiceal and colorectal malignancies.

Comprehensive Understanding and Evolutional Therapeutic Schemes for Pseudomyxoma Peritonei: A Literature Review

Pseudomyxoma peritonei is an infrequent solid tumor in clinical practice. The low morbidity and deficient understanding of this mucus-secreting malignant disease increase the risks of delayed identification or uncontrollable deterioration. In quite a lot cases, patients go through complete cytoreduction surgery and hyperthermic intraperitoneal chemotherapy could receive a long time survival over 5 years. But the recurrence rate is also hard to overlook. Unlike other types of cancer, the standard treatment for this considerable groups has not been confirmed yet. With the advanced medical progression, studies have been carrying out based on pathogenesis, biological characters, and mutated gene location. All but a few get statistical survival benefits, let alone the breaking progress on research or therapeutic practice in the field. We try to give a comprehensive exposition of pseudomyxoma peritonei around the epidemiology, radiologic features, clinical manifestation, present treatment and promising schemes, hoping to arise much attention and reflection on the feasible solutions, especially for the recrudescent part.

Epithelial cell adhesion molecule‑targeting designed ankyrin repeat protein‑toxin fusion Ec1‑LoPE exhibits potent cytotoxic action in prostate cancer cells

Targeted anticancer therapeutics offer the advantage of reducing cytotoxic side effects to normal cells by directing the cytotoxic payload selectively to cancer cells. Designed ankyrin repeat proteins (DARPins) are promising non-immunoglobulin-based scaffold proteins for payload delivery to cancer-associated molecular targets. Epithelial cell adhesion molecule (EpCAM) is overexpressed in 40–60% of prostate cancers (PCs) and is associated with metastasis, increased risk of PC recurrence and resistance to treatment. Here, we investigated the use of DARPin Ec1 for targeted delivery of Pseudomonas exotoxin A variant (LoPE) with low immunogenicity and low non-specific toxicity to EpCAM-expressing prostate cancer cells. Ec1-LoPE fusion protein was radiolabeled with tricarbonyl technetium-99m and its binding specificity, binding kinetics, cellular processing, internalization and cytotoxicity were evaluated in PC-3 and DU145 cell lines. Ec1-LoPE showed EpCAM-specific binding to EpCAM-expressing prostate cancer cells. Rapid internalization mediated potent cytotoxic effect with picomolar IC₅₀ values in both studied cell lines. Taken together, these data support further evaluation of Ec1-LoPE in a therapeutic setting in a prostate cancer model in vivo.

Peritoneal Metastasis: Current Status and Treatment Options

Simple Summary

Surgical and locoregional treatments of peritoneal metastasis, e.g., from colorectal cancer, has gained increasing acceptance after the publication of excellent patient outcomes from many groups around the world. Apart from systemic chemotherapy and surgical removal of the tumor, locoregional therapies such as HIPEC or PIPAC may improve tumor control. Understanding the molecular characteristics of peritoneal metastasis is crucial to evolve future therapeutic strategies for peritoneal metastasis. This includes the genetic background of PM, which is often different from other sites of metastasis, and promotes peritoneal dissemination and the growth of tumor cells. Growing knowledge and insight into the physiology of the peritoneal tumor microenvironment and the specific role of the immune system in this compartment may provide a critical step to move locoregional therapy to the next level. This review summarizes the current knowledge and highlights the molecular characteristics of peritoneal metastasis.

Abstract

Peritoneal metastasis (PM) originating from gastrointestinal cancer was considered a terminal disease until recently. The advent of better systemic treatment, a better understanding of prognostic factors, and finally, the advent of novel loco-regional therapies, has opened the door for the multimodal treatment of PM. These strategies, including radical surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) showed surprisingly good results, leading to the prolonged survival of patients with peritoneal metastasis. This has triggered a significant body of research, leading to the molecular characterization of PM, which may further help in the development of novel treatments. This review summarizes current evidence on peritoneal metastasis and explores potential novel mechanisms and therapeutic approaches to treat patients with peritoneal metastasis.

Novel Perspectives in Pseudomyxoma Peritonei Treatment

Simple Summary

Pseudomyxoma Peritonei (PMP) represents a rare entity which greatly benefits from Cytoreductive Surgery (CRS) associated with Hyperthermic Intraperitoneal Chemotherapy (HIPEC). In fact, CRS-HIPEC represents the treatment with potential chances of cure and long-term disease control of patients affected by PMP. This therapeutic strategy should be performed in referral centers, where a consolidated know-how of this locoregional treatment and a multidisciplinary approach are available. CRS-HIPEC provides excellent results for PMP patients in terms of postoperative outcome, overall and disease-free survival, and quality of life. However, in patients with an extensive or recurrent disease, few therapeutic opportunities are available. This review is focused on the most recent clinical evidence and provides a better understanding of the molecular prognostic factors and potential therapeutic targets in this rare malignancy.

Abstract

Pseudomyxoma Peritonei (PMP) is an anatomo-clinical condition characterized by the implantation of neoplastic cells on peritoneal surfaces with the production of a large amount of mucin. The rarity of the disease precludes the evaluation of treatment strategies within randomized controlled trials. Cytoreductive Surgery (CRS) combined with Hyperthermic Intraperitoneal Chemotherapy (HIPEC) has proven to be the only therapeutic option with potential chances of cure and long-term disease control. The present review discusses the epidemiology, pathogenesis, clinical presentation and treatment of PMP, focusing on the molecular factors involved in tumor progression and mucin production that could be used, in the upcoming future, to improve patient selection for surgery and to expand the therapeutic armamentarium.

Antibody-Based Immunotoxins for Colorectal Cancer Therapy

Monoclonal antibodies (mAbs) are included among the treatment options for advanced colorectal cancer (CRC). However, while these mAbs effectively target cancer cells, they may have limited clinical activity. A strategy to improve their therapeutic potential is arming them with a toxic payload. Immunotoxins (ITX) combining the cell-killing ability of a toxin with the specificity of a mAb constitute a promising strategy for CRC therapy. However, several important challenges in optimizing ITX remain, including suboptimal pharmacokinetics and especially the immunogenicity of the toxin moiety. Nonetheless, ongoing research is working to solve these limitations and expand CRC patients' therapeutic armory. In this review, we provide a comprehensive overview of targets and toxins employed in the design of ITX for CRC and highlight a wide selection of ITX tested in CRC patients as well as preclinical candidates.

Imaging-Guided Therapy Simultaneously Targeting HER2 and EpCAM with Trastuzumab and EpCAM-Directed Toxin Provides Additive Effect in Ovarian Cancer Model

Efficient treatment of disseminated ovarian cancer (OC) is challenging due to its heterogeneity and chemoresistance. Overexpression of human epidermal growth factor receptor 2 (HER2) and epithelial cell adhesion molecule (EpCAM) in approx. 30% and 70% of ovarian cancers, respectively, allows for co-targeted treatment. The clinical efficacy of the monoclonal antibody trastuzumab in patients with HER2-positive breast, gastric and gastroesophageal cancers makes it readily available as the HER2-targeting component. As the EpCAM-targeting component, we investigated the designed ankyrin repeat protein (DARPin) Ec1 fused to a truncated variant of Pseudomonas exotoxin A with reduced immunogenicity and low general toxicity (LoPE). Ec1-LoPE was radiolabeled, evaluated in ovarian cancer cells in vitro and its biodistribution and tumor-targeting properties were studied in vivo. The therapeutic efficacy of Ec1-LoPE alone and in combination with trastuzumab was studied in mice bearing EpCAM- and HER2-expressing SKOV3 xenografts. SPECT/CT imaging enabled visualization of EpCAM and HER2 expression in the tumors. Co-treatment using Ec1-LoPE and trastuzumab was more effective at reducing tumor growth and prolonged the median survival of mice compared with mice in the control and monotherapy groups. Repeated administration of Ec1-LoPE was well tolerated without signs of hepatic or kidney toxicity. Co-treatment with trastuzumab and Ec1-LoPE might be a potential therapeutic strategy for HER2- and EpCAM-positive OC.

Increased Local Inflammatory Response to MOC31PE Immunotoxin After Cytoreductive Surgery and Hyperthermic Intraperitoneal Chemotherapy

Background

Despite extensive cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC), most patients with resectable peritoneal metastases from colorectal cancer experience disease relapse. MOC31PE immunotoxin is being explored as a novel treatment option for these patients. MOC31PE targets the cancer-associated epithelial cell adhesion molecule, and kills cancer cells by distinct mechanisms, simultaneously causing immune activation by induction of immunogenic cell death (ICD).

Methods

Systemic and local cytokine responses were analyzed in serum and intraperitoneal fluid samples collected the first three postoperative days from clinically comparable patients undergoing CRS-HIPEC with (n = 12) or without (n = 26) intraperitoneal instillation of MOC31PE. A broad panel of 27 pro- and antiinflammatory interleukins, chemokines, interferons, and growth factors was analyzed using multiplex technology.

Results

The time course and magnitude of the systemic and local postoperative cytokine response after CRS-HIPEC were highly compartmentalized, with modest systemic responses contrasting substantial intraperitoneal responses. Administration of MOC31PE resulted in changes that were broader and of higher magnitude compared with CRS-HIPEC alone. Significantly increased levels of innate proinflammatory cytokines, such as interleukin (IL)-6, IL-1β, and tumor necrosis factor (TNF) as well as an interesting time response curve for the strong T-cell stimulator interferon (IFN)-γ and its associated chemokine interferon gamma-induced protein/chemokine (C-X-C motif) ligand 10 (IP-10) were detected, all associated with ICD.

Conclusions

Our study revealed a predominately local rather than systemic inflammatory response to CRS-HIPEC, which was strongly enhanced by MOC31PE treatment. The MOC31PE-induced intraperitoneal inflammatory reaction could contribute to improve remnant cancer cell killing, but the mechanisms remain to be elucidated in future studies.

Supplementary Information

The online version contains supplementary material available at 10.1245/s10434-021-10022-0.

Expression and function of epithelial cell adhesion molecule EpCAM: where are we after 40 years?

EpCAM (epithelial cell adhesion molecule) was discovered four decades ago as a tumor antigen on colorectal carcinomas. Owing to its frequent and high expression on carcinomas and their metastases, EpCAM serves as a prognostic marker, a therapeutic target, and an anchor molecule on circulating and disseminated tumor cells (CTCs/DTCs), which are considered the major source for metastatic cancer cells. Today, EpCAM is reckoned as a multi-functional transmembrane protein involved in the regulation of cell adhesion, proliferation, migration, stemness, and epithelial-to-mesenchymal transition (EMT) of carcinoma cells. To fulfill these functions, EpCAM is instrumental in intra- and intercellular signaling as a full-length molecule and following regulated intramembrane proteolysis, generating functionally active extra- and intracellular fragments. Intact EpCAM and its proteolytic fragments interact with claudins, CD44, E-cadherin, epidermal growth factor receptor (EGFR), and intracellular signaling components of the WNT and Ras/Raf pathways, respectively. This plethora of functions contributes to shaping intratumor heterogeneity and partial EMT, which are major determinants of the clinical outcome of carcinoma patients. EpCAM represents a marker for the epithelial status of primary and systemic tumor cells and emerges as a measure for the metastatic capacity of CTCs. Consequentially, EpCAM has reclaimed potential as a prognostic marker and target on primary and systemic tumor cells.

Development of Glypican-3 Targeting Immunotoxins for the Treatment of Liver Cancer: An Update

Hepatocellular carcinoma (HCC) accounts for most liver cancers and represents one of the deadliest cancers in the world. Despite the global demand for liver cancer treatments, there remain few options available. The U.S. Food and Drug Administration (FDA) recently approved Lumoxiti, a CD22-targeting immunotoxin, as a treatment for patients with hairy cell leukemia. This approval helps to demonstrate the potential role that immunotoxins can play in the cancer therapeutics pipeline. However, concerns have been raised about the use of immunotoxins, including their high immunogenicity and short half-life, in particular for treating solid tumors such as liver cancer. This review provides an overview of recent efforts to develop a glypican-3 (GPC3) targeting immunotoxin for treating HCC, including strategies to deimmunize immunotoxins by removing B- or T-cell epitopes on the bacterial toxin and to improve the serum half-life of immunotoxins by incorporating an albumin binding domain.

Colorectal cancer peritoneal metastases: Biology, treatment and next steps

The presence of peritoneal metastases in patients with advanced colorectal cancer is associated with poor prognosis but the mechanisms for this are unclear. This review summarises the current knowledge of the pathophysiology, clinical features, prevalence, prognosis, and molecular biology of peritoneal metastases and the risk factors for the development of peritoneal metastases following resection of a primary colorectal tumour. Furthermore, the evidence for treatment strategies are described including cytoreductive surgery, hyperthermic intraperitoneal chemotherapy, early post-operative intraperitoneal chemotherapy, sequential post-operative intraperitoneal chemotherapy and emerging novel strategies. Active areas of research should include the identification of individuals at high risk of peritoneal metastases after curative resection of primary tumour, development of a surveillance program for high-risk patients, optimisation of systematic therapies and further investigation of the use of intraperitoneal chemotherapy.

ImmunoPeCa trial: Long-term outcome following intraperitoneal MOC31PE immunotoxin treatment in colorectal peritoneal metastasis

BACKGROUND

The ImmunoPeCa trial investigated the use of intraperitoneal MOC31PE immunotoxin as a novel therapeutic principle for the treatment of peritoneal metastasis from colorectal cancer (PM-CRC). We here report long-term outcome from the trial.

METHODS

This was a dose-finding trial aiming to evaluate safety and toxicity (primary endpoint) upon a single dose of intraperitoneal MOC31PE in patients with PM-CRC undergoing CRS-HIPEC with mitomycin C. Overall survival (OS) and disease-free survival (DFS) were secondary endpoints. Twenty-one patients received the study drug at four dose levels on the first postoperative day, including six patients constituting an expansion cohort.

RESULTS

With a 34-month follow-up, the median OS was not reached and the estimated 3-year OS was 78%. Median DFS for all patients was 21 months and the 3-year DFS was 33%, with a median follow-up of 31 months. When excluding patients with potential favorable characteristics from the analysis (n = 4), the median DFS was 13 months and the 3-year OS 72%.

CONCLUSIONS

The promising long-term outcome combined with low systemic absorbance, high drug concentration and cytotoxic activity in peritoneal fluid support further investigations of clinical efficacy.