Safety and efficacy of regorafenib in patients with treatment-refractory metastatic colorectal cancer in Turkey: the single-arm, open-label REGARD study

Combination of dual JAK/HDAC inhibitor with regorafenib synergistically reduces tumor growth, metastasis, and regorafenib-induced toxicity in colorectal cancer

BACKGROUND

Treatment with regorafenib, a multiple-kinase inhibitor, to manage metastatic colorectal cancers (mCRCs) shows a modest improvement in overall survival but is associated with severe toxicities. Thus, to reduce regorafenib-induced toxicity, we used regorafenib at low concentration along with a dual JAK/HDAC small-molecule inhibitor (JAK/HDACi) to leverage the advantages of both JAK and HDAC inhibition to enhance antitumor activity. The therapeutic efficacy and safety of the combination treatment was evaluated with CRC models.

METHODS

The cytotoxicity of JAK/HDACi, regorafenib, and their combination were tested with normal colonic and CRC cells exhibiting various genetic backgrounds. Kinomic, ATAC-seq, RNA-seq, cell cycle, and apoptosis analyses were performed to evaluate the cellular functions/molecular alterations affected by the combination. Efficacy of the combination was assessed using patient-derived xenograft (PDX) and experimental metastasis models of CRC. To evaluate the interplay between tumor, its microenvironment, and modulation of immune response, MC38 syngeneic mice were utilized.

RESULTS

The combination therapy decreased cell viability; phosphorylation of JAKs, STAT3, EGFR, and other key kinases; and inhibited deacetylation of histone H3K9, H4K8, and alpha tubulin proteins. It induced cell cycle arrest at G0-G1 phase and apoptosis of CRC cells. Whole transcriptomic analysis showed that combination treatment modulated molecules involved in apoptosis, extracellular matrix-receptor interaction, and focal adhesion pathways. It synergistically reduces PDX tumor growth and experimental metastasis, and, in a syngeneic mouse model, the treatment enhances the antitumor immune response as evidenced by higher infiltration of CD45 and cytotoxic cells. Pharmacokinetic studies showed that combination increased the bioavailability of regorafenib.

CONCLUSIONS

The combination treatment was more effective than with regorafenib or JAK/HDACi alone, and had minimal toxicity. A clinical trial to evaluate this combination for treatment of mCRCs is warranted.

An Efficacy and Safety Comparison of Regorafenib and Nivolumab in Unresectable Hepatocellular Cancer Patients: A Systematic Review

OBJECTIVE

This systematic review aimed to compare the efficacy and safety of regorafenib and nivolumab, two FDA-approved second-line treatments for unresectable Hepatocellular Carcinoma (HCC).

METHODS

Literature comparing the efficacy and safety of regorafenib and nivolumab in unresectable HCC patients was systematically searched across seven databases, including: PubMed, SCOPUS, Cochrane Database of Systematic Reviews, ScienceDirect, EBSCOhost, EMBASE, and ProQuest, using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. The search was done on April 2nd, 2023. Study quality and risk of bias were assessed using the Agency for Healthcare Research and Quality (AHRQ) and ROBINS-1 tools. The selected studies were included in the qualitative data synthesis.

RESULTS

Three trials found that HCC patients taking nivolumab had statistically insignificantly longer OS, TTP, and progression-free survival than those on regorafenib. Nivolumab increased ORR, with largely partial responses, and mixed DCR, with little statistical significance. All three studies showed that nivolumab had fewer side effects and improved tolerance.

DISCUSSION

Three retrospective cohort studies with a total of 383 regorafenib-receiving cohorts and 230 nivolumab-receiving cohorts were included in the qualitative analysis. Nivolumab was found to be superior in regards of longer overall survival, longer time to progression, higher objective response rate, and lower adverse event occurrence. However, statistical significance was not achieved in most of the parameters.

CONCLUSIONS

The use of nivolumab is preferable as the second-line systemic therapy for unresectable HCC. More high-quality studies are urgently needed to generate quantitative analysis, and to encourage the formation of guidelines for second-line systemic therapy.

Comparing the efficacy of regorafenib and 5-fluorouracil-based rechallenge chemotherapy in the third-line treatment of metastatic colorectal cancer

BACKGROUND

The optimal treatment for metastatic colorectal cancer (mCRC) after the second line is still controversial. Regorafenib has been the standard of care in this setting as it improved overall survival (OS) compared to placebo. In real-world practice chemotherapy rechallenge is also a preferred option even though supporting evidence is not enough. We aim to compare the efficacy of regorafenib and 5-fluorouracil-based (5-FU) rechallenge treatment in the third line setting of mCRC.

METHODS

In this retrospective multi-institutional trial, mCRC patients from 21 oncology centers who progressed after 2 lines of chemotherapy were analyzed. Patients who were treated with regorafenib or rechallenge therapy in the third-line setting were eligible. Rechallenge chemotherapy was identified as the re-use of the 5-FU based regimen which was administered in one of the previous treatment lines. OS, disease control rate (DCR), progression free survival (PFS) and toxicity were analyzed.

RESULTS

Three hundred ninety-four mCRC patients were included in the study. 128 (32.5%) were in the rechallenge, and 266 (67.5%) were in the regorafenib group. Median PFS was 5.82 months in rechallenge and 4 months in regorafenib arms (hazard ratio:1.45,95% CI, p = 0.167). DCR was higher in the rechallenge group than regorafenib (77% vs 49.5%, respectively, p =  < 0.001). Median OS after the third-line treatment was 11.99 (95% CI, 9.49-14.49) and 8.08 months (95% CI, 6.88-9.29) for rechallenge and regorafenib groups, respectively (hazard ratio:1.51, 95% CI, p < 0.001). More adverse effects and discontinuation were seen with regorafenib treatment.

CONCLUSION

Our study revealed that higher disease control and OS rates were achieved with rechallenge treatment compared to regorafenib, especially in patients who achieved disease control in one of the first two lines of therapy.

Regorafenib therapy as a third-line treatment for metastatic colorectal cancer: A single center long term experience

This study examined the effects of regorafenib (Reg) on progression-free survival (PFS), overall survival (OS), and adverse events (AEs) in metastatic colorectal cancer (mCRC) patients who underwent targeted treatment and chemotherapy. Reg was administered as a third-line treatment to 84 patients who had undergone 2 rounds of chemotherapy and targeted therapy and subsequently experienced progression. Treatment was initiated with a daily dose of 80 or 120 mg, based on the patient's ability to tolerate the medication, which was increased to 160 mg/day. The median PFS with Reg was 4 ± 0.2 months, while the median OS was 9 ± 1.2 months. When compared to patients who started Reg treatment at 80 mg, patients starting at 160 mg had longer median PFS and OS (PFS:6 ± 2.1 months vs 4 ± 0.2 months; P = .05; OS:13 ± 0.7 months vs 6 ± 1.3 months; P = .069). Patients with right-sided colon cancer who received Reg as third-line therapy had a significantly longer mPFS than those with left-sided colon cancer (8 months ± 4 vs 4 months ± 0.3, P = .039). Patients with KRAS mutations had a prolonged mPFS than those with panRAS-wild type (6 ± 1.6 months vs 4 ± 0.3 months, P = .06). The mPFS contribution in the BRAF mutant subgroup with poor prognosis is promising, as it is similar to that of patients without BRAF mutations (4 months ± 0.8 × 4 months ± 0.5, P = .74). The most common AEs reported were elevated liver enzyme levels and dermatological toxicities.

Prognostic factors for regorafenib treatment in patients with refractory metastatic colorectal cancer: A real-life retrospective multi-center study

Regorafenib, an oral multikinase inhibitor, has improved survival in metastatic colorectal cancer (mCRC) patients who have progressed on standard therapies. Our study aimed to evaluate prognostic factors influencing regorafenib treatment and assess the optimal dosing regimen in a real-life setting. We retrospectively analysed 263 patients with mCRC from multiple medical oncology clinics in Turkey. Treatment responses and prognostic factors for survival were evaluated using univariate and multivariate analysis. Of the patients, 120 were male, and 143 were female; 28.9% of tumors were located in the rectum. RAS mutations were present in 3.0% of tumors, while BRAF, K-RAS, and N-RAS mutations were found in 3.0%, 29.7%, and 25.9% of tumor tissues, respectively. Dose escalation was preferred in 105 (39.9%) patients. The median treatment duration was 3.0 months, with an objective response rate (ORR) of 4.9%. Grade ≥ 3 treatment-related toxicity occurred in 133 patients, leading to discontinuation, interruption, and modification rates of 50.6%, 43.7%, and 79.0%, respectively. Median progression-free survival (PFS) and overall survival (OS) were 3.0 and 8.1 months, respectively. RAS/RAF mutation (hazard ratio [HR] 1.5, 95% confidence interval [CI] 1.1-2.3; P = 0.01), pretreatment carcinoembryonic antigen (CEA) levels (HR 1.6, 95% CI 1.1-2.3; P = 0.008), and toxicity-related treatment interruption or dose adjustment (HR 1.6, 95% CI 1.1-2.4; P = 0.01) were identified as independent prognostic factors for PFS. Dose escalation had no significant effect on PFS but was associated with improved OS (P < 0.001). Independent prognostic factors for OS were the initial TNM stage (HR 1.3, 95% CI 1.0-1.9; P = 0.04) and dose interruption/adjustment (HR 0.4, 95% CI 0.2-0.9; P = 0.03). Our findings demonstrate the efficacy and safety of regorafenib. Treatment line influences the response, with dose escalation being more favorable than adjustment or interruption, thus impacting survival.

Risk of retinal vein occlusion in colorectal cancer patients receiving anti-vascular endothelial growth factors - a population-based cohort study

BACKGROUND

Anti-vascular endothelial growth factors (VEGFs) treatment has been associated with an increased risk of thromboembolic events. Therefore, the use of anti-VEGFs for patients with colorectal cancers (CRC) has raised concerns about the potential risk of retinal vein occlusion (RVO), an ocular disease caused by embolism or venous stasis. This study aims to evaluate the risk of RVO in patients with CRC treated with anti-VEGFs.

METHOD

We conducted a retrospective cohort study using the Taiwan Cancer Registry and National Health Insurance Database. The study cohort comprised patients newly diagnosed with CRC between 2011 and 2017, who received anti-VEGF treatment. For each patient in the study cohort, a control group comprising four patients newly diagnosed with CRC, but not receiving anti-VEGF treatment, was randomly selected. A washout period of 12 months was implemented to identify new cases. The index date was defined as the date of the first prescription of anti-VEGF drugs. The study outcome was the incidence of RVO, as identified by ICD-9-CM (362.35 and 362.36) or ICD-10-CM codes (H3481 and H3483). Patients were followed from their index date until the occurrence of RVO, death or the end of the study period. Covariates, including patients' age at index date, sex, calendar year of CRC diagnosis, stage of CRC and comorbidities related to RVO, were included. Multivariable Cox proportional hazards regression models were used to calculate hazard ratios (HRs) with adjustments for all covariates to compare the risk of RVO between the anti-VEGF and control groups.

RESULTS

We recruited 6285 patients in the anti-VEGF group and 37,250 patients in the control group, with mean ages of 59.49 ± 12.11 and 63.88 ± 13.17 years, respectively. The incidence rates were 1.06 per 1000 person-years for the anti-VEGF group, and 0.63 per 1000 person-years for the controls. There was no statistically significant difference in RVO risk between the anti-VEGF and control groups (HR: 2.21, 95% CI: 0.87-5.61).

CONCLUSION

Our results indicated no association between use of anti-VEGF and occurrence of RVO among CRC patients, although the crude incidence rate of RVO was higher in patients receiving anti-VEGF, compared to control patients. Future study with larger sample size is required to confirm our findings.

Safety and efficacy of trifluridine/tipiracil in previously treated metastatic colorectal cancer: PRECONNECT Turkey

Background: The efficacy and safety of trifluridine/tipiracil (FTD/TPI) for third-line treatment of metastatic colorectal cancer have been demonstrated. The authors present the Turkish post hoc analysis of the PRECONNECT study. Methods: An international, multicenter, single-arm, open-label, phase IIIb trial evaluating FTD/TPI in patients with ≥2 previous lines of chemotherapy for metastatic colorectal cancer was conducted. The primary end point was safety. Results: In this Turkish cohort (n = 100; eight centers), the most frequent treatment-emergent adverse event was neutropenia (48%). Median progression-free survival was 3.0 months; disease control rate was 36%; quality of life remained stable. Conclusion: Outcomes with FTD/TPI in Turkey are consistent with previous studies and confirm the efficacy and safety of FTD/TPI treatment in the third-line setting. Clinical Trial Registration: NCT03306394 (ClinicalTrials.gov).

The Role of the Tumor Microenvironment and Treatment Strategies in Colorectal Cancer

Colorectal cancer (CRC) has the second highest mortality rate among all cancers worldwide. Surgery, chemotherapy, radiotherapy, molecular targeting and other treatment methods have significantly prolonged the survival of patients with CRC. Recently, the emergence of tumor immunotherapy represented by immune checkpoint inhibitors (ICIs) has brought new immunotherapy options for the treatment of advanced CRC. As the efficacy of ICIs is closely related to the tumor immune microenvironment (TME), it is necessary to clarify the relationship between the immune microenvironment of CRC and the efficacy of immunotherapy to ensure that the appropriate drugs are selected. We herein review the latest research progress in the immune microenvironment and strategies related to immunotherapy for CRC. We hope that this review helps in the selection of appropriate treatment strategies for CRC patients.