Long term response on Regorafenib in non-V600E BRAF mutated colon cancer: a case report

Regorafenib in Patients With Solid Tumors With BRAF Alterations: Results From the Targeted Agent and Profiling Utilization Registry (TAPUR) Study

PURPOSE

Targeted Agent and Profiling Utilization Registry is a phase II basket trial evaluating the antitumor activity of commercially available targeted agents in patients with advanced cancer with genomic alterations known to be drug targets. Results of a cohort of patients with solid tumors with BRAF alterations treated with regorafenib are reported.

METHODS

Eligible patients had measurable disease (RECIST v.1.1), Eastern Cooperative Oncology Group performance status 0-1, adequate organ function, and no standard treatment options. The primary end point was disease control (DC), defined as investigator assessment of patients with complete or partial response (PR) or stable disease of at least 16-weeks duration (SD16+). Low accruing histology-specific cohorts with BRAF alterations treated with regorafenib were collapsed into a single histology-pooled cohort for this analysis. The results were evaluated on the basis of a one-sided exact binomial test with a null DC rate of 15% versus 35% (power, 0.84; α, .10). Secondary end points were objective response (OR), progression-free survival, overall survival, duration of response, duration of stable disease, and safety.

RESULTS

Twenty-eight patients with 12 tumor types with BRAF alterations were enrolled from June 2016 to June 2021. All patients were evaluable for efficacy. Two patients with PR and four with SD16+ were observed for DC and OR rates of 21% (90% CI, 12 to 100) and 7% (95% CI, 1 to 24), respectively. The null hypothesis of 15% DC rate was not rejected (P = .24). Eight patients had at least one grade 3 adverse event or serious adverse event at least possibly related to regorafenib.

CONCLUSION

Regorafenib did not meet prespecified criteria to declare a signal of activity in patients with solid tumors with BRAF alterations.

Targeting All BRAF Alterations: The (Re)-Search Continues

VivekSubbiah & colleagues delve into the @ASCO #TAPURStudy, shedding light on the importance of targeting ALL #BRAFAlterations, beyond V600E. (Re)-search continues, urging us to push the boundaries and unlock new possibilities in #PrecisionMedicine. #CancerResearch #JCOPO.

Atypical (non-V600E) BRAF mutations in metastatic colorectal cancer in population and real-world cohorts

BRAF-V600E mutation (mt) is a strong negative prognostic and predictive biomarker in metastatic colorectal cancer (mCRC). Non-V600Emt, designated atypical BRAFmt (aBRAFmt) are rare, and little is known about their frequency, co-mutations and prognostic and predictive role. These were compared between mutational groups of mCRC patients collected from three Nordic population-based or real-world cohorts. Pathology of aBRAFmt was studied. The study included 1449 mCRC patients with 51 (3%) aBRAFmt, 182 (13%) BRAF-V600Emt, 456 (31%) RAS&BRAF wild-type (wt) and 760 (52%) RASmt tumours. aBRAFmt were seen in 2% of real-world and 4% of population-based cohorts. Twenty-six different aBRAFmt were detected, 11 (22%) class 2 (serrated adenocarcinoma in 2/9 tested), 32 (64%) class 3 (serrated in 15/25) and 4 (8%) unclassified. aBRAFmt patients were predominantly male, had more rectal primaries, less peritoneal metastases, deficient mismatch repair in one (2%), and better survival after metastasectomy (89% 5-year overall survival [OS]-rate) compared with BRAF-V600Emt. aBRAFmt and BRAF-V600Emt had poorer performance status and received fewer treatment lines than RAS&BRAFwt and RASmt. OS among aBRAFmt (median 14.4 months) was longer than for BRAF-V600Emt (11.2 months), but shorter than for RAS&BRAFwt (30.5 months) and RASmt (23.4 months). Addition of bevacizumab trended for better OS for the aBRAFmt. Nine patients with aBRAFmt received cetuximab/panitumumab without response. aBRAFmt represents a distinct subgroup differing from other RAS/BRAF groups, with serrated adenocarcinoma in only half. OS for patients with aBRAFmt tumours was slightly better than for BRAF-V600Emt, but worse than for RASmt and RAS&BRAFwt. aBRAFmt should not be a contraindication for metastasectomy.

Appropriate dose of regorafenib based on body weight of colorectal cancer patients: a retrospective cohort study

PURPOSE

Previous randomized studies have shown a survival benefit of using regorafenib but a high rate of adverse events in unresectable colorectal cancer patients. To reduce these adverse events and improve the tolerability, we examined the appropriate dose of regorafenib based on body weight.

METHODS

We used a nationwide claims database in Japan and examined the efficacy and safety of regorafenib for patients with metastatic colorectal cancer between groups divided by body weight (60 kg) and median average dose (120 mg) between 2013 and 2018. We also assessed overall survival (OS) and adverse events between these groups.

RESULTS

We identified 2530 Japanese patients (heavy weight/high dose: 513, light weight/low dose: 921, heavy weight/low dose: 452, and light weight/high dose: 644). There was no significant difference in the adverse events and OS after inverse probability treatment weighting (IPTW) adjustment between heavy weight/high dose group and light weight/low dose group (hazard ratio, HR=0.97). Among the light-weight patients, higher average dose was associated with shorter OS (IPTW adjusted HR=1.21, 95% CI 1.05 - 1.39, Table 3) while among the heavy-weight patients, there was no significant difference in OS between high and low dose groups (IPTW adjusted HR=1.14, 95% CI 0.95 - 1.37).

CONCLUSION

The findings suggest that a low dose of regorafenib for light-weight patients may be as safe and effective as high doses for heavy-weight patients. Further studies should be conducted to identify an appropriate dose based on each patient's physique and condition.

Long-term response of more than 9 years to regorafenib in a heavily pretreated patient with metastatic colorectal cancer

Colorectal cancer (CRC) is the third most common cancer worldwide, with approximately 1.9 million new diagnoses and 935 000 deaths annually. Overall, there is accumulating evidence that receiving all available treatments leads to a survival advantage and, although tailored treatments might be appropriate for selected patients, the one-size-fits-all approach is still widely used in chemo-refractory patients. Currently, different antiangiogenics and multitarget agents are indicated in treatment of metastatic CRC (mCRC) whereas the identification of useful predictive factors for the treatment response is lacking. Analysis of potential predictive biomarkers of efficacy of regorafenib is still ongoing but may prove to be difficult because of its nonspecific activity across a wide range of angiogenic, oncogenic, stromal, and intracellular signaling kinases. We present a case of a 57-year-old Caucasian woman diagnosed with recurrence after curative surgery for rectal adenocarcinoma stage III (ypT3N2). Despite undergoing multiple lines of standard chemotherapy, disease control could not be maintained. Consequently, regorafenib, a multikinase inhibitor with antiangiogenic proprieties, was started as a late-line treatment and a dose reduction strategy allowed a long-term response of more than 9 years with good tolerability.

Targeting BRAF V600E in metastatic colorectal cancer: where are we today?

Colorectal cancer (CRC) is the second most frequent cause of direct cancer death worldwide. The study of the molecular state of oncogenes has predictive and prognostic value in metastatic CRC (mCRC). The B-raf proto-oncogene (BRAF) gene mutation represents the 8%-12% of all mutations in mCRC. The BRAF V600E mutation, considered the most common alteration of BRAF, corresponds to a constitutive kinase with a high activating capacity of the RAS/RAF/MEK/ERK pathway after a cascade of successive phosphorylations in the transcription of genes. BRAF V600E mutation is more prevalent in women, elderly, right-sided colon cancer and Caucasian population. Unfortunately, it is considered a poor predictive and prognosis biomarker. Patients with mCRC BRAF V600E mutated (BRAFm) are generally associated with poor response to chemotherapy and short progression-free survival and overall survival. Recently, randomised clinical trials have studied the combination of different chemotherapy regimens with angiogenic inhibitors in mCRC BRAFm. In addition, new anti-BRAF and immunotherapy agents have also been studied in this population, with positive results. The objective of this review is to acknowledge the biology and molecular pathway of BRAF, critically analyse the clinical trials and the therapy options published until today and evaluate the options of treatment according to the patient's clinical presentation.

A Promising Role of TGF-β Pathway in Response to Regorafenib in Metastatic Colorectal Cancer: A Case Report

Colorectal cancer (CRC) is one of the most common cancer types around the world. The prognosis of patients with advanced diseases is still poor in spite of currently available therapeutic options. Regorafenib is an oral tyrosine kinase inhibitor (TKI) approved to treat refractory metastatic colorectal cancer (mCRC). We investigated Somatic mutations in several genes involved in immunological response and cancer progression in both long/short responder mCRC patients who underwent third-line therapy with regorafenib to identify predictive biomarkers of response using Ion Torrent PGM sequencing and bioinformatic tools. We found Somatic mutations in TGFBR1, TGFBR2, and TGFBR3 genes in primary tumor and metastases samples of long-responder patients. Furthermore, our bioinformatic results show that they were mainly enriched in immune response, cell junction, and cell adhesion in long responder patients, particularly in primary tumor and metastatic sites. These data suggest that the TGF-b pattern could be the leading actor of a prolonged response to this drug.

Prolonged clinical response with regorafenib administered as second-line therapy in an elderly patient suffering from peritoneal carcinomatosis of colon cancer

Peritoneal carcinomatosis from colorectal cancer (CRC) has a poor prognosis with median survival and clinical responses that are worse than for other metastatic sites, and even more so in pretreated patients proposed for regorafenib therapy. Thus, patients with these characteristics are a therapeutic challange. The present study reports the case of an 83-year-old woman with diffuse peritoneal carcinomatosis from CRC, RAS-mutated, and treated with second-line therapy with the off-label administration of regorafenib at full dose (160 mg once daily, for the first 21 days of each 4-week cycle), refusing conventional chemotherapy. The patient reported an unexpected clinical response, reduced toxicity, excellent adherence to therapy and remained progression-free for 30 months from the start of treatment. In clinical practice, an earlier use of regorafenib and a different selection of patients could be the subject of future studies.

Re-Evaluation of the Survival Paradox Between Stage IIB/IIC and Stage IIIA Colon Cancer

Objective

We conducted this large population-based study to re-evaluate the survival paradox between stage IIB/C and stage IIIA colon cancer based on the newest staging criteria.

Methods

Colon cancer patients were recruited from the Surveillance, Epidemiology, and End Results (SEER) database using SEER*Stat software (version 8.3.4) with strict inclusion criteria. We used Chi-square test to compare categorical variables between patients diagnosed with stage IIB/IIC and stage IIIA colon cancer. Survival probabilities were then assessed using the Kaplan–Meier method. Cox proportional hazards models were used to analyze hazard ratios (HRs) and 95% confidence intervals (CIs) of clinicopathologic characteristics in stage IIB/IIC and stage IIIA colon cancer patients.

Results

In the current study, a total of 9,227 eligible colon cancer patients were collected from the SEER database between 2010 and 2015. It was found that stage IIIA had 66.4% decreased risk of colon cancer-specific mortality compared with stage IIB (HR = 0.336, 95%CI = 0.286–0.394 for stage IIIA, P < 0.001, using stage IIB as the reference) after the adjustment for other known prognostic factors. And T1N2a colon cancer had significantly lower 5-year overall survival (OS) rate compared with T2N1 disease (74.7% vs. 57.1%, P = 0.018).

Conclusions

Our study confirmed the existence of survival paradox between stage IIB/IIC and stage IIIA colon cancer based on the newest staging criteria. What is more, the subgroup analyses revealed that T1N2a had the least influence on the survival paradox. N2a colon cancer seemed to be associated with worse prognosis than T2 disease, which would give us a better understanding of tumor biology of colon cancer and be conducive to the refinement of individualized treatment regimens in stage III disease.

Cellular Mechanisms Accounting for the Refractoriness of Colorectal Carcinoma to Pharmacological Treatment

Simple Summary

Colorectal cancer (CRC) causes a high number (more than 800,000) of deaths worldwide each year. Better methods for early diagnosis and the development of strategies to enhance the efficacy of the therapeutic approaches used to complement or substitute surgical removal of the tumor are urgently needed. Currently available pharmacological armamentarium provides very moderate benefits to patients due to the high resistance of tumor cells to respond to anticancer drugs. The present review summarizes and classifies into seven groups the cellular and molecular mechanisms of chemoresistance (MOC) accounting for the failure of CRC response to the pharmacological treatment.

Abstract

The unsatisfactory response of colorectal cancer (CRC) to pharmacological treatment contributes to the substantial global health burden caused by this disease. Over the last few decades, CRC has become the cause of more than 800,000 deaths per year. The reason is a combination of two factors: (i) the late cancer detection, which is being partially solved by the implementation of mass screening of adults over age 50, permitting earlier diagnosis and treatment; (ii) the inadequate response of advanced unresectable tumors (i.e., stages III and IV) to pharmacological therapy. The latter is due to the existence of complex mechanisms of chemoresistance (MOCs) that interact and synergize with each other, rendering CRC cells strongly refractory to the available pharmacological regimens based on conventional chemotherapy, such as pyrimidine analogs (5-fluorouracil, capecitabine, trifluridine, and tipiracil), oxaliplatin, and irinotecan, as well as drugs targeted toward tyrosine kinase receptors (regorafenib, aflibercept, bevacizumab, cetuximab, panitumumab, and ramucirumab), and, more recently, immune checkpoint inhibitors (nivolumab, ipilimumab, and pembrolizumab). In the present review, we have inventoried the genes involved in the lack of CRC response to pharmacological treatment, classifying them into seven groups (from MOC-1 to MOC-7) according to functional criteria to identify cancer cell weaknesses. This classification will be useful to pave the way for developing sensitizing tools consisting of (i) new agents to be co-administered with the active drug; (ii) pharmacological approaches, such as drug encapsulation (e.g., into labeled liposomes or exosomes); (iii) gene therapy interventions aimed at restoring the impaired function of some proteins (e.g., uptake transporters and tumor suppressors) or abolishing that of others (such as export pumps and oncogenes).

Long-term survival of an advanced colorectal cancer patient treated with Regorafenib: Case report and literature review

Two phase 3 trials reported a prolonged survival in the third-line setting of colorectal cancer patients treated with regorafenib with the longest duration of treatment of 16 months. Herein, we reported a unique case of a patient refractory to conventional chemotherapy who showed a prolonged stable disease with regorafenib.