The FDA on December 20, 2024, granted accelerated approval to BRAFTOVI® with Cetuximab and mFOLFOX6 for patients with metastatic colorectal cancer (mCRC) with a BRAF V600E mutation, as detected by an FDA-approved test. BRAFTOVI® is a product of Array BioPharma Inc., a subsidiary of Pfizer Inc.
Tag: Colon Cancer
No Additional Benefit When Oxaliplatin is Added to 5-FU Based Adjuvant Chemotherapy in High Risk Stage II Colon Cancer
SUMMARY: ColoRectal Cancer (CRC) is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society estimates that approximately 152,810 new cases of CRC were diagnosed in the United States in 2024 and about 53,010 patients died of the disease. The lifetime risk of developing CRC is about 1 in 23.
Colon cancer treatment strategies have advanced significantly over the years. Since 2004, the introduction of Oxaliplatin into adjuvant chemotherapy regimens has been a cornerstone in improving outcomes for patients with Stage III colon cancer. The most commonly adopted protocols include FOLFOX (a combination of Folinic acid or Leucovorin, 5-fluorouracil (5-FU), and Oxaliplatin) and a regimen combining Capecitabine with Oxaliplatin. These regimens gained validation through critical trials such as MOSAIC, NSABP C-07, and XELOXA, which demonstrated the survival benefits of Oxaliplatin-based combinations.
However, for patients with Stage II colon cancer, the role of adjuvant chemotherapy remains controversial. While many oncologists recommend adjuvant therapy for Stage II patients, its effectiveness is not universally supported by clinical data. The QUASAR trial showed limited benefits of Leucovorin and 5-FU in this population. Adding Oxaliplatin to adjuvant regimens has been explored to improve outcomes, particularly for high-risk patients. However, Oxaliplatin can be associated with neuropathy which can be long lasting or permanent, depending on the duration of therapy. Additional toxicities with longer duration of chemotherapy include diarrhea, fatigue as well as more office visits.
High-risk Stage II colon cancer is a heterogeneous group, and definitions of high-risk features vary across studies. High-risk features have included T4 tumors, bowel perforation, obstruction, poor histological differentiation, vascular invasion, or fewer than 10 lymph nodes examined. The heterogeneity of high-risk Stage II colon cancer complicates treatment decisions, with new clinical prognostic factors such as the site of tumor origin in the colon (tumor sidedness), age, and BMI having been described, in addition to the stage of the disease.
To clarify the benefits of Oxaliplatin in Stage II colon cancer, researchers performed a pooled analysis of the MOSAIC and NSABP C-07 trials. These studies collectively included 4,654 patients, of whom 1,595 had Stage II colon cancer, and were treated with either 5-FU and Leucovorin alone or 5-FU and Leucovorin plus Oxaliplatin. The Primary objective was to determine whether the addition of Oxaliplatin to 5-FU and Leucovorin provided a significant survival advantage for Stage II patients, particularly those with high-risk features. The analysis examined outcomes such as Overall Survival (OS) and Time to Relapse (TTR). Prognostic variables included T stage, presence of bowel perforation or obstruction, lymph node count, tumor sidedness, sex, age, and histological differentiation. Multivariable models and Kaplan-Meier survival analyses were employed to assess the impact of these variables. Patients with Stage III colon cancer were included only for interaction tests to compare treatment effects across stages.
The data from this pooled analysis revealed several important findings.
1. Prognostic Factors: Independent prognostic variables for Stage II colon cancer included sex, age, bowel perforation/obstruction, and tumor sidedness. These factors were associated with OS but did not predict a benefit from Oxaliplatin-based treatment.
2. Survival Outcomes: The addition of Oxaliplatin to 5-FU and Leucovorin did not significantly improve OS or TTR in Stage II colon cancer, even among high-risk subgroups. In contrast, a clear benefit was observed in Stage III colon cancer patients, suggesting a differential effect of Oxaliplatin based on cancer stage.
3. High-Risk Subgroup Analysis: Among patients with high-risk features such as T4 tumors or inadequate lymph node sampling, there was no statistically significant OS or TTR benefit from addition of Oxaliplatin to 5-FU and Leucovorin.
4. Interaction Between Stage and Therapy: The analysis confirmed an interaction between cancer Stage (II versus III) and the benefit of Oxaliplatin. Stage II colon cancer patients derived no added advantage from Oxaliplatin, while Stage III patients experienced substantial improvements in survival outcomes.
These results challenge existing guidelines from the American Society of Clinical Oncology (ASCO) and the European Society for Medical Oncology (ESMO), which recommend Oxaliplatin-based regimens for high-risk Stage II colon cancer. The findings suggest that current definitions of high-risk features are insufficient to justify the use of Oxaliplatin in this population. Moreover, discrepancies between Disease-Free Survival (DFS) and OS in Stage II colon cancer indicate that DFS is not a reliable surrogate endpoint in this group. The lack of benefit from Oxaliplatin emphasizes the need for more precise prognostic tools to identify Stage II patients who might benefit from adjuvant therapy.
Several limitations affected the study. Key data on biomarkers, such as MicroSatellite Instability (MSI) and MisMatch Repair (MMR) status, were unavailable for nearly half the cohort, preventing their inclusion in prognostic analyses. Emerging tools like circulating tumor DNA (ctDNA), which show promise in identifying relapse risk, were also unavailable during the study period. Despite the lack of benefit observed with Oxaliplatin, novel prognostic approaches are needed to identify Stage II colon cancer patients at a high risk of relapse. Future clinical trials incorporating ctDNA-based stratification may refine treatment approaches and reduce unnecessary exposure to neurotoxic agents like Oxaliplatin.
In conclusion, for patients with Stage II colon cancer, the addition of Oxaliplatin to 5-FU based adjuvant therapy does not improve Overall Survival or Time To Relapse. Current clinical and pathologic criteria for high-risk classification fail to justify the routine use of Oxaliplatin, emphasizing the need for alternative risk stratification tools. These findings call for a reevaluation of treatment guidelines to ensure that therapeutic decisions are informed by robust, individualized risk assessments.
Assessment of the Addition of Oxaliplatin to Fluoropyrimidine-Based Adjuvant Chemotherapy in Patients with High-Risk Stage II Colon Cancer: An ACCENT Pooled Analysis. Chibaudel B, Raeisi M, Cohen R, et al. J Clin Oncology 2024;42:4187-4195
KRAZATI® (Adagrasib)
The FDA on June 21, 2024, granted accelerated approval to KRAZATI® (Adagrasib) plus Cetuximab for adults with KRAS G12C-mutated locally advanced or metastatic ColoRectal Cancer (CRC), as determined by an FDA-approved test, who have received prior treatment with Fluoropyrimidine-, Oxaliplatin-, and Irinotecan-based chemotherapy. KRAZATI® is a product of Mirati Therapeutics, Inc.
Sotorasib plus Panitumumab in Refractory Colorectal Cancer with Mutated KRAS G12C
SUMMARY: Colorectal Cancer (CRC) is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society estimates that approximately 153,020 new cases of CRC were diagnosed in the United States in 2023 and about 52,550 patients died of the disease. The lifetime risk of developing CRC is about 1 in 23.
Approximately 15-25% of the patients with CRC present with metastatic disease at the time of diagnosis (synchronous metastases) and 50-60% of the patients with CRC will develop metastatic disease during the course of their illness. First line treatment of metastatic CRC includes Oxaliplatin or Irinotecan, in combination with a Fluoropyrimidine and Leucovorin (FOLFOX or FOLFIRI respectively), along with a VEGF targeting agent such as Bevacizumab or EGFR targeting agents such as Cetuximab and Panitumumab. Patients with Stage IV colorectal cancer are now routinely analyzed for extended RAS and BRAF mutations. KRAS mutations are predictive of resistance to EGFR targeted therapy. Patients who progress following these therapies are considered to have refractory disease. These patients sometimes are rechallenged with previously administered chemotherapeutic agents, but often receive STIVARGA® (Regorafenib), an oral multikinase inhibitor with antiangiogenic activity, or LONSURF® (a fixed dose combination of Trifluridine and Tipiracil). These therapies however have shown limited efficacy.
The KRAS (Kirsten rat sarcoma viral oncogene homologue) proto-oncogene encodes a protein that is a member of the small GTPase super family. The KRAS gene provides instructions for making the KRAS protein, which is a part of a signaling pathway known as the RAS/MAPK pathway. By relaying signals from outside the cell to the cell nucleus, the protein instructs the cell to grow, divide and differentiate. KRAS gene is in the Ras family of oncogenes, which also includes two other genes, HRAS and NRAS. When mutated, oncogenes have the potential to change normal cells cancerous. KRAS is the most frequently mutated oncogene in human cancers and are often associated with resistance to targeted therapies and poor outcomes. The KRAS G12C mutation occurs in approximately 12-15% of Non Small Cell Lung Cancers (NSCLC) and in 3-5% of colorectal cancers and other solid cancers. G12C is a single point mutation with a Glycine-to-Cysteine substitution at codon 12. This substitution favors the activated state of KRAS, amplifying signaling pathways that lead to oncogenesis. Currently, no targeted therapies driven by a positive-selection biomarker are approved specifically for the treatment of patients with KRAS-mutated colorectal cancer.
Sotorasib (LUMAKRAS®) is a small molecule that specifically and irreversibly inhibits KRAS G12C protein and traps KRAS G12C in the inactive GDP-bound state, thus blocking downstream proliferation and survival signaling. Unlike the efficacy of single-agent KRAS G12C inhibitors in Non Small Cell Lung Cancer with KRAS G12C mutation, KRAS G12C inhibition alone has limited activity in patients with colorectal cancer. This has been attributed to upstream reactivation of the Epidermal Growth Factor Receptor (EGFR) pathway resulting in treatment-induced resistance, following selective inhibition of KRAS G12C. However, dual KRAS G12C and EGFR blockade can overcome treatment resistance in patients with colorectal cancer with KRAS G12C mutation. In the CodeBreaK 101 Phase 1b trial involving patients with chemorefractory colorectal cancer with mutated KRAS G12C, the Response Rate was 30% with Sotorasib plus Panitumumab, as compared with 9.7% with Sotorasib monotherapy.
CodeBreaK 300 trial is an international, multicenter, open-label, randomized, active-controlled Phase III study, conducted to evaluate the efficacy and safety of two different doses of Sotorasib (960 mg and 240 mg) in combination with Panitumumab as compared with the investigator’s choice of standard-care therapy (Trifluridine-Tipiracil or Regorafenib) in patients with chemorefractory metastatic colorectal cancer with KRAS G12C mutation. A lower dose of Sotorasib 240 mg orally once daily was tested in this study because of the nonlinear pharmacokinetic properties of Sotorasib. A total of 160 patients were randomly assigned in a 1:1:1 ratio to receive Sotorasib 960 mg orally once daily plus Panitumumab 6 mg/kg IV every 2 weeks (the 960 mg Sotorasib/Panitumumab group; N=53), Sotorasib 240 mg orally once daily plus Panitumumab (the 240 mg Sotorasib/Panitumumab group; N=53), with each treatment cycle repeating every 28 days, or the investigator’s choice of standard of care therapy which could be either Trifluridine-Tipiracil 35 mg/m2 (up to a maximum of 80 mg per dose) orally twice daily on days 1-5 and days 8-12 every 28 days, or Regorafenib 160 mg orally once daily for the first 21 days of each 28-day cycle (N=54). Treatment continued until disease progression or unacceptable toxicities. The median age was 61 years and majority of patients had more than 2 or more lines of previous anti-cancer therapy. KRAS G12C mutation was confirmed by prospective central molecular testing. Randomization was stratified according to previous use of antiangiogenic therapy, the time from initial diagnosis of metastatic disease to randomization and ECOG-PS. The Primary end point was Progression Free Survival (PFS) as assessed by Blinded Independent Central Review (BICR). Key Secondary end points included Overall Survival (OS) and Objective Response Rate (ORR).
After a median follow up of 7.8 months, both Sotorasib combinations (960 mg and 240 mg) plus Panitumumab demonstrated significantly longer PFS compared to standard of care therapy. The median PFS was 5.6 months and 3.9 months in the 960 mg Sotorasib/Panitumumab and 240 mg Sotorasib/Panitumumab groups, respectively, as compared with 2.2 months in the standard of care group (HR for 960 mg group=0 49; P=0.006) (HR for 240 mg group=0.58; P=0.03). The improvement in PFS was observed across key subgroups, including tumor sideness/primary tumor location, prior lines of therapy, and the presence or absence of liver metastases. The Objective Response Rate was 26.4%, 5.7%, and 0% in the 960 mg Sotorasib/Panitumumab, 240 mg Sotorasib/Panitumumab, and standard of care groups, respectively. Overall survival data is immature. While this trial was not powered to compare the two Sotorasib/Panitumumab groups directly, the 960-mg dose appeared to yield more clinically significant benefits than the 240-mg dose, across all efficacy endpoints, without additional toxic effects. Grade 3 or higher treatment-related adverse events occurred in 35.8%, 30.2%, and 43.1% of patients, respectively. Skin-related toxic effects and hypomagnesemia were the most common adverse events observed with Sotorasib/Panitumumab.
It was concluded from this study that both doses of Sotorasib (960 mg and 240 mg) in combination with Panitumumab resulted in significantly longer Progression Free Survival and a higher incidence of Response Rate than standard treatment. Ongoing analysis and longer follow up will provide additional insights into Overall Survival outcomes.
Sotorasib plus Panitumumab in Refractory Colorectal Cancer with Mutated KRAS G12C. Fakih MG, Salvatore L, Esaki T, et al. N Engl J Med 2023;389:2125-2139.
FDA Approves KRAZATI® with ERBITUX® for KRAS G12C-Mutated Colorectal Cancer
SUMMARY: The FDA on June 21, 2024, granted accelerated approval to Adagrasib (KRAZATI®) plus Cetuximab (ERBITUX®) for adults with KRAS G12C-mutated locally advanced or metastatic Colorectal Cancer (CRC), as determined by an FDA-approved test, who have received prior treatment with Fluoropyrimidine, Oxaliplatin, and Irinotecan-based chemotherapy.
Colorectal cancer is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society estimates that approximately 152,810 new cases of colorectal cancer will be diagnosed in the United States in 2024 and about 53,010 patients will die of the disease. The lifetime risk of developing colorectal cancer is about 1 in 23.
Approximately 15-25% of the patients with colorectal cancer present with metastatic disease at the time of diagnosis (synchronous metastases) and 50-60% of the patients with colorectal cancer will develop metastatic disease during the course of their illness. First line treatment of metastatic colorectal cancer includes Oxaliplatin or Irinotecan, in combination with a Fluoropyrimidine and Leucovorin (FOLFOX or FOLFIRI respectively), along with a VEGF targeting agent such as Bevacizumab or EGFR targeting agents such as Cetuximab and Panitumumab (VECTIBIX®). Patients with Stage IV colorectal cancer are now routinely analyzed for extended RAS and BRAF mutations. KRAS mutations are predictive of resistance to EGFR targeted therapy. Patients who progress following these therapies are considered to have refractory disease. These patients sometimes are rechallenged with previously administered chemotherapeutic agents, but often receive STIVARGA® (Regorafenib), an oral multikinase inhibitor with antiangiogenic activity, or LONSURF® (a fixed dose combination of Trifluridine and Tipiracil). These therapies however have shown limited efficacy.
The KRAS (Kirsten rat sarcoma viral oncogene homologue) proto-oncogene encodes a protein that is a member of the small GTPase super family. The KRAS gene provides instructions for making the KRAS protein, which is a part of a signaling pathway known as the RAS/MAPK pathway. By relaying signals from outside the cell to the cell nucleus, the protein instructs the cell to grow, divide and differentiate. KRAS gene is in the Ras family of oncogenes, which also includes two other genes, HRAS and NRAS. When mutated, oncogenes have the potential to change normal cells cancerous. KRAS is the most frequently mutated oncogene in human cancers and are often associated with resistance to targeted therapies and poor outcomes. The KRAS G12C mutation occurs in approximately 12-15% of Non Small Cell Lung Cancers (NSCLC) and in 3-5% of colorectal cancers and other solid cancers. G12C is a single point mutation with a Glycine-to-Cysteine substitution at codon 12. This substitution favors the activated state of KRAS, amplifying signaling pathways that lead to oncogenesis. Currently, no targeted therapies driven by a positive-selection biomarker are approved specifically for the treatment of patients with KRAS-mutated colorectal cancer.
Adagrasib (KRAZATI®) is a potent, orally available, small molecule covalent inhibitor of KRAS G12C. This drug irreversibly and selectively binds KRAS G12C in its inactive, GDP-bound state. Unlike Sotorasib (LUMAKRAS®)), which is also a selective covalent inhibitor of KRAS G12C, Adagrasib has a longer drug half-life of 23 hours, as compared to 5 hours for Sotorasib, has dose-dependent extended exposure, and can penetrate the CNS. Unlike the efficacy of single-agent KRAS G12C inhibitors in Non Small Cell Lung Cancer with KRAS G12C mutation, KRAS G12C inhibition alone has limited activity in patients with colorectal cancer. This has been attributed to upstream reactivation of the Epidermal Growth Factor Receptor (EGFR) pathway resulting in treatment-induced resistance, following selective inhibition of KRAS G12C. However, dual KRAS G12C and EGFR blockade can overcome treatment resistance in patients with colorectal cancer with KRAS G12C mutation.
Cetuximab (ERBITUX®) is an anti-EGFR monoclonal antibody that is indicated for the treatment of RAS wild-type metastatic colorectal cancer, either as monotherapy or in combination with chemotherapy. Combining Cetuximab with Adagrasib may overcome treatment resistance and enhance the inhibition of KRAS-dependent signaling and improve outcomes.
The present FDA approval was based on the ongoing KRYSTAL-1, multicenter, expansion cohort Phase 1-2 trial, in which the use of Adagrasib as monotherapy or in combination with Cetuximab was evaluated in patients with previously treated metastatic colorectal cancer with mutant KRAS G12C. Eligible patients had locally advanced or metastatic KRAS G12C-mutated colorectal cancer, and had previous treatment with Fluoropyrimidine, Oxaliplatin, and Irinotecan-based chemotherapy, and a VEGF inhibitor, if eligible. These patients were heavily pretreated, having received a median of three prior lines of therapy, and their disease had shown resistance to previous treatments. Patients received Adagrasib 600 mg orally twice daily along with Cetuximab 500 mg/m2 IV every two weeks, or 400 mg/m2 IV as initial dose followed by 250 mg/m2 IV weekly. Tumor assessments were performed every 6 weeks. Treatment was continued until disease progression or unacceptable toxicity, Adagrasib discontinuation required Cetuximab discontinuation, however patients could continue Adagrasib if Cetuximab was discontinued. The median patient age was 59 years old, and 51% were women and both treatment groups were well balanced. The Primary efficacy endpoint of the study was the confirmed Overall Response Rate (ORR), assessed by Blinded Independent Central Review (BICR). Secondary endpoints included Duration of Response (DOR), Progression Free Survival (PFS), Overall Survival (OS), and Safety. Efficacy was assessed in 94 (N=94) enrolled patients.
The study met its Primary endpoint and the ORR was 34%. All responses were Partial Responses (PR), indicating a reduction in tumor burden in responding patients. The median Duration of Response was 5.8 months, with 31% of responders experiencing a Duration of Response of at least 6 months. The most common adverse reactions were rash, nausea, vomiting, diarrhea, fatigue, musculoskeletal pain, hepatotoxicity, anemia, headache, dry skin, decreased appetite, abdominal pain, constipation, edema, cough, and peripheral neuropathy.
In conclusion, the KRYSTAL-1 trial has demonstrated that Adagrasib in combination with Cetuximab shows promising clinical activity and a manageable safety profile in heavily pretreated patients with metastatic CRC harboring the KRAS G12C mutation. These findings highlight a potential new treatment option for patients who have limited therapeutic alternatives and underscore the evolving landscape of precision medicine in oncology, particularly in targeting specific mutations that drive tumor growth and survival.
https://www.fda.gov/drugs/resources-information-approved-drugs/fda-grants-accelerated-approval-adagrasib-cetuximab-kras-g12c-mutated-colorectal-cancer.
Sotorasib plus Panitumumab in Refractory Colorectal Cancer with Mutated KRAS G12C
SUMMARY: Colorectal Cancer (CRC) is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society estimates that approximately 153,020 new cases of CRC were diagnosed in the United States in 2023 and about 52,550 patients died of the disease. The lifetime risk of developing CRC is about 1 in 23.
Approximately 15-25% of the patients with CRC present with metastatic disease at the time of diagnosis (synchronous metastases) and 50-60% of the patients with CRC will develop metastatic disease during the course of their illness. First line treatment of metastatic CRC includes Oxaliplatin or Irinotecan, in combination with a Fluoropyrimidine and Leucovorin (FOLFOX or FOLFIRI respectively), along with a VEGF targeting agent such as Bevacizumab or EGFR targeting agents such as Cetuximab and Panitumumab. Patients with Stage IV colorectal cancer are now routinely analyzed for extended RAS and BRAF mutations. KRAS mutations are predictive of resistance to EGFR targeted therapy. Patients who progress following these therapies are considered to have refractory disease. These patients sometimes are rechallenged with previously administered chemotherapeutic agents, but often receive STIVARGA® (Regorafenib), an oral multikinase inhibitor with antiangiogenic activity, or LONSURF® (a fixed dose combination of Trifluridine and Tipiracil). These therapies however have shown limited efficacy.
The KRAS (Kirsten rat sarcoma viral oncogene homologue) proto-oncogene encodes a protein that is a member of the small GTPase super family. The KRAS gene provides instructions for making the KRAS protein, which is a part of a signaling pathway known as the RAS/MAPK pathway. By relaying signals from outside the cell to the cell nucleus, the protein instructs the cell to grow, divide and differentiate. KRAS gene is in the Ras family of oncogenes, which also includes two other genes, HRAS and NRAS. When mutated, oncogenes have the potential to change normal cells cancerous. KRAS is the most frequently mutated oncogene in human cancers and are often associated with resistance to targeted therapies and poor outcomes. The KRAS G12C mutation occurs in approximately 12-15% of Non Small Cell Lung Cancers (NSCLC) and in 3-5% of colorectal cancers and other solid cancers. G12C is a single point mutation with a Glycine-to-Cysteine substitution at codon 12. This substitution favors the activated state of KRAS, amplifying signaling pathways that lead to oncogenesis. Currently, no targeted therapies driven by a positive-selection biomarker are approved specifically for the treatment of patients with KRAS-mutated colorectal cancer.
Sotorasib (LUMAKRAS®) is a small molecule that specifically and irreversibly inhibits KRAS G12C protein and traps KRAS G12C in the inactive GDP-bound state, thus blocking downstream proliferation and survival signaling. Unlike the efficacy of single-agent KRAS G12C inhibitors in Non Small Cell Lung Cancer with KRAS G12C mutation, KRAS G12C inhibition alone has limited activity in patients with colorectal cancer. This has been attributed to upstream reactivation of the Epidermal Growth Factor Receptor (EGFR) pathway resulting in treatment-induced resistance, following selective inhibition of KRAS G12C. However, dual KRAS G12C and EGFR blockade can overcome treatment resistance in patients with colorectal cancer with KRAS G12C mutation. In the CodeBreaK 101 Phase 1b trial involving patients with chemorefractory colorectal cancer with mutated KRAS G12C, the Response Rate was 30% with Sotorasib plus Panitumumab, as compared with 9.7% with Sotorasib monotherapy.
CodeBreaK 300 trial is an international, multicenter, open-label, randomized, active-controlled Phase III study, conducted to evaluate the efficacy and safety of two different doses of Sotorasib (960 mg and 240 mg) in combination with Panitumumab as compared with the investigator’s choice of standard-care therapy (Trifluridine-Tipiracil or Regorafenib) in patients with chemorefractory metastatic colorectal cancer with KRAS G12C mutation. A lower dose of Sotorasib 240 mg orally once daily was tested in this study because of the nonlinear pharmacokinetic properties of Sotorasib. A total of 160 patients were randomly assigned in a 1:1:1 ratio to receive Sotorasib 960 mg orally once daily plus Panitumumab 6 mg/kg IV every 2 weeks (the 960 mg Sotorasib/Panitumumab group; N=53), Sotorasib 240 mg orally once daily plus Panitumumab (the 240 mg Sotorasib/Panitumumab group; N=53), with each treatment cycle repeating every 28 days, or the investigator’s choice of standard of care therapy which could be either Trifluridine-Tipiracil 35 mg/m2 (up to a maximum of 80 mg per dose) orally twice daily on days 1-5 and days 8-12 every 28 days, or Regorafenib 160 mg orally once daily for the first 21 days of each 28-day cycle (N=54). Treatment continued until disease progression or unacceptable toxicities. The median age was 61 years and majority of patients had more than 2 or more lines of previous anti-cancer therapy. KRAS G12C mutation was confirmed by prospective central molecular testing. Randomization was stratified according to previous use of antiangiogenic therapy, the time from initial diagnosis of metastatic disease to randomization and ECOG-PS. The Primary end point was Progression Free Survival (PFS) as assessed by Blinded Independent Central Review (BICR). Key Secondary end points included Overall Survival (OS) and Objective Response Rate (ORR).
After a median follow up of 7.8 months, both Sotorasib combinations (960 mg and 240 mg) plus Panitumumab demonstrated significantly longer PFS compared to standard of care therapy. The median PFS was 5.6 months and 3.9 months in the 960 mg Sotorasib/Panitumumab and 240 mg Sotorasib/Panitumumab groups, respectively, as compared with 2.2 months in the standard of care group (HR for 960 mg group=0 49; P=0.006) (HR for 240 mg group=0.58; P=0.03). The improvement in PFS was observed across key subgroups, including tumor sideness/primary tumor location, prior lines of therapy, and the presence or absence of liver metastases. The Objective Response Rate was 26.4%, 5.7%, and 0% in the 960 mg Sotorasib/Panitumumab, 240 mg Sotorasib/Panitumumab, and standard of care groups, respectively. Overall survival data is immature. While this trial was not powered to compare the two Sotorasib/Panitumumab groups directly, the 960-mg dose appeared to yield more clinically significant benefits than the 240-mg dose, across all efficacy endpoints, without additional toxic effects. Grade 3 or higher treatment-related adverse events occurred in 35.8%, 30.2%, and 43.1% of patients, respectively. Skin-related toxic effects and hypomagnesemia were the most common adverse events observed with Sotorasib/Panitumumab.
It was concluded from this study that both doses of Sotorasib (960 mg and 240 mg) in combination with Panitumumab resulted in significantly longer Progression Free Survival and a higher incidence of Response Rate than standard treatment. Ongoing analysis and longer follow up will provide additional insights into Overall Survival outcomes.
Sotorasib plus Panitumumab in Refractory Colorectal Cancer with Mutated KRAS G12C. Fakih MG, Salvatore L, Esaki T, et al. N Engl J Med 2023;389:2125-2139.
Sotorasib plus Panitumumab in Refractory Colorectal Cancer with Mutated KRAS G12C
SUMMARY: Colorectal Cancer (CRC) is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society estimates that approximately 153,020 new cases of CRC were diagnosed in the United States in 2023 and about 52,550 patients died of the disease. The lifetime risk of developing CRC is about 1 in 23.
Approximately 15-25% of the patients with CRC present with metastatic disease at the time of diagnosis (synchronous metastases) and 50-60% of the patients with CRC will develop metastatic disease during the course of their illness. First line treatment of metastatic CRC includes Oxaliplatin or Irinotecan, in combination with a Fluoropyrimidine and Leucovorin (FOLFOX or FOLFIRI respectively), along with a VEGF targeting agent such as Bevacizumab or EGFR targeting agents such as Cetuximab and Panitumumab. Patients with Stage IV colorectal cancer are now routinely analyzed for extended RAS and BRAF mutations. KRAS mutations are predictive of resistance to EGFR targeted therapy. Patients who progress following these therapies are considered to have refractory disease. These patients sometimes are rechallenged with previously administered chemotherapeutic agents, but often receive STIVARGA® (Regorafenib), an oral multikinase inhibitor with antiangiogenic activity, or LONSURF® (a fixed dose combination of Trifluridine and Tipiracil). These therapies however have shown limited efficacy.
The KRAS (Kirsten rat sarcoma viral oncogene homologue) proto-oncogene encodes a protein that is a member of the small GTPase super family. The KRAS gene provides instructions for making the KRAS protein, which is a part of a signaling pathway known as the RAS/MAPK pathway. By relaying signals from outside the cell to the cell nucleus, the protein instructs the cell to grow, divide and differentiate. KRAS gene is in the Ras family of oncogenes, which also includes two other genes, HRAS and NRAS. When mutated, oncogenes have the potential to change normal cells cancerous. KRAS is the most frequently mutated oncogene in human cancers and are often associated with resistance to targeted therapies and poor outcomes. The KRAS G12C mutation occurs in approximately 12-15% of Non Small Cell Lung Cancers (NSCLC) and in 3-5% of colorectal cancers and other solid cancers. G12C is a single point mutation with a Glycine-to-Cysteine substitution at codon 12. This substitution favors the activated state of KRAS, amplifying signaling pathways that lead to oncogenesis. Currently, no targeted therapies driven by a positive-selection biomarker are approved specifically for the treatment of patients with KRAS-mutated colorectal cancer.
Sotorasib (LUMAKRAS®) is a small molecule that specifically and irreversibly inhibits KRAS G12C protein and traps KRAS G12C in the inactive GDP-bound state, thus blocking downstream proliferation and survival signaling. Unlike the efficacy of single-agent KRAS G12C inhibitors in Non Small Cell Lung Cancer with KRAS G12C mutation, KRAS G12C inhibition alone has limited activity in patients with colorectal cancer. This has been attributed to upstream reactivation of the Epidermal Growth Factor Receptor (EGFR) pathway resulting in treatment-induced resistance, following selective inhibition of KRAS G12C. However, dual KRAS G12C and EGFR blockade can overcome treatment resistance in patients with colorectal cancer with KRAS G12C mutation. In the CodeBreaK 101 Phase 1b trial involving patients with chemorefractory colorectal cancer with mutated KRAS G12C, the Response Rate was 30% with Sotorasib plus Panitumumab, as compared with 9.7% with Sotorasib monotherapy.
CodeBreaK 300 trial is an international, multicenter, open-label, randomized, active-controlled Phase III study, conducted to evaluate the efficacy and safety of two different doses of Sotorasib (960 mg and 240 mg) in combination with Panitumumab as compared with the investigator’s choice of standard-care therapy (Trifluridine-Tipiracil or Regorafenib) in patients with chemorefractory metastatic colorectal cancer with KRAS G12C mutation. A lower dose of Sotorasib 240 mg orally once daily was tested in this study because of the nonlinear pharmacokinetic properties of Sotorasib. A total of 160 patients were randomly assigned in a 1:1:1 ratio to receive Sotorasib 960 mg orally once daily plus Panitumumab 6 mg/kg IV every 2 weeks (the 960 mg Sotorasib/Panitumumab group; N=53), Sotorasib 240 mg orally once daily plus Panitumumab (the 240 mg Sotorasib/Panitumumab group; N=53), with each treatment cycle repeating every 28 days, or the investigator’s choice of standard of care therapy which could be either Trifluridine-Tipiracil 35 mg/m2 (up to a maximum of 80 mg per dose) orally twice daily on days 1-5 and days 8-12 every 28 days, or Regorafenib 160 mg orally once daily for the first 21 days of each 28-day cycle (N=54). Treatment continued until disease progression or unacceptable toxicities. The median age was 61 years and majority of patients had more than 2 or more lines of previous anti-cancer therapy. KRAS G12C mutation was confirmed by prospective central molecular testing. Randomization was stratified according to previous use of antiangiogenic therapy, the time from initial diagnosis of metastatic disease to randomization and ECOG-PS. The Primary end point was Progression Free Survival (PFS) as assessed by Blinded Independent Central Review (BICR). Key Secondary end points included Overall Survival (OS) and Objective Response Rate (ORR).
After a median follow up of 7.8 months, both Sotorasib combinations (960 mg and 240 mg) plus Panitumumab demonstrated significantly longer PFS compared to standard of care therapy. The median PFS was 5.6 months and 3.9 months in the 960 mg Sotorasib/Panitumumab and 240 mg Sotorasib/Panitumumab groups, respectively, as compared with 2.2 months in the standard of care group (HR for 960 mg group=0 49; P=0.006) (HR for 240 mg group=0.58; P=0.03). The improvement in PFS was observed across key subgroups, including tumor sideness/primary tumor location, prior lines of therapy, and the presence or absence of liver metastases. The Objective Response Rate was 26.4%, 5.7%, and 0% in the 960 mg Sotorasib/Panitumumab, 240 mg Sotorasib/Panitumumab, and standard of care groups, respectively. Overall survival data is immature. While this trial was not powered to compare the two Sotorasib/Panitumumab groups directly, the 960-mg dose appeared to yield more clinically significant benefits than the 240-mg dose, across all efficacy endpoints, without additional toxic effects. Grade 3 or higher treatment-related adverse events occurred in 35.8%, 30.2%, and 43.1% of patients, respectively. Skin-related toxic effects and hypomagnesemia were the most common adverse events observed with Sotorasib/Panitumumab.
It was concluded from this study that both doses of Sotorasib (960 mg and 240 mg) in combination with Panitumumab resulted in significantly longer Progression Free Survival and a higher incidence of Response Rate than standard treatment. Ongoing analysis and longer follow up will provide additional insights into Overall Survival outcomes.
Sotorasib plus Panitumumab in Refractory Colorectal Cancer with Mutated KRAS G12C. Fakih MG, Salvatore L, Esaki T, et al. N Engl J Med 2023;389:2125-2139.
FRUZAQLA® (Fruquintinib)
The FDA on November 8, 2023, approved FRUZAQLA® (Fruquintinib) for adult patients with metastatic ColoRectal Cancer (mCRC) who received prior Fluoropyrimidine, Oxaliplatin, and Irinotecan-based chemotherapy, an anti-VEGF therapy, and, if RAS wild-type and medically appropriate, an anti-EGFR therapy. FRUZAQLA® is a product of Takeda Pharmaceuticals, Inc.
FDA Approves Fruquintinib in Refractory Metastatic Colorectal Cancer
SUMMARY: The FDA on November 8, 2023, approved Fruquintinib (FRUZAQLA®) for adult patients with metastatic Colorectal Cancer (mCRC) who received prior Fluoropyrimidine, Oxaliplatin, and Irinotecan-based chemotherapy, an anti-VEGF therapy, and, if RAS wild-type and medically appropriate, an anti-EGFR therapy. Colorectal Cancer (CRC) is the third most common cancer diagnosed in both men and women in the United States. The American Cancer Society estimates that approximately 153,020 new cases of CRC will be diagnosed in the United States in 2023 and about 52,550 patients are expected to die of the disease. The lifetime risk of developing CRC is about 1 in 23.
Approximately 15-25% of the patients with CRC present with metastatic disease at the time of diagnosis (synchronous metastases) and 50-60% of the patients with CRC will develop metastatic disease during the course of their illness. First line treatment of metastatic CRC includes Oxaliplatin or Irinotecan, in combination with a Fluoropyrimidine and Leucovorin (FOLFOX or FOLFIRI respectively), along with a VEGF targeting agent such as Bevacizumab or EGFR targeting agents such as Cetuximab and Panitumumab. Patients with Stage IV CRC are now routinely analyzed for extended RAS and BRAF mutations. KRAS mutations are predictive of resistance to EGFR targeted therapy. Patients who progress following these therapies are considered to have refractory disease. These patients sometimes are rechallenged with previously administered chemotherapeutic agents, but often receive STIVARGA® (Regorafenib), an oral multikinase inhibitor with antiangiogenic activity, or LONSURF® (a fixed dose combination of Trifluridine and Tipiracil). Regorafenib has limited efficacy and its adverse effects, particularly hepatotoxicity and fatigue, may be difficult to manage. Treatment options are limited for those who progress on these therapies and there is therefore a strong unmet clinical need.
The VEGF pathway plays a very important role in the neoangiogenesis associated with tumor proliferation. Antiangiogenic agents targeting the VEGF pathway inhibit new blood vessel growth and lead to vascular regression, tumor vessel normalization and constriction, in addition to offsetting the ability of chemotherapy to induce VEGF. This benefit was noted in the SUNLIGHT trial which demonstrated longer Overall Survival and Progression Free Survival among patients with refractory metastatic CRC, treated with LONSURF® plus Bevacizumab, compared to LONSURF® alone (N Engl J Med 2023; 388:1657-1667).
Fruquintinib is a highly selective and potent, oral small molecule inhibitor of VEGFR1/2/3. Fruquintinib was designed to have enhanced selectivity that limits off-target kinase activity, allowing for high drug exposure, sustained target inhibition, and flexibility for the potential use as part of combination therapy.
The present FDA approved was based on two Phase III trials, FRESCO and FRESCO-2. FRESCO is a randomized, double-blind, placebo-controlled, multicenter Phase III clinical trial conducted in China to evaluate the efficacy and safety of oral Fruquintinib, as third-line or later therapy in patients with metastatic CRC. It should be noted that unlike treatment patterns in North America and Europe, VEGF inhibitors such as Bevacizumab and Aflibercept are not routinely integrated into first- or second-line therapy in China. In this study 416 eligible patients (N=416) who had tumor progression following treatment regimens that included Fluoropyrimidine, Oxaliplatin, and Irinotecan were randomly assigned to receive Fruquintinib 5 mg (N=278) or placebo (N=138), both in combination with best supportive care, given orally once daily for 21 days, followed by 7 days off in 28-day cycles, until disease progression or intolerable toxicity. Randomization was stratified by prior use of VEGF inhibitor treatment (yes versus no) and K-ras mutational status (wild type versus mutated). The mean age was 55 years and most baseline demographics, disease characteristics, and prior treatments were similar between the treatment groups. Over 65% of patients had liver metastases. The Primary end point was Overall Survival (OS). Secondary efficacy endpoints included Progression Free Survival (PFS), Objective Response Rate (ORR), Disease Control Rate, Duration of Response and Safety.
The median Overall Survival was significantly prolonged with Fruquintinib compared with placebo (9.3 months versus 6.6 months; HR for death=0.65; P<0.001). The median PFS was also significantly increased with Fruquintinib (3.7 months versus 1.8 months; HR for progression or death=0.26; P<0.001).
The FRESCO-2 study is a global, multi-regional, randomized, placebo-controlled, Phase III trial conducted separately in the U.S., Europe, Japan and Australia among patients with heavily pretreated metastatic colorectal cancer. The reason for this trial was that practice patterns are different in these countries compared to China, with VEGF inhibitors such as Bevacizumab routinely integrated into first- or second-line therapy in these countries. In this study, 691 eligible patients (N=691) were randomly assigned (2:1) to receive Fruquintinib 5 mg (N=461) or matched placebo (N=230) orally once daily on days 1–21 in 28-day cycles, plus best supportive care. Patients received therapy until disease progression or unacceptable toxicity. This study included histologically or cytologically documented metastatic colorectal adenocarcinoma who had received all current standard approved cytotoxic and targeted therapies and progressed on or were intolerant to LONSURF® or Regorafenib, or both. Patients had received a median of 4 lines of previous systemic therapy for metastatic disease, and 73% of the eligible patients had received more than 3 lines of therapy for metastatic disease. Patients were stratified based on previous therapy with LONSURF® or Regorafenib, or both, RAS mutation status, and duration of metastatic disease. The Primary endpoint was Overall Survival (OS). Secondary endpoints included Progression Free Survival (PFS) and Duration of Response.
This study met its Primary endpoint and the median OS was 7.4 months in the Fruquintinib group versus 4.8 months in the placebo group (HR=0.66; P<0.0001). This represented a 34% reduction in the risk of death in the Fruquintinib group. The median PFS in the Fruquintinib group was 3.7 months which was also statistically significant. The median Duration of Response was 10.7 months, the Disease Control Rate was 56%, and 41% of patients were alive at 9 months. The most common Grade 3 or worse adverse events in the Fruquintinib group included hypertension (14%)), asthenia (8%), and hand-foot syndrome (6%).
Both FRESCO and FRESCO-2 trials demonstrated a statistically significant and clinically meaningful improvement in Overall Survival, and Progression Free Survival in patients with refractory metastatic colorectal cancer, when treated with Fruquintinib. This innovative therapy fulfills an unmet need and provides a new treatment option for this heavily pretreated group of patients.
Effect of Fruquintinib vs Placebo on Overall Survival in Patients with Previously Treated Metastatic Colorectal Cancer-The FRESCO Randomized Clinical Trial. Li J, Qin S, Xu R_H, et al. JAMA. 2018;319:2486-2496.
Fruquintinib versus placebo in patients with refractory metastatic colorectal cancer (FRESCO-2): an international, multicentre, randomised, double-blind, phase 3 study. Dasari A, Lonardi S, Garcia-Carbonero R, et al. Lancet. 2023;402:41-53. doi:10.1016/S0140-6736(23)00772-9.
LONSURF® (Trifluridine and Tipiracil ) with Bevacizumab
The FDA on August 2, 2023, approved LONSURF® with Bevacizumab, for metastatic ColoRectal Cancer (mCRC) previously treated with Fluoropyrimidine, Oxaliplatin and Irinotecan-based chemotherapy, an anti-VEGF biological therapy, and if RAS wild-type, an anti-EGFR therapy. FDA had previously approved single-agent LONSURF® for this indication in September 2015. LONSURF® is a product of Taiho Oncology, Inc.