Pharmacotherapeutic group: Antineoplastic agents, protein kinase inhibitor; ATC Code: L01EX05
Mechanism of action and pharmacodynamic effects
Regorafenib is an oral tumour deactivation agent that potently blocks multiple protein kinases, including kinases involved in tumour angiogenesis (VEGFR1, ‑2, ‑3, TIE2), oncogenesis (KIT, RET, RAF‑1, BRAF, BRAFV600E), metastasis (VEGFR3, PDGFR, FGFR) and tumour immunity (CSF1R). In particular, regorafenib inhibits mutated KIT, a major oncogenic driver in gastrointestinal stromal tumours, and thereby blocks tumour cell proliferation. In preclinical studies regorafenib has demonstrated potent antitumour activity in a broad spectrum of tumour models including colorectal, gastrointestinal stromal and hepatocellular tumour models which is likely mediated by its anti‑angiogenic and anti‑proliferative effects. In addition, regorafenib reduced the levels of tumour associated macrophages and has shown anti‑metastatic effects in vivo. Major human metabolites (M‑2 and M‑5) exhibited similar efficacies, compared to regorafenib in in vitro and in vivo models.
Clinical efficacy and safety
Metastatic colorectal cancer (CRC)
The clinical efficacy and safety of Stivarga have been evaluated in an international, multi‑centre, randomised, double‑blind, placebo‑controlled phase III study (CORRECT) in patients with metastatic colorectal cancer who have progressed after failure of standard therapy.
The primary efficacy endpoint was Overall Survival (OS). Secondary endpoints were Progression‑Free Survival (PFS), Objective Tumour Response Rate (ORR) and Disease Control Rate (DCR).
In total, 760 patients were randomised 2:1 to receive 160 mg regorafenib (4 tablets Stivarga each containing 40 mg regorafenib) orally once daily (N=505) plus Best Supportive Care (BSC or matching placebo (N=255) plus BSC for 3 weeks on therapy followed by 1 week off therapy. The mean daily regorafenib dose received was 147 mg.
Patients continued therapy until disease progression or unacceptable toxicity. A pre‑planned interim analysis for efficacy was performed when 432 deaths had occurred. The study was un‑blinded after this planned interim analysis of OS had crossed the pre‑specified efficacy boundary.
Of the 760 randomised patients, the median age was 61 years, 61% were male, 78% were Caucasian, and all patients had baseline ECOG Performance Status (PS of 0 or 1. PS ≥2 was reported during Stivarga treatment in 11.4% of patients. The median treatment duration and daily dose, as well as the rate of dose modification and dose reduction were similar to those observed in patients with a reported PS ≥ 2 receiving placebo (8.3%). The majority of patients with PS ≥2 discontinued treatment for progressive disease. The primary site of disease was colon (65%), rectum (29%), or both (6%). A KRAS mutation was reported in 57% of patients at study entry.
Most patients (52%) received 3 or fewer previous lines of treatment for metastatic disease. Therapies included treatment with fluoropyrimidine‑based chemotherapy, an anti‑VEGF therapy, and, if the patient was KRAS wild type, an anti‑EGFR therapy.
The addition of Stivarga to BSC resulted in significantly longer survival, compared to placebo plus BSC with a p value of 0.005178 from stratified log rank test, a hazard ratio of 0.774 [95% CI 0.636, 0.942] ) and a median OS of 6.4 months vs. 5.0 months (see Table 5 and Figure 1). PFS was significantly longer in patients receiving Stivarga plus BSC (hazard ratio: 0.494, p<0.000001, see Table 5). The response rate (complete response or partial response) was 1% and 0.4% for Stivarga and placebo treated patients, respectively (p=0.188432, 1-sided). The DCR (complete response or partial response or stable disease) was significantly higher in patients treated with Stivarga (41.0% vs. 14.9%, p<0.000001, 1 sided).
Table 5: Efficacy results from the CORRECT study
| Efficacy parameter | Hazard ratio* (95% CI) | P‑value (one‑sided) | Median (95% CI) |
| Stivarga plus BSC§ (N=505) | Placebo plus BSC§ (N=255) |
| OS | 0.774 (0.636, 0.942) | 0.005178 | 6.4 months (5.9, 7.3) | 5.0 months (4.4, 5.8) |
| PFS** | 0.494 (0.419, 0.582) | <0.000001 | 1.9 months (1.9, 2.1) | 1.7 months (1.7, 1.7) |
§ BSC Supportive Care
* Hazard ratio < 1 favours Stivarga
** based on investigator's assessment of tumour response
Figure 1: Kaplan‑Meier curve of OS
Subgroup analyses for OS and PFS according to age (<65; ≥65), gender, ECOG PS, primary site of disease, time from first diagnosis of metastatic disease, prior anticancer treatment, prior treatment lines for metastatic disease, and KRAS mutation status showed a treatment effect favouring the regorafenib regimen over the placebo regimen.
Subgroup analysis results by historical KRAS mutational status showed a treatment effect for OS in favour of regorafenib over placebo for patients with KRAS wild-type tumours whereas a numerically lower effect was reported in patients with KRAS mutant tumours; the treatment effect for PFS favouring regorafenib was observed regardless of KRAS mutational status. The hazard ratio (95% CI) of OS was 0.653 (0.476 to 0.895) for patients with KRAS wild-type tumours and 0.867 (0.670 to 1.123) for patients with KRAS mutant tumours, with no evidence of heterogeneity in treatment effect (non-significant interaction test). The hazard ratio (95% CI) of PFS was 0.475 (0.362 to 0.623) for patients with KRAS wild-type tumours and 0.525 (0.425 to 0.649) for patients with KRAS mutant tumours.
A second phase III, international, multi-centre, randomised, double blind, placebo-controlled study (CONCUR) evaluated the efficacy and safety of Stivarga in 204 pre-treated Asian patients (> 90% East Asian) with metastatic colorectal cancer who have progressed after failure of fluoropyrimidine-based chemotherapy. Only 59.5 % of patients enrolled in the CONCUR study were also previously treated with VEGF- or EGFR-targeted agents. The primary efficacy endpoint was OS. The addition of Stivarga to BSC resulted in a significantly longer survival, compared to placebo plus BSC with a hazard ratio of 0.550 (p = 0.000159 stratified log rank test) and a median OS of 8.8 months vs. 6.3 months [95% CI 0.395, 0.765]. PFS was also significantly longer in patients receiving Stivarga plus BSC (hazard ratio: 0.311, p<0.000001), median PFS 3.2 months with Stivarga vs. 1.7 months with placebo. The safety profile of Stivarga plus BSC in the CONCUR study was consistent with the safety profile observed in the CORRECT study.
Gastrointestinal stromal tumours (GIST)
The clinical efficacy and safety of Stivarga have been evaluated in an international, multi-centre, randomised, double-blind, placebo-controlled phase III study (GRID) in patients with gastrointestinal stromal tumours (GIST) previously treated with 2 tyrosine kinase inhibitors (imatinib and sunitinib).
The analysis of the primary efficacy endpoint Progression-Free Survival (PFS) was conducted after 144 PFS events (central blinded assessment). Secondary endpoints including Time To Progression (TTP) and Overall Survival (OS (interim analysis) were also assessed.
In total, 199 patients with GIST were randomised 2:1 to receive either 160 mg regorafenib plus Best Supportive Care (BSC) (N=133) orally once daily or matching placebo plus BSC (N=66) for 3 weeks on therapy followed by 1 week off therapy. The mean daily regorafenib dose received was 140 mg.
Patients continued therapy until disease progression or unacceptable toxicity. Patients receiving placebo who experienced disease progression were offered open-label regorafenib (cross-over option). Patients receiving regorafenib who experienced disease progression and for whom in the investigator's opinion, treatment with regorafenib was providing clinical benefit, were offered the opportunity to continue open-label regorafenib.
Of the 199 randomised patients, the mean age was 58 years, 64% were male, 68% were Caucasian, and all patients had baseline ECOG Performance Status (PS of 0 or 1. The overall median time since most recent progression or relapse to randomisation was 6 weeks.
Regorafenib plus BSC resulted in significantly longer PFS, compared to placebo plus BSC with a hazard ratio of 0.268 [95% CI 0.185, 0.388] and a median PFS of 4.8 months vs. 0.9 months (p < 0.000001). The relative risk of disease progression or death was reduced by approximately 73.2% in regorafenib-treated patients, compared to placebo treated patients (see Table 6, Figure 2).The increase in PFS was consistent independent of age, sex, geographic region, prior lines of treatment, ECOG PS.
TTP was significantly longer in patients receiving regorafenib plus BSC than in patients receiving placebo plus BSC with a hazard ratio of 0.248 [95% CI 0.170, 0.364], and median TTP of 5.4 months vs. 0.9 months (p<0.000001) (see Table 6).
The HR for OS was 0.772 (95% CI, 0.423, 1.408; p = 0.199; median OS not reached in either arm); 85% of patients initially randomised to the placebo arm received post-progression treatment with regorafenib (see Table 6, Figure 3).
Table 6: Efficacy results from the GRID study
| Efficacy parameter | Hazard ratio* (95% CI) | P-value (one-sided) | Median (95% CI) |
| Stivarga plus BSC§ (N=133) | Placebo plus BSC§ (N=66) |
| PFS | 0.268 (0.185, 0.388) | <0.000001 | 4.8 months (4.0, 5.7) | 0.9 months (0.9, 1.1) |
| TTP | 0.248 (0.170,0.364) | <0.000001 | 5.4 months (4.1, 5.7) | 0.9 months (0.9, 1.1) |
| OS | 0.772 (0.423, 1.408) | 0.199 | NR** | NR** |
§ Best Supportive Care
* Hazard ratio < 1 favours Stivarga
** NR: not reached
Figure 2: Kaplan-Meier curves of PFS
Figure 3: Kaplan-Meier curves of OS
In addition, 56 placebo plus BSC patients received open-label Stivarga after cross-over following disease progression and a total of 41 Stivarga plus BSC patients continued Stivarga treatment after disease progression. The median secondary PFS (as measured by the investigator's assessment) were 5.0 and 4.5 months, respectively.
Hepatocellular carcinoma (HCC)
The clinical efficacy and safety of Stivarga have been evaluated in an international, multi-centre, randomised, double-blind, placebo-controlled phase III study (RESORCE) in patients with hepatocellular carcinoma who have been previously treated with sorafenib.
The primary efficacy endpoint was Overall Survival (OS). Secondary endpoints were Progression-Free Survival (PFS), Time To Progression (TTP), Objective Tumour Response Rate (ORR) and Disease Control Rate (DCR).
In total, 573 patients with HCC were randomised 2:1 to receive either 160 mg regorafenib orally once daily (n=379) plus Best Supportive Care (BSC) or matching placebo (n=194) plus BSC for 3 weeks on therapy followed by 1 week off therapy. The mean daily regorafenib dose received was 144 mg. Patients were eligible to participate in the study if they experienced radiological disease progression during treatment with sorafenib and if they had a liver function status of Child-Pugh class A. Patients who permanently discontinued sorafenib therapy due to sorafenib-related toxicity or who tolerated less than 400 mg sorafenib once daily prior to withdrawal were excluded from the study. Randomisation was performed within 10 weeks after the last treatment with sorafenib. Patients continued therapy with Stivarga until clinical or radiological disease progression or unacceptable toxicity. However, patients could continue Stivarga therapy past progression at the discretion of the investigator.
Demographics and baseline disease characteristics were comparable between the Stivarga- and placebo-treated groups and are shown below for all 573 randomised patients:
• Median age: 63 years
• Male: 88%
• Caucasian: 36%, Asian: 41%
• ECOG Performance Status (PS) of 0: 66% or ECOG PS of 1: 34%
• Child-Pugh A: 98%, Child-Pugh B: 2%
• Aetiology included Hepatitis B (38%), Hepatitis C (21%), Non-Alcoholic Steato Hepatitis (NASH, 7%)
• Absence of both macroscopic vascular invasion and extra-hepatic tumour spread: 19%
• Barcelona Clinic Liver Cancer (BCLC) stage B: 13%; BCLC stage C: 87%
• Loco-regional transarterial embolisation or chemoinfusion procedures: 61%
• Radiotherapy prior to regorafenib treatment: 15%
• Median duration of sorafenib treatment: 7.8 months
The addition of Stivarga to BSC resulted in a statistically significant improvement in OS compared to placebo plus BSC with a hazard ratio of 0.624 [95% CI 0.498, 0.782], p=0.000017 stratified log rank test, and a median OS of 10.6 months vs. 7.8 months (see Table 7 and Figure 4).
Table 7: Efficacy results from the RESORCE study
| Efficacy parameter | Hazard ratio* (95% CI) | P‑value (one‑sided) | Median (95% CI) |
| Stivarga plus BSC§ (N=379) | Placebo plus BSC§ (N=194) |
| OS | 0.624 (0.498,0.782) | 0.000017 | 10.6 months (9.1, 12.1) | 7.8 months (6.3, 8.8) |
| PFS** | 0.453 (0.369, 0.555) | <0.000001 | 3.1 months (2.8, 4.2) | 1.5 months (1.4, 1.6) |
| TTP** | 0.439 (0.355,0.542) | <0.000001 | 3.2 months (2.9, 4.2) | 1.5 months (1.4, 1.6) |
| | | | Percentages |
| ORR**# | NA | 0.003650 | 11% | 4% |
| DCR **# | NA | <0.000001 | 65% | 36% |
§ Best Supportive Care
* Hazard ratio < 1 favours Stivarga
** based on investigator's assessment of tumour response by modified RECIST
# Response rate (complete or partial response), DCR (complete response, partial response and stable disease maintained for 6 weeks)
Figure 4: Kaplan-Meier curve of OS
Figure 5: Kaplan-Meier curve of PFS (mRECIST)
Paediatric population
The European Medicines Agency has waived the obligation to submit the results of studies with Stivarga in all subsets of the paediatric population in the treatment of adenocarcinoma of the colon and rectum, gastrointestional stromal tumours and hepatocellular carcinoma (see section 4.2 for information on paediatric use).
A multicentre, randomised, controlled, open-label study (CT3 portion of the FaR-RMS study) evaluated the safety and efficacy of regorafenib in combination with vincristine and irinotecan (VIRR) compared to standard therapy vincristine, irinotecan, and temozolomide (VIRT) in patients with a first or subsequent relapses of rhabdomyosarcoma.
Upon data review of 103 patients, including 84 paediatric patients from 6 months to less than 18 years old, at the first interim futility analysis, the recruitment of the study was terminated without formal evaluation of the primary endpoint of 1-year event-free survival (EFS). The futility boundary was met (EFS HR >1), indicating a low probability that VIRR would achieve the protocol defined 15% superiority over VRT.