Pharmacotherapeutic group: Antineoplastic agents, ATC code: L01XX73
Mechanism of action
Sotorasib is a potent and highly selective KRASG12C (Kirsten rat sarcoma viral oncogene homolog) inhibitor, which covalently and irreversibly binds to the unique cysteine of KRASG12C. Inactivation of KRASG12C by sotorasib blocks tumour cell signalling and survival, inhibits cell growth, and promotes apoptosis selectively in tumours harbouring KRASG12C, an oncogenic driver of tumourigenesis across multiple cancer types. The potency and selectivity of sotorasib is enhanced through the unique binding to both the P2 pocket and the His95 surface groove, locking the protein in an inactive state that prevents downstream signalling, without affecting wild-type KRAS.
Sotorasib demonstrated in vitro and in vivo inhibition of KRASG12C with minimal detectable off-target activity against other cellular proteins and processes. Sotorasib impaired oncogenic signalling and tumour cell survival at clinically relevant exposures in numerous pre-clinical models expressing KRASG12C. Sotorasib also enhanced antigen presentation and inflammatory cytokine production only in tumour cells with KRASG12C. Sotorasib induced anti-tumour inflammatory responses and immunity, driving permanent and complete tumour regressions in immunocompetent mice implanted with KRASG12C expressing tumours.
Clinical efficacy and safety
LUMYKRAS for the treatment of previously treated KRAS G12C-mutated NSCLC (CodeBreaK 100)
The efficacy of LUMYKRAS was demonstrated in a single-arm, open-label, multicentre trial (CodeBreaK 100) that enrolled patients with locally advanced or metastatic KRAS G12C-mutated NSCLC who had disease progression after receiving prior therapy. Key eligibility criteria included progression on an immune checkpoint inhibitor and/or platinum-based chemotherapy, an Eastern Cooperative Oncology Group Performance Status (ECOG PS) of 0 or 1, and at least one measurable lesion as defined by Response Evaluation Criteria in Solid Tumours (RECIST v1.1). All patients were required to have KRAS G12C-mutated NSCLC prospectively identified in tumour samples using a validated test performed in a central laboratory.
A total of 126 patients were enrolled and treated with LUMYKRAS 960 mg once daily as monotherapy until disease progression or unacceptable toxicity; 124 patients had at least one measurable lesion at baseline as assessed by Blinded Independent Central Review (BICR) according to RECIST v1.1 and were included in the analysis for response-related efficacy outcomes. The median duration of treatment was 5.5 months (range: 0 to 15) with 48% of patients treated for ≥ 6 months and 33% of patients treated for ≥ 9 months.
The major efficacy outcome measures were objective response rate (ORR) and duration of response (DOR) as evaluated by a BICR according to RECIST v1.1. Additional efficacy outcome measures included disease control rate (DCR), time to response (TTR), progression-free survival (PFS), and overall survival (OS).
The baseline demographic and disease characteristics of the study population were: median age 64 years (range: 37 to 80); 50% Female; 82% White, 15% Asian, 2% Black; 70% ECOG PS 1; 96% had stage IV disease; 99% with non-squamous histology; 81% former smokers, 12% current smokers, 5% never smokers.
All patients received at least 1 prior line of systemic therapy for metastatic NSCLC; 43% received only 1 prior line of therapy, 35% received 2 prior lines of therapy, 22% received 3 prior lines of therapy, 91% received prior anti-PD-1/PD-L1 immunotherapy, 90% received prior platinum-based chemotherapy, 81% received both platinum-based chemotherapy and anti-PD-1/PD-L1. The sites of known extra-thoracic metastasis included 48% bone, 21% brain, and 21% liver.
Efficacy results are summarised in table 4. The ORR was 37% (95% CI: 29, 47). The patients with objective responses had DOR ranging from 1.2 to 11.1 months, and 43% were still on therapy with ongoing response after a median duration of follow-up of 9.6 months. The median TTR was 1.4 months (range: 1.2 to 10.1), with 70% of responses occurring within the first 7 weeks.
Table 4. Efficacy results in CodeBreaK 100 for patients with KRAS G12C-mutated NSCLC
| Efficacy parameter | LUMYKRAS N = 124 |
| ORR, % (95% CI)a | 37.1 (28.6, 46.2) |
| Complete response (CR), % | 2.4 |
| Partial response (PR), % | 34.7 |
| DORa | |
| Medianb, months (range) | 10.0 (1.2, 11.1) |
| Patients with duration ≥ 6 months, % | 56.5 |
| DCR (95% CI) | 80.6 (72.6, 87.2) |
| PFSa | |
| Median, months (95% CI) | 6.8 (5.1, 8.2) |
| 6-month PFS, % (95% CI) | 52.2 (42.6, 60.9) |
| 9-month PFS, % (95% CI) | 37.2 (28.1, 46.3) |
| Efficacy parameter | LUMYKRAS N = 126 |
| OS | |
| Median, months (95% CI) | 12.5 (10.0, NE) |
| 6-month OS, % (95% CI) | 75.5 (66.8, 82.2) |
| 9-month OS, % (95% CI) | 63.5 (54.3, 71.4) |
| 12-month OS, % (95% CI) | 51.4 (41.9, 60.1) |
CI = confidence interval; DCR = disease control rate; DOR = duration of response; NE = not estimable; ORR = objective response rate; OS = overall survival; PFS = progression-free survival
a Response-related efficacy outcome
b Estimated using Kaplan-Meier method
Cardiac electrophysiology
The effect of sotorasib on the QT interval was assessed in 156 patients administered sotorasib 960 mg once daily in clinical studies. Sotorasib did not prolong the QT interval to any clinically relevant extent. At peak concentrations, the mean change from baseline was less than 5 msec. No patients had a large mean increase in QTc (> 20 msec) in the study.
Paediatric population
The Medicines and Healthcare products Regulatory Agency has waived the obligation to submit the results of studies with LUMYKRAS in all subsets of the paediatric population in NSCLC (see section 4.2 for information on paediatric use).
This medicinal product has been authorised under a so-called 'conditional approval' scheme. This means that further evidence on this medicinal product is awaited.
The Medicines and Healthcare products Regulatory Agency will review new information on this medicinal product at least every year and this SmPC will be updated as necessary.