Pharmacotherapeutic group: Antineoplastic and immunomodulating agents, antineoplastic agents, protein kinase inhibitors, ATC code: L01EX12.
Mechanism of action
Larotrectinib is an adenosine triphosphate (ATP)‑competitive and selective tropomyosin receptor kinase (TRK) inhibitor that was rationally designed to avoid activity with off‑target kinases. The target for larotrectinib is the TRK family of proteins inclusive of TRKA, TRKB, and TRKC that are encoded by NTRK1, NTRK2 and NTRK3 genes, respectively. In a broad panel of purified enzyme assays, larotrectinib inhibited TRKA, TRKB, and TRKC with IC50 values between 5‑11 nM. The only other kinase activity occurred at 100‑fold higher concentrations. In in vitro and in vivo tumour models, larotrectinib demonstrated anti‑tumour activity in cells with constitutive activation of TRK proteins resulting from gene fusions, deletion of a protein regulatory domain, or in cells with TRK protein overexpression.
In‑frame gene fusion events resulting from chromosomal rearrangements of the human genes NTRK1, NTRK2, and NTRK3 lead to the formation of oncogenic TRK fusion proteins. These resultant novel chimeric oncogenic proteins are aberrantly expressed, driving constitutive kinase activity subsequently activating downstream cell signalling pathways involved in cell proliferation and survival leading to TRK fusion‑positive cancer.
Acquired resistance mutations after progression on TRK inhibitors have been observed. Larotrectinib had minimal activity in cell lines with point mutations in the TRKA kinase domain, including the clinically identified acquired resistance mutation, G595R. Point mutations in the TRKC kinase domain with clinically identified acquired resistance to larotrectinib include G623R, G696A, and F617L.
The molecular causes for primary resistance to larotrectinib are not known. It is therefore not known if the presence of a concomitant oncogenic driver in addition to an NTRK gene fusion affects the efficacy of TRK inhibition. The measured impact of any concomitant genomic alterations on larotrectinib efficacy is provided below (see clinical efficacy).
Pharmacodynamic effects
Cardiac electrophysiology
In 36 healthy adult subjects receiving single doses ranging from 100 mg to 900 mg, VITRAKVI did not prolong the QT interval to any clinically relevant extent.
The 200 mg dose corresponds to a peak exposure (Cmax) similar to that observed with larotrectinib 100 mg BID at steady state. A shortening of QTcF was observed with VITRAKVI dosing, with a maximum mean effect observed between 3 and 24 hours after Cmax, with a geometric mean decrease in QTcF from baseline of ‑13.2 msec (range ‑10 to ‑15.6 msec). Clinical relevance of this finding has not been established.
Clinical efficacy
Overview of studies
The efficacy and safety of VITRAKVI were studied in three multicentre, open‑label, single‑arm clinical studies in adult and paediatric cancer patients (Table 5). Two studies are still ongoing.
Patients with and without documented NTRK gene fusion were allowed to participate in Study 1 and Study 3 (“SCOUT”). Patients enrolled to Study 2 (“NAVIGATE”) were required to have TRK fusion‑positive cancer. The pooled primary analysis set of efficacy includes 364 patients with TRK fusion‑positive cancer enrolled across the three studies that had measurable disease assessed by RECIST v1.1, a non‑CNS primary tumour and received at least one dose of larotrectinib as of July 2024. These patients were required to have received prior standard therapy appropriate for their tumour type and stage of disease or who, in the opinion of the investigator, would have had to undergo radical surgery (such as limb amputation, facial resection, or paralysis causing procedure), or were unlikely to tolerate, or derive clinically meaningful benefit from available standard of care therapies in the advanced disease setting. The major efficacy outcome measures were overall response rate (ORR) and duration of response (DOR), as determined by a blinded independent review committee (BIRC).
In addition, 60 patients with primary CNS tumours and measurable disease at baseline were treated in Study 2 (“NAVIGATE”) and in Study 3 (“SCOUT”). Fifty-seven of the 60 primary CNS tumour patients had received prior cancer treatment (surgery, radiotherapy and/or previous systemic therapy). Tumour responses were assessed by the investigator using RANO or RECIST v1.1 criteria.
Identification of NTRK gene fusions relied on tissue samples for the molecular test methods: next generation sequencing (NGS) used in 327 patients, polymerase chain reaction (PCR) used in 14 patients, fluorescence in situ hybridization (FISH) used in 18 patients, and other testing methods (Sequencing, Nanostring, Sanger sequencing, or Chromosome Microarray) used in 5 patients.
Table 5: Clinical studies contributing to the efficacy analyses in solid and primary CNS tumours
| Study name, design and patient population | Dose and formulation | Tumour types included in efficacy analysis | n |
| Study 1 NCT02122913 • Phase 1, open‑label, dose escalation and expansion study; expansion phase required tumours with an NTRK gene fusion • Adult patients (≥ 18 years) with advanced solid tumours with an NTRK gene fusion | Doses up to 200 mg once or twice daily (25 mg, 100 mg capsules or 20 mg/mL oral solution) | Thyroid (n=4) Salivary gland (n=3) GIST (n=2)a Soft tissue sarcoma (n=2) NSCLC (n=1)b, c Unknown primary cancer (n=1) | 13 |
| Study 2 “NAVIGATE” NCT02576431 • Phase 2 multinational, open label, tumour “basket” study • Adult and paediatric patients ≥ 12 years with advanced solid tumours with an NTRK gene fusion | 100 mg twice daily (25 mg, 100 mg capsules or 20 mg/mL oral solution) | NSCLC (n=29)b, c Soft tissue sarcoma (n=28) Thyroid (n=26)b Colon (n=25) Salivary gland (n=24) Primary CNS (n=19) Melanoma (n=10)b Breast, non‑secretory (n=10)b Pancreas (n=7) Breast, secretory (n=5) Cholangiocarcinoma (n=4) GIST (n=3)a Gastric (n=3) Prostate (n=2) Appendix, Atypical carcinoid lung cancer, Bone sarcoma, Cervix, Hepatice, Duodenal, External auditory canalb, Oesophageal, SCLCb, d, Rectal, Testesb, Thymus, Unknown primary cancer, Urothelial, Uterus (n=1 each) | 210 |
| Study 3 “SCOUT” NCT02637687 • Phase 1/2 multinational, open‑label, dose escalation and expansion study; Phase 2 expansion cohort required advanced solid tumours with an NTRK gene fusion, including locally advanced infantile fibrosarcoma • Paediatric patients from birth to 21 years with advanced cancer or with primary CNS tumours | Doses up to 100 mg/m2 twice daily (25 mg, 100 mg capsules or 20 mg/mL oral solution) | Infantile fibrosarcoma (n=49) Soft tissue sarcoma (n=42)b Primary CNS (n=41) Congenital mesoblastic nephroma (n=2) Bone sarcoma (n=2) Breast secretory, Cervix, Lipofibromatosis, Melanoma, Thyroid (n=1 each) | 141 |
| Total number of patients (n)* | 364 |
* consist of 304 patients with IRC tumour response assessment and 60 patients with primary CNS tumours (including astrocytoma, ganglioglioma, glioblastoma, glioma, glioneuronal tumours, neuronal and mixed neuronal‑glial tumours, oligodendroglioma, and primitive neuro‑ectodermal tumour, not specified) with investigator tumour response assessment
a GIST: gastrointestinal stromal tumour
b brain metastases were observed in some patients in the following tumour types: lung (NSCLC, SCLC), thyroid, melanoma, breast (non‑secretory), external auditory canal, soft tissue sarcoma and testes
c NSCLC: non‑small cell lung cancer
d SCLC: small cell lung cancer
e hepatocellular carcinoma
Baseline characteristics for the pooled 304 patients with solid tumours with an NTRK gene fusion were as follows: median age 44.5 years (range 0‑90 years); 33% < 18 years of age, and 67% ≥ 18 years; 55% white and 47% male; and ECOG PS 0‑1 (88%), 2 (10%), or 3 (2%). Ninety‑one percent of patients had received prior treatment for their cancer, defined as surgery, radiotherapy, or systemic therapy. Of these, 72% had received prior systemic therapy with a median of 1 prior systemic treatment regimen. Twenty‑eight percent of all patients had received no prior systemic therapy. Of those 304 patients the most common tumour types represented were soft tissue sarcoma (24%), infantile fibrosarcoma (16%), lung cancer (11%), thyroid cancer (10%), salivary gland tumour (9%) and colon cancer (8%).
Baseline characteristics for the 60 patients with primary CNS tumours with an NTRK gene fusion assessed by investigator were as follows: median age 9.1 years (range 0‑79 years); 43 patients < 18 years of age, and 17 patients ≥ 18 years, and 39 patients white and 28 patients male; and ECOG PS 0‑1 (52 patients), or 2 (5 patients). Fifty-seven (95%) patients had received prior treatment for their cancer, defined as surgery, radiotherapy, or systemic therapy. There was a median of 1 prior systemic treatment regimen received.
Efficacy results
The pooled efficacy results for overall response rate, duration of response and time to first response, in the primary analysis population (n=304) and with post‑hoc addition of primary CNS tumours (n=60) resulting in the pooled population (n=364), are presented in Table 6 and Table 7.
Table 6: Pooled efficacy results in solid tumours including and excluding primary CNS tumours
| Efficacy parameter | Analysis in solid tumours excluding primary CNS tumours (n=304)a | Analysis in solid tumours including primary CNS tumours (n=364)a, b |
| Overall response rate (ORR) % (n) [95% CI] | 65% (198) [59, 70] | 60% (219) [55, 65] |
| Complete response (CR) | 22% (66) | 20% (71) |
| Pathological complete responsec | 7% (20) | 5% (20) |
| Partial response (PR) | 37% (112) | 35% (128) |
| Time to first response (median, months) [range] | 1.84 [0.89, 22.90] | 1.84 [0.89, 49.87] |
| Duration of response (median, months) [range] % with duration ≥ 12 months % with duration ≥ 24 months % with duration ≥ 36 months % with duration ≥ 48 months | 43.3 [0.0+, 84.7+] 80% 66% 57% 48% | 43.3 [0.0+, 84.7+] 79% 65% 54% 47% |
+ denotes ongoing
a Independent review committee analysis by RECIST v1.1 for solid tumours except primary CNS tumours (304 patients).
b Evaluated using either RANO or RECIST v1.1 criteria for primary CNS tumours (60 patients).
c A pathological CR was a CR achieved by patients who were treated with larotrectinib and subsequently underwent surgical resection with no viable tumour cells and negative margins on post‑surgical pathology evaluation. The pre‑surgical best response for these patients was reclassified pathological CR after surgery following RECIST v.1.1.
Table 7: Overall response rate and duration of response by tumour type*
| Tumour type | Patients (n=364) | ORRa | DOR |
| % | 95% CI | months | Range (months) |
| ≥ 12 | ≥ 24 | ≥ 36 |
| Soft tissue sarcoma | 72 | 68% | 56%, 79% | 80% | 72% | 60% | 0.03+, 84.7+ |
| Primary CNS | 60 | 35% | 23%, 48% | 66% | 50% | 50% | 2.8+, 70.9+ |
| Infantile fibrosarcoma | 49 | 94% | 83%, 99% | 83% | 66% | 60% | 1.6+, 73.7+ |
| Lung | 32 | 69% | 50%, 84% | 75% | 52% | 45% | 1.9+, 67.2+ |
| Thyroid | 31 | 65% | 45%, 81% | 85% | 63% | 47% | 3.7, 83.9+ |
| Salivary gland | 27 | 85% | 66%, 96% | 91% | 86% | 76% | 2.7, 81.1+ |
| Colon | 25 | 48% | 28%, 69% | 83% | 62% | 31% | 3.9, 56.3+ |
| Breast | 16 | | | | | | |
| Non‑secretoryc | 10 | 30% | 7%, 65% | 67% | 0% | 0% | 7.4, 15.3 |
| Secretoryb | 6 | 83% | 36%, 100% | 80% | 80% | 80% | 11.1, 69.2+ |
| Melanoma | 11 | 45% | 17%, 77% | 50% | NR | NR | 1.9+, 23.2+ |
| Pancreas | 7 | 14% | 0%, 58% | 0% | 0% | 0% | 5.8, 5.8 |
| Gastrointestinal stromal tumour | 5 | 80% | 28%, 99% | 75% | 38% | 38% | 9.5, 50.4+ |
| Bone sarcoma | 3 | 33% | 1%, 91% | 0% | 0% | 0% | 9.5, 9.5 |
| Congenital mesoblastic nephroma | 2 | 100% | 16%, 100% | 100% | 100% | 50% | 32.9, 44.5 |
| Cervix | 2 | 50% | 1%, 99% | 100% | NR | NR | 18.7+, 18.7+ |
| Unknown primary cancer | 2 | 100% | 16%, 100% | 0 | 0 | 0 | 5.6, 7.4 |
| External auditory canal | 1 | 100% | 3%, 100% | 100% | 100% | 100% | 45.1+, 45.1+ |
| Lipofibromatosis | 1 | 100% | 3%, 100% | 100% | NR | NR | 17.7+, 17.7+ |
DOR: duration of response
NE: not evaluable
NR: not reached
* no data are available for the following tumour types: cholangiocarcinoma (n=4); gastric (n=3); prostate (n=2); appendix, hepatic, duodenal, oesophageal, rectal, testes, thymus, urothelial, uterus (n=1 each)
+ denotes ongoing response
a evaluated per independent review committee analysis by RECIST v1.1 for all tumour types except patients with a primary CNS tumour who were evaluated using either RANO or RECIST v1.1 criteria
b with 2 complete, 2 partial response
c with 1 complete, 2 partial response
Due to the rarity of TRK fusion‑positive cancer, patients were studied across multiple tumour types with a limited number of patients in some tumour types, causing uncertainty in the ORR estimate per tumour type. The ORR in the total population may not reflect the expected response in a specific tumour type.
In the adult sub‑population (n=222), the ORR was 51%. In the paediatric sub‑population (n=142), the ORR was 74%.
In 257 patients with wide molecular characterisation before larotrectinib treatment, the ORR in 120 patients who had other genomic alterations in addition to NTRK gene fusion was 53%, and in 137 patients without other genomic alterations ORR was 68%.
Pooled primary analysis set
The pooled primary analysis set consisted of 304 patients and did not include primary CNS tumours. Median time on treatment before disease progression was 15.9 months (range: 0.1 to 99.4 months) based on July 2024 cut‑off. Fifty‑five percent of patients had received VITRAKVI for 12 months or more, 37% had received VITRAKVI 24 months or more, and 28% had received VITRAKVI 36 months or more. Follow‑up was ongoing at the time of the analysis for 27% of patients.
At the time of analysis, the median duration of response is 43.3 months (range: 0.0+ to 84.7+), an estimated 80% [95% CI: 74, 86] of responses lasted 12 months or longer, 66% [95% CI: 59, 74] of responses lasted 24 months or longer, and 57% [95% CI: 49, 64] of responses lasted 36 months or longer. Eighty‑three percent (83%) [95% CI: 79, 88] of patients treated were alive one year after the start of therapy, 73% [95% CI: 68, 78] after two years after the start of therapy, and 68% [95% CI: 63, 74] after three years with the median for overall survival not yet being reached. Median progression free survival was 28.0 months at the time of the analysis, with a progression free survival rate of 63% [95% CI: 57, 69] after 1 year, 54% [95% CI: 48, 60] after 2 years, and 44% [95% CI: 38, 50] after 3 years.
The median change in tumour size in the pooled primary analysis set was a decrease of 66%.
Patients with primary CNS tumours
At the time of data cut‑off, of the 60 patients with primary CNS tumours confirmed response was observed in 21 patients (35%) with 5 of the 60 patients (8%) being complete responders and 16 patients (27%) being partial responders. Further 24 patients (40%) had stable disease. 13 patients (22%) had progressive disease. At the time of data cut‑off, time on treatment ranged from 1.2 to 67.3 months and was ongoing in 20 out of 60 patients, with all of these patients receiving post‑progression treatment.
Conditional approval
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 (MHRA) will review new information on this medicinal product at least every year and this SmPC will be updated as necessary.