Clinical Pharmacology for Rozlytrek
Mechanism Of Action
Entrectinib is an inhibitor of the tropomyosin receptor tyrosine kinases (TRK) TRKA, TRKB, and TRKC (encoded by the neurotrophic tyrosine receptor kinase [NTRK] genes NTRK1, NTRK2, and NTRK3, respectively), proto-oncogene tyrosine-protein kinase ROS1 (ROS1), and anaplastic lymphoma kinase (ALK) with IC50 values of 0.1 to 2 nM. Entrectinib also inhibits JAK2 and TNK2 with IC50 values > 5 nM. The major active metabolite of entrectinib, M5, showed similar in vitro activity against TRK, ROS1, and ALK.
Fusion proteins that include TRK, ROS1, or ALK kinase domains can drive tumorigenic potential through hyperactivation of downstream signaling pathways leading to unconstrained cell proliferation. Entrectinib demonstrated in vitro and in vivo inhibition of cancer cell lines derived from multiple tumor types harboring NTRK, ROS1, and ALK fusion genes.
Entrectinib demonstrated steady-state brain-to-plasma concentration ratios of 0.4 – 2.2 in multiple animal species (mice, rats, and dogs) and demonstrated in vivo anti-tumor activity in mice with intracranial implantation of TRKA- and ALK-driven tumor cell lines.
Pharmacodynamics
Entrectinib exposure-response relationships and the time course of pharmacodynamic responses are unknown.
Cardiac Electrophysiology
Across clinical trials, 3.1% of 355 patients, who received ROZLYTREK at doses ranging from 100 mg to 2600 mg daily under fasting or fed conditions (75% received 600 mg orally once daily) and had at least one post-baseline ECG assessment, experienced QTcF interval prolongation of > 60 ms after starting ROZLYTREK and 0.6% had a QTc interval > 500 ms [see WARNINGS AND PRECAUTIONS].
Pharmacokinetics
The pharmacokinetics for entrectinib and its pharmacologically active major circulating metabolite M5 were characterized in adult patients with ROS1-positive NSCLC, NTRK gene fusion-positive solid tumors, and healthy subjects. The pharmacokinetics of entrectinib and M5 are linear and are not dose-dependent or time-dependent. Steady state is achieved within one week for entrectinib and two weeks for M5 following daily administration of ROZLYTREK. The pharmacokinetic parameters for entrectinib and M5 are described in Table 11.
Table 11. Pharmacokinetic Parameters for Entrectinib and Metabolite M5
| Parameter |
Entrectinib
Mean* (% CV) |
M5
Mean* (% CV) |
| AUCD1 (nM*h) |
31800 (48%) |
10200 (82%) |
| AUCss (nM*h) |
48000 (77%) |
24000 (97%) |
| CmaxD1 (nM) |
2250 (58%) |
622 (79%) |
| Cmaxss (nM) |
3130 (80%) |
1250 (90%) |
| Racc(AUC) |
1.55 (49%) |
2.84 (93%) |
| * Geometric mean |
Absorption
The maximum entrectinib plasma concentration was reached 4 – 6 hours after oral administration of a 600 mg dose.
Entrectinib exposure following a single oral dose (600 mg) of ROZLYTREK oral pellets was not clinically significant compared to ROZLYTREK capsule administered with a light meal (250 calories: 25% fat) in healthy subjects. In STARTRK-2, STARTRK-NG and TAPISTRY studies, ROZLYTREK was administered without regard to food in patients.
Entrectinib exposure of a single dose (600 mg) of ROZLYTREK capsules as a suspension with water or milk, administered orally or through a nasogastric or gastric tube, was not clinically significant compared to administration of intact ROZLYTREK capsules in healthy subjects under fasted conditions.
Effect of Food
A high-fat (approximately 50% of total caloric content), high-calorie (approximately 800 to 1000 calories) meal did not have a significant effect on entrectinib exposure of ROZLYTREK capsules.
Distribution
Entrectinib and its active major metabolite M5 are both > 99% bound to human plasma proteins in vitro.
The estimated apparent volume of distribution (V/F) was 551 L and 81.1 L for entrectinib and M5, respectively.
Elimination
The estimated apparent clearance (CL/F) was 19.6 L/h and 52.4 L/h for entrectinib and M5, respectively. The elimination half-lives of entrectinib and M5 were estimated to be 20 and 40 hours, respectively.
Metabolism
Entrectinib is metabolized primarily by CYP3A4 (~76%). The active metabolite M5 (formed by CYP3A4) is the only major active circulating metabolite identified. M5 has similar pharmacological potency to entrectinib in vitro and circulating M5 exposures at steady-state in patients were 40% of the corresponding entrectinib exposure.
Excretion
Following oral administration of a single oral dose of [14C]-labeled entrectinib, 83% of radioactivity was excreted in feces (36% of the dose as unchanged entrectinib and 22% as M5) with minimal excretion in urine (3%).
Specific Populations
No clinically significant differences in the pharmacokinetics of entrectinib were observed based on sex, race (White, Asian and Black), mild to moderate renal impairment (CLcr 30 to < 90 mL/min) and mild hepatic impairment (total bilirubin ≤ ULN with aspartate aminotransferase > ULN or total bilirubin > 1.0 – 1.5 times ULN with any aspartate aminotransferase). The impact of severe renal impairment on the pharmacokinetics of entrectinib is unknown.
Hepatic Impairment
Following administration of a single oral dose of ROZLYTREK 100 mg (1/6 of the recommended dose), the entrectinib AUCINF was increased by 39% for the mild, 39% for the moderate, and 23% for the severe hepatic impairment groups compared to the normal hepatic function group. The combined AUClast of entrectinib and M5 was increased by 16% for the mild, 16% for the moderate, and 4% for the severe hepatic impairment groups compared to the normal hepatic function group. Large variability in systemic exposure of entrectinib was observed in the hepatic impairment groups.
Pediatric Patients > 6 Months
In pediatric patients older than 6 months administered 300 mg/m2 (based on BSA) of ROZLYTREK once daily, systemic exposure of the sum of entrectinib and M5 in pediatric patients receiving 300 mg/m2 of ROZLYTREK once daily is within the range of the adults treated with 600 mg of ROZLYTREK once daily.
The available efficacy and safety data also confirm the adequacy of the recommended doses [see Use In Specific Populations].
Pediatric Patients > 1 To ≤ 6 Months
In pediatric patients > 1 to ≤ 6 months administered 250 mg/m2 (based on BSA) of ROZLYTREK once daily, systemic exposure of the sum of entrectinib and M5 in pediatric patients was at the lower range of the adults administered 600 mg of ROZLYTREK once daily.
The available efficacy and safety data also confirm the adequacy of the recommended doses [see Use In Specific Populations].
Drug Interaction Studies
Clinical Studies
Effect of CYP3A Inhibitors on Entrectinib
Coadministration of itraconazole (a strong CYP3A inhibitor) with a single 100 mg dose of ROZLYTREK capsule increased entrectinib AUC0-INF by 6-fold and Cmax by 1.7-fold [see DRUG INTERACTIONS]. Coadministration of a moderate CYP3A inhibitor with ROZLYTREK capsule is predicted to increase entrectinib AUC0-Tau by 3-fold and Cmax by 2.9-fold. Based on physiologically based pharmacokinetic (PBPK) modelling, a similar magnitude of the effect is expected in children as young as 2 years old.
Effect of CYP3A Inducers on Entrectinib
Coadministration of rifampin (a strong CYP3A inducer) with a single 600 mg dose of ROZLYTREK capsule reduced entrectinib AUC0-INF by 77% and Cmax by 56% [see DRUG INTERACTIONS]. Coadministration of a moderate CYP3A inducer with ROZLYTREK capsule is predicted to reduce entrectinib AUC0-Tau by 56% and Cmax by 43%.
Effect of Gastric Acid Reducing Drugs on Entrectinib
Coadministration of a proton pump inhibitor (PPI), lansoprazole with a single 600 mg dose of ROZLYTREK capsule reduced entrectinib AUC by 25% and Cmax by 23%.
Coadministration of lansoprazole, with a single 600 mg dose of ROZLYTREK capsule as oral suspension in water increased entrectinib AUC by 25% and Cmax by 17%. These changes are not likely to be clinically significant.
Effect of Entrectinib on CYP Substrates
Coadministration of 600 mg dose of ROZLYTREK capsule once daily with oral midazolam (a sensitive CYP3A substrate) in patients increased the midazolam AUC by 50% but reduced midazolam Cmax by 21% [see DRUG INTERACTIONS].
Effect of Entrectinib on Transporters
Coadministration of a single 600 mg dose of ROZLYTREK capsule with digoxin [a sensitive P-glycoprotein (P-gp) substrate] increased digoxin Cmax by 28% and AUC by 18%.
In Vitro Studies
Entrectinib is not a substrate of P-gp or BCRP, but M5 is a substrate of P-gp and BCRP. Entrectinib and M5 are not substrates of OATP1B1 or OATP1B3.
Clinical Studies
ROS1-Positive Non-Small Cell Lung Cancer
The efficacy of ROZLYTREK was evaluated in a pooled subgroup of patients with ROS1-positive metastatic NSCLC who received ROZLYTREK at various doses and schedules (90% received ROZLYTREK 600 mg orally once daily) and were enrolled in one of three multicenter, single-arm, open-label clinical trials: ALKA, STARTRK-1 (NCT02097810) and STARTRK-2 (NCT02568267). To be included in this pooled subgroup, patients were required to have histologically confirmed, recurrent or metastatic, ROS1-positive NSCLC, ECOG performance status ≤ 2, measurable disease per RECIST v 1.1, ≥ 18 months of follow-up from first post-treatment tumor assessment, and no prior therapy with a ROS1 inhibitor. Identification of ROS1 gene fusion in tumor specimens was prospectively determined in local laboratories using either a fluorescence in situ hybridization (FISH), next-generation sequencing (NGS), or polymerase chain reaction (PCR) laboratory-developed tests. All patients were assessed for CNS lesions at baseline. The major efficacy outcome measures were overall response rate (ORR) and duration of response (DOR) according to RECIST v1.1 as assessed by Blinded Independent Central Review (BICR). Intracranial response according to Response Evaluation Criteria in Solid Tumors (RECIST v1.1) was assessed by BICR. Tumor assessments with imaging were performed every 8 weeks.
Efficacy was assessed in 92 patients with ROS1-positive NSCLC. The median age was 53 years (range: 27 to 86); female (65%); White (48%), Asian (45%), and Black (5%); and Hispanic or Latino (2.4%); never smoked (59%); and ECOG performance status 0 or 1 (88%). Ninety-nine percent of patients had metastatic disease, including 42% with CNS metastases; 96% had adenocarcinoma; 65% received prior platinum-based chemotherapy for metastatic or recurrent disease and no patient had progressed in less than 6 months following platinum-based adjuvant or neoadjuvant therapy. ROS1 positivity was determined by NGS in 79%, FISH in 16%, and PCR in 4%. Twenty-five percent had central laboratory confirmation of ROS1 positivity using an analytically validated NGS test.
Efficacy results are summarized in Table 12.
Table 12. Efficacy Results in ROS1-Positive NSCLC Patients per BICR Assessment
| Efficacy Parameters |
ROZLYTREK
n = 92 |
| Overall Response Rate (95% CI) |
74% (64, 83) |
| Complete Response |
15% |
| Partial Response |
59% |
| Duration of Response (DOR)* |
n = 68 |
| Range (months) |
2.4, 55.2+ |
| % DOR ≥ 9 months |
75% |
| % DOR ≥ 12 months |
57% |
| % DOR ≥ 18 months |
38% |
Confidence Interval (CI) calculated using the Clopper-Pearson method.
* Observed DOR
+denotes ongoing response |
Among the 92 patients, 10 had measurable CNS metastases at baseline as assessed by BICR and had not received radiation therapy to the brain within 2 months prior to study entry. Responses in intracranial lesions were observed in 7 of these 10 patients.
NTRK Gene Fusion-Positive Solid Tumors
Efficacy In Adult Patients
The efficacy of ROZLYTREK was evaluated in a pooled subgroup of adult patients with unresectable or metastatic solid tumors with a NTRK gene fusion enrolled in one of three multicenter, single-arm, open-label clinical trials: ALKA, STARTRK-1 (NCT02097810) and STARTRK-2 (NCT02568267). To be included in this pooled subgroup, patients were required to have progressed following systemic therapy for their disease, if available, or would have required surgery causing significant morbidity for locally advanced disease; measurable disease per RECIST v1.1; at least 2 years of follow-up from first post-treatment tumor assessment; and no prior therapy with a TRK inhibitor. Patients received ROZLYTREK at various doses and schedules (94% received ROZLYTREK 600 mg orally once daily) until unacceptable toxicity or disease progression. Identification of positive NTRK gene fusion status was prospectively determined in local laboratories or a central laboratory using various nucleic acid-based tests. The major efficacy outcome measures were ORR and DOR, as determined by a BICR according to RECIST v1.1. Intracranial response according to RECIST v1.1 as evaluated by BICR. Tumor assessments with imaging were performed every 8 weeks.
Efficacy was assessed in the first 54 adult patients with solid tumors with an NTRK gene fusion enrolled into these trials. The median age was 58 years (range: 21 to 83); female (59%); White (80%), Asian (13%) and Hispanic or Latino (7%); and ECOG performance status 0 (43%) or 1 (46%). Ninety-six percent of patients had metastatic disease, including 22% with CNS metastases, and 4% had locally advanced, unresectable disease. All patients had received prior treatment for their cancer including surgery (n = 43), radiotherapy (n = 36), or systemic therapy (n = 48). Forty patients (74%) received prior systemic therapy for metastatic disease with a median of 1 prior systemic regimen and 17% (n = 9) received 3 or more prior systemic regimens. The most common cancers were sarcoma (24%), lung cancer (19%), salivary gland tumors (13%), breast cancer (11%), thyroid cancer (9%), and colorectal cancer (7%). A total of 52 (96%) patients had an NTRK gene fusion detected by NGS and 2 (4%) had an NTRK gene fusion detected by other nucleic acid-based tests. Eighty-three percent of patients had central laboratory confirmation of NTRK gene fusion using an analytically validated NGS test.
Efficacy results are summarized in Tables 13, 14, and 15.
Table 13. Efficacy Results for Adult Patients with Solid Tumors Harboring NTRK Gene Fusions
| Efficacy Parameter |
ROZLYTREK
n = 54 |
| Overall Response Rate (95% CI) |
59% (45, 72) |
| Complete Response |
13% |
| Partial Response |
46% |
| Duration of Response* |
n = 32 |
| Range (months) |
2.8, 47.8+ |
| % with duration ≥ 6 months |
72% |
| % with duration ≥ 9 months |
66% |
| % with duration ≥ 12 months |
56% |
* Observed DOR
+ denotes ongoing response |
Table 14. Efficacy by Tumor Type
| Tumor Type |
Patients
n = 54 |
ORR |
DOR |
| % |
95% CI |
Range (months) |
| Sarcoma |
13 |
46% |
19%, 75% |
2.8, 33.6+ |
| Non-small cell lung cancer |
10 |
60% |
26%, 88% |
3.7, 47.8+ |
| Salivary (MASC) |
7 |
86% |
42%, 100% |
2.8, 38.5+ |
| Breast cancer |
6 |
83% |
36%, 100% |
4.2, 42.3+ |
| Thyroid cancer |
5 |
60% |
NA |
7.9, 31.5+ |
| Colorectal cancer |
4 |
25% |
NA |
15.1 |
| Neuroendocrine cancers |
3 |
CR |
NA |
32.9+ |
| Pancreatic cancer |
3 |
PR, PR |
NA |
7.1, 12.9 |
| Gynecological cancers |
2 |
PR |
NA |
38.2 |
| Cholangiocarcinoma |
1 |
PR |
NA |
9.3 |
+denotes ongoing response
MASC: mammary analogue secretory carcinoma; NA = not applicable due to small numbers or lack of response; PR = partial response. |
Table 15. Efficacy Results by NTRK Gene Fusion Partner
| NTRK Partner |
Patients
n = 54 |
ORR |
DOR |
| % |
95% CI |
Range (months) |
| ETV6 – NTRK3 |
25 |
72% |
51%, 88% |
2.8, 47.8+ |
| TPM3 – NTRK1 |
4 |
50% |
7%, 93% |
2.8, 15.1 |
| TPR – NTRK1 |
4 |
100% |
40%, 100% |
5.6, 33.6+ |
| LMNA – NTRK1 |
2 |
PR, PD |
NA |
4.2 |
| SQSTM1 – NTRK1 |
2 |
PR, PD |
NA |
18.8+ |
| PEAR1 – NTRK1 |
2 |
SD, NE |
NA |
NA |
| EML4 – NTRK3 |
2 |
PR, NE |
NA |
13.2 |
| CD74 – NTRK1 |
1 |
PR |
NA |
10.4 |
| PLEKHA6 – NTRK1 |
1 |
PR |
NA |
9.3 |
| CDC42BPA – NTRK1 |
1 |
PR |
NA |
29.4 |
| EPS15L1 – NTRK1 |
1 |
PR |
NA |
3.7 |
| RBPMS – NTRK3 |
1 |
PR |
NA |
4.6 |
| ERC1 – NTRK1 |
1 |
SD |
NA |
NA |
| PDIA3 – NTRK1 |
1 |
SD |
NA |
NA |
| TRIM33 – NTRK1 |
1 |
SD |
NA |
NA |
| AKAP13 – NTRK3 |
1 |
SD |
NA |
NA |
| KIF7 – NTRK3 |
1 |
SD |
NA |
NA |
| FAM19A2 – NTRK3 |
1 |
PD |
NA |
NA |
| CGN – NTRK1 |
1 |
NE |
NA |
NA |
| SQSTM1 – NTRK2 |
1 |
NE |
NA |
NA |
+denotes ongoing response
PR = partial response; PD = progressive disease; SD = stable disease; NA = not applicable due to small numbers or lack of response; NE = not evaluable. |
Among the subset of patients who received prior systemic therapy for metastatic disease, the ORR was 53%, similar to that seen in the overall population. Among the 54 adult patients, 4 had measurable CNS metastases at baseline as assessed by BICR and had not received radiation therapy to the brain within 2 months of study entry. Responses in intracranial lesions were observed in 3 of these 4 patients.
Efficacy In Pediatric Patients
The efficacy of ROZLYTREK was evaluated in pediatric patients with unresectable or metastatic solid tumors with a NTRK gene fusion enrolled in one of two multicenter, open-label clinical trials: STARTRK-NG (NCT02650401) and TAPISTRY (NCT04589845). To be included in the analysis, patients were required to have received at least 1 dose of ROZLYTREK; measurable or evaluable disease at baseline; at least 6 months of follow-up; and no prior therapy with a TRK inhibitor. Patients received ROZLYTREK 20 mg to 600 mg based on body surface area (BSA) orally or via enteral feeding tube once daily in 4-week cycles until unacceptable toxicity or disease progression. The major efficacy outcome measure was overall response rate (ORR) as assessed by BICR according to RECIST v1.1 for extracranial tumors and according to Response Assessment in Neuro-Oncology (RANO) for primary central nervous system (CNS) tumors. An additional efficacy outcome measure was DOR as evaluated by BICR.
Efficacy was assessed in 33 pediatric patients with NTRK fusion-positive solid tumors treated with ROZLYTREK. The median age was 4 years (range: 2 months to 15 years); male (52%); White (58%), Asian (30%), other races (9%), Black or African American (3.0%), and Hispanic or Latino (9%). Seventy-one percent of patients had locally advanced disease and 29% had metastatic disease. Eighty-five percent of patients had received prior treatment for their cancer including surgery (n=20), radiotherapy (n=7) and/or systemic therapy (n=22). The sites for metastatic disease included other (4 patients), brain (3 patients) and lung (2 patients).
Efficacy results are summarized in Tables 16 and 17.
Table 16. Efficacy Results for Pediatric Patients with Solid Tumors Harboring NTRK Gene Fusions
| Efficacy Parameter* |
ROZLYTREK
n = 33 |
| Overall Response Rate (95% CI) |
70% (51, 84) |
| Complete Response |
42% |
| Partial Response |
27% |
| Duration of Response** |
n = 23 |
| Median in months (95% CI) |
25.4 (14.3, NE) |
| % with duration ≥ 12 months |
43% |
* Includes patients with measurable and evaluable disease. BICR analysis by RECIST v1.1 for solid tumors (16 patients) and by RANO criteria for primary CNS tumors (17 patients)
** Observed DOR
NE = not estimable |
Table 17. Efficacy Results for Pediatric Patients with Solid Tumors Harboring NTRK Gene Fusions by Tumor Type
| Tumor Type |
Patients
n = 33 |
ORR |
DOR |
| % |
95% CI |
Range (months) |
| Primary CNS* |
17 |
53% |
28%, 77% |
5.5, 30.4+ |
| Infantile fibrosarcoma |
8 |
88% |
47%, 100% |
3.7+, 24+ |
| Spindle Cell |
6 |
100% |
54%, 100% |
3.7+, 12.9+ |
| Sarcoma (other) |
1 |
0%** |
NA |
NA |
| Melanoma |
1 |
100% |
NA |
42. 4+ |
*Median time to first objective response for patients with primary CNS tumors was 1.9 months
+denotes ongoing response
** Patient with evaluable but non-measurable disease at baseline
NA = not applicable due to small numbers or lack of response |
Table 18. Efficacy Results for Pediatric Patients with Solid Tumors Harboring NTRK by Gene Fusion Partner
| NTRK Partner |
Patients
n = 33 |
ORR |
DOR |
| % |
95% CI |
Range (months) |
| ETV6 – NTRK3 |
7 |
86% |
42%, 100% |
11.9+ -42.4+ |
| LMNA – NTRK1 |
5 |
80% |
28%, 99% |
7.4+ -12.9+ |
| TPM3 – NTRK1 |
3 |
100% |
29%, 100% |
3.7+ -24.0+ |
| TPR – NTRK1 |
3 |
67% |
9%, 99% |
8.1+ -14.3 |
| EML4-NTRK3 |
2 |
50% |
1.3%, 99% |
13.8+ |
| BCAN-NTRK1 |
1 |
CR |
NA |
11.8+ |
| EML1-NTRK2 |
1 |
CR |
NA |
11.8 |
| QKI-NTRK2 |
1 |
CR |
NA |
11.1+ |
| TFG-NTRK3 |
1 |
CR |
NA |
3.7+ |
| KANK1-NTRK2 |
1 |
PR |
NA |
5.5 |
| KIF5B-NTRK2 |
1 |
PR |
NA |
12.9+ |
| TNS3-NRTK2 |
1 |
PR |
NA |
9.5 |
| ARHGEF2-NTRK1 |
1 |
SD |
NA |
NA |
| KIF21B-NTRK1 |
1 |
SD |
NA |
NA |
| BCR-NTRK2 |
1 |
SD |
NA |
NA |
| GKAP1-NTRK2 |
1 |
SD |
NA |
NA |
| DNM3-NTRK2 |
1 |
PD |
NA |
NA |
| PARP6-NTRK3 |
1 |
PD |
NA |
NA |
+denotes ongoing response
PR = partial response; PD = progressive disease; SD = stable disease; NA = not applicable due to small numbers or lack of response |