Date: 2017-06-03
Type of
information: Presentation of results at a congress
phase: 1
Announcement: presentation of results at the American Society of Clinical Oncology (ASCO) annual meeting, in Chicago
Company: Loxo Oncology (USA - CT)
Product: LOXO- 101 (larotrectinib - (S)-N-(5-((R)-2-(2,5-difluorophenyl)pyrrolidin-1-yl)pyrazolo[1,5-a]pyrimidin-3-yl)-3-hydroxypyrrolidine-1-carboxamide hydrogen sulfate
Action
mechanism: enzyme inhibitor/kinase inhibitor/TRK inhibitor. LOXO-101 is a potent, oral, selective inhibitor of tropomyosin receptor kinase (TRK) signaling molecules. The TRK family (TRKA, TRKB, and TRKC) has been implicated in diverse tumor types such as lung cancer, head and neck cancer, melanoma, colorectal cancer, sarcoma, and breast cancer. LOXO-101 was built specifically to inhibit TRK and is currently being evaluated in a Phase 1 dose escalation trial for patients with advanced solid tumors. LOXO-101 was developed in collaboration with Array BioPharma.
Disease: pediatric patients with advanced solid or primary central nervous system tumors
Therapeutic
area: Cancer - Oncology
Country: USA
Trial
details: The Phase 1 clinical trial is a multicenter, open-label trial in pediatric patients with advanced solid or primary CNS tumors. In order to meet the criteria for enrollment, patients must be between one year of age and 21 years of age with a locally advanced or metastatic solid tumor or primary CNS tumor that has progressed, or was nonresponsive to available therapies, and for which no standard or available curative therapy exists. Patients as young as one month old are eligible for enrollment if they have a diagnosis of infantile/congenital fibrosarcoma, with a documented NTRK fusion that has progressed, or was nonresponsive to available therapies, and for whom no standard or available curative therapy exists. (NCT02637687)
Latest
news:
- • On June 3, 2017, Loxo Oncology announced interim clinical data from all three ongoing larotrectinib (LOXO-101) clinical trials in patients whose tumors harbor tropomyosin receptor kinase (TRK) fusions. These data, demonstrating a 76 percent confirmed objective response rate (ORR) across tumor types, are being presented at the 2017 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago (abstract LBA2501). The larotrectinib pediatric data, included in this presentation, are also being presented in a separate oral presentation (abstract 10510). The ASCO presentation includes adult and pediatric patients with RECIST-evaluable TRK fusion cancers enrolled across all three larotrectinib clinical trials, and employs an April 14, 2017 data cut-off. These patients will serve as the basis for the larotrectinib New Drug Application (NDA), which the company expects to submit in late 2017 or early 2018 for evaluation by the FDA. The primary analysis for the NDA will rely upon central, independent radiology review, which will be performed in the second half of 2017. The company plans to announce these data, which will also include additional patient follow-up, before the end of 2017.
- Key Data Presented at ASCO: The primary efficacy outcome measure for the analysis presented at ASCO is objective response rate (ORR) as measured by RECIST v 1.1. Key secondary endpoints include duration of response (DOR), progression-free survival (PFS) and safety. The data presented at ASCO, summarized below, are based on response assessments as performed by each respective clinical trial site (local, investigator-assessed radiology). A separate response assessment performed by independent radiologists, not yet conducted, will be required to support global regulatory filings.
- Consistent with written FDA correspondence, TRK fusion patients enrolled in Loxo Oncology’s Phase 1 adult trial, Phase 2 trial (NAVIGATE), and Phase 1/2 pediatric trial (SCOUT) contributed to the primary efficacy analysis. The data presented are based on the intent to treat (ITT) principle, using the first 55 TRK fusion patients with RECIST-evaluable disease enrolled to the three clinical trials, regardless of prior therapy or tumor tissue diagnostic method.
- Forty-three adult and 12 pediatric patients were enrolled, identified by 15 different lab tests. TRK fusion patients carried primary diagnoses of appendiceal cancer, breast cancer, cholangiocarcinoma, colorectal cancer, gastrointestinal stromal tumor (GIST), infantile fibrosarcoma, lung cancer, mammary analogue secretory carcinoma of the salivary gland, melanoma, pancreatic cancer, thyroid cancer, and various sarcomas. One patient had central nervous system (CNS) metastases at study entry.
* Includes unconfirmed responses with confirmatory scans pending (4 PR, 1 CR). All patients with unconfirmed responses remain in response and ongoing on study.
|
Enrolled Patients with Confirmatory Response Data Available (n=50) |
All Enrolled Patients (n=55)* |
| Objective Response Rate
(ORR = PR+CR) |
76%
(95% CI: 62% – 87%) |
78%
(95% CI: 65% – 88%) |
| Partial Response (PR) |
64% |
65%* |
| Complete Response (CR) |
12% |
13%* |
| Stable Disease |
12% |
11% |
| Progressive Disease |
12% |
11% |
- * Includes unconfirmed responses with confirmatory scans pending (4 PR, 1 CR). All patients with unconfirmed responses remain in response and ongoing on study.
- As shown in the above table, the confirmed ORR is 76 percent in 50 patients for whom follow-up was sufficiently long to include a confirmatory scan. The ORR is 78 percent when an additional 5 patients, recently enrolled, with unconfirmed PR (n=4) and CR (n=1), are included. ORR was generally consistent across tumor types, TRK gene fusions, and various diagnostic tests. In the pediatric setting, larotrectinib showed promising activity in the pre-surgical management of patients with infantile fibrosarcoma, with 3 patients treated to best response, which allowed for subsequent referral to surgery with curative intent.
- Median DOR and PFS have not been reached. Ninety-three percent of all responding patients either remain on drug or received surgery with curative intent. Seventy-five percent of all patients enrolled either remain on drug or received surgery with curative intent.
- The safety data presented at ASCO encompass the entire larotrectinib safety database in cancer patients (n=125) intended to support an NDA. The most common treatment-emergent adverse events, regardless of relationship to larotrectinib, included fatigue (15% Grade 1, 18% Grade 2, 5% Grade 3), dizziness (22% Grade 1, 4% Grade 2, 2% Grade 3), nausea (20% Grade 1, 5% Grade 2, 2% Grade 3), and anemia (8% Grade 1, 9% Grade 2, 9% Grade 3). Seven (13%) of patients required a dose reduction due to an adverse event. Of note, all patients requiring dose reduction experienced tumor regression (1 CR, 5 PR, 1 SD), which has continued on the reduced dose. Nearly all of the dose reductions were due to infrequent neurocognitive adverse events, likely a result of on-target TRK inhibition in the CNS. No patients discontinued larotrectinib due to an adverse event.
- Six patients responded to larotrectinib but subsequently progressed, a pattern referred to as “acquired resistance.” Progression biopsies from five of six patients indicate a consistent mechanism of acquired resistance, namely a solvent front mutation. A solvent front mutation is an amino acid substitution in a kinase that reduces the binding potency of a targeted drug. In the case of NTRK1 and NTRK3, these solvent front amino acid substitutions are denoted as G595R and G623R, respectively. The presence of an acquired resistance mutation in a primary activating oncogene suggests that the involved cancer cell remains dependent on the aberrant signaling pathway that had been successfully drugged previously.
- • On April 19, 2016, Loxo Oncology announced the publication of a manuscript in the online edition of the journal Pediatric Blood and Cancer describing a confirmed RECIST partial response in the first patient enrolled in the recently opened pediatric Phase 1 dose-escalation trial of LOXO-101. The manuscript was co-authored with Nemours Children's Hospital, Northwestern University and St. Jude Children's Research Hospital .
The peer-reviewed manuscript describes a 16-month old female patient with advanced infantile fibrosarcoma (IFS), a rare pediatric cancer. Genetic testing revealed an ETV6-NTRK3 fusion, which is frequently found in IFS. Following multiple unsuccessful surgeries and courses of chemotherapy, the patient was enrolled in the pediatric Phase 1 trial of LOXO-101, which employs a liquid formulation of the drug designed specifically for pediatric patients unable to swallow capsules. Her disease involved the neck, face, skull, mastoids and cervical vasculature. Throughout the first cycle of treatment with LOXO-101, the parents noted improved engagement and playfulness. At the end of cycle 1 (day 28), imaging of the brain and neck showed tumor regression of more than 90 percent from baseline. Repeat scans at the end of cycle 2 showed a continued decrease in tumor volume. During the preparation of the manuscript, the patient was in study cycle 5, with a RECIST confirmed partial response, and was beginning to achieve normal developmental milestones. The patient experienced no adverse events related to LOXO-101.
- • On December 22, 2015, Loxo Oncology, announced the enrollment of the first patient in its Phase 1 trial of LOXO-101 in pediatric patients with advanced solid or primary central nervous system (CNS) tumors.
The Phase 1 clinical trial is a multicenter, open-label trial in pediatric patients with advanced solid or primary CNS tumors. Loxo Oncology plans to open as many as 15 clinical sites in the U.S. In the dose-escalation phase, LOXO 101 will be administered orally twice daily, with the initial starting dose level intended to match the pharmacokinetic exposures of the 100 mg twice daily dose that is currently being employed in the LOXO-101 Phase 2 basket trial in adult patients. The actual dose for each patient will depend on patient body size and age. The trial will also utilize a liquid formulation of LOXO-101 designed specifically for pediatric patients unable to swallow capsules. The primary endpoint of the trial is to explore the safety of LOXO-101. Secondary endpoints include the characterization of pharmacokinetic properties, the identification of the maximum tolerated dose and/or the Phase 2 dose, a description of antitumor activity, and a description of pain and health related quality of life impact. In order to meet the criteria for enrollment, patients must be between one year of age and 21 years of age with a locally advanced or metastatic solid tumor or primary CNS tumor that has progressed, or was nonresponsive to available therapies, and for which no standard or available curative therapy exists. Patients at least one month old are eligible for enrollment if they have a diagnosis of infantile/congenital fibrosarcoma, with a documented NTRK fusion that has progressed, or was nonresponsive to available therapies, and for whom no standard or available curative therapy exists.
Additional patient cohorts may be enrolled in an expansion phase of the Phase 1 trial to better characterize safety and efficacy in patients with specific abnormalities in the NTRK genes or proteins.
Is
general: Yes
