FDA Approval Summary: Selpercatinib for the Treatment of Lung and Thyroid Cancers with RET Gene Mutations or Fusions.

On May 8, 2020, the FDA granted accelerated approval to selpercatinib for (i) adult patients with metastatic RET fusion-positive non-small cell lung cancer (NSCLC), (ii) adult and pediatric patients ≥12 years of age with advanced or metastatic RET-mutant medullary thyroid cancer who require systemic therapy, and (iii) adult and pediatric patients ≥12 years of age with advanced or metastatic RET fusion-positive thyroid cancer who require systemic therapy and who are radioactive iodine refractory (if radioactive iodine is appropriate). Approval was granted on the basis of the clinically important effects on the overall response rate (ORR) with prolonged duration of responses observed in a multicenter, open-label, multicohort clinical trial (LIBRETTO-001, NCT03157128) in patients whose tumors had RET alterations. ORRs within the approved patient populations ranged from 64% [95% confidence interval (CI), 54-73] in prior platinum-treated RET fusion-positive NSCLC to 100% (95% CI, 63-100) in systemic therapy-naïve RET fusion-positive thyroid cancer, with the majority of responders across indications demonstrating responses of at least 6 months. The product label includes warnings and precautions for hepatotoxicity, hypertension, QT interval prolongation, hemorrhagic events, hypersensitivity, risk of impaired wound healing, and embryo-fetal toxicity. This is the first approval of a drug specifically for patients with RET alterations globally.

Bradford D ，Larkins E ，Mushti SL ，Rodriguez L ，Skinner AM ，Helms WS ，Price LSL ，Zirkelbach JF ，Li Y ，Liu J ，Charlab R ，Turcu FR ，Liang D ，Ghosh S ，Roscoe D ，Philip R ，Zack-Taylor A ，Tang S ，Kluetz PG ，Beaver JA ，Pazdur R ，Theoret MR ，Singh H ... -  《-》

FDA Approval Summary: Pralsetinib for the Treatment of Lung and Thyroid Cancers With RET Gene Mutations or Fusions.

The FDA granted accelerated approval for pralsetinib on September 4, 2020 for non-small cell lung cancer (NSCLC) and December 1, 2020 for thyroid cancer, for: (i) adult patients with metastatic RET fusion-positive NSCLC, (ii) adult and pediatric patients ≥12 years of age with advanced or metastatic RET-mutant medullary thyroid cancer who require systemic therapy, and (iii) adult and pediatric patients ≥12 years of age with advanced or metastatic RET fusion-positive thyroid cancer who require systemic therapy and who are radioactive iodine refractory (if radioactive iodine is appropriate). Approval was based on the results of a multicenter, open-label, multi-cohort clinical trial (ARROW, NCT03037385), demonstrating substantial overall response rates (ORR) and durable responses in patients with RET-altered tumors. ORRs within the approved patient populations ranged from 57% [95% confidence interval (CI), 46-68] in patients with RET fusion-positive NSCLC previously treated with platinum chemotherapy to 89% (95% CI, 52-100) in patients with RET fusion-positive thyroid cancer, with response duration of at least 6 months in most responders. The product label includes warnings and precautions for pneumonitis, hypertension, hepatotoxicity, hemorrhagic events, tumor lysis syndrome, risk of impaired wound healing, and embryo-fetal toxicity. This article summarizes the major considerations during FDA review leading to the approval of pralsetinib.

Kim J ，Bradford D ，Larkins E ，Pai-Scherf LH ，Chatterjee S ，Mishra-Kalyani PS ，Wearne E ，Helms WS ，Ayyoub A ，Bi Y ，Sun J ，Charlab R ，Liu J ，Zhao H ，Liang D ，Ghosh S ，Philip R ，Pazdur R ，Theoret MR ，Beaver JA ，Singh H ... -  《-》

Efficacy of Selpercatinib in RET-Altered Thyroid Cancers.

RET mutations occur in 70% of medullary thyroid cancers, and RET fusions occur rarely in other thyroid cancers. In patients with RET-altered thyroid cancers, the efficacy and safety of selective RET inhibition are unknown. We enrolled patients with RET-mutant medullary thyroid cancer with or without previous vandetanib or cabozantinib treatment, as well as those with previously treated RET fusion-positive thyroid cancer, in a phase 1-2 trial of selpercatinib. The primary end point was an objective response (a complete or partial response), as determined by an independent review committee. Secondary end points included the duration of response, progression-free survival, and safety. In the first 55 consecutively enrolled patients with RET-mutant medullary thyroid cancer who had previously received vandetanib, cabozantinib, or both, the percentage who had a response was 69% (95% confidence interval [CI], 55 to 81), and 1-year progression-free survival was 82% (95% CI, 69 to 90). In 88 patients with RET-mutant medullary thyroid cancer who had not previously received vandetanib or cabozantinib, the percentage who had a response was 73% (95% CI, 62 to 82), and 1-year progression-free survival was 92% (95% CI, 82 to 97). In 19 patients with previously treated RET fusion-positive thyroid cancer, the percentage who had a response was 79% (95% CI, 54 to 94), and 1-year progression-free survival was 64% (95% CI, 37 to 82). The most common adverse events of grade 3 or higher were hypertension (in 21% of the patients), increased alanine aminotransferase level (in 11%), increased aspartate aminotransferase level (in 9%), hyponatremia (in 8%), and diarrhea (in 6%). Of all 531 patients treated, 12 (2%) discontinued selpercatinib owing to drug-related adverse events. In this phase 1-2 trial, selpercatinib showed durable efficacy with mainly low-grade toxic effects in patients with medullary thyroid cancer with and without previous vandetanib or cabozantinib treatment. (Funded by Loxo Oncology and others; LIBRETTO-001 ClinicalTrials.gov number, NCT03157128.).

Wirth LJ ，Sherman E ，Robinson B ，Solomon B ，Kang H ，Lorch J ，Worden F ，Brose M ，Patel J ，Leboulleux S ，Godbert Y ，Barlesi F ，Morris JC ，Owonikoko TK ，Tan DSW ，Gautschi O ，Weiss J ，de la Fouchardière C ，Burkard ME ，Laskin J ，Taylor MH ，Kroiss M ，Medioni J ，Goldman JW ，Bauer TM ，Levy B ，Zhu VW ，Lakhani N ，Moreno V ，Ebata K ，Nguyen M ，Heirich D ，Zhu EY ，Huang X ，Yang L ，Kherani J ，Rothenberg SM ，Drilon A ，Subbiah V ，Shah MH ，Cabanillas ME ... -  《-》

Efficacy of Selpercatinib in RET Fusion-Positive Non-Small-Cell Lung Cancer.

RET fusions are oncogenic drivers in 1 to 2% of non-small-cell lung cancers (NSCLCs). In patients with RET fusion-positive NSCLC, the efficacy and safety of selective RET inhibition are unknown. We enrolled patients with advanced RET fusion-positive NSCLC who had previously received platinum-based chemotherapy and those who were previously untreated separately in a phase 1-2 trial of selpercatinib. The primary end point was an objective response (a complete or partial response) as determined by an independent review committee. Secondary end points included the duration of response, progression-free survival, and safety. In the first 105 consecutively enrolled patients with RET fusion-positive NSCLC who had previously received at least platinum-based chemotherapy, the percentage with an objective response was 64% (95% confidence interval [CI], 54 to 73). The median duration of response was 17.5 months (95% CI, 12.0 to could not be evaluated), and 63% of the responses were ongoing at a median follow-up of 12.1 months. Among 39 previously untreated patients, the percentage with an objective response was 85% (95% CI, 70 to 94), and 90% of the responses were ongoing at 6 months. Among 11 patients with measurable central nervous system metastasis at enrollment, the percentage with an objective intracranial response was 91% (95% CI, 59 to 100). The most common adverse events of grade 3 or higher were hypertension (in 14% of the patients), an increased alanine aminotransferase level (in 12%), an increased aspartate aminotransferase level (in 10%), hyponatremia (in 6%), and lymphopenia (in 6%). A total of 12 of 531 patients (2%) discontinued selpercatinib because of a drug-related adverse event. Selpercatinib had durable efficacy, including intracranial activity, with mainly low-grade toxic effects in patients with RET fusion-positive NSCLC who had previously received platinum-based chemotherapy and those who were previously untreated. (Funded by Loxo Oncology and others; LIBRETTO-001 ClinicalTrials.gov number, NCT03157128.).

Drilon A ，Oxnard GR ，Tan DSW ，Loong HHF ，Johnson M ，Gainor J ，McCoach CE ，Gautschi O ，Besse B ，Cho BC ，Peled N ，Weiss J ，Kim YJ ，Ohe Y ，Nishio M ，Park K ，Patel J ，Seto T ，Sakamoto T ，Rosen E ，Shah MH ，Barlesi F ，Cassier PA ，Bazhenova L ，De Braud F ，Garralda E ，Velcheti V ，Satouchi M ，Ohashi K ，Pennell NA ，Reckamp KL ，Dy GK ，Wolf J ，Solomon B ，Falchook G ，Ebata K ，Nguyen M ，Nair B ，Zhu EY ，Yang L ，Huang X ，Olek E ，Rothenberg SM ，Goto K ，Subbiah V ... -  《-》

Tumour-agnostic efficacy and safety of selpercatinib in patients with RET fusion-positive solid tumours other than lung or thyroid tumours (LIBRETTO-001): a phase 1/2, open-label, basket trial.

Selpercatinib is a first-in-class, highly selective RET kinase inhibitor with CNS activity that has shown efficacy in RET fusion-positive lung and thyroid cancers. RET fusions occur rarely in other tumour types. We aimed to investigate the efficacy and safety of selpercatinib in a diverse group of patients with RET fusion-positive non-lung or thyroid advanced solid tumours (ie, a tumour-agnostic population). LIBRETTO-001 is an ongoing phase 1/2, single-group, open-label, basket trial of selpercatinib in patients aged 18 years and older (or ≥12 years, where permitted by regulatory authorities) with RET-altered cancers. The trial is being conducted at 89 sites in 16 countries; the tumour-agnostic population was enrolled at 30 sites (outpatient and inpatient medical facilities) across eight countries. A prespecified interim analysis of LIBRETTO-001 was planned to investigate the efficacy and safety of selpercatinib in a tumour-agnostic population of patients with RET fusion-positive advanced solid tumours; the data cutoff date was Sept 24, 2021. Eligible patients had disease progression on or after previous systemic therapies or no satisfactory therapeutic options and an Eastern Cooperative Oncology Group performance status of 0-2. Selpercatinib was orally administered in a continuous 28-day cycle. Patients enrolled in the phase 1 dose-escalation portion received between 20 mg once daily or 20-240 mg twice daily; the phase 2 recommended dose was 160 mg twice daily. The primary endpoint was the objective response rate as determined by the independent review committee. The efficacy-evaluable tumour-agnostic population was defined as patients with RET fusion-positive cancer, other than non-small-cell lung cancer and thyroid cancer, who had at least 6 months of follow-up from the first study dose at the time of data cutoff (all responders at the time of data cutoff were followed up for at least 6 months from the onset of response unless they progressed or died earlier). Safety was analysed in the tumour-agnostic population of patients who had been enrolled and received selpercatinib on or before the data cutoff date. This study is registered with ClinicalTrials.gov (NCT03157128) and is still recruiting participants. Between Dec 4, 2017, and Aug 4, 2021, 45 patients with RET fusion-positive tumour-agnostic cancers were enrolled from the phase 1 dose-escalation and phase 2 dose-expansion cohorts of the trial. 43 (96%) of 45 patients received a starting dose of selpercatinib at the recommended dose of 160 mg twice daily. Of the two patients who did not, one received a dose of 160 mg twice daily via intra-patient dose escalation (as allowed per protocol for patients enrolled in the phase 1 portion of the study at lower doses) and the other patient's starting dose of 120 mg twice daily was never escalated. Of the 41 efficacy-evaluable patients, the objective response rate as per the independent review committee was 43·9% (95% CI 28·5-60·3; 18 of 41 patients). The most common grade 3 or worse treatment-emergent adverse events were hypertension (ten [22%] of 45 patients), increased alanine aminotransferase (seven [16%]), and increased aspartate aminotransferase (six [13%]). Treatment-emergent serious adverse events occurred in 18 (40%) of 45 patients. No treatment-related deaths occurred. Selpercatinib showed clinically meaningful activity in the RET fusion-positive tumour-agnostic population, with a safety profile consistent with that observed in other indications. Comprehensive genomic testing that includes RET fusions will be crucial for identifying patients who might benefit from selpercatinib. Loxo Oncology.

Subbiah V ，Wolf J ，Konda B ，Kang H ，Spira A ，Weiss J ，Takeda M ，Ohe Y ，Khan S ，Ohashi K ，Soldatenkova V ，Szymczak S ，Sullivan L ，Wright J ，Drilon A ... -  《-》