Toripalimab Granted FDA Fast Track Status for Mucosal Melanoma

The FDA has granted toripalimab a fast track designation for use in the frontline treatment of patients with mucosal melanoma, according to an announcement from Junshi Biosciences, the drug developer.¹

Toripalimab has been approved for marketing in China and over 30 trials have investigated its use spanning 15 indications on a global scale. The regulatory agency also gave the green light to an investigational new drug application for a phase 3 trial that will examine the PD-1 monoclonal antibody in combination with axitinib (Inlyta) compared with pembrolizumab (Keytruda) in the first-line treatment of 220 patients with unresectable, locally advanced or metastatic mucosal melanoma.

In the trial, participants will be randomized 1:1 to either toripalimab plus axitinib or pembrolizumab. The primary end point of the trial is progression-free survival (PFS), with key secondary end points comprised of objective response rate (ORR), duration of response (DOR), overall survival (OS), and safety.

Previously, data from a single-arm, open-label phase 1b trial (NCT03086174) showed that the toripalimab/axitinib combination demonstrated promising activity in patients with advanced mucosal melanoma.² Specifically, the combination elicited an ORR of 48.5%, which included 1 complete response and 15 partial responses. The median DOR was 13.7 months with the doublet.

To enroll on the trial, patients had to have pathologically confirmed metastatic mucosal disease, at least 1 measurable lesion via RECIST v1.1 criteria, adequate organ and bone marrow function, and an ECOG performance status of 0-1. The primary objective of the trial was dose-limiting toxicity and secondary objectives comprised pharmacokinetic profile of toripalimab, ORR, disease control rate, DOR, PFS, OS, PD-L1 status, ORR, and others.

Additional findings presented during the 2020 ASCO Virtual Scientific Program showed that the humanized IgG4 monoclonal antibody against PD-1, when used in combination with axitinib, led to a median PFS of 7.5 months (95% CI, 3.9-14.8). The 1-year PFS rate achieved with the doublet was 41.4% and the 2-year PFS rate was 13.8%. Moreover, the median OS with toripalimab/axitinib was 20.7 months (95% CI, 10.2–not evaluable). The 1-year OS rate with the doublet was 65.5%, while the 2-year rate was 44.8%.

Regarding safety, the doublet was found to be well tolerated and no dose-limiting toxicities were observed in the first 6 participants who were evaluated in the dose-finding portion of the trial. Notably, axitinib did not impact the PK parameters of toripalimab compared with toripalimab alone. Ninety-seven percent of patients reported toxicities associated with the treatment, but the majority were grade 1 or 2 in severity.

In December 2018, the National Medical Products Administrated (NMPA) granted toripalimab conditional approval for use as a second-line treatment in patients with unresectable or metastatic melanoma. The agent was added to the 2019 and 2020 Guidelines of Chinese Society of Clinical Oncology for the Diagnosis and Treatment of Melanoma.

Moreover, in April 2020, the NMPA accepted a supplemental new drug application (sNDA) for the agent’s use in the third-line treatment of patient with recurrent/metastatic nasopharyngeal carcinoma; a sNDA was also accepted in May 2020 for toripalimab as a second-line treatment for patients with metastatic urothelial carcinoma. Both applications were granted priority review by the agency in July 2020.

References

1. FDA grants toripalimab fast track designation for mucosal melanoma. News release. Junshi Biosciences. January 24, 2021. Accessed January 25, 2021. http://bit.ly/369BENm.

2. Sheng X, Yan X, Chi Z, et al. Overall survival and biomarker analysis of a phase 1b combination study of toripalimab, a humanized IgG4 mAb against programmed death-1 (PD-1) with axitinib in patients with metastatic mucosal melanoma. J Clin Oncol. 2020;38(suppl 15):10007. doi:10.1200/JCO.2020.38.15_suppl.10007