Protagonist, Janssen Win Breakthrough Therapy Designation for Oncology Candidates

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Shares of Protagonist Therapeutics climbed nearly 4% in premarket trading after the company announced its lead drug candidate rusfertide snagged Breakthrough Therapy Designation from the U.S. Food and Drug Administration.

California-based Protagonist is developing rusfertide as a potential treatment of patients with polycythemia vera (PV) for the reduction of erythrocytosis. Specifically, the drug candidate is being developed for those patients who no longer require additional treatment for thrombocytosis and/or leukocytosis.

Suneel Gupta, chief development officer at Protagonist, expressed excitement over winning the designation for rusfertide. Gupta said PV is a severe disease with unmet medical needs. Better treatment options are needed for those patients, Gupta said. PV is a rare type of blood cancer that causes the marrow to make too many red blood cells. The increase of red blood cells causes a thickening of the blood and can cause serious and life-threatening blood clots. 

“Rusfertide is a natural hormone mimetic and may stand out as the first non-cytoreductive therapeutic drug for PV. We look forward to working closely with FDA regulators to advance and complete all relevant clinical studies, both ongoing and planned, as quickly as possible,” Gupta said in a statement.

The FDA based its designation on data from an ongoing Phase II study of rusfertide in PV patients. The ongoing data was presented in December at the American Society of Hematology meeting. 

The data showed that most patients treated with rusfertide were able to eliminate therapeutic phlebotomies and maintain a target hematocrit level of less than 45%, Protagonist said. Additionally, data showed these patients were able to reverse their iron deficiency and also saw improvements in their PV symptoms. The company will present updated data from the ongoing Phase II study at the European Hematology Association next week. 

Breakthrough Therapy Designation is granted to experimental drugs that may demonstrate substantial improvement over existing therapies on one or more clinically significant endpoints. Drugs that receive this designation can also benefit from expedited development and regulatory reviews. 

Previously, the FDA granted orphan drug status and Fast Track Designation to rusfertide in this indication.

Protagonist isn’t the only company this week to be awarded Breakthrough Therapy Designation. Janssen’s multiple myeloma asset teclistamab was also given the designation. 

Teclistamab is an off-the-shelf, T-cell redirecting, bispecific antibody that targets both B-cell maturation antigen (BCMA) and CD3 receptors. The Breakthrough Therapy Designation followed PRIME (PRIority MEdicines) designation granted by the European Medicines Agency for teclistamab.

Peter Lebowitz, Global Therapeutic Area Head in Oncology at Janssen Research & Development, was pleased with both the FDA and EMA designations. He said the teclistamab program “exemplifies our commitment to advancing science for patients living with multiple myeloma.” 

Lebowitz also said the designations strengthen the company’s robust portfolio in oncology. The FDA designation for teclistamab marked the 11th such designation received by Janssen's Oncology Therapeutic Area.

The FDA awarded Breakthrough Therapy Designation for teclistamab based on data from the Phase I MajesTEC-1 study, which evaluated the oncology asset in adults with measurable multiple myeloma that is relapsed or refractory to established therapies or be intolerant of those established multiple myeloma therapies. 

Results from preclinical studies demonstrate that teclistamab kills myeloma cell lines and bone marrow-derived myeloma cells from heavily pretreated patients. Updated results from the MajesTEC-1 study will be presented at the 2021 American Society of Clinical Oncology Annual Meeting next week. 

Teclistamab is currently being evaluated in a Phase II clinical study for the treatment of relapsed or refractory multiple myeloma and is also being explored in combination studies.