Novartis announced that the European Commission (EC) approved Rydapt (midostaurin) for two indications in rare, hard-to-treat cancers. Rydapt is approved for use in combination with standard daunorubicin and cytarabine induction and high-dose cytarabine consolidation chemotherapy, and for patients in complete response followed by Rydapt single agent maintenance therapy, for adults with newly diagnosed acute myeloid leukemia (AML) who are FLT3 mutation-positive. It was also cleared for use as monotherapy for the treatment of adults with aggressive systemic mastocytosis (ASM), systemic mastocytosis with associated hematological neoplasm (SM-AHN) or mast cell leukemia.

The approval follows a positive opinion issued by the European Medicines Agency's (EMA) Committee for Medicinal Products for Human Use (CHMP) on July 20, 2017 and applies to all 28 EU member states, plus Iceland, Liechtenstein and Norway. Rydapt represents the first and only targeted therapy for FMS-like tyrosine kinase 3 (FLT3)-mutated AML and the only treatment for three subtypes of SM, collectively known as advanced SM, in the EU, all of which have limited life expectancy and few treatment options. Rydapt represents the first major advancement for the treatment of patients with newly diagnosed FLT3-mutated AML in more than 25 years.

"Novartis is proud that we can deliver Rydapt, a breakthrough medicine, to patients with serious and hard-to-treat diseases where there are few treatment options," said Bruno Strigini, CEO, Novartis Oncology. "For patients with FLT3-mutated AML, there have been no meaningful advancements in more than 25 years and with Rydapt they now have a targeted medicine that could significantly extend their lives."

For newly diagnosed FLT3-mutated AML, the approval is based on data from the RATIFY (CALGB 10603 [Alliance]) trial, which was conducted in collaboration with the Alliance for Clinical Trials in Oncology and 13 international cooperative groups. RATIFY is the largest trial to date among people with this specific type of AML and results of the trial were recently published in the New England Journal of Medicine (NEJM). The study showed a 23% reduction in the risk of death with Rydapt plus standard chemotherapy compared with placebo plus standard chemotherapy. Median overall survival of 74.7 months and 25.6 months, respectively (hazard ratio [HR] = 0.77, 95% confidence interval [CI], 0.63, 0.95; one-sided p=0.0078).  

In the RATIFY trial, the most frequent adverse reactions (incidence greater than or equal to 30%) in the Rydapt plus standard chemotherapy arm were febrile neutropenia, nausea, exfoliative dermatitis, vomiting, headache, petechiae (small red skin spots) and pyrexia. The most frequent Grade 3/4 adverse reaction (greater than or equal to 5%) was febrile neutropenia, lymphopenia, device-related infection, exfoliative dermatitis, hyperglycemia and nausea.

For advanced SM, the approval is based on two single-arm open-label multicenter trials, including the Phase II study (CPKC412D2201), the largest prospective trial ever conducted in this rare disorder, the results of which were also published in NEJM. The efficacy of Rydapt was established using modified Valent criteria, with patients demonstrating an overall response rate, defined as a major or partial response, of 59.6% (95% [CI], 48.6, 69.8%). Efficacy was also assessed in a post-hoc analysis using the 2013 International Working Group-Myeloproliferative Neoplasms Research and Treatment-European Competence Network on Mastocytosis (IWG-MRT-ECNM) consensus criteria (n=113). This assessment estimated an overall response rate of 28.3% (95% CI, 20.2, 37.6).

In advanced SM, the most frequent adverse reactions were nausea, vomiting, diarrhea, peripheral edema and fatigue. The most frequent Grade 3/4 adverse reactions were fatigue, sepsis, pneumonia, febrile neutropenia and diarrhea.

In order to further investigate the potential of Rydapt in AML, Novartis is planning a Phase III study in newly diagnosed AML patients without a FLT3 mutation (wildtype).

In advanced SM, the uncontrolled growth of neoplastic mast cells causes organ damage (e.g., liver dysfunction), low blood counts and weight loss. People with the disease also suffer from debilitating systemic symptoms such as pruritus (severe itching of the skin) caused by mast cells releasing inflammatory mediators, such as histamine, into the blood.

The uncontrolled proliferation of mast cells is caused in many people by a KIT gene mutation - the most common mutation, encoding the D816V substitution, occurs in approximately 90% of patients. The KIT gene mutation results in activation of the KIT enzyme, which triggers the abnormal proliferation and survival of mast cells.

Rydapt (midostaurin) is an oral, targeted therapy, a type of treatment that interferes with certain pathways that are involved in the growth, progression and spread of cancer. Rydapt inhibits multiple kinases, including FLT3, which help regulate many essential cell processes, interrupting cancer cells' ability to grow and multiply. Rydapt induces cell death in leukemic cells expressing FLT3 ITD or TKD mutant receptors, or in cells overexpressing FLT3 wildtype receptors.