FDA Approves GAMMAGARD LIQUID® Based on Safety Data From an RWE Study

CIDP is a neurological disorder causing progressive weakness and impaired sensory function in the legs and arms due to immune-mediated damage to the myelin sheath of peripheral nerves. It can occur at any age and in both genders; however, most patients with CIDP are male, and the prevalence of CIDP increases with age.

The efficacy and safety of intravenous (IV) administration of GAMMAGARD LIQUID in adults with CIDP were evaluated in Study 161403 Epoch 2, a prospective, open label, single arm, multicenter Phase III study. To further support the safety of GAMMAGARD LIQUID in patients with CIDP, the manufacturer, Takeda Pharmaceuticals, performed a retrospective study, Study TAK-771-4002, using data from two real-world healthcare data sources.

Clinical Evidence

The Phase III Study 161403 consisted of two study epochs. In Epoch 1, subjects were randomized in a 1:1 ratio to receive either HYQVIA^® [IG infusion 10% (human) with recombinant human hyaluronidase (rHuPH20)] or 0.25% albumin placebo solution with rHuPH20. Subjects experiencing relapse during Epoch 1 were offered the opportunity to enroll in Epoch 2, receiving GAMMAGARD LIQUID by IV in the open label single arm study. A total of 20 subjects enrolled in Epoch 2.

The primary objective of Study 161403 Epoch 2 Phase III trial was to evaluate the efficacy of GAMMAGARD LIQUID IV for the treatment of CIDP in improving neuromuscular disability and impairment measured by improvement in the adjusted Inflammatory Neuropathy Cause and Treatment disability score. In the primary analysis set, the responder rate was 100%. The secondary objectives included the evaluation of safety and tolerability.

Study TAK-771-4002, conducted by Takeda Pharmaceuticals, was an observational, nonrandomized, active comparator, retrospective cohort study based on the Optum and MarketScan data sources in the US. This study evaluated the comparative safety of off-label use of GAMMAGARD LIQUID and other brands of IGIV products indicated for the treatment of CIDP (GAMUNEX^®-C or PRIVIGEN^®). The primary objective of the study in Ig-experienced patients was to determine whether rates of Adverse Events of special interest (AESI) [thrombotic events, acute kidney injury (AKI), and hemolytic events] among participants initiating GAMMAGARD LIQUID differ from rates among participants initiating a comparator IGIV product. Secondary objectives included evaluating the rates of other Adverse Events.

The Study TAK-771-4002 enrolled 916 Ig-experienced patients in Optum and 1,697 Ig-experienced patients in MarketScan. The reviewers pointed out that although both Study 161403 Epoch 2 and TAK-771-4002 evaluated the use of GAMMAGARD LIQUID, the patient populations differed because in the observational study, both Ig-naïve and Ig-experienced patients were included, while Study 161403 Epoch 2 only included Ig-experienced patients. Hence, a pooled safety analysis was not performed.

Appraisal

The FDA concluded that data from both Study 161403 Epoch 2 and the retrospective observational Study TAK-771-4002, “provide substantial evidence of effectiveness and sufficient evidence of safety of GAMMAGARD LIQUID as a therapy to improve neuromuscular disability and impairment in adult patients with CIDP,”¹ a testament to the potential of RWE to support regulatory decision-making.

Author: Catia Proenca, Director in Real-World Solutions