Givosiran

In a clinical drug-drug interaction study, givosiran resulted in a weak to moderate reduction in activity of certain CYP450 enzymes in the liver thereby increasing plasma exposures:

• CYP1A2: 1.3-fold increase in C_max and 3.1-fold increase in AUC_0–∞ of caffeine
• CYP2D6: 2.0-fold increase in C_max and 2.4-fold increase in AUC_0–∞ of dextromethorphan
• CYP2C19: 1.1-fold increase in C_max and 1.6-fold increase in AUC_0–∞ of omeprazole
• CYP3A4: 1.2-fold increase in C_max and 1.5-fold increase in AUC_0–∞ of midazolam
• CYP2C9: no effect on the exposure of losartan

Caution is recommended during the use of medicinal products that are substrates of CYP1A2 or CYP2D6 while on treatment with givosiran as this medicinal product may increase or prolong their therapeutic effect, or alter their adverse event profiles Consider decreasing the CYP1A2 or CYP2D6 substrate dosage in accordance with the approved product labelling.

Transaminase elevations have been observed in patients treated with givosiran. Transaminase
elevations primarily occurred between 3 to 5 months following initiation of treatment.

Liver function tests should be performed prior to initiating treatment. These tests should be repeated monthly during the first 6 months of treatment, and as clinically indicated thereafter. Interrupting or discontinuing treatment should be considered for clinically relevant transaminase elevations. In case of subsequent improvement in transaminase levels, resumption of treatment at a 1.25 mg/kg dose after interruption could be considered. There are limited data on efficacy and safety of the lower dose, particularly in patients who previously experienced transaminase elevations. There are no data on sequentially increasing the 1.25 mg/kg dose to the 2.5 mg/kg dose after dose interruption for transaminase elevations.

In clinical studies, anaphylaxis occurred in one patient who had a history of allergic asthma and atopy. Signs and symptoms of anaphylaxis should be monitored. If anaphylaxis occurs, administration of this medicinal product should be immediately discontinued and appropriate medical treatment should be instituted.

There are no or limited amount of data from the use of givosiran in pregnant women. Studies in animals have shown reproductive toxicity in the presence of maternal toxicity. The use of this medicinal product could be considered during pregnancy taking into account the expected health benefit for the woman and potential risks to the foetus.

It is unknown whether givosiran is excreted in human milk. A risk to the newborns/infants cannot be excluded. Available pharmacodynamic/toxicological data in animals have shown excretion of givosiran in milk. A decision must be made whether to discontinue breast-feeding or to discontinue/abstain from givosiran therapy taking into account the benefit of breast feeding for the child and the benefit of therapy for the woman.

Fertility

There are no data on the effects of givosiran on human fertility. No impact on male or female fertility was detected in animal studies.

Givosiran has no or negligible influence on the ability to drive and use machines.

Summary of the safety profile

The most frequently occurring adverse reactions reported in patients treated with givosiran are injection site reactions (ISRs) (36%), nausea (32.4%) and fatigue (22.5%). The adverse reactions resulting in discontinuation of treatment were elevated transaminases (0.9%) and anaphylactic reaction (0.9%).

Tabulated list of adverse reactions

The adverse reactions are presented as MedDRA preferred terms under the MedDRA system organ class (SOC) by frequency. Within each frequency grouping, adverse reactions are presented in order of decreasing seriousness. The frequency of the adverse reactions is expressed according to the following categories: very common (≥1/10), common (≥1/100 to <1/10), uncommon (≥1/1,000 to <1/100)

Table 1. Adverse reactions:

^a Includes pruritus, eczema, erythema, rash, rash pruritic, urticaria.
^b Includes blood creatinine increased, glomerular filtration rate decreased, chronic kidney disease (decreased eGFR), renal impairment.

Description of selected adverse reactions

Liver function tests

In the placebo-controlled study, 7 (14.6%) patients treated with givosiran and one (2.2%) patient treated with placebo had an increased alanine aminotransferase (ALT) more than 3 times the ULN. In 5 patients treated with givosiran the transaminase elevations resolved with ongoing dosing at 2.5 mg/kg. Per protocol, one patient (with variegate porphyria) with ALT more than 8 times the ULN discontinued treatment and one patient with ALT more than 5 times the ULN interrupted treatment and resumed dosing at 1.25 mg/kg. ALT elevations in both patients resolved.

Injection site reactions

In placebo-controlled and open-label clinical studies, injection site reactions have been reported in 36% of patients and generally have been mild or moderate in severity, mostly transient and resolved without treatment. The most commonly reported symptoms included erythema, pain, and pruritus. Injection-site reactions occurred in 7.8% of injections and did not result in discontinuation of treatment. Three patients (2.7%) experienced single, transient, recall reactions of erythema at a prior injection site with a subsequent dose administration.

Immunogenicity

In placebo-controlled and open-label clinical studies, 1 of 111 patients with AHP (0.9%), developed treatment emergent anti-drug antibodies (ADA) during treatment with givosiran. ADA titres were low and transient with no evidence of an effect on clinical efficacy, safety, pharmacokinetic or pharmacodynamic profiles of the medicinal product.