Rizast

Rizast (auranofin) is indicated in the management of adults with active classical or definite rheumatoid arthritis (ARA criteria) who have had an insufficient therapeutic response to, or are intolerant of, an adequate trial of full doses of one or more nonsteroidal anti-inflammatory drugs. Rizast should be added to a comprehensive baseline program, including non-drug therapies.

Unlike anti-inflammatory drugs, Rizast does not produce an immediate response. Therapeutic effects may be seen after three to four months of treatment, although improvement has not been seen in some patients before six months.

When cartilage and bone damage has already occurred, gold cannot reverse structural damage to joints caused by previous disease. The greatest potential benefit occurs in patients with active synovitis, particularly in its early stage.

In controlled clinical trials comparing Rizast with injectable gold, Rizast was associated with fewer dropouts due to adverse reactions, while injectable gold was associated with fewer dropouts for inadequate or poor therapeutic effect. Physicians should consider these findings when deciding on the use of Rizast in patients who are candidates for chrysotherapy.

Usual Adult Dosage

The usual adult dosage of Rizast (auranofin) is 6 mg daily, given either as 3 mg twice daily or 6 mg once daily. Initiation of therapy at dosages exceeding 6 mg daily is not recommended because it is associated with an increased incidence of diarrhea. If response is inadequate after six months, an increase to 9 mg (3 mg three times daily) may be tolerated. If response remains inadequate after a three-month trial of 9 mg daily, Rizast therapy should be discontinued. Safety at dosages exceeding 9 mg daily has not been studied.

Transferring from Injectable Gold

In controlled clinical studies, patients on injectable gold have been transferred to Rizast (auranofin) by discontinuing the injectable agent and starting oral therapy with Rizast, 6 mg daily. When patients are transferred to Rizast, they should be informed of its adverse reaction profile, in particular the gastrointestinal reactions. (See PATIENT INFORMATION.) At six months, control of disease activity of patients transferred to Rizast and those maintained on the injectable agent was not different. Data beyond six months are not available.

Rizast (auranofin) is contraindicated in patients with a history of any of the following gold-induced disorders: anaphylactic reactions, necrotizing enterocolitis, pulmonary fibrosis, exfoliative dermatitis, bone marrow aplasia or other severe hematologic disorders.

WARNINGS

Danger signs of possible gold toxicity include fall in hemoglobin, leukopenia below 4,000 WBC/cu mm, granulocytes below 1,500/cu mm, decrease in platelets below 150,000/cu mm, proteinuria, hematuria, pruritus, rash, stomatitis or persistent diarrhea.

Thrombocytopenia has occurred in 1–3% of patients (See ADVERSE REACTIONS) treated with Rizast (auranofin), some of whom developed bleeding. The thrombocytopenia usually appears to be peripheral in origin and is usually reversible upon withdrawal of Rizast. Its onset bears no relationship to the duration of Rizast therapy and its course may be rapid. While patients' platelet counts should normally be monitored at least monthly (See PRECAUTIONS - Laboratory Tests), the occurrence of a precipitous decline in platelets or a platelet count less than 100,000/cu mm or signs and symptoms (e.g., purpura, ecchymoses or petechiae) suggestive of thrombocytopenia indicates a need to immediately withdraw Rizast and other therapies with the potential to cause thrombocytopenia, and to obtain additional platelet counts. No additional Rizast should be given unless the thrombocytopenia resolves and further studies show it was not due to gold therapy.

Proteinuria has developed in 3-9% of patients (See ADVERSE REACTIONS) treated with Rizast. If clinically significant proteinuria or microscopic hematuria is found (See PRECAUTIONS - Laboratory Tests), Rizast and other therapies with the potential to cause proteinuria or microscopic hematuria should be stopped immediately.

PRECAUTIONS

General

The safety of concomitant use of Rizast (auranofin) with injectable gold, hydroxychloroquine, penicillamine, immunosuppressive agents (e.g., cyclophosphamide, azathioprine, or methotrexate) or high doses of corticosteroids has not been established.

Medical problems that might affect the signs or symptoms used to detect Rizast toxicity should be under control before starting Rizast (auranofin).

The potential benefits of using Rizast in patients with progressive renal disease, significant hepatocellular disease, inflammatory bowel disease, skin rash or history of bone marrow depression should be weighed against 1) the potential risks of gold toxicity on organ systems previously compromised or with decreased reserve, and 2) the difficulty in quickly detecting and correctly attributing the toxic effect.

The following adverse reactions have been reported with the use of gold preparations and require modification of Rizast treatment or additional monitoring. See ADVERSE REACTIONS for the approximate incidence of those reactions specifically reported with Rizast.

Gastrointestinal Reactions

Gastrointestinal reactions reported with gold therapy include diarrhea/loose stools, nausea, vomiting, anorexia and abdominal cramps. The most common reaction to Rizast is diarrhea/ loose stools reported in approximately 50% of the patients. This is generally manageable by reducing the dosage (e.g., from 6 mg daily to 3 mg) and in only 6% of the patients is it necessary to discontinue Rizast (auranofin) permanently. Ulcerative enterocolitis is a rare serious gold reaction. Therefore, patients with gastrointestinal symptoms should be monitored for the appearance of gastrointestinal bleeding.

Cutaneous Reactions

Dermatitis is the most common reaction to injectable gold therapy and the second most common reaction to Rizast. Any eruption, especially if pruritic, that develops during treatment should be considered a gold reaction until proven otherwise. Pruritus often exists before dermatitis becomes apparent, and therefore should be considered to be a warning signal of a cutaneous reaction. Gold dermatitis may be aggravated by exposure to sunlight or an actinic rash may develop. The most serious form of cutaneous reaction reported with injectable gold is generalized exfoliative dermatitis.

Mucous Membrane Reactions

Stomatitis, another common gold reaction, may be manifested by shallow ulcers on the buccal membranes, on the borders of the tongue, and on the palate or in the pharynx. Stomatitis may occur as the only adverse reaction or with a dermatitis. Sometimes diffuse glossitis or gingivitis develops. A metallic taste may precede these oral mucous membrane reactions and should be considered a warning signal.

Renal Reactions

Gold can produce a nephrotic syndrome or glomerulitis with proteinuria and hematuria. These renal reactions are usually relatively mild and subside completely if recognized early and treatment is discontinued. They may become severe and chronic if treatment is continued after the onset of the reaction. Therefore it is important to perform urinalyses regularly and to discontinue treatment promptly if proteinuria or hematuria develops.

Hematologic Reactions

Blood dyscrasias including leukopenia, granulocytopenia, thrombocytopenia and aplastic anemia have all been reported as reactions to injectable gold and Rizast. These reactions may occur separately or in combination at anytime during treatment. Because they have potentially serious consequences, blood dyscrasias should be constantly watched for through regular monitoring (at least monthly) of the formed elements of the blood throughout treatment.

Miscellaneous Reactions

Rare reactions attributed to gold include cholestatic jaundice; gold bronchitis and interstitial pneumonitis and fibrosis; peripheral neuropathy; partial or complete hair loss; fever.

Laboratory Tests

CBC with differential, platelet count, urinalysis, and renal and liver function tests should be performed prior to Rizast (auranofin) therapy to establish a baseline and to identify any preexisting conditions.

CBC with differential, platelet count and urinalysis should then be monitored at least monthly; other parameters should be monitored as appropriate.

Carcinogenesis/Mutagenesis

In a 24-month study in rats, animals treated with auranofin at 0.4, 1.0 or 2.5 mg/kg/day orally (3, 8 or 21 times the human dose) or gold sodium thiomalate at 2 or 6 mg/kg injected twice weekly (4 or 12 times the human dose) were compared to untreated control animals.

There was a significant increase in the frequency of renal tubular cell karyomegaly and cytomegaly and renal adenoma in the animals treated with 1.0 or 2.5 mg/kg/day of auranofin and 2 or 6 mg/kg twice weekly of gold sodium thiomalate. Malignant renal epithelial tumors were seen in the 1.0 mg/kg/day and the 2.5 mg/kg/day auranofin and in the 6 mg/kg twice weekly gold sodium thiomalatetreated animals.

In a 12-month study, rats treated with auranofin at 23 mg/kg/day (192 times the human dose) developed tumors of the renal tubular epithelium, whereas those treated with 3.6 mg/ kg/day (30 times the human dose) did not.

In an 18-month study in mice given oral auranofin at doses of 1, 3 and 9 mg/kg/day (8, 24 and 72 times the human dose), there was no statistically significant increase above controls in the instances of tumors.

In the mouse lymphoma forward mutation assay, auranofin at high concentrations (313 to 700 ng/mL) induced increases in the mutation frequencies in the presence of a rat liver microsomal preparation. Auranofin produced no mutation effects in the Ames test (Salmonella), in the in vitro assay (Forward and Reverse Mutation Inducement Assay with Saccharomyces), in the in vitro transformation of BALB/T3 cell mouse assay or in the Dominant Lethal Assay.

Pregnancy

Teratogenic Effects

Pregnancy Category C. Use of Rizast (auranofin) by pregnant women is not recommended. Furthermore, women of childbearing potential should be warned of the potential risks of Rizast therapy during pregnancy. (See below.)

Pregnant rabbits given auranofin at doses of 0.5, 3 or 6 mg/kg/day (4.2 to 50 times the human dose) had impaired food intake, decreased maternal weights, decreased fetal weights and an increase above controls in the incidence of resorptions, abortions and congenital abnormalities, mainly abdominal defects such as gastroschisis and umbilical hernia. Pregnant rats given auranofin at a dose of 5 mg/kg/day (42 times the human dose) had an increase above controls in the incidence of resorptions and a decrease in litter size and weight linked to maternal toxicity. No such effects were found in rats given 2.5 mg/kg/day (21 times the human dose).

Pregnant mice given auranofin at a dose of 5 mg/kg/day (42 times the human dose) had no teratogenic effects.

There are no adequate and well-controlled Rizast studies in pregnant women.

Nursing Mothers

Nursing during Rizast therapy is not recommended.

Following auranofin administration to rats and mice, gold is excreted in milk. Following the administration of injectable gold, gold appears in the milk of nursing women; human data on auranofin are not available.

Pediatric Use

Rizast (auranofin) is not recommended for use in pediatric patients because its safety and effectiveness have not been established.

The adverse reactions incidences listed below are based on observations of 1) 4,784 Rizast treated patients in clinical trials (2,474 U.S., 2,310 foreign), of whom 2,729 were treated more than one year and 573 for more than three years; and 2) postmarketing experience. The highest incidence is during the first six months of treatment; however, reactions can occur after many months of therapy. With rare exceptions, all patients were on concomitant nonsteroidal anti-inflammatory therapy; some of them were also taking low dosages of corticosteroids.

Reactions occurring in more than 1% of Rizast-treated patients

Gastrointestinal: loose stools or diarrhea (47%); abdominal pain (14%); nausea with or without vomiting (10%); constipation; anorexia*; flatulence*; dyspepsia*; dysgeusia.

Dermatological: rash (24%); pruritus (17%); hair loss; urticaria.

Mucous Membrane: stomatitis (13%); conjunctivitis*; glossitis.

Hematological: anemia; leukopenia; thrombocytopenia; eosinophilia.

Renal: proteinuria*; hematuria.

Hepatic: elevated liver enzymes.

*Reactions marked with an asterisk occurred in 3-9% of the patients. The other reactions listed occurred in 1-3%.

Reactions occurring in less than 1% of Rizast-treated patients

Gastrointestinal: dysphagia; gastrointestinal bleeding† melena† positive stool for occult blood†; ulcerative enterocolitis.

Dermatological: angioedema.

Mucous Membrane: gingivitis†.

Hematological: aplastic anemia; neutropenia†; agranulocytosis; pure red cell aplasia; pancytopenia.

Hepatic: jaundice.

Respiratory: interstitial pneumonitis.

Neurological: peripheral neuropathy.

Ocular: gold deposits in the lens or cornea unassociated clinically with eye disorders or visual impairment.

† Reactions marked with a dagger occurred in 0.1-1% of the patients. The other reactions listed occurred in less than 0.1%.

Reactions reported with injectable gold preparations, but not with Rizast (auranofin) (based on clinical trials and on postmarketing experience)

Cutaneous Reactions: generalized exfoliative dermatitis.

Incidence of Adverse Reactions for Specific Categories— 18 Comparative Trials

The acute oral LD50 for auranofin is 310 mg/kg in adult mice and 265 mg/ kg in adult rats. The minimum lethal dose in rats is 30 mg/kg.

In case of acute overdosage, immediate induction of emesis or gastric lavage and appropriate supportive therapy are recommended.

Rizast overdosage experience is limited. A 50-year-old female, previously on 6 mg Rizast daily, took 27 mg (9 capsules) daily for 10 days and developed an encephalopathy and peripheral neuropathy. Rizast was discontinued and she eventually recovered.

There has been no experience with treating Rizast overdosage with modalities such as chelating agents. However, they have been used with injectable gold and may be considered for Rizast overdosage.