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Pegylated Interferon alpha-2b, (PegIFN), Virafin



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2D chemical structure of 215647-85-1
Chemical structure of peginterferon α-2a and α-2b. Abbreviations: PeG-IFN, peginterferon; IFN, interferon; Lys, lysine; His, histidine; Cys, cysteine; Ser, serine. 

Chemical structure of peginterferon α-2a and α-2b. Abbreviations: PeG-IFN, peginterferon; IFN, interferon; Lys, lysine; His, histidine; Cys, cysteine; Ser, serine.

Pegylated Interferon alpha-2b

(PegIFN), Virafin

Zydus seeks DCGI approval for the use of Pegylated Interferon alpha-2b in  treating COVID-19 - The Indian Practitioner
CAS99210-65-8, 98530-12-2, 215647-85-1
Mol weight19268.9111
  • Interferon α2b, pegylated
  • PegIFN a-2b
  • PegIFN a-2b (biologics)
  • PegIFN α-2b
  • PegIntron
  • Pegaferon
  • PegiHep
  • Peginterferon alfa-2b
  • Peginterferon α-2b
  • Pegylated interferon alfa-2b
  • Pegylated interferon α-2b
  • Pegylated interferons, PegIFN a-2b
  • Proteinaceous biopharmaceuticals, PegIFN a-2b
  • Sch 54031
  • Sylatron
  • ViraferonPeg

Active Moieties

Interferon alfa-2bunknown43K1W2T1M698530-12-2Not applicable
Clinical data
Trade namesPegIntron, Sylatron, ViraferonPeg, others
AHFS/Drugs.comProfessional Drug Facts
License dataEU EMAby INN
Routes of
Subcutaneous injection
ATC codeL03AB10 (WHO)
Legal status
Legal statusUS: ℞-only [1][2]EU: Rx-only
Pharmacokinetic data
Elimination half-life22–60 hrs
showIUPAC name
CAS Number215647-85-1 
ECHA InfoCard100.208.164 
Chemical and physical data
Molar mass19269.17 g·mol−1




New Delhi: ,,,,,,

Zydus Cadila received emergency use approval from the Drugs Controller General of India (DGCI) on Friday for the use of “Virafin”, Pegylated Interferon alpha-2b (PegIFN) in treating moderate COVID-19 infection in adults.

A single-dose subcutaneous regimen of the antiviral Virafin will make the treatment more convenient for the patients. When administered early on during COVID-19, Virafin will help patients recover faster and avoid much of the complications, the company said.

In a release, Cadila Health highlighted that “the drug has also shown efficacy against other viral infections.”

Speaking on the development, Dr Sharvil Patel, Managing Director, Cadila Healthcare Limited said, “The fact that we are able to offer a therapy which significantly reduces the viral load when given early on can help in better disease management. It comes at a much-needed time for patients and we will continue to provide them access to critical therapies in this battle against COVID-19.”

In its Phase III clinical trials, the therapy had shown better clinical improvement in the patients suffering from COVID-19. During the trials, a higher proportion of patients administered with PegIFN arm were RT-PCR negative by day 7. The drug ensures faster viral clearance and has several add-on advantages compared to other anti-viral agents, the release further reads.

The development and the nod from DGCI come at a time when India is combating the second wave of coronavirus.

The central government in one of its major announcements decided to administer COVID-19 vaccines to all age above 18 years.

India recorded 3,32,730 new COVID-19 cases in the last 24 hours, the highest single-day spike since the pandemic broke out last year. India has crossed the mark of 3 lakh COVID-19 cases for two consecutive days now. This has taken the cumulative count of the COVID infection in the country to 1,62,63,695.

2CommentsThe country has recorded 2,263 new deaths due to COVID-19 in the last 24 hours. As many as 1,86,920 people have succumbed to the viral infection in India so far. There are 24,28,616 active COVID-19 cases in the country now.


  • Interferon alpha-2a plays an important role for the treatment of chronic hepatitis C, but it is limited in its efficacy by the short in vivo half-life. To improve the half-life and efficacy, interferon alpha-2a was conjugated with a polyethylene glycol moiety. Pegylation changes physicochemical and biological properties of the protein. One effect is the decrease of the proteolytic degradation and the renal clearance. This increases the half-life of the pegylated protein in blood. Another effect is the altered distribution in the body, depending on the size of the PEG moiety of the protein. Interferon alpha 2a pegylated with a large polyethylene glycol moiety (PEG moiety) such as a 40 kDa branched polyethylene moietywherein R and R’ are independently lower alkyl; n and n’ are integers having a sum of from 600 to 1500; and the average molecular weight of the polyethylene glycol units in said conjugate is from about 26,000 daltons to about 66,000 daltons;
    has an improved biological activity and exhibits sustained adsorption and reduced renal clearance, resulting in a strong antiviral pressure throughout a once-weekly dosing schedule, see Perry M. C., et al. Drugs, 2001,15,2263-2288 and Lamb M. W., et al. The Annals of Pharmacotherapy, 2002, 36, 933-938.
  • [0003]See also Monkarsh et al. Analytical Biochemistry, 1997, 247, 434- 440 (Positional Isomers of Mono-pegylated Interferon α-2a) and Bailon et al. Bioconjugate Chemistry, 2001, 12, 195-202 (Rational Design of a Potent, Long-Lasting Form of interferon).
  • [0004]The method for the pegylation of interferon alpha-2a is described in EP A 809 996. Since this pegylation is performed by reaction of PEG2-NHS of formulawith primary amino groups on for example lysine or to the N-terminus of the interferon or more PEG moieties may be attached and form a mixture of unpegylated, mono- and multiple-pegylated interferon. Monopegylated interferon alpha can be isolated from the mixture by methods known in the art. Furthermore, since interferon alpha-2a molecule exhibits 12 sites for pegylation (11 lysines and the N-terminus) it is a mixture of positional isomers. From these possible twelve isomers, nine were isolated and characterized, each of these being conjugated to the branched polyethylene glycol chain at a specific lysine, namely,
    at Lys(31) to form interferon alpha 2a pegylated at Lys(31) [referred to as PEG-Lys(31)],
    at Lys(49) to form interferon.alpha 2a pegylated at Lys(49) [referred to as PEG-Lys(49)],
    at Lys(70) to form interferon alpha 2a pegylated at Lys(70) [referred to as PEG-Lys(70)],
    at Lys(83) to form interferon alpha 2a pegylated at Lys(83) [referred to as PEG-Lys(83)],
    at Lys(112) to form interferon alpha 2a pegylated at Lys(112) [referred to as PEG-Lys(112)],
    at Lys(121) to form interferon alpha 2a pegylated at Lys(121) [referred to as PEG-Lys(121)],
    at Lys(131) to form interferon alpha 2a pegylated at Lys(131) [referred to as PEG-Lys(131)],
    at Lys(134) to form interferon alpha 2a pegylated at Lys(134) [referred to as PEG-Lys(134)],
    at Lys(164) to form interferon alpha 2a pegylated at Lys(164) [referred to as PEG-Lys(164)].
  • [0005]It has been found that PEG-Lys(31) and PEG-Lys(134) have higher activities in an antiviral assay than the mixture, the activity of PEG-Lys(164) was equal to the mixture, whereas the activities of PEG-Lys(49), PEG-Lys(70), PEG-Lys(83), PEG-Lys(112), PEG-Lys(121) and PEG-Lys(131) were lower.
  • The following examples will further illustrate the invention

Example 1A Separation of the positional isomers

  • [0035]A two-step isolation and purification scheme was used to prepare the monopegylated isoforms of PEG-interferon alpha 2a.
  • a) The first step was a separation of the positional isomers on a preparative low pressure liquid chromatography column with a weak-cation exchange matrix (TOSOH-BIOSEP, Toyopearl CM-650S, e.g. Resin Batch no. 82A the diameter of the column being 16 mm, the length 120 cm). A linear pH-gradient of increasing sodium acetate concentration (25 mM, pH 4.0 up 75 mM to pH 7.8) was applied at a flow rate of 0.7 mL/min. Detection was at 280 nm. With this chromatographic step species 1, 2, 5,6 and a mixture of 3, 4, 4a, 7 and 8 could be collected, see Table 1.
  • b) The fractions were further separated and purified in the second preparation step. A preparative column with the same matrix as the analytical strong-cation exchange column (Resin Batch no. 82A having a ion exchange capacity of 123 mEq/ml) as described above but larger dimensions (30 mm i.d. and 70 mm length), further a higher flow rate and an extended run time was used. As for the analytical method the column was pre-equilibrated with 3.4 mM sodium acetate, 10% ethanol and 1% diethylene glycol, adjusted to pH 4.4 (buffer A). After loading the PEG-IFN samples, the column was washed with buffer A, followed by an ascending linear gradient to 10 mM dibasic potassium phosphate, 10% ethanol and 1% diethylene glycol, adjusted to pH 6.6 (buffer B). The flow rate was 1.0 mL/min and the detection at 218 nm.
  • [0036]The protein concentration of the PEG-IFN alpha 2a isomer was determined by spectrophotometry, based on the 280 nm absorption of the.protein moiety of the PEG-IFN alpha 2a.
  • [0037]An analytical elution profile of 180 µg of PEG-IFN alpha 2a is shown in Figure 1. The result of this method is a separation into 8 peaks, 2 peaks with baseline separation and 6 with partial separation. The decrease of the baseline absorption towards the end of the chromatogram suggests that there were no other monopegylated species of IFN alpha 2a eluting at higher retention time.
  • [0038]In addition, looking carefully at the IEC-chromatogram a further peak close to the detection limit is visible between peaks 2 and 3 indicating the presence of additional positional isomers that should also contribute to the specific activity of the PEG-IFN alpha 2a mixture. Additional species were expected as the interferon alpha-2a molecule exhibits 12 sites for pegylation (11 lysines and the N-terminus). However, given the low abundance of the these species, they were not isolated and characterised.
  • [0039]Isomer samples derived from IEC optimisation runs were investigated directly after the isolation (t = 0) and after 2 of weeks of storage at 5°C (data not shown). No significant differences were observed for the protein derived from IEC-peaks with regard to the protein content as determined by spectrometric methods; nor were any changes to be detected in the monopegylation site, the content of oligo-PEG-IFN alpha 2a, the amount of aggregates and the bioassay activity. Taking into account the relative abundance of the individual isomers – as determined by the IEC method – as well as the specific activities – as determined in the anti-viral assay – almost the total specific bioactivity of the PEG-IFN alpha 2a mixture used for their isolation is recovered (approximately 93%).
  • [0040]The analytical IE-HPLC was used to check the purity of the individual isomers with respect to contamination with other positional isomers in the IEC fractions. The peaks 2, 3, 4, 4a, 5 and 7 had more than 98%, the peaks 1 and 8 had 93% and peak 6 had 88 % purity. Table 1:PEG-peptides identified by comparison of the Lys-C digest spectra of the isomers and the reference standard.Identified PEG Sites in the separated PEG-IFN SpeciesPeakmissing peaks in peptide mapPEG-IFNPEG siteMr (DA)SequencePeak 1K31A,E24-49Peak 2K134I, I’134-164Peak 3K131C122-131aPeak 4K121B, C113-131Peak 4aK164b134-164a,bPeak 5K70D, F50-83Peak 6K83D, H71-112Peak 7K49E, F32-70Peak 8K112B, H84-121a132-133 too small to detect.a,b RP-HPLC.
  • [0041]The fractions were characterised by the methods described in examples 2 to 6.

Example 1B Analytical separation of positional isomers of mono-pegylated interferon alpha 2a

  • [0042]HPLC Equipment:HP1100Column:SP-NPR, TosoH Bioscience, Particle size: 2.5µm, nonporous, Order#: 13076Injection:5-10 µg monopegylated IFNmobile Phase:Buffer A:  10% v/vEthanol 1% v/vDiethylenglycol 2.3 mMNa-Acetat 5.2 mMAcetic acid, in purified water, no pH adjustment Buffer B:  10% v/vEthanol 1% v/vDiethylenglycol 16.4 mMKH2PO4 4.4 mMK2HPO4, in purified water, no pH adjustmentGradient:0 Min40 %B 2 Min40 %B 2.1 Min48 %B 25 Min68 %B 27 Min75 %B 30 Min75 %B 34 Min40 %B 40 Min40 %BFlow:1.0 ml/min Column Temperature:25°C Detection:218 nm a typical Chromatogram is given in Figure 8.

Example 2 Analysis of the fractions by mass spectrometry peptide mapping

  • [0043]Mass spectra were recorded on a MALDI-TOF MS instrument (PerSeptive Biosystems Voyager-DE STR with delayed extraction). Each IEC fraction (Ion Exchange Chromatography) was desalted by dialysis, reduced with 0.02 M 1,4-dithio-DL-threitol (DTT) and alkylated with 0.2 M 4-vinyl pyridine. Then the proteins were digested with endoproteinase Lys-C (Wako Biochemicals) in 0.25 M Tris (tris(hydroxymethyl)-aminoethane) at pH 8.5 with an approximate enzyme to protein ratio of 1:30. The reaction was carried out over night at 37 °C.
  • [0044]A solution of 20 mg/ml α-cyano-4-hydroxycinnamic acid and 12 mg/ml nitrocellulose in acetone/isopropanol 40/60 (v/v) was used as matrix (thick-layer application). First, 0.5 µL of matrix was placed on the target and allowed to dry. Then, 1.0 µL of sample was added. The spectra were obtained in linear positive ionisation mode with an accelerating voltage of 20.000 V and a grid voltage of 95 %. At least 190 laser shots covering the complete spot were accumulated for each spectrum. Des-Arg1-bradykinin and bovine insulin were used for internal calibration.

Example 3 high-performance liquid chromatography (RP-HPLC) Peptide Mapping

  • [0045]The peptides were characterized by reverse-phase high-performance liquid chromatography (RP-HPLC) Peptide Mapping. The IEC fractions were reduced, alkylated and digested with endoproteinase Lys-C as described for the MALDI-TOF MS peptide mapping. The analysis of the digested isomers was carried out on a Waters Alliance HPLC system with a Vydac RP-C18 analytical column (5 µm, 2.1 × 250 mm) and a precolumn with the same packing material. Elution was performed with an acetonitrile gradient from 1 % to 95 % for 105 min in water with a flow rate of 0.2 mL/min. Both solvents contained 0.1 % (v/v) TFA. 100 µL of each digested sample were injected and monitored at 215 nm.

Example 4 MALDI-TOF spectra of undigested protein

  • [0046]An 18 mg/ml solution of trans-3-indoleacrylic acid in acetonitrile/0.1 % trifluoroacetic acid 70/30 (v/v) was premixed with the same volume of sample solution. Then 1.0 µL of the mixture was applied to the target surface. Typically 150 – 200 laser shots were averaged in linear positive ionisation mode. The accelerating voltage was set to 25.000 V and the grid voltage to 90 %. Bovine albumin M+ and M2+ were used for external calibration.

Example 5 SE-HPLC (size exclusion HPLC)

  • [0047]SE-HPLC was performed with a Waters Alliance 2690 HPLC system equipped with a TosoHaas TSK gel G 4000 SWXL column (7.8 × 300 mm). Proteins were eluted using a mobile phase containing 0.02 M NaH2PO4, 0.15 M NaCl, 1% (v/v) diethylene glycol and 10 % (v/v) ethanol (pH 6.8) at a flow rate of 0.4 mL/min and detected at 210 nm. The injection amounts were 20 µg of each isomers.
  • [0048]Size Exclusion HPLC and SDS-PAGE were used to determine the amount of oligo-PEG-IFN alpha 2a forms and aggregates in the different IEC fractions. The reference material contains 2.3 % aggregates and 2.2 % oligomers (Figure 4).
  • [0049]Peaks 1, 4, 4a, 5, 6 and 8 contain < 0.7 % of the oligopegylated IFN alpha 2a forms, whereas in,peaks 2, 3, and 7 the percentage of the oligopegylated IFN alpha 2a forms are under the detection limit (< 0.2 %). In the case of the aggregates a different trend could be seen. In all peaks the amount of aggregates is below 0.9 %.

Example 6 SDS-PAGE

  • [0050]SDS-PAGE was carried out both under non-reducing and under reducing conditions using Tris-Glycine gels of 16 % (1.5 mm, 10 well). Novex Mark 12 molecular weight markers with a mass range from 2.5 to 200 kDa were used for calibration, bovine serum albumin (BSA) was used as sensitivity standard (2 ng). Approximately 1 µg of all the samples and 0.5 µg of standard were applied to the gel. The running conditions were 125 V and 6 W for 120 min. The proteins were fixed and stained using the silver staining kit SilverXpress from Novex.
  • [0051]The gels that were recorded under non-reducing conditions for the IEC fractions 1- 8 (Figure 2) show a pattern that is comparable to that of the PEG-IFN alpha 2a reference standard.
  • [0052]Under reducing conditions, the gels show an increase in intensity of the minor bands at about 90 kDa as compared to the standard. Between 6 and 10 kDa protein fragments appear for peaks 6, 7 and 8 (Figure 3). Both bands together correspond to approximately 1 % of clipped material. In the lanes of isomer 1, 5, 6, 7, 8 additional bands with more than 100 kDa can be seen which are also present in the standard. These can be assigned to oligomers. Thus SDS-PAGE confirms the results of the SE-HPLC analysis.
  • [0053]Overall, RP-HPLC and SDS-PAGE experiments indicate that the purity of the IEC fractions can be considered comparable to the PEG-IFN alpha 2a reference standard.
  • [0054]The structure of the PEG-IFN alpha 2a species derived from the 9 IEC-fractions were identified based on the results of the methods described above using the strategy mentioned above.

Example 7 The antiviral activity (AVA)

  • [0055]The antiviral activity was estimated by its protective effect on Madin-Darby bovine kidney (MDBK) cells against the infection by vesticular stomatitis virus (VSV) and compared with a PEG-IFN alpha 2a standard. Samples and reference standard were diluted in Eagle’s Minimum Essential Medium (MEM) containing 10 % fetal bovine serum to a final concentration of 10 ng/mL (assay starting concentration). Each sample was assayed in quadruplicate.
  • [0056]The antiviral protection of Madin-Darby bovine kidney cells (MDBK) with vesicular stomatitis virus was tested according to the method described in Virol. 1981, 37, 755-758. All isomers induced an activity in the anti-viral assay as presented in Table 2. The activities range between 1061 and 339 U/µg, indicating that the difference in specific activities of the protein in the positional isomers is significant. The know-how and the results generated so far will allow the initiation of further investigations to establish this structure-function relationship between the positional isomers and the IFN alpha receptors. Table 2:In Vitro Antiviral Activities of PEG-IFN alpha 2a and individual PEG-IFN alpha 2a isomers. The Antiviral activity was determined in MDBK cells infected with vesicular stomatitis virus. The results present the averages of three assays performed independently.Antiviral Assay of PEG-IFNPeakU/µgPEG-IFN1061 ± 50Peak 11818 ± 127Peak 21358 ± 46Peak 3761197Peak 4339 ± 33Peak 4a966 ± 107Peak 5600 ± 27Peak 6463 ± 25Peak7513 ± 20Peak 8468 ± 23
  • [0057]The results are further illustrated by the following figures
  • Figure 1: Analytical IEC-HPLC of 180µg of PEG-IFN alpha 2a. An analytical strong-cation exchange column was used to check the purity of the separated positional isomers from each purification step (TOSOH-BIOSEP, SP-SPW,10 µm particle size, 7.5 mm diameter, 7.5 cm length).
  • Figure 2: A/B: SDS-PAGE analysis with Tris-glycine (16%), the samples were electrophoresed under non-reduced conditions. The gels were stained for protein with Silver Stain. Lanes: M, molecular weight marker proteins/ 2, Peak 1/ 3, Peak 2/ 4, Peak 3/ 5, Peak 4/ 6, Peak 4a/ 7, Peak 5/ 8, Peak 6/ 9, Peak 7/10, Peak 8/ 11, Ix PEG-IFN standard/ 12, 1.5x PEG-IFN standard/ C1, IFN standard.
  • Figure 3: A/B: SDS-PAGE analysis with Tris-glycine (16%), the samples were electrophoresed under reduced conditions. The gels were stained for protein with Silver Stain. Lanes: M, molecular weight marker proteins/ 2, Peak 1/ 3, Peak 2/ 4, Peak 3/ 5, Peak 4/ 6, Peak 4a/ 7, Peak 5/ 8, Peak 6/ 9, Peak 7/ 10, Peak 8/ 11, 1x PEG-IFN standard/ 12, 1.5x PEG-IFN standard/ C1, IFN standard.
  • Figure 4: Size Exclusion (SE-) HPLC was used to determine the amount of oligo PEG-IFN forms and aggregates in the different IEC fractions. SE-HPLC was performed with a TosoHaas TSK gel G 4000 SWXL column (7.8 × 300 mm).
  • Figure 5: MALDI-TOF spectrometry was used to determine the molecular weight of each isomer in order to ensure that the PEG-IFN molecules were still intact after IEC chromatography and to confirm the monopegylation.
  • Figure 6: MALDI-TOF Lys-C peptide maps of the PEG-IFN reference standard and the peaks 1, 2, 3, 4, 4a, 5, 6, 7, 8. Missing peaks compared to the standard are indicated by arrows.
  • Figure 7: RP-HPLC chromatograms of the Lys-C digests of the PEG-IFN reference and peak 4a
  • Figure 8: Analytical HPLC of 5-10µg of PEG-IFN alpha 2a mixture of positional isomers on a column charged with SP-NPR, TosoH Bioscience, Particle size: 2.5µm, nonporous as described in Example 1B..
  • Figure 9: Ribbon structure of interferon alpha-2a showing the pegylation sites. This is the high resolution structure of human interferon alpha-2a determined with NMR spectroscopy see JMol. Biol. 1997, 274, 661-675. The pegylation sites of pegylated interferon alpha-2a are coloured red and labelled with residue type and residue number.

Pegylated interferon alfa-2b, sold under the brand name PegIntron among others, is a medication used to treat hepatitis C and melanoma.[3] For hepatitis C it is typically used with ribavirin and cure rates are between 33 and 82%.[3][4] For melanoma it is used in addition to surgery.[3] It is given by injection under the skin.[3]

Side effects are common.[5] They may include headache, feeling tired, mood changes, trouble sleeping, hair loss, nausea, pain at the site of injection, and fever.[3] Severe side effects may include psychosisliver problemsblood clotsinfections, or an irregular heartbeat.[3] Use with ribavirin is not recommended during pregnancy.[3] Pegylated interferon alfa-2b is in the alpha interferon family of medications.[3] It is pegylated to protect the molecule from breakdown.[5]

Pegylated interferon alfa-2b was approved for medical use in the United States in 2001.[3] It is on the World Health Organization’s List of Essential Medicines.[6]

Peginterferon alfa-2b is a form of recombinant interferon used as part of combination therapy to treat chronic Hepatitis C, an infectious liver disease caused by infection with Hepatitis C Virus (HCV). HCV is a single-stranded RNA virus that is categorized into nine distinct genotypes, with genotype 1 being the most common in the United States, and affecting 72% of all chronic HCV patients 3. Treatment options for chronic Hepatitis C have advanced significantly since 2011, with the development of Direct Acting Antivirals (DAAs) resulting in less use of Peginterferon alfa-2b. Peginterferon alfa-2b is derived from the alfa-2b moeity of recombinant human interferon and acts by binding to human type 1 interferon receptors. Activation and dimerization of this receptor induces the body’s innate antiviral response by activating the janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway. Use of Peginterferon alfa-2b is associated with a wide range of severe adverse effects including the aggravation and development of endocrine and autoimmune disorders, retinopathies, cardiovascular and neuropsychiatric complications, and increased risk of hepatic decompensation in patients with cirrhosis. The use of Peginterferon alfa-2b has largely declined since newer interferon-free antiviral therapies have been developed.

In a joint recommendation published in 2016, the American Association for the Study of Liver Diseases (AASLD) and the Infectious Diseases Society of America (IDSA) no longer recommend Peginterferon alfa-2b for the treatment of Hepatitis C 2. Peginterferon alfa-2b was used alongside Ribavirin( with the intent to cure, or achieve a sustained virologic response (SVR), after 48 weeks of therapy. SVR and eradication of HCV infection is associated with significant long-term health benefits including reduced liver-related damage, improved quality of life, reduced incidence of Hepatocellular Carcinoma, and reduced all-cause mortality 1.

Peginterferon alfa-2b is available as a variable dose injectable product (tradename Pegintron) used for the treatment of chronic Hepatitis C. Approved in 2001 by the FDA, Pegintron is indicated for the treatment of HCV with Ribavirin or other antiviral drugs Label. When combined together, Peginterferon alfa-2b and Ribavirin have been shown to achieve a SVR between 41% for genotype 1 and 75% for genotypes 2-6 after 48 weeks of treatment.

Medical uses

It is used to treat hepatitis C and melanoma. For hepatitis C it is typically used with ribavirin. For melanoma it is used in addition to surgery.[3]

For hepatitis C it may also be used with boceprevirtelaprevirsimeprevir, or sofosbuvir.[5]

In India, in 2021, DGCI approved emergency use of Zydus Cadila‘s Virafin in treating moderate COVID-19 infection.[7]

Host genetic factors

For genotype 1 hepatitis C treated with pegylated interferon-alfa-2a or pegylated interferon-alfa-2b combined with ribavirin, it has been shown that genetic polymorphisms near the human IL28B gene, encoding interferon lambda 3, are associated with significant differences in response to the treatment. This finding, originally reported in Nature,[8] showed that genotype 1 hepatitis C patients carrying certain genetic variant alleles near the IL28B gene are more likely to achieve sustained virological response after the treatment than others. A later report from Nature[9] demonstrated that the same genetic variants are also associated with the natural clearance of the genotype 1 hepatitis C virus.

Side effects

Common side effects include headache, feeling tired, mood changes, trouble sleeping, hair loss, nausea, pain at the site of injection, and fever. Severe side effects may include psychosisliver problemsblood clotsinfections, or an irregular heartbeat.[3] Use with ribavirin is not recommended during pregnancy.[3]

Mechanism of action

One of the major mechanisms of PEG-interferon alpha-2b utilizes the JAK-STAT signaling pathway. The basic mechanism works such that PEG-interferon alpha-2b will bind to its receptor, interferon-alpha receptor 1 and 2 (IFNAR1/2). Upon ligand binding the Tyk2 protein associated with IFNAR1 is phosphorylated which in turn phosphorylates Jak1 associated with IFNAR2. This kinase continues its signal transduction by phosphorylation of signal transducer and activator of transcription (STAT) 1 and 2 via Jak 1 and Tyk2 respectively. The phosphorylated STATs then dissociate from the receptor heterodimer and form an interferon transcription factor with p48 and IRF9 to form the interferon stimulate transcription factor-3 (ISGF3). This transcription factor then translocates to the nucleus where it will transcribe several genes involved in cell cycle control, cell differentiation, apoptosis, and immune response.[10][11]

PEG-interferon alpha-2b acts as a multifunctional immunoregulatory cytokine by transcribing several genes, including interleukin 4 (IL4). This cytokine is responsible for inducing T helper cells to become type 2 helper T cells. This ultimately results in the stimulation of B cells to proliferate and increase their antibody production. This ultimately allows for an immune response, as the B cells will help to signal the immune system that a foreign antigen is present.[12]

Another major mechanism of type I interferon alpha (IFNα) is to stimulate apoptosis in malignant cell lines. Previous studies have shown that IFNα can cause cell cycle arrest in U266, Daudi, and Rhek-1 cell lines.[13]

A follow-up study researched to determine if the caspases were involved in the apoptosis seen in the previous study as well as to determine the role of mitochondrial cytochrome c release. The study confirmed that there was cleavage of caspase-3, -8, and -9. All three of these cysteine proteases play an important role in the initiation and activation of the apoptotic cascade. Furthermore, it was shown that IFNα induced a loss in the mitochondrial membrane potential which resulted in the release of cytochrome c from the mitochondria. Follow-up research is currently being conducted to determine the upstream activators of the apoptotic pathway that are induced by IFNα.[14]


It was developed by Schering-Plough. Merck studied it for melanoma under the brand name Sylatron. It was approved for this use in April 2011.


  1. ^ “PegIntron- peginterferon alfa-2b injection, powder, lyophilized, for solution PegIntron- peginterferon alfa-2b kit”DailyMed. Retrieved 28 September 2020.
  2. ^ “Sylatron- peginterferon alfa-2b kit”DailyMed. 28 August 2019. Retrieved 28 September 2020.
  3. Jump up to:a b c d e f g h i j k l “Peginterferon Alfa-2b (Professional Patient Advice) –”http://www.drugs.comArchived from the original on 16 January 2017. Retrieved 12 January 2017.
  4. ^ “ViraferonPeg Pen 50, 80, 100, 120 or 150 micrograms powder and solvent for solution for injection in pre-filled pen CLEAR CLICK – Summary of Product Characteristics (SPC) – (eMC)” Archived from the original on 13 January 2017. Retrieved 12 January 2017.
  5. Jump up to:a b c “Peginterferon alfa-2b (PegIntron)”Hepatitis C OnlineArchived from the original on 23 December 2016. Retrieved 12 January 2017.
  6. ^ World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
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  8. ^ Ge D, Fellay J, Thompson AJ, et al. (2009). “Genetic variation in IL28B predicts hepatitis C treatment-induced viral clearance”. Nature461 (7262): 399–401. Bibcode:2009Natur.461..399Gdoi:10.1038/nature08309PMID 19684573S2CID 1707096.
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DR ANTHONY MELVIN CRASTO, Born in Mumbai in 1964 and graduated from Mumbai University, Completed his Ph.D from ICT, 1991,Matunga, Mumbai, India, in Organic Chemistry, The thesis topic was Synthesis of Novel Pyrethroid Analogues, Currently he is working with GLENMARK PHARMACEUTICALS LTD, Research Centre as Principal Scientist, Process Research (bulk actives) at Mahape, Navi Mumbai, India. Total Industry exp 30 plus yrs, Prior to joining Glenmark, he has worked with major multinationals like Hoechst Marion Roussel, now Sanofi, Searle India Ltd, now RPG lifesciences, etc. He has worked with notable scientists like Dr K Nagarajan, Dr Ralph Stapel, Prof S Seshadri, Dr T.V. Radhakrishnan and Dr B. K. Kulkarni, etc, He did custom synthesis for major multinationals in his career like BASF, Novartis, Sanofi, etc., He has worked in Discovery, Natural products, Bulk drugs, Generics, Intermediates, Fine chemicals, Neutraceuticals, GMP, Scaleups, etc, he is now helping millions, has 9 million plus hits on Google on all Organic chemistry websites. His friends call him Open superstar worlddrugtracker. His New Drug Approvals, Green Chemistry International, All about drugs, Eurekamoments, Organic spectroscopy international, etc in organic chemistry are some most read blogs He has hands on experience in initiation and developing novel routes for drug molecules and implementation them on commercial scale over a 30 year tenure till date Dec 2017, Around 35 plus products in his career. He has good knowledge of IPM, GMP, Regulatory aspects, he has several International patents published worldwide . He has good proficiency in Technology transfer, Spectroscopy, Stereochemistry, Synthesis, Polymorphism etc., He suffered a paralytic stroke/ Acute Transverse mylitis in Dec 2007 and is 90 %Paralysed, He is bound to a wheelchair, this seems to have injected feul in him to help chemists all around the world, he is more active than before and is pushing boundaries, He has 9 million plus hits on Google, 2.5 lakh plus connections on all networking sites, 50 Lakh plus views on dozen plus blogs, He makes himself available to all, contact him on +91 9323115463, email, Twitter, @amcrasto , He lives and will die for his family, 90% paralysis cannot kill his soul., Notably he has 19 lakh plus views on New Drug Approvals Blog in 216 countries...... , He appreciates the help he gets from one and all, Friends, Family, Glenmark, Readers, Wellwishers, Doctors, Drug authorities, His Contacts, Physiotherapist, etc

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