Sanofi un­der fire af­ter dengue vac­cine furore

BioSpectrum (Asia) - - Bio Content - Priyanka Ba­j­pai­j­pai@mmac­

Dengue fever is a mosquito­borne dis­ease caused by four virus serotypes (1 to 4) as cat­e­gorised by the World Health Or­gan­i­sa­tion. Over­all, the dis­ease is seen as a threat to about half of the world’s pop­u­la­tion. Some 400 mil­lion peo­ple are be­lieved to be in­fected an­nu­ally.

In De­cem­ber 2015, Dengvaxia, the world’s first promis­ing vac­cine against dengue virus de­vel­oped by French phar­ma­ceu­ti­cal com­pany Sanofi Pas­teur, was li­censed and ap­proved for com­mer­cial use in 11 coun­tries namely Mex­ico, the Philip­pines, In­done­sia, Brazil, El Sal­vador, Costa Rica, Paraguay, Gu­ata­mala, Peru, Thai­land, as well as Sin­ga­pore in Oc­to­ber last year. It is ap­proved but not yet launched in Hon­duras, Malaysia, Aus­tralia, Ar­gentina, Venezuela, Bo­livia, Bangladesh and Cam­bo­dia.

How­ever, re­cently Dengvaxia faced a ma­jor set­back af­ter Sanofi re­leased the find­ings of a new study based on six years’ worth of clin­i­cal trial data that showed dengue vac­cine could worsen symp­toms for those not pre­vi­ously in­fected with dengue.

The anal­y­sis con­firmed that Dengvaxia pro­vides per­sis­tent pro­tec­tive ben­e­fit against dengue fever in those who had prior in­fec­tion. The French man­u­fac­turer how­ever warned that for peo­ple who are not pre­vi­ously in­fected with the dis­ease, the symp­toms could worsen af­ter im­mu­ni­sa­tion.

Fol­low­ing the dis­clo­sure, the Philip­pines Depart­ment of Health (DoH) has sus­pended the dengue vac­cine, amid wide­spread fears about its safety and grow­ing pub­lic furore over its use in 830,000 school chil­dren and piqued con­gres­sional cu­rios­ity about how Dengvaxia en­tered the Health depart­ment’s multi­bil­lion-peso, an­ti­dengue vac­ci­na­tion pro­gram. More than 80,000 school chil­dren had re­ceived the vac­cine last year in the world’s first pub­lic dengue im­mu­ni­sa­tion pro­gramme.

FDA sus­pends sale & dis­tri­bu­tion of Dengvaxia

The in­ci­dence of dengue has grown dra­mat­i­cally around the world in re­cent decades. The ac­tual num­bers of dengue cases are un­der­re­ported and many cases are mis­clas­si­fied. The Food and Drug Ad­min­is­tra­tion (FDA) has im­posed ad­min­is­tra­tive

sanc­tions on French drug­maker Sanofi Pas­teur. Sus­pen­sion of the cer­tifi­cate of prod­uct regis­tra­tion of the con­tro­ver­sial dengue vac­cine Dengvaxia for one year and an em­blem­atic fine of 100,000 pe­sos (about $2,000) has also been or­dered on the com­pany.

The ad­min­is­tra­tive sanc­tions cover ad­min­is­tra­tive lapses on the part of the Sanofi, in­clud­ing skirt­ing the reg­u­la­tory re­quire­ment of post-mar­ket­ing sur­veil­lance re­ports.

Dengue vac­cine mar­ket

Ac­cord­ing to the global dengue vac­cine mar­ket re­port 2017-2021, rapid growth in dis­ease preva­lence is one of the pri­mary causes of driv­ing the mar­ket. The preva­lence and in­ci­dence of dengue is ris­ing rapidly. Global warm­ing and pop­u­la­tion den­sity are two pri­mary fac­tors that at­tribute to the rise in dengue cases world­wide. As per the Na­tional In­sti­tutes of Health (NIH), 3.6 bil­lion peo­ple that re­side in trop­i­cal and sub­trop­i­cal re­gions are at risk of dengue trans­mis­sion. Global es­ti­mates vary, but nearly 0.05 to 0.2 bil­lion cases of dengue in­fec­tions are re­ported an­nu­ally. In 2011, an­nual cases of se­vere dengue were around 0.5 mil­lion, and mor­tal­ity due to dengue was above 20,000 as per the NIH. As per the NIH, in 2012, the up­per bound to­tal was 3.97 bil­lion for peo­ple at risk of dengue in 128 coun­tries glob­ally.

Sta­tus of Dengvaxia in other mar­kets

Af­ter the of­fi­cial re­lease of the state­ment from Sanofi that peo­ple who have had no pre­vi­ous in­fec­tion of the dis­ease might be at a higher risk of wors­ened symp­toms af­ter im­mu­ni­sa­tion, other coun­tries where the vac­cine has been ap­proved and li­censed are also mon­i­tor­ing the anti-dengue vac­cine closely.

Brazil has al­ready rec­om­mended re­stricted use of the anti-dengue vac­cine to those pre­vi­ously in­fected with dengue. How­ever, the drug has not been sus­pended en­tirely un­like the Philip­pines.

Sin­ga­pore is also aware of the sit­u­a­tion and is tak­ing pre­ven­tive mea­sures. Sin­ga­pore’s Health Sciences Au­thor­ity (HSA) is work­ing with Sanofi to strengthen risk warn­ings on the drug’s pack­ag­ing. Health­care pro­fes­sion­als and physi­cians have been ad­vised to mon­i­tor and not ad­min­is­ter dengue vac­cine to pa­tients who have not been pre­vi­ously in­fected by the virus.

It is known that Sanofi has spent 20 years de­vel­op­ing the world’s first dengue vac­cine at a cost of around 1.5 bil­lion eu­ros (S$2.4 bil­lion).

HSA agrees that Sanofi Pas­teur’s find­ings con­firm its 2016 as­sess­ment of a pos­tu­lated risk of higher in­ci­dence of se­vere dengue fol­low­ing vac­ci­na­tion of those not pre­vi­ously in­fected. In the cur­rent sce­nario, HSA has sug­gested peo­ple look­ing for im­mu­ni­sa­tion against the dis­ease should first con­sult their doc­tors on the af­ter ben­e­fits and risks of the vac­cine. In or­der to in­crease aware­ness amongst the pop­u­la­tion, HSA has also shared this in­for­ma­tion with health­care pro­fes­sion­als, the me­dia, as well as the pub­lic.

Sin­ga­pore govern­ment is keep­ing no stones un­turned on this is­sue. The au­thor­ity is also work­ing with the health min­istry in par­al­lel to of­fer sero­log­i­cal test­ing, which will help iden­tify pre­vi­ous dengue in­fec­tion in the Sin­ga­pore pop­u­la­tion. Also, in Sin­ga­pore, dengue vac­ci­na­tion is not part of the na­tional im­mu­ni­sa­tion pro­gramme. This will fur­ther curb im­mu­ni­sa­tion to the pop­u­la­tion in large and will only be ad­min­is­tered to in­di­vid­u­als where the ben­e­fits out­weigh the risk. HSA has also as­sured

that it would fur­ther strengthen the warn­ings and rec­om­men­da­tions in the pre­scrib­ing in­for­ma­tion to en­sure safe use of Sanofi’s vac­cine, as well as in­creas­ing the aware­ness within the com­mon man about the pros and cons of Dengvaxia vac­cine.

Sanofi’s stand­ing on the is­sue

The French drug man­u­fac­turer, Sanofi has main­tained that there has been no ev­i­dence of se­vere dengue in vac­ci­nated in­di­vid­u­als in the real-world ex­pe­ri­ence with the vac­cine.

The com­pany has con­firmed that the long-term safety eval­u­a­tion of Dengvaxia showed sig­nif­i­cantly fewer hos­pi­tal­i­sa­tions due to dengue in vac­ci­nated peo­ple over nine years old com­pared with those who had not been vac­ci­nated. Sanofi plans to dis­cuss the reg­u­la­tory fil­ing for Dengvaxia with new la­belling rec­om­men­da­tions with the US FDA. The vac­cine is still un­der review by the Euro­pean health reg­u­la­tors.

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