Skin spray con­tra­cep­tive next big thing

Birth con­trol meth­ods may shortly be­come even more con­ve­nient, writes Stephen Pin­cock

The Weekend Australian - Travel - - Health -

AL­MOST 50 years af­ter women first be­gan tak­ing the pill, Aus­tralian re­searchers are work­ing on what they think could be the next ma­jor break­through in avoid­ing preg­nancy — a con­tra­cep­tive spray. If early re­sults bear fruit, women may one day sim­ply spray an in­vis­i­ble, odour­less prepa­ra­tion onto the inside of their arm — no pills, im­plants or de­vices.

This method — if con­clu­sively shown to work — may also have the ad­van­tage of be­ing less sen­si­tive to missed or late doses, a prob­lem with daily con­tra­cep­tive pills.

‘‘ It’s a con­cept that is highly ac­cept­able to a lot of women,’’ says re­searcher Ian Fraser from the Univer­sity of Syd­ney. ‘‘ There are a mi­nor­ity of women who find cur­rent meth­ods not to their lik­ing — and some who like the con­cept of do­ing things a lit­tle dif­fer­ently.’’

The tech­nol­ogy for de­liv­er­ing con­tra­cep­tives through the skin has been de­vel­oped by Acrux, a small Melbourne firm founded by re­searchers from Monash Univer­sity.

Their de­vice looks rather like a large asthma in­haler. A wo­man would place it against the fore­arm and push a but­ton to de­liver through the skin a con­trolled dose of hor­mones as con­tained in a pill.

The so-called ‘‘ trans­der­mal’’ de­liv­ery method has al­ready been shown to work for pur­poses other than birth con­trol. In July last year ap­proval was granted in the US for mar­ket­ing of the Acrux sys­tem for de­liv­er­ing hor­mones across the skin to treat menopause symp­toms. The com­pany is also plan­ning a large trial us­ing their sys­tem to de­liver testos­terone as a treat­ment for men with a con­di­tion known as male hy­pog­o­nadism.

The com­pany has been work­ing for sev­eral years on spray-on con­tra­cep­tives, but the first for­mal re­sults only ap­peared in a sci­en­tific jour­nal in De­cem­ber.

In that pa­per, Fraser, a pro­fes­sor of re­pro­duc­tive medicine, and doc­tor Edith Weis­berg, di­rec­tor of re­search at the Syd­ney Cen­tre for Re­pro­duc­tive Health Re­search at Fam­ily Plan­ning NSW, de­scribe a study that in­cluded six healthy post-menopausal women.

Each re­ceived five daily doses of a con­tra­cep­tive hor­mone called Nestorone, a deriva­tive of pro­ges­terone that has the high­est an­tiovu­la­tory po­tency of all the pro­gesto­gens cur­rently avail­able.

The re­searchers wanted to as­sess whether the Acrux sys­tem could de­liver hor­mone into the women’s blood­stream in quan­ti­ties that would be suf­fi­cient to stop ovu­la­tion women still of child­bear­ing age.

Al­though post-menopausal women wouldn’t use the sys­tem in real life, they were ideal to study be­cause their bod­ies con­tain lower lev­els of nat­u­ral hor­mones that could con­fuse the re­sults, Fraser says.

The re­sults, pub­lished in the jour­nal Con­tra­cep­tion (2007;76:432-438), were en­cour­ag­ing. They showed ‘‘ the fea­si­bil­ity of achiev­ing serum lev­els of Nestorone suf­fi­cient to block ovu­la­tion and po­ten­tially pro­vide ef­fec­tive con­tra­cep­tion’’, the au­thors wrote.

Doc­tor Deb­o­rah Bate­son, med­i­cal co­or­di­na­tor of Fam­ily Plan­ning NSW, who wasn’t in­volved in the study, says she is cau­tiously op­ti­mistic about the find­ings. ‘‘ It’s early days ob­vi­ously, but the ex­cit­ing thing is that they showed that it is a vi­able con­cept.’’ For her, a con­tra­cep­tive spray would be use­ful be­cause it might of­fer women an­other choice for avoid­ing preg­nancy. ‘‘ To in­crease choices is gen­er­ally a good thing to do.’’

Since the con­tra­cep­tive pill hit the Aus­tralian mar­ket in Jan­uary 1961, those choices have ex­panded sig­nif­i­cantly. Women can now choose patches, in­tra-uter­ine de­vices, di­aphragms, im­plants and other meth­ods for con­tra­cep­tion.

Still, the pill re­mains far and away the most com­monly re­ported method. One re­cent anal­y­sis of Aus­tralia’s 2001 Na­tional Health Sur­vey, pub­lished in the Jour­nal of Bioso­cial Science (2007;36:735-44), showed that more than three-quar­ters of all women aged 18-49 had used the con­tra­cep­tive pill, in­clud­ing more than half of those un­der age 20.

A spray might over­come some of the prob­lems as­so­ci­ated with other meth­ods, Bate­son said. ‘‘ Con­tra­cep­tive patches, for ex­am­ple, do come with their prob­lems, par­tic­u­larly in a coun­try like Aus­tralia where peo­ple go to the beach a lot. A once-a-day spray is a very at­trac­tive op­tion. You can’t smell it or see it, and you can ad­min­is­ter it your­self.’’

Women may also be in­ter­ested to know that the Acrux spray-on tech­nol­ogy has very close ties to sun­screen.

The prod­uct’s roots can be traced back some 20 years, to the labs of re­searchers Bar­rie Fin­nin and Barry Reed from the Vic­to­rian Col­lege of Phar­macy, now part of Monash Univer­sity.

The two men were look­ing for ways to de­liver drugs across the skin us­ing creams or

in lo­tions, and had tried a host of ap­proaches when they de­cided sun­screen to the mix.

‘‘ We were look­ing at things that might con­trol hy­per­pig­men­ta­tion of the skin,’’ Fin­nin re­calls. ‘‘ We dis­cov­ered that when you in­clude sun­screen in the prepa­ra­tion, the other drugs you in­cluded got across.’’

Soon, the re­searchers dis­cov­ered that the chem­i­cals do­ing the job of fer­ry­ing drugs across the skin were a group of mol­e­cules de­signed to block ul­tra­vi­o­let light.

‘‘ It is just a co­in­ci­dence that they also have th­ese other prop­er­ties,’’ said Fin­nin. ‘‘ It’s just dif­fer­ent to add one of those for­tu­nate things. I would like to say I was clever enough to have pre­dicted it, but I didn’t.’’

It may have been a fluke, but Fin­nin and Reed quickly re­alised its value. Then, a PhD stu­dent named Tim Morgan showed that if you de­liver the mix of sun­screen in­gre­di­ents and drugs via aerosol or spray, it in­creased their ab­sorp­tion through the tough outer lay­ers of the skin even fur­ther.

‘‘ At that time, we re­alised we had some­thing that was po­ten­tially very com­mer­cially valu­able,’’ Fin­nin said. By 1997 they had pro­vi­sional patents on their in­ven­tion, and in 1998 they founded Acrux to help raise funds for fur­ther re­search.

‘‘ It’s es­sen­tially an off­shoot of sun­screen tech­nol­ogy,’’ says Ian Fraser. He ex­plains that a dose of hor­mones de­liv­ered with the Acrux sys­tem is ab­sorbed across the outer lay­ers of skin within 30 sec­onds, and then sits in the deeper lay­ers of the skin where they are slowly re­leased into the blood­stream over the fol­low­ing 36 hours.

‘‘ You’ve got this reser­voir in the deeper lay­ers of the skin,’’he said. In the study his group pub­lished last year, there was still a sub­stan­tial amount of the con­tra­cep­tive in the blood­stream of the women 27 hours af­ter the fi­nal dose.

This slow-re­lease mech­a­nism might have a sig­nif­i­cant ben­e­fit for those women who find it hard to time the pill ex­actly.

‘‘ The ma­jor­ity of women miss a pill from time to time, and a mi­nor­ity miss a pill ev­ery month,’’ he says. ‘‘ Most of the preg­nan­cies that oc­cur with women who are tak­ing the pill are due to the dif­fi­cul­ties in re­mem­ber­ing to take it at a cer­tain time ev­ery day.’’

With a spray that builds up a reser­voir un­der the skin, ‘‘ it does mean that if you’re a bit late, or even miss your next dose, it doesn’t mat­ter so much,’’ Fraser said.

Ul­ti­mately Acrux would like to de­velop a con­tra­cep­tive spray that com­bines Nestorone with es­tro­gen, in the same way that the most widely used con­tra­cep­tive pills in­clude both es­tro­gen and pro­ges­terone.

CEO Jon Pilcher says test­ing of com­bi­na­tions is al­ready un­der way.

‘‘ We’re cur­rently run­ning a trial in Melbourne and Bris­bane with a daily com­bi­na­tion,’’ he says. Re­sults should be out by the mid­dle of the year.

those

Pic­ture: Amos Aik­man

Un­der trial: Doc­tor Edith Weis­berg with the Acrux spray-on ap­pli­ca­tor

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