Less than one year af­ter Alex­ion part­ed with $25 mil­lion up­front to se­cure ac­cess to a sec­ond an­ti-FcRn as­set, it is aban­don­ing the ex­per­i­men­tal drug. The dis­con­tin­u­a­tion, dis­closed at the SVB Leerink Glob­al Health­care Con­fer­ence in New York dur­ing a fire­side chat, bodes well for ri­val Im­muno­vant.

The drug (ABY-039), part­nered for de­vel­op­ment with Swe­den’s Af­fi­body, was for­sak­en on the ba­sis of ear­ly-stage da­ta that was not viewed fa­vor­ably, Baird and SVB Leerink an­a­lysts not­ed.

“We be­lieve that this find­ing could have been due to a neg­a­tive safe­ty sig­nal, as Alex­ion al­so ac­knowl­edged that they knew the pro­gram was high-risk, due to the fact that pri­or bac­te­r­i­al se­quences had sug­gest­ed an in­creased like­li­hood of im­muno­genic­i­ty,” Baird’s Bri­an Sko­r­ney said.

“Giv­en this con­text, we do not be­lieve this dis­con­tin­u­a­tion should raise ques­tions re­gard­ing the po­ten­tial ben­e­fits and mech­a­nis­tic prop­er­ties in­volved with FcRn in­hi­bi­tion since Alex­ion di­a­logue may in­fer the de­ci­sion was safe­ty-based.”

Im­muno­vant’s ri­val drug, IMVT-1401, is in mul­ti­ple on­go­ing Phase II tri­als. SVB Leerink’s Thomas Smith has mod­eled peak sales of ~$2.7 bil­lion for the com­pa­ny’s three iden­ti­fied lead in­di­ca­tions: myas­the­nia gravis, thy­roid eye dis­ease and warm au­toim­mune he­molyt­ic ane­mia.

“(T)he dis­con­tin­u­a­tion of ABY-039 reads through as an in­cre­men­tal pos­i­tive for Im­muno­vant. Mov­ing for­ward, we con­tin­ue to be­lieve that IMVT-1401 pos­sess­es best-in-class po­ten­tial as a rapid­ly ad­min­is­tered and high­ly ef­fi­ca­cious FcRn in­hibitor,” Sko­r­ney said.

With the dis­con­tin­u­a­tion of ABY-039, there is one less FcRn an­ti­body in clin­i­cal de­vel­op­ment. How­ev­er, Alex­ion has an­oth­er an­ti-FcRn as­set it will hold on to — ALXN1830 — which it scored in a 2018 buy­out deal of Syn­tim­mune ($400 mil­lion up­front, with a po­ten­tial $800 mil­lion in mile­stones). There are al­so oth­er com­pa­nies in the space, in­clud­ing ar­genx, Har­bour Bio­Med and Mo­men­ta.

The neona­tal Fc re­cep­tor (FcRn) is an im­munoglob­u­lin G (IgG) and al­bu­min bind­ing pro­tein ex­pressed on the cell sur­face of most hematopoi­et­ic, en­dothe­lial, and ep­ithe­lial cells.

FcRn re­cy­cles IgG an­ti­bod­ies by shut­tling them away from lyso­so­mal degra­da­tion, there­by pre­serv­ing path­o­gen­ic an­ti­body lev­els in IgG-me­di­at­ed dis­eases such as myas­the­nia gravis (a long-term neu­ro­mus­cu­lar con­di­tion). Drugs de­signed to in­hib­it FcRn, there­fore, are de­signed to de­crease to­tal IgG — cru­cial­ly path­o­gen­ic IgG — to treat pa­tients.

So­cial im­age: Alex­ion

While the US biosimilars industry has generally been a disappointment since its inception, with FDA approving 33 biosimilars since 2015, just a fraction of those have immediately followed their approvals with launches. And more than a handful of biosimilars for two of the biggest blockbusters of all time — AbbVie’s Humira and Amgen’s Enbrel — remain approved by FDA but still have not launched because of legal settlements.

As President Biden’s Build Back Better Act — and, with it, potentially the Democrats’ last shot at major drug pricing reforms in the foreseeable future — remains on life support, the Congressional Budget Office isn’t helping their case.

The CBO last week released a new slide deck, outlining an update to its model on how Medicare negotiations might take a bite out of new drugs making it to market. The new model estimates a 10% long-term reduction in the number of new drugs, whereas a previous CBO report from August estimated that 8% fewer new drugs will enter the market over 30 years.