Fol­low­ing a suc­cess­ful Phase III study in April show­cas­ing the safe­ty and po­ten­tial of its new sleep drug, Idor­sia post­ed some mixed news in the sec­ond Phase III study, but that won’t stop a planned fil­ing aimed at reg­u­la­to­ry ap­proval.

The drug, a dual orex­in re­cep­tor an­tag­o­nist (DO­RA) called dari­dorex­ant, was found to sig­nif­i­cant­ly im­prove sleep main­te­nance and sub­jec­tive to­tal sleep time in 25 mg dos­es, repli­cat­ing re­sults from the first Phase III study. How­ev­er, im­prove­ments in sleep on­set and day­time func­tion­ing nar­row­ly missed sta­tis­ti­cal sig­nif­i­cance, de­spite nu­mer­i­cal con­sis­ten­cy with the April study.

Idor­sia al­so test­ed 10 mg dos­es of dari­dorex­ant in the study and found pos­i­tive re­sponse across all four ef­fi­ca­cy mea­sures, but all fell short of be­ing sta­tis­ti­cal­ly sig­nif­i­cant.

The new study mea­sured dari­dorex­ant’s ef­fects in 924 adult and el­der­ly pa­tients. Side ef­fects from the tests re­mained low, as with the first study, with se­ri­ous in­stances re­main­ing bal­anced across dosage amounts and place­bos, ac­cord­ing to the biotech.

Re­sults from the two stud­ies re­gard­ing the 25 mg dos­es and place­bos will now be pooled, and some an­a­lysts ex­pect this will of­fer a promis­ing pro­file to take to reg­u­la­tors. Ques­tions will like­ly re­main, how­ev­er, giv­en the cau­tion that reg­u­la­tors usu­al­ly take when ap­prov­ing in­som­nia treat­ments.

Pe­ter Welford at Jef­feries sees the poor re­sults for the low dose as a good thing, as it re­moves any temp­ta­tion the FDA may have to for­go the high dose and go with the less threat­en­ing low­er dose — as they did with Mer­ck. But its suc­cess is still no sure thing.

Im­por­tant­ly the low­er 10mg dose showed small­er non-sig­nif­i­cant ben­e­fits, re­mov­ing the risk reg­u­la­tors en­dorse a sub­op­ti­mal dose to err on the side of cau­tion, in our view. Com­mer­cial un­cer­tain­ties re­main.

In­som­nia drugs gen­er­al­ly are slow to be­come avail­able and are dif­fi­cult to pro­duce. The drugs are al­so heav­i­ly reg­u­lat­ed, as the FDA demon­strat­ed when it im­posed black box warn­ings last year on a slew of more com­mon­ly-known drugs like Lunes­ta, Am­bi­en and Sonata.

Where DO­RAs dif­fer from tra­di­tion­al in­som­nia drugs is in the in­hi­bi­tion of orex­in sig­nal­ing. Orex­ins, dis­cov­ered in 1998, are hor­mones pro­duced by the hy­po­thal­a­mus that reg­u­late sleep, arousal and ap­petite.

On­ly two DO­RAs have hit the mar­ket in the US, but they al­so faced up­hill climbs. Mer­ck’s Bel­som­ra (chem­i­cal­ly known as su­vorex­ant), re­leased in 2014, re­quired warn­ing la­bels re­gard­ing next-day resid­ual ef­fects and abuse po­ten­tial, among oth­er safe­ty risks.

Ad­di­tion­al­ly, Ei­sai’s DO­RA Dayvi­go (lem­borex­ant) scored an FDA ap­proval in De­cem­ber and launched last month but al­so need­ed sim­i­lar warn­ings.

Idor­sia spun off of Swiss phar­ma com­pa­ny Acte­lion af­ter a $30 bil­lion ac­qui­si­tion by John­son & John­son in ear­ly 2017. Idor­sia had been Acte­lion’s old re­search and de­vel­op­ment de­part­ment and is head­ed up by Acte­lion’s founder and CEO, Jean-Paul Clozel. Dari­dorex­ant is one of four de­vel­op­men­tal drugs cur­rent­ly in Idor­sia’s pipeline that has reached the Phase III stage.

Amgen is shrugging off a 14-year development alliance and the tens of millions of dollars spent to develop a new heart drug at Cytokinetics after a Phase III trial turned up weak data — leaving Cytokinetics to soldier on alone.

Omecamtiv mecarbil technically worked, meeting the primary composite endpoint in the Phase III GALACTIC-HF study. But it missed a key secondary endpoint, which analysts had been following as a key marker for success — reduction of cardiovascular (CV) death. While Cytokinetics celebrated the results, its stock tanked 43% upon the news, and analysts warned of an uncertain path ahead. Now, Amgen wants out.

A month and a half after becoming the experimental treatment of choice for a newly diagnosed president, Regeneron’s antibody cocktail has received emergency use authorization from the FDA. It will be used to treat non-hospitalized Covid-19 patients who are at high-risk of progressing.

Although the Rgeneron drug is not the first antibody treatment authorized by the FDA, the news comes as a significant milestone for a company and a treatment scientists have watched closely since the outbreak began.