Exhibit 24

POWER OF ATTORNEY K N OW ALL PER SONS BY THE SE PR ESENTS t h at the undersigned hereby constitutes, d es ignat es an d appoints Ja n el l e D ' A l v i se, Francois Paradis, and J aso n Comerfo r d as s uc h person's true and la wfu l atto rne ys - i n - fac t an d agents , each wi th fu ll power of s ub s titution a nd resubstitution an d fu ll power to act a l one and w ithou t t h e other, for the undersigned and in the unders i g ned' s n a m e, place and stead, in any a nd al l capacit ie s, to : (a) execute for and on be hal f of the u nd ersigned , in the undersigned ' s capacity as a n officer and / or d i rector of Acast i Ph ar m a In c . (t h e "Company"), Fo rm s 3 , 4 , and 5 in acco r dance w i th Section 1 6 (a) of the Sec uritie s Exc han ge Act of 1934 and the rul es thereunder (or any s uc cesso r fo rm s) ; (b) do and perform a n y and all acts for and on be h a l f of the u ndersigned w h ic h m ay b e necessary or de s i ra ble to complete and execute any suc h Form 3 , 4 , o r 5 , comp l e t e a nd exec ut e any a m en dm e n t o r ame ndm ents ther e t o , a nd t im ely file suc h form with the SEC a nd a n y stock exchange or s im ila r aut h or i ty ; and (c) t ake any other action of any type w h atsoeve r in co n nection wit h th e fo r egoi n g w hich , i n the opinion of suc h atto rne y - in - fa ct, ma y be of benefit to , in the best inte r est of, or l ega ll y r equ ir e d by , t h e undersigned , it being und e r stood that t h e docum e nt s execu te d by such attorney - i n - fact on behalf of the undersigned pursuant to t hi s Power of Atto rn e y s h a ll be in such form a nd sha ll contai n such terms a n d condition s as s uch attorney - in - fact m ay app ro ve in s u c h attorney - in - fac t ' s di scret i on . The und ers i gned h e r eby gra n ts to each s u ch attorney - in - fact ful l power an d a uthorit y to do and pe r form any a nd eve r y act and th in g whatsoever req ui site , ne cessary , or prope r t o b e done in the exercise of a n y of the ri g h ts and po wers herein gra nt ed, as full y to a ll i ntents and pu rposes as the un ders i gned mi g ht o r co u l d do if perso n a ll y present, w ith full power of s ub st ituti o n or revocat i on, h e r e b y rat i fyi n g and confirming a ll th at s u c h atto rn ey - in - fac t , or suc h a tt orney - in - fact's s u bs titu te or substitutes, sha ll l awfull y do or cause to be done b y v i rtue of this power of attorney an d the r ig ht s and po we r s h e rein granted . T h e unders i gned ac kn owle d ges that the forego i ng attorneys - in - fact, i n serv i ng in s u c h capacity at the request of the under s i g n e d , are not assum in g , n o r is the Company ass umin g a n y of the undersigned's r es p o n sib i lities to comp l y w ith Sectio n 16 of the Sec u rit i es Exchange Act of 1 934 . This Power of Attorney s h a ll remain i n fu ll force and effect until the undersigned is no longer requi r ed to fi l e Forms 3 , 4 , a nd 5 w i t h respect to the undersigned's ho l d i ngs of a n d transactio n s i n secur itie s issued by the Co mp any , unl ess ea rli er revoked by t h e u nde r signed in a sig n ed w ri t in g de li vered to t h e fo r ego in g atto rne ys - in - fact, except that in respect of a n y person h ere i n appo int ed as an attomey - in fact of th e undersigned, th is P ower of Atto rn ey s h al l b e r evoke d a nd s h a ll cease to be effect i ve imm e di a t e l y wit h r espect to such person at s uch time as s u c h perso n sha ll no l onger be em plo ye d by any of th e Compa n y a nd it s su b s idiari es . LE GAL _ l : 62 81 2036. 1

- 2 - [Signature Page Fo l l ows] IN W I TNESS WHEREOF, t h e und ers i gned has exec ut ed thi s in strume nt as of th e [•] day of [·] , 2021. Name: ROBERT L. FISHER, JR, NOTARY PUBLIC MY COMM I SS I ON EXPIRES JU(Y 31, 2022 - ,. . .. - - . : . - .. . - . . ' - .. LE G A L . 1 · 62812036 I

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