Mystery solved: Roivant is Pfizer's TYK2 partner—and is cutting other programs to fund late-phase trials

Pfizer has revealed the new home of its TYK2 inhibitors. Months after disclosing a pact with a mystery startup, the Big Pharma has taken the wrapping off a deal with Priovant Therapeutics, a new Roivant unit that will seek to bring brepocitinib to market in dermatomyositis and lupus.

Until late last year, Pfizer represented the chief challenger to Bristol Myers Squibb in the TYK2 inhibitor space. Bristol Myers’ drug candidate, deucravacitinib, failed a midphase ulcerative colitis trial in October, but clinical data in other indications have kept alive hopes that TYK2 inhibitors can live up to their billing as delivering biologiclike efficacy in an oral dosage form. 

Pfizer disclosed the out-licensing of its midphase TYK2 candidates brepocitinib and PF-06826647 in the wake of the Bristol Myers setback without naming the other party in the deal. All we knew was the drug candidates had gone to “a new company formed in collaboration with a partner that has a proven track record in late-stage inflammation and immunology drug development.”

Now, we know that the new company is Priovant, an autoimmune disease biotech that Pfizer has set up with Roivant. Pfizer has taken a 25% stake in Priovant in return for rights to its TYK2 candidates. 

Priovant has licensed brepocitinib and PF-06826647, now known as ropsacitinib, but the statement to disclose the formation of the startup focuses squarely on the former. Brepocitinib recently moved into a phase 3 clinical trial in dermatomyositis, a rare disease that causes muscle inflammation and skin rash. A phase 2b trial in systemic lupus erythematosus is already underway and set to deliver data next year. 

The plan is for the phase 3 dermatomyositis clinical trial to serve as a single registration study. Priovant envisages the phase 2b study in lupus serving as one of the two trials it will need to win approval in that indication. Bristol Myers’ deucravacitinib, the front runner in TYK2, is in four phase 3 trials, two apiece in plaque psoriasis and psoriatic arthritis.

Slimmed-down pipeline

To free up cash for opportunities including Priovant, other Vant subsidiaries are trimming their pipelines. News of the Pfizer deal emerged within minutes of an update on the rest of the Roivant stable, which revealed the discontinuation of six programs.

Dermavant accounts for half of the discontinued programs, with the completion of a strategic pipeline review leading it to stop development of DMVT-502 for vitiligo and atopic dermatitis, DMVT-503 for acne and DMVT-504 for hyperhidrosis. The other cut drug candidates are the lentiviral sickle cell disease gene therapy ARU-1801—the only clinical-phase asset in Aruvant’s pipeline—the bacteriophage-encoded lysin LSVT-1701 and Cytovant Sciences’ lead TCR-T program CVT-TCR-01.

SVB Securities analysts said they viewed the pipeline reorganization positively. "Priovant adds a late-stage drug and catalysts (including registrational data in systemic lupus erythematosus in 2H23), while the discontinuation of ARU-1801 and other drugs frees up resources," they said in a June 28 note.

"The addition of brepocitinib is likely to result in upward revisions to consensus sales given its late stage in development, but given the competitive landscape in larger immune indications (eg with BMY’s TYK2 inhibitor deucravacitinib nearing approval) it seems likely to be a niche drug," the analysts added.