Spero Therapeutics announced today that it entered into a license agreement with Innovent Biologics so that it could in-license a next-generation anti-CD40L antibody by the name of SP001 for the treatment of patients with immunology and inflammatory disorders. This third-generation anti-CD40L antibody has been designed in a different manner to use an Fc domain silencing design so that it could overcome the limitations of prior anti-CD40L antibody therapies that were plagued with platelet activations [thrombotic events].

The thing is that there is a certain limitation to this specific deal in that it does have rights to develop, research, manufacture, and commercialize SP001 for the treatment of patients with immune-mediated diseases globally. However, the key item is that it can’t do so in the Greater China region, which includes Mainland China, Hong Kong, Macau, and Taiwan.

The beauty of this deal is that it will allow both Spero and Innovent Biologics to establish proof of concept [POC] in two phase 2 clinical studies. With respect to Spero, it is set to initiate its very own phase 2 study using SP001 for the treatment of patients with IgG4-related disease [IgG4-RD] in Q2 of 2027. At the same time, the plan is for Innovent to initiate a phase 2 study of this drug [known as IBI355 in that territory] in China to treat patients with Sjögren’s Disease.

Speaking of which, Innovent already completed two healthy volunteer studies and also one phase 1b multiple-ascending dose [MAD] trial to see if the drug was worth moving forward in development with. The thing is that in order for Spero to get its hands on this in-licensing of SP001, it is going to have to give up a lot. It is first going to have to pay Innovent an upfront payment. Along with the potential for development, regulatory, and commercial milestone payments totaling $1.1 billion. Along with the typical tiered royalties on net sales of any products that are ultimately marketed.

There are several other drugs that are taking a certain approach to treating immunology and inflammatory [I&I] disorders by depleting B-cells. However, with respect to the science here, the goal is to use CD40L inhibition versus both antigen-presenting cells [APCs] on one side and then B-cells on the other side. Only the ligands that activate both of these two are inhibited. There are no B-cells that are depleted, which means that this is an entirely different approach. As noted beforehand, the drug was designed in such a way to have an Fc-silenced design so that it can solve the platelet activation concerns observed in prior generation anti-CD40L antibodies.

The company is not without any type of accomplishment, though. That’s because it, along with its partner GlaxoSmithKline, was able to receive FDA approval of Utebzi [tebipenem pivoxil] for the treatment of adults with complicated urinary tract infections [cUTIs]. This is very important, because in order for Spero to have the cash it needs to be able to fund its phase 2 study of SP001 for the treatment of patients with IgG4-RD, it is going to need a lot of cash. Having said that, it established a royalty financing deal with affiliates of Healthcare Royalty, a business of KKR [HCRx].

The point of this deal is so that HCRx can receive future royalty and milestone payments from sales of Utebzi. In exchange, Spero is to receive $105 million in non-dilutive funding. Again, this is going to be used to help fund the phase 2 study using SP001 for the treatment of patients with IgG4-RD. The cash runway guidance given after completing this non-dilutive financing is that it will have enough to fund its operations into 2029. It is my opinion, though, that it will be awhile before it gets clinical data from this program released. Thus, it might likely have to raise cash again before it can get to such a point to reveal data from this mid-stage study.