Chiesi invests up to $486M in Gossamer's pulmonary hypertension drug

Italian pharmaceutical company Chiesi Farmaceutici has entered into an agreement with Gossamer Bio to jointly develop and market seralutinib (GB002), an experimental inhaled medication for pulmonary hypertension. This partnership involves potential financial commitments of up to $486 million, encompassing milestones and other payments.

Initially, Gossamer Bio will be compensated $160 million by Chiesi as a development reimbursement fee. In addition to this sum, Gossamer could receive up to $146 million tied to regulatory milestones, and a further $180 million contingent on achieving specific sales targets. The drug, seralutinib, acts as an inhibitor for PDGFRα/β, CSF1R, and c-KIT and is administered via a dry powder inhaler.

Gossamer has been advancing seralutinib primarily for treating pulmonary arterial hypertension (PAH). A pivotal Phase III trial known as PROSERA is currently underway, with analysts from H. C. Wainwright predicting a top-line readout in the fourth quarter of 2025. Expanding the drug’s utility, Gossamer and Chiesi plan to initiate another Phase III trial by mid-2025 to evaluate its efficacy for pulmonary hypertension associated with interstitial lung disease (PH-ILD). Giuseppe Accogli, CEO of Chiesi Group, expressed optimism that seralutinib could be a groundbreaking therapy for both conditions.

The efficacy of seralutinib has been corroborated by data from the Phase II TORREY study, recently published in the Lancet Respiratory Medicine. The study demonstrated that seralutinib significantly reduced pulmonary vascular resistance (PVR) at 24 weeks compared to a placebo. Additionally, improvements were observed in the structure and function of the right heart.

According to the deal’s terms, Chiesi holds exclusive rights to commercialize seralutinib outside the US. For these territories, they will pay Gossamer a royalty ranging from the mid-to-high teens based on net sales. Within the US, both companies will evenly split commercial profits and losses. Gossamer will spearhead the commercialization efforts, contributing 50% to commercial activities and overseeing the booking of sales for both PAH and PH-ILD. Chiesi, on the other hand, will lead the US commercialization efforts for any additional indications.

This agreement follows closely a significant development in the market: Merck & Co.'s recent FDA approval of Winrevair (sotatercept-csrk) in March. Winrevair is notable for being the first activin signaling inhibitor for PAH approved in the US, potentially providing Merck & Co. with a strategic advantage as it navigates challenges related to its Keytruda issues.

Overall, the collaboration between Chiesi Farmaceutici and Gossamer Bio represents a significant step forward in the treatment landscape for pulmonary hypertension. By combining their resources and expertise, the companies aim to bring an innovative therapeutic option to patients suffering from these debilitating conditions.