Gossamer unveils new pipeline plans a year after lead program fizzled out in phase 2

Almost a year to the day after Gossamer Bio’s lead program failed twice in phase 2, the California biotech is unveiling two preclinical assets ready to enter the clinic in an effort to turn things around.

GB5121 and GB7208 are both central nervous system-penetrant Bruton’s tyrosine kinase (BTK) inhibitors, a drug class that has been rapidly replacing chemotherapy in a number of blood cancers. Several of these therapies have been approved, including Johnson & Johnson’s Imbruvica and AstraZeneca’s Calquence.

“BTK is a validated target, but we believe that existing BTK therapies are ill-equipped to address diseases and disorders within the CNS, including indications in oncology and autoimmune disorders,” said Gossamer CEO, chairman and co-founder Faheem Hasnain, during an Oct. 11 conference call.

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Gossamer’s new therapies are “specifically optimized and designed” to address the limitations of existing therapies and address the CNS, Hasnain added.

Chief Scientific Officer Laura Carter, Ph.D., said Gossamer’s candidates are different because they are highly selective, meaning they hit their target without causing side effects elsewhere.

Gossamer plans to develop GB5121 in CNS lymphoma, a rare form of non-Hodgkin lymphoma where the cancer forms in the brain or spinal cord. The candidate is expected to move into human testing in healthy volunteers in the fourth quarter of this year, and the company is targeting a potentially registrational phase 1b/2 study for the second half of 2022.

The other asset that will be advanced into the clinic is a multiple sclerosis candidate. GB7208 demonstrated a “superior” outcome to Sanofi’s tolebrutinib, also known as SAR442168, in a preclinical disease model, according to Gossamer. The therapy is expected to be tested in healthy volunteers in 2022 and in MS patients the following year.

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Gossamer plans to conduct early clinical development alone but may consider partnerships down the line for phase 3 if needed.

The in-house discovered candidates will join Gossamer’s existing clinical therapies, GB002 in pulmonary arterial hypertension and GB004 in ulcerative colitis. Data for those phase 2 assets are due next year.

Gossamer trimmed its pipeline a year ago when GB001 failed two midphase studies in asthma and chronic rhinosinusitis. Once Gossamer’s lead program, GB001 joined a heap of failed DP2 inhibitors that included Novartis’ fevipiprant, which sputtered out in a collection of phase 3 studies.

As of February, Gossamer was trying to push ahead with GB001 by seeking a partner but would not be pursuing further clinical trials alone. Given that many Big Pharmas have tried and failed to advance DP2 inhibitors, Gossamer was going to have a tough time selling the idea. In the company’s two most recent earnings releases, no mention was made of GB001.

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The failure spurred an executive leadership shuffle, with former CEO Hasnain reappointed to his role. Gossamer also lost its chief scientist, Luisa Salter-Cid, Ph.D., a Bristol Myers Squibb veteran who now serves as chief scientific officer of Pioneering Medicines for Flagship Pioneering.

Gossamer needed to beef up its pipeline to turn the ship around, and executives are hoping GB5121 and GB7208 will do just that.