Santhera Pharmaceuticals AG is looking for a new partner for its Parkinson's disease drug fipamezole after Ipsen SA returned its rights to the drug, which covered territories outside of North America and Japan.

Paris-based Ipsen would receive milestone and royalty payments should Liestal, Switzerland-based Santhera enter another deal on the drug. It is also retaining a call option that would allow it to gain worldwide rights should Santhera fail to find another taker or fail to progress the program internally. The latter clause is a form of insurance.

"This is out in the distant future," Santhera CEO Thomas Meier told BioWorld Today. "Neither party [is interested] in having the asset sitting around and nothing happening with it."

Fipamezole, a first-in-class selective adrenergic alpha-2 receptor antagonist, completed a Phase IIb trial in the management of levodopa-induced dyskinesia (LID) in Parkinson's patients several years ago. The condition, which occurs in about 40 percent of patients, arises from long-term use of levodopa and is characterized by disabling involuntary movements.

Although the trial did not attain statistical significance, a subsequent analysis indicated that poor management of its Indian arm contributed to the result. In the American arm of the study, the drug appeared to reduce LID without any clinically relevant worsening of Parkinsonian features of the disease.

Ipsen, which entered a deal worth €13 million (US$16.9 million) up front and another potential €128 million in milestones, is the second company to exit an agreement on fipamezole. Santhera's North American licensee, Biovail Corp., now part of Valeant Pharmaceutical International Inc., of Mississauga, Ontario, did so in 2010, having previously paid $12 million up front and put another $180 million on the table in potential milestones.

Ipsen's exit is linked to that of Biovail, in the sense that Biovail was to be the primary driver of the program. But a planned Phase III trial in North America never happened, and Ipsen was unwilling to commit resources to funding a Phase III program itself.

"I wouldn't exclude that we wouldn't take it on ourselves to some degree," Meier said. But Santhera does not have enough resources – either in cash or personnel – to complete a full Phase III program either. "A global partnership would be the desired outcome."

Two other drugs, both metabotropic glutamate receptor 5 antagonists, are in Phase II trials for managing LID. They include AFQ-056 and dipraglurant (ADX48621), which Basel, Switzerland-based Novartis AG and Geneva-based Addex Pharmaceuticals SA are developing, respectively.

Santhera reported CHF31.4 million (US$33.8 million) in cash on June 30, 2011, but is currently valued at little more than half that sum. It is focusing primarily on Catena (idebenone), which has a provisional approval in Canada for treating Friedreich's ataxia.

It failed to gain approval in Europe in the same indication, but it is under review there at present as a treatment for Leber's hereditary optical neuropathy (LHON), a mitochondrially inherited disease that can lead to loss of central vision and blindness in young adults. It can arise from mutations in any one of several genes encoding constituents of Complex I, the first component of the electron transport chain in mitochondria.

A decision on its marketing authorization application is expected in the second half of the year – the European Medicines Agency accepted the dossier for review in July 2011. The right label – and reimbursement on par with its current Canadian price – would be sufficient to make the company profitable, Meier said.

Enrollment in a Phase III trial in Duchenne's muscular dystrophy is ongoing, and earlier-stage studies are under way in primary progressive multiple sclerosis and Melas syndrome, an inherited mitochondrial disorder. Once it has a decision in the LHON indication, the company may also consider revisiting Friedreich's ataxia.

"We have learned from the Phase III studies that failed how we could do it better," Meier said.

Shares in Santhera (ZURICH:SANN) were largely unchanged Tuesday. After an initial dip, the stock moved into positive territory in the late afternoon, to reach CHF4.80, a gain of 0.8 percent.