Pharmacyclics, Inc., a clinical-stage biopharmaceutical company,  has enrolled fifth patient in SPARK (MCL2001) clinical trial of ibrutinib in patients with relapsed or refractory mantle cell lymphoma (MCL).

The enrollment of the fifth patient has subsequently triggered a second $50 million milestone payment obligation from Janssen Biotech, Inc. (Janssen), one of the Janssen Pharmaceutical Companies of Johnson & Johnson, worldwide collaborator on ibrutinib in oncology and sponsor of this MCL trial.

As Pharmacyclics or Janssen initiate specific clinical trials and enroll the 5th patient, additional milestone payments of $50 million may be triggered up to a total of $250 million.

"We formed this partnership with Janssen, with the intention to broadly expand and propel the clinical development of ibrutinib. The speed at which we have moved into important clinical trials in CLL and now MCL is a validation of this joint venture's ability to convert plans into actualities," said Bob Duggan, chairman and CEO of Pharmacyclics. "We are satisfied with the early progress this partnership is generating and we look forward to providing a material update in December, during the American Society of Hematology Meeting."

The SPARK study is a single-arm, multi-center Phase II trial of ibrutinib in MCL patients who received at least one prior rituximab-containing chemotherapy regimen and who progressed after bortezomib therapy. The primary endpoint of the study is overall response rate.  The key secondary endpoints include overall survival rate, progression-free survival rate, and pharmacokinetic data of ibrutinib. This global study conducted by Janssen is planned to enroll 110 patients worldwide.

On December 8, 2011, Pharmacyclics entered into a worldwide collaboration with Janssen to develop and commercialize ibrutinib, a novel, oral, first-in-class Bruton's Tyrosine Kinase (BTK) inhibitor. Pharmacyclics received from Janssen an upfront payment totaling $150 million upon signing the contract. With the dosing of a fifth patient in the SPARK Study, as announced today, a milestone payment of $50 million has been earned. Pharmacyclics may receive up to an additional $725 million in development and regulatory milestone payments; for total potential upfront and milestone payments of $975 million.

Following regulatory approval, both Pharmacyclics and Janssen will book revenue and co-commercialize ibrutinib. In the US, Pharmacyclics will book sales and take the lead role in US commercial strategy development. Both Pharmacyclics and Janssen will share in commercialization activities. Outside the United States, Janssen will book sales and lead and perform commercialization activities. Profits and losses from the commercialization activities will be split 50/50 on a worldwide basis. Development and commercialization activities under the collaboration will be managed through a shared governance structure. Each company will lead development for specific indications as stipulated in a global development plan, with development costs shared on a 40/60 basis (Pharmacyclics 40% and Janssen 60%).

Pharmacyclics is a clinical-stage biopharmaceutical company focused on developing and commercializing innovative small-molecule drugs for the treatment of cancer and immune mediated diseases.