Background
Janssen held patents on Invega Sustenna® — a monthly injectable formulation of paliperidone palmitate for treating schizophrenia. The formulation was a long-acting injectable (LAI) using paliperidone palmitate as a prodrug that is slowly hydrolyzed to the active drug paliperidone after intramuscular injection, providing therapeutic drug levels for approximately four weeks. Mylan filed an ANDA challenging the patents as obvious, arguing that a skilled formulator would have been motivated to combine known LAI antipsychotic formulation techniques with paliperidone (the active metabolite of risperidone) to arrive at the claimed monthly injectable formulation.
The district court found the claims obvious after a full bench trial. Janssen appealed, arguing the district court erred in its analysis of the prior art motivation to combine and in discounting secondary considerations of non-obviousness.
The Court’s Holding
The Federal Circuit affirmed. The court upheld the district court’s finding that a person of ordinary skill in the pharmaceutical formulation arts would have been motivated to develop a paliperidone LAI because: (1) paliperidone was a known active metabolite of risperidone, which already had a successful long-acting injectable formulation; (2) the LAI formulation approach used for risperidone was well-established and could be adapted to paliperidone; and (3) there was a known clinical need for monthly LAI antipsychotics to improve patient compliance.
On secondary considerations, the court found that Janssen’s evidence of commercial success and long-felt need was insufficient to overcome the strong obviousness showing — particularly because paliperidone’s identity as the active metabolite of risperidone made the motivation to develop a paliperidone LAI straightforward given risperidone’s existing LAI formulation. The nexus between the patent claims and the commercial success was also weakened by the blocking effect of prior patents on paliperidone itself.
Key Takeaways
- When a pharmaceutical compound is the known active metabolite of an already-approved drug with a known formulation strategy, developing a similar formulation for the metabolite may be obvious — particularly when the known formulation approach is well-established and the clinical rationale (compliance improvement) is clear.
- Long-acting injectable antipsychotic formulations are difficult to patent when the LAI approach is established in the class and the motivation to extend the approach to a related compound is clear from the prior art and clinical literature.
- Secondary considerations of non-obviousness (commercial success, long-felt need) can be significantly weakened when: (1) earlier blocking patents on related compounds may have suppressed motivation to develop the invention; and (2) the commercial success was driven by factors other than the patented formulation improvements.
- Generic pharmaceutical companies challenging LAI antipsychotic patents can build strong obviousness cases by combining formulation prior art for related drugs with published clinical literature establishing the motivation to develop monthly injectable formulations for medication compliance.
Why It Matters
The Janssen v. Mylan decision was significant in the ongoing Hatch-Waxman litigation over the Invega Sustenna franchise — a multi-billion-dollar product line for Johnson & Johnson’s pharmaceutical subsidiary. The ruling contributed to a line of cases establishing that long-acting injectable antipsychotic formulations based on prodrug chemistry related to previously approved compounds face serious obviousness challenges when the formulation approach is well-established in the drug class.
The case also illustrates the limitations of secondary considerations in pharmaceutical obviousness cases: even highly commercially successful drugs can fail to establish non-obviousness through secondary considerations when the prior art motivation to develop the formulation was strong and the technical path was well-established. For the pharmaceutical industry, the decision highlighted the difficulty of obtaining durable patent protection for LAI formulations of next-generation antipsychotics when the formulation platform is already proven in closely related compounds.