Trials of rival drugs from AstraZeneca plc (ADR)(NYSE:AZN)  and TESARO Inc (NASDAQ:TSRO) will determine the adoption of the PARP inhibitor, Rubraca from Clovis Oncology Inc (NASDAQ:CLVS). According to Debjit Chattopadhyay, a Janney analyst, trials from AstraZeneca and Tesaro are likely to change the role of PARP inhibitors from being second to front-line treatments. This will result in a reduction of the pool of Rubraca patients.

At the moment AstraZeneca and Tesaro are in the process of testing PARP (Poly ADP ribose polymerase) to establish whether or not the enzymes could offer any help in the treatment of ovarian and other cancers.

Many more trials are in waiting

There seems to be much more into Rubraca’s adoption. Chattopadhyay says that the adoption may also be affected by AstraZeneca’s SOLO-2 trial as well as Tesaro’s PRIMA. However, there was a notable progression of PARP inhibitor niraparib from an earlier phase three trial from Tesaro, commonly known as NOVA.

Nonetheless, Chattopadhyay says, “If SOLO-2 is not in the same ballpark as NOVA, questions on interchangeability of PARPs could impact Clovis shares heading into ARIEL-3 readout.”

For ARIEL-3, Rubraca is a maintenance treatment, which is commonly used in patients with an ovarian fallopian tube.

Clovis stock fell 1.1% to $61.83. However, this year has had a 40% fun so far. Chattopadhyay acknowledges that Clovis shares have been doing well since early November classifying the rise as “too far, too fast.”

Clearly, there has been a neck and neck race between the Clovis drug, which was approved in December and Tesaro’s New Drug Application for an ovarian cancer drug. This won priority review a day after the Clovis approval.   At the same time, there have been important plans for acquisitions. For $5.2 billion Takeda Pharmaceuticals is planning to acquire Ariad Pharmaceuticals as well as Merrimack Pharmaceuticals Inc (NASDAQ:MACK) $575 million divestiture from an oncology asset.