On 1/27/23 Loxo@Lilly announced the Federal Drug Administration (FDA)’s accelerated approval of pirtobrutinib in adult patients with relapsed or refractory mantle cell lymphoma (MCL) following at least 2 lines of systemic therapy, including a BTK inhibitor.
From the Loxo press release:
Jaypirca (pirtobrutinib, formerly known as LOXO-305) (pronounced jay-pihr-kaa) is a highly selective (300 times more selective for BTK versus 98% of other kinases tested in preclinical studies), non-covalent (reversible) inhibitor of the enzyme BTK. BTK is a validated molecular target found across numerous B-cell leukemias and lymphomas including mantle cell lymphoma. Jaypirca is a U.S. FDA-approved oral prescription medicine, 100 mg or 50 mg tablets taken as a once-daily 200 mg dose with or without food until disease progression or unacceptable toxicity.
MCL is a more aggressive and rarer sister B cell lymphoma that is in some ways similar to chronic lymphocytic leukemia and small lymphocytic lymphoma (CLL / SLL).
A number of drugs such as the BTK inhibitors can be used to treat both types of blood cancers. It is not unusual for the first FDA approval to be obtained in MCL, where the need for new therapies might be even greater than in CLL / SLL.
Because of its reversable binding compared to the irreversible binding of all the other approved BTK inhibitors (ibrutinib, acalabrutinib, and zanubrutinib), pirtobrutinib should work for many patients who have progressed on those drugs in both MCL and in CLL / SLL and indeed studies, including the BRUIN trial have already confirmed its efficacy in just such circumstances. And it has been extremely well tolerated in trials.
We know that there are several trials underway with the hope of a speedy approval in CLL / SLL.
But CLL / SLL patients may not need to wait for that approval. Once a drug has been approved for one indication, it can be used “off label” for another. This is good news for CLL patients, as long as everything can be worked out between the insurers and the company and charities to help cover the medication cost.
Here is the official FDA press release: FDA grants accelerated approval to pirtobrutinib for relapsed or refractory mantle cell lymphoma.
Here is the official Loxo@Lilly press release: U.S. FDA Approves Jaypirca™ (pirtobrutinib), the First and Only Non-Covalent (Reversible) BTK Inhibitor, for Adult Patients with Relapsed or Refractory Mantle Cell Lymphoma After at Least Two Lines of Systemic Therapy, Including a BTK Inhibitor.
Another powerful cancer slaying arrow in our quiver.