FDA Expands Ibrutinib Approval for Patients with CLL

Earlier today the US FDA announced approval for the expanded use of ibrutinib (Imbruvica) to treat patients with chronic lymphocytic leukemia (CLL), who carry a deletion in chromosome 17 (17p deletion). This chromosome is often associated with poor responses to standard CLL treatments. Additionally the FDA also approved,

“…new labeling to reflect that Imbruvica’s clinical benefit in treating CLL has been verified. In February 2014, Imbruvica received accelerated approval to treat CLL based on its effect on overall response rate. New clinical trial results examining progression-free survival and overall survival have confirmed the drug’s clinical benefit.”

This approval and new labeling reflect the results of previous clinical studies of CLL patients with 17p deletion. Please look to this blog and our clinical trials page for further developments regarding the use of ibrutinib in patients with CLL.

Zydelig Approved by FDA for Patients with CLL, FL, & SLL

Earlier this afternoon the FDA announced the approval of Zydelig (idelalisib) for patients with relapsed chronic lymphocytic leukemia (CLL). Accelerated approval was also granted for the use of  Zydelig in patients with relapsed follicular B-cell non-Hodgkin lymphoma (FL) and relapsed small lymphocytic lymphoma (SLL). According to the FDA press release:

“Zydelig’s safety and effectiveness to treat relapsed CLL were established in a clinical trial of 220 participants who were randomly assigned to receive Zydelig and Rituxan or placebo and Rituxan. The trial was stopped for efficacy following the first pre-specified interim analysis point, which showed participants treated with Zydelig and Rituxan lived 10.7 months without their disease progressing (progression-free survival) compared to about 5.5 months for participants treated with placebo and Rituxan. Results from a second interim analysis continued to show a statistically significant improvement for Zydelig and Rituxan over placebo and Rituxan.”

“Zydelig’s safety and effectiveness to treat relapsed FL and relapsed SLL were established in a clinical trial with 123 participants with slow-growing (indolent) non-Hodgkin lymphomas. All participants were treated with Zydelig and were evaluated for complete or partial disappearance of their cancer after treatment (objective response rate, or ORR). Results showed 54 percent of participants with relapsed FL and 58 percent of participants with SLL experienced ORR.”

Commenting on this welcomed development Dr. Richard Furman said, “We are very excited to have idelalisib to add to our armentarium of agents that are now available for use and would like to thank all of the patients and their families who made this possible by participating in the clinical trials.” Look to this blog and our clinical trials page for further developments regarding the use of Zydelig in the treatment of CLL, FL, & SLL patients.

Ibrutinib and the Improvement in CLL Patient Care

Furman Face By Dr. Richard Furman MD

Ibrutinib is a first in line of new treatments, known as tyrosine kinase inhibitors that display promise in promoting improved response rates in refractory CLL patients. Unlike chemotherapy which cannot differentiate between healthy and cancerous cells, ibrutinib specifically inhibits the Bruton’s tyrosine kinase (BTK) enzyme in the body’s cancerous B-cells. By inhibiting the enzyme, ibrutinib deprives B-cells of their activating chemical signal. This enzyme is expressed only in B-cells, allowing ibrutinib to exclusively target B-cells, affording a tremendous amount of specificity. This specificity allows for an excellent tolerability of ibrutinib in CLL patients, thus increasing quality of life.

This is significant for CLL patients as chemotherapy treatment often comes with disadvantages. A patient achieving a complete recovery will experience marrow toxicity, and be at risk of developing secondary acute myeloid leukemia and/or myelodysplastic syndrome. Even common CLL regimens like FCR (fludarabine + cyclophosphamide + rituximab), expose patients to major risks.

These initial disadvantages are exacerbated by patient relapse and further chemotherapy. For example a patient, who at diagnosis exhibits a very good response to their first line of chemotherapy treatment and another positive response in their second line of chemotherapy, would ultimately be given a 7-9 year median survival rate from their initial chemotherapy. Unfortunately, survival past that 9 year rate is unlikely, as increased chemotherapy leads to a corresponding decrease in longevity. Any increase in longevity beyond that 9 year mark would require treatment besides standard chemotherapy agents. Accordingly, length of survival is the long term promise and improvement held by tyrosine kinase inhibitors like ibrutinib. The side effects associated with chemotherapy regimens are non-existent for ibrutinib.

Due to the nature of currently available chemotherapy treatment, successful benchmarks are increasingly focused on complete response and partial response rates with chemotherapy, and not on overall survival. Chemotherapy focuses on the complete response, partial response, and minimal residual disease status of patients. Conversely, ibrutinib and other similar treatments display significant improvements towards progression free survival and overall survival, even when accounting for patients who develop resistance and require additional therapy.

Increasingly, the avoidance of chemotherapy is the most important aspect of CLL therapy. My hope is to begin using tyrosine kinase inhibitors like ibrutinib earlier in treatment, and avoid chemotherapy. This would lead to vast improvements in patient quality of life and the important metrics of long term survival.