What is the Difference Between Paclitaxel and Nab-paclitaxel

The key difference between paclitaxel and nab-paclitaxel is that paclitaxel is a solvent-based drug while nab-paclitaxel is an albumin-bound nanoparticle formulation and free of solvents, which can cause side effects.  

Paclitaxel and nab-paclitaxel are taxanes used as chemotherapeutic agents treating various cancers, including breast, lung, and pancreatic. These drugs primarily prevent the separation of chromosomes during cell division by promoting the assembly and stability of microtubules. Both drugs are administered as an intravenous infusion, but nab-paclitaxel requires a shorter duration. Nab-paclitaxel is generally more effective, better tolerated, and associated with fewer side effects. However, the choice between nab-paclitaxel over paclitaxel depends on the type of cancer, the patient’s overall health, and the risk of side effects.

CONTENTS

1. Overview and Key Difference
2. What is Paclitaxel  
3. What is Nab-paclitaxel
4. Similarities – Paclitaxel and Nab-paclitaxel
5. Paclitaxel vs Nab-paclitaxel in Tabular Form
6. Summary – Paclitaxel vs Nab-paclitaxel

What is Paclitaxel?

Paclitaxel is a first-line antineoplastic agent prescribed to cure advanced carcinomas in the ovary, breast, and lungs. It is a derivative of taxanes, which contain an aromatic hetero-polycyclic molecular framework. Paclitaxel promotes the assembly and stabilization of microtubules by binding with the β sub-unit of tubulin. The stability of the microtubule impairs the normal dynamics of the microtubule network essential for interphase and mitosis. This effect of paclitaxel destroys the cell’s ability to use its cytoskeleton flexibly. In addition, paclitaxel induces apoptosis in cancer cells by inhibiting Bcl-2 (B-cell leukemia 2).

Paclitaxel is infused into cancer patients and binds with plasma protein after absorption. The drug is primarily metabolized into 6a-hydroxy-paclitaxel by the hepatic CYP2C8. The drug is primarily eliminated with a half-life of 52.7 hours in the feces, and a small amount of the drug is incorporated into the urine. The symptoms of overdose include bone marrow suppression and peripheral neurotoxicity.

What is Nab-paclitaxel?

Nab-paclitaxel or nanoparticle albumin-bound paclitaxel is an infusible formulation of paclitaxel used to treat breast, lung, and ovarian cancers and Kaposi’s sarcoma. It is more effective and better tolerated than normal paclitaxel in chemotherapy. As the name suggests, nab-paclitaxel is produced by binding paclitaxel to albumin, making the drug more stable and easier to deliver to cancer cells. In addition, nab-paclitaxel is associated with fewer incidences of side effects. However, neutropenia, peripheral sensory neuropathy, diarrhea, nausea, and vomiting are still common, even among nab-paclitaxel-treated patients.

Nab-paclitaxel is administered as an intravenous infusion weekly for up to 12 weeks. Recent data on nab-paclitaxel suggest that when combined with other agents such as gemcitabine in treating pancreatic cancers. The drug was approved for clinical use in 2005 and enlisted on the WHO’s list of essential medicines.

What are the Similarities Between Paclitaxel and Nab-paclitaxel?

• Paclitaxel and nab-paclitaxel are used to treat cancer.
• They are both taxanes.
• Both drugs work by binding to microtubules.
• They have similar side effects, such as neuropathy, anemia, pain, and diarrhea.

What is the Difference Between Paclitaxel and Nab-paclitaxel?

Paclitaxel and nab-paclitaxel are chemotherapeutic drugs used for various types of cancers by targeting tubulin polymerization. However, there is a key difference between Paclitaxel and Nab-paclitaxel. Paclitaxel is a solvent-based chemotherapeutic agent with low solubility in water and requires the use of solvents like Cremophor EL and ethanol during administration. In contrast, nab-paclitaxel is well dissolved in water, eliminating the need for specific solvents. Premedication with corticosteroids, antihistamines, and H2 blockers is often required to reduce hypersensitivity reactions associated with paclitaxel treatment. In comparison, premedication is not required for nab-paclitaxel.

Comparable to paclitaxel, nab-paclitaxel is safe, effective, well tolerated, and associated with lower incidents of side effects. However, nab-paclitaxel is more expensive than conventional solvent-based paclitaxel.

Below is a summary of the difference between Paclitaxel and Nab-paclitaxel in tabular form for side-by-side comparison.

Summary – Paclitaxel vs Nab-paclitaxel

Paclitaxel and nab-paclitaxel are chemotherapeutic agents used to treat breast, lung, and pancreatic cancer. They are taxanes and, therefore, work by binding to microtubules and preventing the separation of chromosomes during cell division. However, there is a distinct difference between paclitaxel and nab-paclitaxel can be identified. Paclitaxel is a solvent-based drug, while nab-paclitaxel is an albumin-bound nanoparticle formulation. Therefore, comparable to paclitaxel, nab-paclitaxel is free from solvents and associated with lesser side effects. In addition, nab-paclitaxel is more effective and better tolerated. However, nab-paclitaxel is more expensive. The drug choice depends on the specific cancer being treated and the patient’s characteristics.

Reference:

1. Alqahtani, Fulwah Yahya, et al. “Paclitaxel.” Profiles of Drug Substances, Excipients and Related Methodology, 2019, pp. 205–238.
2. Yardley, Denise A. “NAB-Paclitaxel Mechanisms of Action and Delivery.” Journal of Controlled Release, vol. 170, no. 3, 2013, pp. 365–372.

Image Courtesy:

1. “Taxol” By Calvero. – Selfmade with ChemDraw. (Public Domain) via Commons Wikimedia