Novel abiraterone formulation succeeds in phase 3 prostate cancer trial

TAVT-45 granules for oral suspension ("TAVT-45”), a novel formulation of abiraterone acetate (Zytiga), demonstrated therapeutic equivalence and comparable safety compared with standard abiraterone in patients with metastatic prostate cancer, achieving the primary end point of the phase 3 TAVT45CO2 trial.^1,2

The TAVT-45 formulation of abiraterone was created for patients with dysphagia, who would have difficulty swallowing a tablet. In the TAVT45CO2 trial, serum testosterone levels measured in patients’ blood samples at days 9 and 10 demonstrated an equivalent pharmacodynamic effect between TAVT-45 and reference abiraterone acetate, meeting the primary end point of the study.

The key secondary end point of the study was also met, as there was not a statistically significant difference between the TAVT-45 and reference abiraterone arms regarding the percent of patients who achieved a PSA level decrease of ≥50% from baseline at any point over the 84-day treatment period.

"It is encouraging to see a familiar efficacy and safety profile for TAVT-45, which is consistent with data established for abiraterone acetate as a standard of care in the treatment of metastatic prostate cancer," Kenneth M. Kernen, MD, study investigator and partner in the Michigan Institute of Urology, stated in a press release. "The positive results from this clinical study further support and validate the use of TAVT-45 as a novel, oral, easy-to-drink formulation of abiraterone acetate. As a physician, this would be a welcome potential treatment alternative that may also help patients adhere to their medication regimens and may ultimately improve clinical outcomes."

Overall, the open-label phase 3 TAVT45CO2 study (NCT04887506) had a targeted enrollment of 107 patients with pathologically confirmed metastatic castration-sensitive prostate cancer (CSPC) or metastatic castration-resistant prostate cancer (CRPC)and an ECOG performance status of 0 to 2 at screening. Among patients with CRPC, prior chemotherapy with docetaxel was allowed if the patient finished the treatment ≥1 year before enrollment. No other prior chemotherapy was allowed, and patients were excluded from enrollment if they had prior treatment with abiraterone or enzalutamide (Xtandi).

Patients were randomized to prednisone plus either standard abiraterone (500 mg oral tablet twice daily) or TAVT-45 (250 mg abiraterone granules for oral suspension in a sachet, administered twice daily).

Tavanta Therapeutics, the developer of TAVT-45, plans to share the specific data from the study at an upcoming medical conference and submit the results for publication. The company also intends to submit a New Drug Application for TAVT-45to the FDA. The standard formulation of abiraterone currently has FDA-approved indications for both metastatic CSPC and metastatic CRPC.

"The positive results from the TAVT45C02 trial demonstrate that TAVT-45 may provide an easy-to-swallow alternative to Zytiga, benefitting many patients with dysphagia or difficulty swallowing large tablets," Andreas Maetzel, MD, PhD, chief medical officer of Tavanta, stated in the press release. "Approximately 20% to 30% of cancer patients, including many patients with prostate cancer, have difficulty swallowing pills and capsules. We believe these patients may benefit from an alternate formulation like TAVT-45 that would allow them to take their much-needed medications in an easier-to-take formulation."

References

1. Tavanta Therapeutics Announces Positive Top-line Results from Pivotal Phase 3 Trial of TAVT-45 for the Treatment of Metastatic Prostate Cancer. Published online and accessed January 5, 2023. https://prn.to/3WNhwZG

2. NIH US National Library of Medicine ClinicalTrials.gov. TAVT-45 (Abiraterone Acetate) Granules in Patients With Prostate Cancer. Last updated May 14, 2021. https://clinicaltrials.gov/ct2/show/NCT04887506