163P - Outcomes and toxicity of fosfesterol in metastatic castration-resistant prostate cancer: Experience from a low middle income country

Background

Though there are multiple drugs approved for the treatment of metastatic castration-resistant prostate cancer (CRPC), high cost can be a limiting factor in using them in a resource-limited setting. It is important to have less expensive alternatives in low-middle-income countries so that majority of the patients can have access to such a medications. We are sharing our experience in using Fosfesterol which is a cheap and orally administered estrogen analogue in metastatic CRPC.

Methods

This is a retrospective study done in a high-volume cancer center in South India. Case records of patients with CRPC who received low-dose oral Fosfestrol (120 mg three times a day) were reviewed and baseline characteristics, treatment details, outcomes, and toxicity details were recorded. Descriptive statistics were used wherever appropriate, and survival was estimated using the Kaplan Meir method.

Results

A total of 65 patients received Fosfesterol during the study period. The median age was 65 years (range 50-83 years). Thirty-four patients (53%) had other medical comorbidities.Skeletal only metastasis was commonest pattern of metastasis (n= 41,64%) followed by skeletal with nodal metastasis (n=15,23%). The majority of the patients had upfront surgical castration (n=60,93%). All the patients had adenocarcinoma and 38 patients (58%) had a high Gleason’s score (GS). Twelve patients (19%) had a GS of 7 and 5 patients (8%) had a GS of 6. GS was not available in 10 patients (15%). Forty-one patients (63%) had a PSA response (decrease of ≥50% in the PSA concentration from the baseline PSA value) and 54 patients (83%) had a symptomatic response. At the end of a median follow-up of 16 months, Median PFS was 8.3 months (CI 4.7-11.8) and the median OS was 27.5 months (CI 25.4-29.5). Twenty-nine patients (45%) received some form of subsequent treatment after stopping Fosfesterol. Most common toxicity observed was thrombosis (n=9,13%) followed by gynecomastia (n=4,6%).

Conclusions

Oral Fosfesterol is a cheap and effective agent in metastatic CRPC with a favorable toxicity profile. More studies are required to define the exact role of this drug in the management of metastatic CRPC.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.