5-alpha Reductase Inhibitor
Cross-indication landscape: approved drugs, active Phase 3, sponsors, and upcoming readouts.
About 5-alpha Reductase Inhibitor
5-alpha Reductase Inhibitors are a class of drugs that work by blocking the action of the enzyme 5-alpha reductase. This enzyme is responsible for converting testosterone into dihydrotestosterone (DHT), a more potent androgen. By reducing DHT levels, these drugs can impact conditions driven by androgen activity.
Currently, 5-alpha Reductase Inhibitors are primarily approved for the treatment of benign prostatic hyperplasia (BPH) and androgenetic alopecia (male pattern baldness). The first-in-class drug, PROSCAR (finasteride), was approved by Merck in 1992 for BPH. This was followed by PROPECIA (finasteride) in 1997, also by Merck, for androgenetic alopecia. The field has since seen the development of next-generation inhibitors with potentially improved profiles.
The clinical utility of 5-alpha Reductase Inhibitors is well-established, particularly in managing lower urinary tract symptoms associated with BPH. While the originator drugs continue to hold significant market share, the landscape is evolving with the introduction of generics and combination therapies, offering patients and physicians a wider range of treatment options.
6 FDA-approved 5-alpha Reductase Inhibitor drugs, including AVODART, with 5 active Phase 3 trials. Explore approved drugs, the cross-indication pipeline, sponsors, and the Phase 3 readout calendar below.
Approved 5-alpha Reductase Inhibitor Drugs
6 totalThe 5-alpha Reductase Inhibitor class was pioneered by Merck with the introduction of PROSCAR (finasteride) in 1992 for benign prostatic hyperplasia, followed by PROPECIA (finasteride) in 1997 for androgenetic alopecia. These initial approvals established the therapeutic utility of inhibiting DHT production. The class evolved with the development of dutasteride, first approved as AVODART by GlaxoSmithKline (now WAYLIS THERAP) in 2001 for BPH, which offers dual inhibition of both Type 1 and Type 2 5-alpha reductase enzymes, unlike finasteride which primarily targets Type 2. Dutasteride, as seen in AVODART and the combination product JALYN (dutasteride), offers a broader spectrum of inhibition compared to finasteride. This dual inhibition is associated with more profound and sustained reductions in DHT. While finasteride is typically dosed once daily, dutasteride's longer half-life allows for flexible dosing, and its efficacy in head-to-head comparisons for BPH has demonstrated superiority in achieving prostate volume reduction and symptom improvement. Today, 5-alpha Reductase Inhibitors remain a cornerstone therapy for BPH, often used as first-line treatment for men with moderate to severe symptoms. The availability of generic finasteride and dutasteride has increased accessibility and driven down costs. Combination products like JALYN, pairing dutasteride with tamsulosin, offer a convenient single-pill solution for BPH management. The class is generally well-tolerated, with the primary side effects related to sexual dysfunction, although these are typically reversible upon discontinuation.
Methodology
Approved drugs sourced from FDA `pharmClassEpc` (Established Pharmacologic Class) labeling. Active industry trials matched by intervention name (brand or generic) — same coverage approach as our target pages, with the same limitation: pre-approval candidates using development codes won't match until they're approved.
"Active" = RECRUITING / ACTIVE_NOT_RECRUITING / NOT_YET_RECRUITING. Sponsor counts include any company running at least one active industry trial.