1696MO - Partial orphan cancer drugs: FDA approval, clinical benefit, trials, epidemiology, price, beneficiaries, and spending

Background

The Orphan Drug Act (ODA) incentivizes drug development for rare diseases with limited sales potential. Yet, orphan drugs frequently turn into multi-billion-dollar blockbusters, particularly those used to treat rare and common diseases: partial orphans. This study analyses the development, US Food and Drug Administration (FDA) approval, epidemiology, and economics of full, partial, and non-orphan cancer drugs.

Methods

170 drugs with FDA approval for 455 cancer indications were identified between 2000-2022. Full, partial, and non-orphan drugs were compared regarding their regulatory approval, clinical benefit, trials, epidemiology, price, beneficiaries, and spending with data extracted from FDA documents, Global Burden of Disease study, and Medicare & Medicaid.

Results

We identified 110 full, 22 partial, and 38 non-orphan cancer drugs. Time from first to second FDA approval was shorter for partial than non-and full orphans (median 1.3 vs 1.6 vs 2.3 years). Full orphans, relative to partial and non-orphans, were more frequently third-line (17% vs 8 vs 7, p=.025) monotherapies (74% vs 58 vs 58, p=.002) for hematologic cancers (66% vs 4 vs 0, p<.001) supported by smaller (median 154 patients vs 416 vs 536, p<.001) open-label (56% vs 64 vs 87, p<.001) single-arm trials (19% vs 23 vs 50, p<.001). Disease incidence was lower and disease severity higher for full than partial and non-orphans. Full orphans offered a significantly greater overall survival (median: 4.0 vs 2.8 vs 2.8, p<.001) and progression-free survival (median: 5.1 vs 2.5 vs 3.6, p<.001). Monthly prices were higher for full and partial than non-orphans (median $17177 vs 13284 vs 12457, p<.001). Beneficiaries (8790 vs 4390 vs 1730) and spending ($570 vs 305 vs 156 million) per drug were greater for partial than non-and full orphans.

Conclusions

The benefit, trials, and epidemiology of partial orphan cancer drugs are more similar to non-orphans than full orphans. Yet, partial orphans receive all of the ODA’s incentives and are swiftly extended to new indications, resulting in greater prices, beneficiaries, and spending. Establishing a maximum revenue threshold for the ODA’s benefits alongside indication-specific pricing could reduce expenditure on partial orphans.

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.