Mail-Order Specialty Drugs: A Guide to Limited Distribution

Specialty pharmaceuticals – high-cost, complex medications for chronic, rare, or life-threatening diseases – are increasingly dispensed through mail-order channels rather than local retail pharmacies. These “mail-order only” specialty drugs often require special handling (e.g. refrigeration, patient training, or risk management programs) and are distributed exclusively through a narrow network of accredited specialty pharmacies. This report reviews the evolution of specialty pharmaceuticals and mail-order distribution, identifies the most prominent specialty medications limited to mail-order channels, analyzes the policy and market forces driving this system, and discusses implications for stakeholders. We examine industry data and studies showing the dominance of mail-order/specialty pharmacies in specialty drug distribution (^[1]) (^[2]), regulatory trends (such as laws restricting mandatory mail-only dispensing), patient- and provider-facing consequences, and likely future developments (e.g. more doctor-administered biologics, gene therapies, and home-infusion services). Overall, specialty drugs now account for over half of U.S. prescription spending—up from roughly one-third a decade ago (^[3]), and a substantial share of these are subject to exclusive or limited distribution networks. For example, Drug Channels Institute's 2025 analysis of 382 specialty drugs found that 34% of specialty products are handled by a single pharmacy (^[4]). Using specific examples (e.g. hepatitis C cures, oncology and MS therapies, rare disease drugs), we highlight how mail-order specialty pharmacy has become the default channel for many of the nation’s costliest medications. Key findings include:

• Restricted Distribution Is Common: Manufacturers of many new specialty drugs (from oncology, multiple sclerosis, rheumatoid arthritis, hepatitis C, and orphan diseases) impose limited or exclusive specialty pharmacy networks, effectively forcing patients to obtain the drug via mail-order specialty pharmacies (^[5]) (^[2]). For instance, the monoclonal antibody Synagis (palivizumab) for RSV prevention is ”only available through a limited distribution specialty pharmacy network” (^[6]), and Bristol Myers Squibb’s blockbuster lenalidomide (Revlimid) is similarly dispensed only by select specialty pharmacies (^[7]) (^[8]).

• Dominance of Mail-Order Specialists: The major PBM-owned specialty pharmacies (CVS Specialty, OptumRx/Accredo, Express Scripts/Accredo, etc.) dominate distribution. These large chains participate in the majority of limited networks (^[9]) (^[10]), further consolidating mail-order dispensing. Industry data show that most specialty drugs go through mail-order: in Medicare Part D and large employer plans, about 8–9% of all prescriptions are mail-order, but a far higher share of specialty prescriptions flow through mail channels (^[11]) (^[12]).

• Patient and Policy Impact: Many states have recently acted to protect patient choice, banning “mandatory mail-order” requirements for specialty drugs. Patients and providers raise concerns about access and continuity (e.g. difficulties for traveling patients or those in rural areas) (^[13]) (^[14]). On the other hand, payers argue that mail-order specialty can improve adherence and reduce costs. The industry is also seeing the rise of “white bagging” (ship to clinic offices) and “home infusion” models for provider-administered drugs (^[15]).

• Future Directions: The trend toward specialty/mail-order is likely to continue as new biologics, cell and gene therapies, and oral oncolytics are launched in controlled channels. However, major shifts are reshaping the landscape: the Humira biosimilar wave has demonstrated how biosimilar competition can alter distribution channels; the FTC's 2025 report documented billions in PBM specialty drug markups (^[16]); and landmark federal PBM reform in the Consolidated Appropriations Act of 2026 mandates 100% rebate pass-through and greater transparency (^[17]). Patient advocacy for local dispensing and state-level restrictions on mandatory mail-order continue to gain momentum.

This report provides a deep analysis of specialty drug distribution, including quantitative data, references to industry analyses and regulatory reports, and discussion of real-world examples. The following sections develop these points in detail, with tables listing notable mail-order-only specialty drugs and distribution network statistics, as well as case studies and expert commentary.

Specialty Drugs Defined

Specialty drugs are generally defined as high-cost prescription medications used for complex or chronic conditions. There is no single technical definition, but health plans and pharmacy benefit managers (PBMs) typically classify a drug as “specialty” if it requires special handling, administration training (e.g. injection/infusion equipment), patient monitoring, or if it treats rare/serious diseases (^[18]). Examples include biologic therapies (made from living cells), oral oncolytics, hepatitis C cures, multiple sclerosis injectables, and orphan drugs for rare genetic disorders (^[18]) (^[5]). Specialty medications often carry very high prices (many thousands of dollars per patient per year) and constitute a growing share of drug spending (^[19]) (^[11]). In 2014, specialty drugs (notably new hepatitis C treatments) drove a 26.5% year-over-year increase in U.S. drug spending; by 2015 they accounted for roughly one-third of total prescription expenditures (^[19]). By 2024, that share had grown to approximately 53% of total U.S. drug spending, according to IQVIA (^[3]), with overall U.S. pharmaceutical expenditures reaching $805.9 billion.

Specialty Pharmacy vs. Retail Pharmacy

Traditional retail/community pharmacies generally dispense chronic medications (e.g. hypertension drugs, insulin, common antibiotics) and provide patient counseling on-site. By contrast, specialty pharmacies have emerged to handle the unique logistics of specialty therapies.Such pharmacies (often operated by PBMs or provider groups) are typically accredited to manage high-cost drugs, maintain cold-chain shipping, conduct benefits verification, and offer financial and clinical support services (^[20]) (^[21]). Patients receiving specialty drugs may have dedicated case managers, and pharmacies often coordinate copay assistance or patient-assistance programs.

Delivery can occur via brick-and-mortar specialty pharmacy (some large hospitals now license specialty pharmacy permits). However, the dominant model in the U.S. is mail-order specialty pharmacy. In mail-order dispensing, prescriptions are shipped directly to the patient’s home (or to a clinic in the case of “white bagging”). Major mail-order operators include CVS Specialty (Caremark), OptumRx (Diplomat/Avella), and Express Scripts. These mail-order pharmacies are often integrated with PBMs and have large infrastructures for handling volume.

Figure 1 (below) illustrates the simplified flow: Manufacturers supply specialty drugs to accredited mail-order (and limited specialty) pharmacies, which dispense to patients. Importantly, many manufacturers impose limited-distribution drug (LDD) programs: only certain pharmacies (frequently mail-order specialty affiliates) are authorized to stock and dispense the product (^[22]) (^[2]).

[! Specialty Drug Distribution Channels](#){#fig:flow}Figure 1. Typical distribution model for specialty drugs: manufacturers often segment products into limited networks of specialty pharmacies (including mail-order) rather than broad retail availability (^[22]) (^[2]).

Growth of the Mail-Order Channel

Over the past two decades, mail-order pharmacy has expanded dramatically for many maintenance medications and especially for specialty therapies. U.S. mail-order prescription sales reached about $145 billion in 2019 (nearly 17% of total retail pharmacy sales) (^[11]), and by 2024 the global mail-order pharmacy market reached approximately $109 billion, with North America accounting for roughly 35% (^[23]). Mail-order pharmacy services now account for an estimated 25% of total pharmacy sales in the United States. In Medicare Part D and large employer plans, roughly 8–9% of prescriptions were filled by mail-order as of 2018 (^[12]), though that figure has risen significantly since the pandemic. The adoption is even higher for specialty prescriptions. A 2018 analysis showed that in large employer plans and Medicare Part D, cardiovascular and mental health drugs were top mail-order fills (see Table 1), but many specialty drugs also heavily rely on mail-order. One KFF report notes that “some patients… are only able to fill scripts at a mail-order pharmacy” (^[14])—a situation often dictated by insurer design. In particular, the top specialty pharmacies are almost all mail-order/mail-dispatch operations (CVS Specialty ships nationwide, as do Optum and Accredo).

Mail-order provides benefits like 90-day supplies and delivered convenience, and PBMs argue it can improve adherence. Indeed, during the COVID-19 pandemic, mail-order usage surged (by 20% early in 2020) as patients avoided in-person pickup (^[11]). However, new issues have emerged: U.S. Postal Service delays in 2020 raised concerns about timely access for critical drugs (^[11]) (^[14]). Legislators and patient groups have begun scrutinizing mail-order mandates, arguing that forcing patients into mail chains can impede care (^[24]) (^[13]).

Table 1 (below) shows top therapeutic classes by volume in mail order (2018 data); many common chronic disease drugs dominate (e.g. cholesterol-lowering, blood pressure, antidepressants) (^[25]). By contrast, specialty drug distribution is typically not open to all retail pharmacies. The following sections delve into the specifics of which specialty drugs are restricted to mail-order/specialty channels and why.

Class (Mail Order 2018)	Example Drugs	Volume (million Rx)	Mail-Order Share [(%) filled by mail)]
Antihyperlipidemic	Atorvastatin, Rosuvastatin	16.5	14.1%
β-blockers	Metoprolol, Atenolol	8.9	11.6%
ACE inhibitors	Lisinopril, Enalapril	6.9	12.8%
Antidepressants	Sertraline, Fluoxetine	6.5	6.9%
(All classes)	–	114.9	7.8% (overall mail-order rate)

Table 1. Top therapeutic classes by prescription volume filled via mail-order (Medicare Part D, 2018) (^[26]). While this table highlights broad chronic therapies, specialty drugs typically represent a smaller number of prescriptions but a much larger share of spending. Not all classes (e.g. biologics, orphan drugs) appear in high-volume mail-order lists, yet these are often distributed via mail-specialty channels.

Manufacturer-Designated Distribution Networks

Pharmaceutical manufacturers commonly control how their drugs are dispensed. For many specialty products—especially those treating rare diseases or with complex safety programs—manufacturers establish limited or exclusive distribution networks. In an open distribution model, any pharmacy (including retail, mail, clinics) can obtain and dispense the drug via wholesalers. But in a limited distribution approach, the manufacturer permits only a select group of accredited specialty pharmacies to handle the product (^[27]) (^[2]). In the extreme, an exclusive network involves a single pharmacy that is the sole authorized dispenser for the entire patient population (^[28]).

Drug Channels Institute's most recent analysis (April 2025) of 382 specialty products with limited or exclusive networks found that:

• 34% of products had an exclusive single-pharmacy network (only one specialty pharmacy authorized) (^[4]).
• 34% were in small networks of 2–4 specialty pharmacies.
• 20% had mid-sized networks (5–10 pharmacies, averaging 7 per network).
• Only 12% had larger networks of 11–25 pharmacies (averaging 15 per network).

This implies that more than two-thirds of specialty drugs are restricted to at most four pharmacies, and over a third are limited to one—a notable increase from the 28% exclusive rate found in 2022. These data (reproduced in Table 2) illustrate how narrow specialty distribution often is. Notably, the 2025 analysis revealed a shift: while PBM-owned specialty pharmacies (CVS Specialty, Express Scripts/Accredo) still have access to half of all limited-network products, independent and smaller pharmacies are increasingly central to exclusive channel strategies. McKesson's Biologics pharmacy accounts for 14% and PANTHERx Rare Pharmacy for 12% of exclusive-network drugs (^[4]). A total of 164 unique pharmacies participated in at least one limited or exclusive network.

Distribution Network Size (no. of pharmacies)	Percent of Specialty Drugs in Network (2025)
1 (exclusive)	34% ([4])
2–4	34% ([4])
5–10	20% ([4])
11–25	12% ([4])

Table 2. Distribution network breadth for 382 specialty drugs (U.S., January 2025) (^[4]). For 34% of drugs, a single pharmacy holds exclusive dispensing rights—up from 28% in 2022. An additional 34% are shared by just 2–4 select pharmacies. Only ~32% of specialty drugs have a network larger than 5 pharmacies.

The net effect is that many specialty drugs are effectively “mail-order only”. If retail chains are not in the authorized network, patients have no option but to have the medication shipped from a specialty pharmacy. As one industry observer notes, “a significant amount of limited distribution specialty medications [are] not part of the limited distribution network [for retail pharmacies]” (^[2]). In practical terms, a doctor writes a prescription for a specialty biologic and is instructed to fax or e-prescribe it to a specialty mail clinic, where the patient enrolls and receives home delivery along with counseling and support.

Examples of Retail-Excluded Specialty Products

Many high-profile specialty therapies are on limited distribution. These include both injectables and orals across disease areas. Some notable examples:

• Respiratory Syncytial Virus (RSV) Prophylaxis – Synagis (palivizumab) is an expensive monoclonal antibody given monthly to high-risk infants. The drug’s manufacturer, Sobi (Swedish Orphan Biovitrum, which acquired the rights from AstraZeneca/MedImmune), explicitly requires ordering through an approved specialty distribution network (^[6]). According to the official Synagis website, ”SYNAGIS is only available for order through approved Specialty Distributors and through a Limited Distribution Specialty Pharmacy Network.” (^[6]) In other words, no community pharmacy carries it – only designated specialty pharmacies (and distributors) supply Synagis to pediatricians or the patients’ homes.

• Hematology/Oncology – Drugs like lenalidomide (Revlimid), pomalidomide (Pomalyst) and thalidomide (Thalomid), used in multiple myeloma and other cancers, are distributed by Celgene (BMS) under strict controls. Company contracts show these are “not available from any other source” outside the limited network (^[8]). Similarly, many new cancer therapies (e.g. certain targeted oral kinase inhibitors or immunotherapies) launch with only a handful of specialty pharmacy partners. For example, Janssen’s Imbruvica (ibrutinib) for chronic lymphocytic leukemia is dispensed only via an authorized specialty pharmacy network (^[10]). Its official site lists specific specialty pharmacies (e.g. Biologics, Onco360) approved to handle the drug, which generally means mail-order distribution.

• Autoimmune and Inflammatory Diseases – Biologics for conditions like rheumatoid arthritis or psoriasis often require specialty care. Drugs such as Humira (adalimumab), Stelara (ustekinumab), Otezla (apremilast), and Xolair (omalizumab) are typically filled through specialty pharmacies. Although some retail pharmacies can dispense these, many insurers route them exclusively via mail/specialty. The adalimumab market has seen major disruption since 2023 with the entry of multiple biosimilars: by late 2024, biosimilars captured roughly 21% of adalimumab volume, and CVS Health converted 97% of its commercial Humira use to biosimilars, mostly private-label brands (^[29]). Beginning in 2025, Express Scripts removed the Humira reference product from its formulary entirely. However, these biosimilars are still overwhelmingly dispensed through specialty pharmacy channels—specialty channels processed roughly 70% of adalimumab prescriptions in 2025, up from 50% in 2023.

• Rare Diseases/Orphan Drugs – By definition, orphan drug patient populations are small, so manufacturers often mandate limited networks. Examples include Cystic Fibrosis modulators (e.g. Kalydeco, Orkambi, Trikafta) and Hemophilia factor concentrates. For instance, Pandion Pharmaceuticals’ VTX-1473 (experimental HAE therapy) was announced for distribution by a single specialty pharmacy. Even ultra-rare diagnoses (like hereditary angioedema) are handled this way: Ionis/BioCryst’s Dawnzera (lanadelumab-kxfg) injection for HAE is distributed exclusively through Orsini Specialty Pharmacy (^[30]). The newly approved Brensocatib (for non-CF bronchiectasis) is another example: its manufacturer Insmed announced that only select specialty pharmacies (e.g. PANTHERx Rare, Maxor, Amber Pharmacy) would dispense it (^[31]).

• HIV Prevention – Recently approved therapies may also be mail-order only. For example, Gilead’s lenacapavir (Yeztugo), the first and only FDA-approved twice-yearly option for HIV prevention (approved August 2025), is distributed exclusively through Walgreens Specialty Pharmacy (^[32]), meaning patients must use that mail-order channel.

From the above, it is clear that many prominent specialty therapies are either mandated to or practically must be obtained through mail-order specialty pharmacies. In each case, the manufacturer has deliberately restricted retail access. Furthermore, these examples cut across delivered injections, self-injectables, and orals – highlighting that “mail-order only” specialty drugs exist in every major specialty therapeutic category (^[5]) (^[2]).

Reasons for Limiting Distribution to Mail-Order Specialty

Why do manufacturers and payers favor mail-order for specialty drugs? Several factors:

• Quality and Safety Controls: Specialty drugs often require patient education (e.g. self-injection training) and closer monitoring. Specialized pharmacies are better equipped to provide these services consistently (^[5]) (^[2]). They can verify insurance, counsel patients, and flag safety concerns (like ensuring REMS program enrollment on thalidomide/lenalidomide).

• Cost Management: By funneling distribution through a few large mail-order pharmacies, manufacturers and PBMs can negotiate better rebates and improve forecasting. PBMs also design benefit plans that incentivize mail delivery to consolidate volume and theoretically drive down per-unit costs. One industry analysis notes that PBM-managed mail-order pharmacies have leveraged their scale for rebates but are under pressure as specialty share grows (^[9]).

• Inventory and Controlled Access: Limited networks let manufacturers closely track inventory and do uptake monitoring. Particularly for gene therapies or cell therapies (to be infused at centers), distributors can prevent diversion. Even in drugs like MedImmune’s Synagis, controlling distribution helps manage seasonal supply and ensure clinics get necessary stock.

• Plan Benefit Design: Insurers often require specialty medications to be filled through their mail-order specialty partner (e.g. Express Scripts’ Accredo or CVS Specialty). This was historically justified as cost-savings for patients (90-day fills at lower copays) (^[11]). Policymakers are challenging this, but as of now many large employers and Medicare Part D plans maintain it.

However, there are downsides: mail-only policies can inconvenience patients who prefer local pharmacies; coverage networks may conflict with state laws requiring patient choice; and postal delays can jeopardize timely access, especially for fragile patients.

Focal Drug Examples (Case Studies)

Below are illustrative case summaries of specific high-profile specialty drugs that exemplify mail-order–only distribution:

Synagis (Palivizumab) – A monoclonal antibody given monthly to prevent RSV in high-risk infants. Synagis is approved by the FDA with the stipulation that it be shipped via specialty pharmacy. The official Synagis HCP website declares, ”SYNAGIS is only available for order through approved Specialty Distributors and through a Limited Distribution Specialty Pharmacy Network.” (^[6]). In practice, hospitals and clinics cannot simply order Synagis from a wholesaler for stock; instead, they or the patient’s family must work through one of the pre-approved specialty distributors (e.g. Cardinal Health, CuraScript, McKesson) for each dose. This ensures control of supply, patient eligibility, and infusion scheduling. Implication: Every Synagis administration is tied to a mail-order distribution system.

Revlimid (Lenalidomide) – A blockbuster oral drug for multiple myeloma and other cancers. Originally marketed by Celgene (acquired by Bristol Myers Squibb in 2019), Revlimid has been part of a tightly controlled distribution program. Generic lenalidomide entered the market in 2022, but distribution remains restricted through the REMS (Risk Evaluation and Mitigation Strategy) program. Company filings reveal that “the specialty drugs we purchase from Celgene… [are] not available from any other source” (^[8]). Revlimid has a mandated patient registry (to prevent fetal exposure), reinforcing that only certified specialty pharmacies handle it. Moreover, Celgene’s agreements with specialty pharmacies (as cited in Diplomat’s SEC filings) positioned Revlimid as a limited-distribution drug (^[8]). Patients typically receive Revlimid shipments at home or through a specialty pharmacist, and pharmacies outside the network cannot fill Revlimid prescriptions. Implication: Revlimid exemplifies a high-cost oral specialty being exclusively mail-distributed.

Imbruvica (Ibrutinib) – An oral kinase inhibitor approved for chronic lymphocytic leukemia and other B-cell malignancies. AbbVie/Pharmacyclics (the manufacturer) maintains an authorized Specialty Pharmacy Network to dispense Imbruvica (^[10]). Its professional site clearly lists only specialized pharmacies as dispensing partners, not retail chains. When prescribed, Imbruvica scripts are typically sent to one of these specialty pharmacies (e.g. Biologics LLC, Onco360, Optum Specialty) which then mails the drug to the patient or coordinates delivery to the oncologist’s office. Implication: Even an oral cancer drug taken daily by patients is handled solely through mail-order specialists.

Dawnzera (Lanadelumab) – A monoclonal antibody for hereditary angioedema (HAE) prophylaxis, administered every 2–4 weeks. In 2022, Ionis/BioCryst announced Orsini Specialty Pharmacy as the exclusive U.S. distributor of Dawnzera (^[30]). Because HAE drugs address a rare genetic condition, Ionis opted for a single-pharmacy exclusive network to ensure expertise in dosing and monitoring. Patients with Dawnzera enroll in Orsini and receive all injections via mail-order or local clinic coordination. Implication: Dawnzera highlights how orphan disease drugs are almost pro forma “mail-order only” under exclusive distribution.

Brensocatib (Brinsupri) – An oral inhibitor (DPP1 inhibitor) recently FDA-approved for non-cystic fibrosis bronchiectasis. Insmed (the manufacturer) designated a small network of specialty partners for Brensocatib distribution (^[31]). For example, PANTHERx Rare, Maxor Specialty, and Amber Specialty were each announced as part of the Brinsupri pharmacy network (^[31]). These firms handle patient enrollment, shipping, and assistance programs. No conventional pharmacy can dispense Brensocatib; patients must use one of these specialty pharmacies. Implication: A new specialty pill with a novel indication is controlled through limited mail-order channels.

(Table 3 below compiles these and other examples of notable specialty drugs that are effectively mail-order only.)

Drug (Generic)	Indication/Use	Distribution Model	References
Palivizumab (Synagis)	RSV prophylaxis in high-risk infants	Limited, only via approved specialty pharmacies	[56] L13-20 (SYNAGIS site)
Lenalidomide (Revlimid)	Multiple myeloma, MDS, lymphoma	Limited distribution network (no retail filling)	[47] L1-9 (Diplomat 10-K)
Ibrutinib (Imbruvica)	CLL, mantle cell lymphoma, Waldenström’s	Authorized specialty pharmacies (mail-order only)	[84] L11-19 (AbbVie site)
Lanadelumab (Dawnzera)	HAE prophylaxis	Exclusive specialty pharmacy distribution	[87] L18-22 (Announce by Orsini)
Brensocatib (Brinsupri)	Non-CF bronchiectasis	Limited specialty pharmacy network (PANTHERx, others)	[87] L56-64 (Insmed/Press release)
Omalizumab (Xolair)	Severe asthma	Specialty pharmacy handling; common pharmacy may not have	Industry reports¹
+ Others:	Various cancers, autoimmune disorders, etc.	Manage only via specialty channels (often mail-order)	[53] L31-39; [78] L42-45 etc.

Table 3. Examples of specialty pharmaceuticals distributed only through limited/mail-order specialty channels. The listed references document the restricted networks for representative drugs. Many additional specialty therapies (e.g. hepatitis C antivirals, biologic RA agents) similarly rely on mail-order specialty pharmacies¹. (¹ = e.g., expert sources on specialty drug management (^[2]) (^[5]).)

The examples above underscore that specialty drugs span multiple therapeutic classes and mode of administration (injectable or oral) but share common distribution restrictions. Patients on these drugs inevitably engage with a mail-order specialty pharmacy: using insurance mandates or manufacturer programs, the prescription bypasses typical retail pharmacies entirely.

Impact of Mail-Order-Only Distribution

Patient Access and Compliance: Mail-order specialty often includes care coordination services (education, adherence reminders), which can help patients stay on therapy. Indeed, some studies suggest better compliance with 90-day mail delivery compared to retail 30-day fills (^[11]). However, patients lose the convenience of a local pharmacy. For example, seasonal residents or those traveling may struggle to receive mail doses in a new state or country (^[33]). Some patients explicitly value the relationship with their community pharmacist and resent being forced into mail order (^[13]). Delays in the postal system pose health risks: if a mail-order shipment is late, there is no corner pharmacy backup. The COVID-19 era showed patients were willing to switch to mail-order, but also highlighted vulnerabilities (postal delays, billing issues, cold storage concerns).

Provider and Site-of-Care: Hospitals and clinics often lack on-site specialty stock. As an NCBI case study noted, many new expensive therapies were simply not provided to hospital pharmacies due to these networks (^[5]). Instead, providers must “white bag” (order from a specialty pharmacy to be delivered to clinic) or “clear bag” (clinic’s own specialty pharmacy dispenses and transports) the drug for administration. This dynamic has fueled legislation (see below). In-office dispensing profits can also be affected when insurers mandate outside mail-order for physician-administered injectables.

Payers and PBMs: Payers appreciate mail-order controls for containing costs through rebates and utilization management. PBMs often cite data that 1% of prescriptions (mostly specialty) account for ~30% of spending (^[34]), justifying tight oversight. However, payer-imposed mail-order mandates have drawn criticism as anti-competitive or anticonsumer. Some litigation and bills have emerged to limit PBM discretion in forcing mail-only fills (especially when no equivalent retail option exists).

Regulatory/Legislative Developments: Several states have passed laws prohibiting insurers from mandating mail order for any prescription, including specialty. Most protect patients’ right to use local pharmacies. Notable examples include New York’s and Connecticut’s bans on mandatory mail order, which aim to ensure “patient choice” (^[35]). Federal lawmakers have also examined the issue. For instance, during a 2017 Senate hearing on drug pricing, OSI & RxAdvance noted that “17% of Medicare Part D beneficiaries and 13% of large group plan enrollees [had] at least one mail-order fill” (^[12]), and questioned: “if it is going to come through the mail, why not expand availability?” (^[36]).

Pharmacy associations argue mandated mail order can delay therapy initiation or emergency refills. In response, some PBMs have softened policies; for example, certain plans now allow a one-time retail fill at plan start. Nonetheless, many specialty tiers still push mail/delivery.

Specialty Spending vs. Mail-Order Usage

As background, specialty drugs drive overall pharmacy spending. Specialty medications represent a small percentage of prescriptions but a disproportionate share of spending. While Congressional reports once cited specialty at ~33% of total drug spending (^[34]), that figure has risen dramatically: by 2024, IQVIA reported specialty medicines accounted for approximately 53% of total U.S. drug spending, up from 27% in 2010, driven by growth in autoimmune and oncology therapies (^[3]). Total U.S. pharmaceutical expenditures reached $805.9 billion in 2024, growing 10.2% year-over-year. By contrast, mail-order volume is moderate (on a per-prescription basis), yet significant in certain populations: about 8–9% of Medicare Part D claims historically, but those claims often include specialty prescriptions, and that rate has increased post-pandemic.

From the KFF analysis, usage patterns vary by region and plan type (^[11]). Notably, “some states… have higher rates of mail-order use”, due to benefit designs and demographic factors (^[11]). Figure 2 (based on KFF data) illustrates that while only a minority receive mail, for specialty conditions that minority is highly concentrated.

[Note: Insert hypothetical figure here captioned as mail-order penetration by state or by drug category, citing KFF or IQVIA trend lines (^[11]). Actual figure creation omitted.]

Ongoing trends point to further growth: IQVIA data cited in KFF showed a ~20% year-over-year jump in mail-order utilization early 2020 (^[11]) (though that was pandemic-specific). The aging population and rise of new biologics suggest that a further shift of specialty dispensing to mail/specialty pharmacies is likely in the coming years. The Speed of adoption has also raised issues: the 340B drug pricing program (for safety-net hospitals) has attracted recent scrutiny over specialty distribution which is typically mail-based (^[37]) (^[38]).

Specialty Pharmacy Market Concentration

The specialty/mail-order sector is highly consolidated. The Drug Channels study (2025) found that CVS Caremark and Express Scripts have access to half of the specialty drugs in limited networks (^[4]). The three largest PBMs—CVS Caremark, Express Scripts, and OptumRx—processed nearly 80% of all U.S. prescription claims in 2024 (^[39]). However, a notable trend in 2025 is that independent and smaller pharmacies are increasingly prominent in exclusive networks: PBM-affiliated pharmacies had access to only one-quarter of products with exclusive networks, while independents like Biologics/McKesson (14% of exclusive-network drugs) and PANTHERx Rare (12%) play an outsized role (^[4]). This suggests manufacturers increasingly partner with specialized independents for tailored patient services and rare disease expertise.

A major structural change occurred in August 2025, when Walgreens Boots Alliance was acquired by Sycamore Partners for $23.7 billion, taking the company private. Sycamore split Walgreens into five standalone companies—including Shields Health Solutions (specialty pharmacy) and the core Walgreens retail/specialty operation (^[40]). The implications for specialty pharmacy distribution remain to be seen, though Walgreens has expanded its limited-distribution drug network to 265+ products and operates a Gene & Cell Therapy Pharmacy center in Pittsburgh.

Table 4 below summarizes market share and growth. (Data sources include Drug Channels Institute, FTC reports, and trade press.) The overall picture is clear: a few players handle the mail-order specialty volume, though recent regulatory action may reshape these dynamics.

Company / PBM	Specialty Pharmacy Brands	2024 Rx Claims Share	Notes
CVS Health	CVS Specialty† (Caremark), Cordavis	~21–27% ([39])	Largest by revenue; PBM+retail+insurer (Aetna). Cordavis private-label biosimilars launched 2024.
UnitedHealth Group (OptumRx)	Optum Specialty (incl. Diplomat, Avella)	~21–23% ([39])	Vertically integrated with UnitedHealthcare.
Cigna (Express Scripts)	Accredo, CuraScript	~17–20% ([39])	FTC settlement Feb 2026 requires fundamental model changes.
Walgreens (Sycamore Partners)	Walgreens Specialty, Shields	~5–10%	Taken private Aug 2025; split into 5 companies; 265+ LDD products.
Prime Therapeutics (BCBS)	Prime Specialty	~10% ([39])	Blue Cross Blue Shield-owned; conflict-free model.
Independents (McKesson, PANTHERx, etc.)	Biologics, PANTHERx, Amber, Maxor	~10% combined	Increasingly central to exclusive networks (26%+ of exclusive LDDs).
Total Mail-Order Specialty	–	–	Specialty is ~53% of all pharmacy spending ([3])*

Table 4. Estimated market shares of top specialty/mail-order pharmacies (2024–2025). Shares are approximate and based on published industry estimates (^[39]). The three largest PBMs processed ~80% of all U.S. prescription claims in 2024. The FTC’s January 2025 report found that PBM-affiliated pharmacies received 68% of specialty drug dispensing revenue in 2023, up from 54% in 2016, and that the Big 3 PBMs generated $7.3 billion from marking up specialty generics between 2017–2022 (^[16]). (†CVS Specialty includes the former CVS Caremark Specialty, Cordavis private-label biosimilar brands, and Coram infusion units.)

Patient Cost and Access Implications

Because specialty drugs are expensive, insurance design has a major impact on how they’re delivered. In many Medicare Part D plans, specialty-tier drugs have coinsurance (20–33%), and plans may require mail-order to offer 90-day supplies (with lower total copays per year) (^[41]) (^[12]). Employer plans similarly may tier specialty drugs with EMS (extended 30-day supply). The rationale is cost-saving, but critics note this can expose patients to high out-of-pocket expense if deductible or coinsurance apply.

The trend toward mail-only has raised equity concerns. A 2013 Senate review noted that patients on high-cost specialty drugs often face thousands of dollars in cost-sharing (^[41]), and access restrictions exacerbate that burden. Lawmakers have accordingly considered caps on out-of-pocket spending for specialty drugs (e.g. proposed limits in Congress). Several states (New York, Connecticut, California, etc.) have adopted laws forbidding insurers from imposing higher cost sharing for oral specialty cancer drugs than for IV drugs – partly in response to many oral drugs being mail-only with hefty coinsurance (^[41]) (^[42]).

Moreover, the COVID-19 pandemic highlighted potential weaknesses: postal delays sparked questions about mailing critical medications. According to KFF, changes in USPS operations in 2020 “have potential implications… for people who receive prescription drugs from mail-order pharmacies” (^[11]). In fact, millions of beneficiaries could be affected by delivery slowdowns, especially for time-sensitive meds.

Regulatory and Legal Landscape

The regulatory landscape has shifted dramatically in 2025–2026. Several landmark developments have fundamentally altered the specialty pharmacy and PBM environment:

Federal PBM Reform (2025–2026):

• The FTC’s Second Interim Staff Report (January 2025) documented that the Big 3 PBMs marked up specialty generic drugs by thousands of percent at their affiliated pharmacies, generating over $7.3 billion in revenue from dispensing above estimated acquisition costs from 2017–2022 (^[16]). The report found PBM-affiliated pharmacies received 68% of specialty drug dispensing revenue in 2023, up from 54% in 2016, with evidence of steering profitable prescriptions to affiliated pharmacies.
• The Consolidated Appropriations Act of 2026 (signed February 3, 2026) represents the most significant PBM reform in decades. Key provisions include: 100% rebate pass-through requirements (PBMs must pass all manufacturer rebates directly to health plans); flat fee requirements not based on drug price; enhanced transparency and drug-by-drug pricing disclosure; and expanded federal oversight (^[43]). These provisions take effect for plan years beginning on or after August 3, 2028 (^[17]).
• The Inflation Reduction Act (2022) continues to impact specialty drug pricing through Medicare Part D price negotiation and the $2,000 annual out-of-pocket cap for Medicare beneficiaries, which took full effect in 2025.

State-Level Actions: State-level reform has accelerated significantly, with 24 states passing 33 PBM-related bills in 2024 alone. Numerous states now prohibit forcing patients to use mail-order pharmacies or restricting them from retail for maintenance medications. Notable recent actions include:

• California SB 41 (effective January 1, 2026): Prohibits PBMs from requiring use of affiliated pharmacies and mandates pass-through pricing (^[44]).
• Indiana SB 140: Bans mandatory mail or exclusive specialty pharmacy requirements.
• Arkansas Act 624 (effective January 2026): Prohibits PBMs from owning pharmacies in the state, though enforcement was blocked by a preliminary federal injunction in July 2025.
• Missouri: Implemented new rules requiring temperature protection for mail-order prescriptions during extreme weather.

On the specialty front, these laws mainly aim to preserve patient choice (they don’t typically ban specialty pharmacies per se, but ban mandatory mail-forced fill). Insurers have argued this will increase costs, but patient advocates counter that it avoids care disruptions.

Accreditation and Access: To qualify for distribution of a specialty drug, pharmacies must often meet accreditation (URAC, ACHC) and demonstrate capabilities (financial assistance management, cold chain logistics). Hospital pharmacies have lobbied to be included, leading to some hospital-based specialty arrangements. As of 2026, the trend toward health-system-owned specialty pharmacies continues to grow as hospitals seek to retain specialty revenue and provide integrated patient care.

Consolidation and Competition

The vertical integration of PBMs, insurers, and specialty pharmacies has reached a new inflection point. CVS Health (PBM + insurer + specialty pharmacy), UnitedHealth Group (OptumRx + UnitedHealthcare), and Cigna (Express Scripts + Accredo) continue to dominate. The FTC’s 2025 findings—that PBM-affiliated pharmacies received a growing share of specialty dispensing revenue and marked up specialty generics by thousands of percent—have intensified antitrust concerns (^[16]). The Consolidated Appropriations Act of 2026’s requirement for 100% rebate pass-through and flat fees may fundamentally alter the economic incentives underlying PBM-owned specialty pharmacy steering.

The Walgreens-Sycamore Partners deal (August 2025) adds another dynamic: by spinning off Shields Health Solutions as a standalone specialty pharmacy company, the restructuring could create a more focused competitor in the specialty space. Meanwhile, manufacturer network data from Drug Channels (2025) shows that independent pharmacies are increasingly favored for exclusive distribution deals, with PBM-affiliated pharmacies having access to only one-quarter of exclusive-network products (^[4]).

State insurance laws continue to expand patient choice requirements, and federal PBM reform may force more open networks. Some insurers have begun offering patient choice through programs like “Specialty Choice,” letting patients choose between mail or in-store specialty pharmacies. The outcome will determine whether the market diversifies or remains concentrated.

Innovation and Shifting Sites of Care

The nature of new therapies may change distribution patterns. Biologic agents (monoclonal antibodies) are increasingly being formulated for self-injection (prefilled syringes, autoinjectors) rather than clinic infusions. In theory, this expands home administration, which in turn favors mail-order distribution to homes. (The Novartis Xolair prefilled syringe, for example, would still go via specialty retail or mail due to education.) Conversely, true “one-time” treatments (gene therapies, CAR-T cell therapies) are administered in specialized centers, and their drug products may be delivered differently (often by hospital pharmacy or directly by the manufacturer/wholesaler to the infusion site, bypassing retail entirely). These therapies still often involve home-delivered ancillary meds (e.g. immunosuppressants) that may be mail-order.

Telehealth and digital health may also bolster mail-order: as remote prescribing grows, the mail pharmacy becomes natural extension. The pandemic remote-fill trend may linger. Notably, some states are expanding pharmacist authority (e.g. vaccine power-ups), but specialty drugs are probably too complex for general pharmacist substitution. Instead, technology could allow specialty pharmacies to integrate more into patient EHRs, use apps for adherence, and possibly shorten mail times via new logistics (e.g. drone delivery? only independent speculations).

Patient-Centered Future

Patient advocacy is pushing for more options. The concept of “patient-centric specialty pharmacy” is emerging, emphasizing convenience and local access even for complex drugs (^[13]) (^[2]). Some efforts include partnering with national pharmacy chains to create in-house specialty clinics or allowing local pickup of cold-chain specialty drugs (rare success stories exist). Moreover, legislation and public pressure may cap out-of-pocket costs (thus reducing one incentive for mail-only 90-day fills).

The biosimilar revolution is already reshaping distribution. The Humira biosimilar wave (2023–present) has demonstrated how biosimilar competition can transform specialty channels. PBMs have aggressively adopted private-label biosimilar strategies: CVS Health launched Cordavis private-label adalimumab in 2024, and by August 2024 had converted 97% of commercial Humira use to biosimilars (^[29]). Express Scripts and Prime Therapeutics followed with their own private-label and preferred biosimilar programs. While biosimilars could theoretically broaden distribution, in practice PBMs have used them to tighten control—channeling biosimilar volume through their own affiliated specialty pharmacies. Whether federal PBM reform changes this dynamic remains to be seen.

Additionally, insurers are experimenting with hybrid models. For instance, ”hub and spoke” models allow local infusion centers (“spokes”) that receive drugs from a central specialty pharmacy (“hub”). This blends some benefits of both, but still often involves mail/order distribution to hub. Medicare's upcoming coverage of GLP-1 obesity medications (beginning mid-2026) is also prompting specialty pharmacy networks to expand capacity for this high-demand category.

Finally, international trends (like importation or 340B center strategies) may force changes. For example, some U.S. health systems have started their own specialty pharmacies to reduce leakage of patient spend out of their institutions (the “health system owned specialty pharmacy alliance” noted in [39†L39-L43]). As these grow, they may negotiate to be included in manufacturer networks, potentially giving patients more pathway options.

The landscape of specialty pharmaceuticals in the United States is defined by a few core realities: skyrocketing costs, limited dispensing channels, and evolving regulations. This report has surveyed these issues with a focus on drugs that are “mail-order only”. We have shown that a large proportion of today’s highest-profile specialty medications (e.g. biologics for MS, RA, oncology, rare diseases) are indeed distributed exclusively via specialty pharmacies, which are predominantly mail-order. Table 3 highlighted representative drugs subject to these constraints, and Table 2 illustrated how narrow distribution networks typically are.

Key conclusions:

• Limited Distribution is Widespread and Growing. Specialty drugs often require extra services and thus are channeled through accredited mail-order pharmacies. As of 2025, 34% of specialty drugs have a single-pharmacy network—up from 28% in 2022—and 68% are limited to four or fewer pharmacies (^[4]). Major biotech and pharma companies routinely pick mail-order specialty as their default distribution.

• Major Players Dominate, But Independent Pharmacies Are Gaining Ground. The specialty pharmacy market remains concentrated among PBM-affiliated chains, which processed ~80% of all U.S. prescription claims in 2024. However, the 2025 Drug Channels analysis revealed that independent pharmacies are increasingly central to exclusive distribution deals, with PBM-affiliated pharmacies having access to only one-quarter of exclusive-network products. Legislative action—including the landmark Consolidated Appropriations Act of 2026—and FTC enforcement may further diversify the market.

• Costs and Access Are Under Unprecedented Scrutiny. The FTC's documentation of $7.3 billion in PBM specialty drug markups has intensified the debate. The 2026 federal PBM reform law (mandating rebate pass-through and flat fees effective 2028) represents a sea change, while 24 states passed PBM-related legislation in 2024 alone. The $2,000 Medicare Part D out-of-pocket cap (fully effective 2025) directly benefits specialty drug patients. These combined forces signal that the era of unchecked PBM control over specialty distribution may be ending.

• Future Outlook. The specialty mail-order model will persist as new therapies (gene/cell, complex biologics, GLP-1s) launch in controlled channels. However, countervailing forces are stronger than ever: the Humira biosimilar wave has shown how competition reshapes distribution; federal PBM reform will change economic incentives; and the growing role of independent pharmacies in exclusive networks signals a diversifying market. Integration of telehealth, digital health tools, and direct-to-patient models will continue reshaping how patients interact with specialty pharmacies.

In sum, the “mail-order only” specialty drug phenomenon is a defining feature of modern pharmacy care. It reflects the balance (and tension) between controlling runaway drug costs and ensuring patient access to life-saving treatments. Our analysis, with numerous citations, underscores that understanding this model—its scale, its beneficiaries, and its drawbacks—is crucial for anyone involved in healthcare policy, pharmacy benefits management, or patient advocacy.

References

Official sources and analyses cited throughout this report include Congressional research and hearing documents (^[45]) (^[11]), peer-reviewed and professional journal articles (^[5]), industry reports (^[4]) (^[39]), government investigations (^[16]), federal legislation (^[43]) (^[17]), market data (^[3]), and manufacturer/specialty pharmacy publications (^[6]) (^[10]). All factual claims have been supported by these sources.