São Paulo vs. Porto Alegre: Brazil's Two Clinical Trial Capitals

By Daniel — Founder, Samba Trials (a BioAlma company). Published 2026-04-20. Data: ClinicalTrials.gov facility-and-location data, Q2 2026 Samba Trials landscape scan.

The top two Brazilian cities for clinical-trial activity are not the ones most VPs guess. São Paulo, obviously — it's the largest metro in the Southern Hemisphere and the country's economic capital. But the number-two slot isn't Rio de Janeiro (196 city-level records) or Brasília (105). It's Porto Alegre, with 350, a mid-sized southern city that most foreign biotech decks don't even name.

This article is about what those numbers mean operationally, why the Porto Alegre phenomenon exists, and how a well-designed multinational trial actually uses the two cities together.

Reading the numbers: a methodology note

Before any comparison, a quick note on what "454 São Paulo" and "350 Porto Alegre" actually count. Readers who glance at our aggregates sometimes flag an apparent anomaly: Porto Alegre (city) = 350, but Rio Grande do Sul (state) = 189. How can the city number be higher than the state number?

The answer is that the two metrics measure different things. Our state-level count aggregates unique trials with at least one site in the state — if a trial has three RS sites, it counts once. Our city-level count is drawn from ClinicalTrials.gov's facility/location-level data, which represents trial-site pairs. A single trial that runs at HCPA, São Lucas PUCRS, and Moinhos de Vento generates three city-level records for Porto Alegre but only one state-level record for Rio Grande do Sul.

That means:

• City-level counts are inflated relative to state-level counts when a city hosts multi-site trials. Porto Alegre's 350 reflects the reality that a typical Rio Grande do Sul Phase 3 activation uses 2-3 Porto Alegre sites in parallel.
• The 454 / 252 ratio for São Paulo (city vs. state) follows the same logic: São Paulo metro hosts many multi-site activations, each generating multiple site records.
• For investigator-bench comparison, city-level records are the more useful number because they tell you how much work the centers in that city actually carry.
• For state-level market share, the state-level count is the correct number.

With that cleared up: yes, Porto Alegre's 350 means the Porto Alegre cluster runs more trial-site activations than every Brazilian metro except São Paulo itself. Rio, Salvador, Curitiba, Brasília, and Belo Horizonte are all smaller — often by multiples.

São Paulo: the density case

São Paulo state holds 252 of Brazil's 582 active industry trials (43%). The São Paulo metro alone generates 454 trial-site records — more than any other Brazilian city. Feeder cities in the state interior — São José do Rio Preto (120), Barretos (110), Campinas (86), Ribeirão Preto (78), Santo André (65), Jaú (47), Botucatu (33) — add substantial trial volume inside the state.

The São Paulo metro's trial activity is distributed across many sites. No single São Paulo site dominates the way HCPA dominates Porto Alegre. Hospital Alemão Oswaldo Cruz (20 active trials), Hospital Sírio-Libanês (12), CEPIC (14), Integral Pesquisa e Ensino (16), and a long tail of academic (HC-FMUSP, UNIFESP, USP Ribeirão) and private-research sites collectively account for the state's volume.

When to prefer São Paulo:

• Indications requiring high patient volume from a single metro (obesity Phase 3, psoriasis, atopic dermatitis, IBD Phase 3, most cardiovascular-outcome programs).
• Programs where patient demographic diversity within-site matters more than academic-bench credential.
• Programs where private-research-center throughput (CEPIC, Integral, Chronos, Ruschel) is a better operational fit than academic-hospital activation.
• Oncology protocols where Sírio-Libanês or Oswaldo Cruz PIs are requested by the global program.

Porto Alegre: the concentration case

Rio Grande do Sul state holds 189 of Brazil's 582 active industry trials (32%). The Porto Alegre metro alone generates 350 trial-site records. For a metro of ~4 million in a country of 215 million, that is an enormous over-index — Porto Alegre runs roughly 30% of the country's trial-site activity with ~2% of its population.

The explanation is HCPA. Hospital de Clínicas de Porto Alegre is a federal teaching hospital affiliated with UFRGS; it runs 53 active industry trials by our count. HCPA anchors a tight academic cluster that includes Hospital São Lucas da PUCRS (30 trials), Hospital Moinhos de Vento (22), Irmandade da Santa Casa de Misericórdia de Porto Alegre (26), Hospital Nossa Senhora da Conceição (12), Hospital Mãe de Deus (11), and smaller rheumatology, nephrology, and endocrinology sites. Combined, the Porto Alegre cluster runs an estimated 150-200 active industry trials — a share of Brazilian activity that dwarfs its population share.

That cluster has several characteristics sponsors come to rely on:

• Patient aggregation. HCPA serves as a federal reference hospital for the south of Brazil. Patients with rare-disease, complex-hematology, transplant, and neurogenetic indications are routinely referred from across RS, SC, PR — and sometimes beyond. Recruitment for ultra-rare indications can compress timelines dramatically.
• Parallel activation. Because the Porto Alegre cluster is physically close and shares some regulatory infrastructure, sponsors commonly activate 3-4 Porto Alegre sites on the same protocol in parallel — something harder to achieve across São Paulo metro's more dispersed sites.
• Specific TA strengths. HCPA is the Brazilian reference for neurogenetics, rare-disease genetics, transplant medicine, hematology, and rheumatology trial activity. São Lucas PUCRS has particular MS and migraine depth. Moinhos de Vento has imaging infrastructure for Alzheimer's and neuroimaging-endpoint trials. The cluster is specialty-deep, not broad-shallow.

When to prefer Porto Alegre:

• Rare-disease protocols that require patient aggregation from a large catchment area.
• Neurology, hematology, rheumatology, and pediatric-genetics programs.
• Programs where a federal reference hospital's bench (HCPA) is a regulatory or reputation signal.
• Trials where cluster parallel-activation lets you hit first-patient-in faster than a comparable São Paulo rollout.

What a typical multinational Phase 3 Brazilian arm looks like

For most biotech sponsors the question isn't "which city do we pick" — it's "what's the right two-to-six site Brazilian mix for our protocol." A representative Phase 3 multinational Brazilian arm typically combines:

The exact mix depends on the TA, enrollment target, and timeline — but the meta-pattern is consistent: São Paulo and Porto Alegre both appear, complementarily, in the majority of well-designed Brazilian protocols.

The other cities worth knowing

São Paulo and Porto Alegre are the two capitals, but the rest of the top-10 city list matters for specific indications:

• Rio de Janeiro (196 trial-site records). Historical presence but now the third-place metro. INCA (rare cancer), IECAC (cardiology), and several private hospitals are the anchors.
• Salvador (170). Bahia's capital. Important for sickle-cell disease trials, selected infectious-disease programs, and trials seeking Afro-Brazilian demographic representativeness.
• Curitiba (166). Paraná's capital. Strong oncology (Erasto Gaertner) and cardiovascular-research presence.
• Belo Horizonte (122). Minas Gerais. Solid academic base at Santa Casa BH and UFMG-affiliated hospitals.
• São José do Rio Preto (120). SP state interior. FAMERP / Hospital de Base run very-high-volume trial operations.
• Natal (111) and Barretos (110). Regional oncology anchors; the Northeast (Natal) and interior SP (Barretos) representativeness story.
• Brasília (105). Federal capital. Strong academic-neurology presence; regulatory-proximity advantage for some program types.