This medication conflict checker helps people with hypophosphatasia (HPP) and their caregivers see whether a current medicine could affect eligibility for an HPP study. Select one or more medications below to screen the active trials and registries for possible conflicts.
HPP has 1 approved drug, Strensiq (asfotase alfa), and the studies that matter most right now are built around it: the Phase 3 trials of efzimfotase alfa enrolled people who had never taken Strensiq (HICKORY and MULBERRY) or people already on it for at least 6 months (CHESTNUT), and BioMarin's oral ALE1 study excludes anyone who has ever had enzyme replacement. Beyond that, the medicines people with HPP commonly take, pain relievers, vitamin B6, bone drugs prescribed for a mistaken osteoporosis diagnosis, and seizure medicines, each show up differently in eligibility criteria. The checker reads the published criteria of every active HPP study and flags the ones that mention your medicine.
Enzyme Replacement Therapy
Strensiq (asfotase alfa) — the single biggest eligibility factor. Studies of new HPP drugs usually sort people by whether they have ever taken asfotase alfa: HICKORY and MULBERRY required no prior Strensiq, CHESTNUT required at least 6 months on it at 6 mg/kg a week, and the ALE1 study excludes any prior enzyme replacement or gene therapy. A registry such as the Global HPP Registry takes people on or off treatment.
Bone Drugs
Bisphosphonates (alendronate, risedronate, ibandronate, zoledronic acid), teriparatide — NORD advises people with HPP to avoid bisphosphonates, which can worsen the disease, and many adults were prescribed one before HPP was recognized. Trials commonly exclude any treatment for osteoporotic diseases or any drug that affects bone structure; the ALE1 study does both. Teriparatide, used off-label in some adults with HPP fractures, falls under the same exclusions. Tell the study team exactly what you took and when.
Pain Relievers
NSAIDs (ibuprofen, naproxen), acetaminophen, prescription pain medicines — bone, joint and muscle pain is part of HPP and NSAIDs are standard supportive care. Pain medicines rarely exclude anyone outright, but trials that measure walking, sit-to-stand or pain scores may ask for a stable dose for several weeks before screening so the measurement is not blurred by a dose change.
Vitamins and Minerals
Vitamin B6 (pyridoxine), vitamin D, calcium — pyridoxine controls seizures in severely affected infants and is not a reason for exclusion. Calcium and vitamin D need care in HPP because blood calcium can already run high; study protocols often ask about them and may exclude uncontrolled high calcium or active hyperparathyroidism, which is an exclusion in the efzimfotase alfa trials, rather than the supplements themselves.
Seizure and Other Daily Medicines
Anti-seizure drugs, blood pressure, thyroid, diabetes and mood medicines — the medicines for other conditions are rarely the reason a trial excludes you. When the checker flags one at low confidence it usually means the trial excludes a disorder that could interfere with the study or with how the drug is absorbed, in the protocol's words, and the study doctor decides case by case whether yours counts.
Took a bisphosphonate before your HPP diagnosis?
Many adults were treated for osteoporosis for years before anyone checked their alkaline phosphatase. Bisphosphonates stay in bone long after the last dose, so a study may still count them as a bone-active drug and ask about dates and total exposure. Bring that history, including any infusions of zoledronic acid, to the screening call; it does not always exclude you, but the team has to know.
On Strensiq? Switch studies are the ones built for you
Being on enzyme replacement closes the door to treatment-naive trials but opens others. CHESTNUT enrolled children on a stable Strensiq dose and compared switching with staying; its extension continues. If efzimfotase alfa is approved in 2027, the question of switching moves from trials to the clinic. Registries welcome people on treatment and their data feed the FDA-required study of long-term response.
Registries and natural history studies take almost everyone
Most open HPP studies today are observational: the Global HPP Registry, Duke's natural history study, the Paris adult registry and AstraZeneca's ATLANTIS study of people with a single ALPL variant. They collect blood tests, X-rays and symptoms without changing your treatment, so your medicine list almost never matters. Joining one is also how researchers find people for future drug trials.
Don't see your medication listed?
The checker covers the medicines that appear most often in HPP eligibility criteria: enzyme replacement, bone-active drugs, pain relievers, vitamins and minerals, seizure medicines and common daily medications. If yours is missing, it has not come up in current HPP criteria, but tell the study team about everything you take, including supplements, when you contact them.
How the medication conflict checker works: This free tool helps people with hypophosphatasia learn whether their current medications could affect clinical trial eligibility. It scans the published eligibility criteria of every active HPP study and flags the ones that may exclude your treatment. Matches are sorted by confidence: high confidence means the study names your exact drug, medium confidence means it names your drug class, and low confidence means it uses broad language that may or may not apply. Select one or more of your medications above to see which studies you may still qualify for. Always confirm eligibility with the study team, who will weigh your full history, your ALP and PLP levels, your gene result and your bone specialist's assessment.
Across 1,853 open rare disease treatment trials, a third exclude people over a medication they commonly take. See which medications and diseases, in our September 2026 analysis.
Sources: Eligibility details above come from ClinicalTrials.gov records NCT06079281 (HICKORY), NCT06079359 (MULBERRY), NCT06079372 (CHESTNUT) and NCT07179640 (ALE1), read October 18, 2026, and from NORD's hypophosphatasia report on bisphosphonate avoidance.