Treatment of Hypoparathyroidism Tamara Vokes, MD University of Chicago Section of Endocrinology Disclosure • NPS pharmaceutical – consultant and investigator • Discussing unapproved indications Hypopara – definition and prevalence • Rare endocrine disorder characterized by low serum calcium and high phosphate due to absent or inappropriately low PTH • Prevalence – not known • Estimate – 78-80,000 in the US Etiology – inadequate PTH secretion • Post-surgical (78%) – Thyroid surgery: total thyroidectomy (38%), partial (9%) – Parathyroid surgery (21%) – Head and neck cancer (5%) • Autoimmune – Isolated – Polyglandular failure – Activating antibodies against calcium sensing receptors Etiology – rare causes • Genetic (7%) – Familial hypocalcemic hypercalciuria (gain of function mutation in CaSR) – Polyglandular autoimmune syndrome (mutation in autoimmune regulation gene – AIRE) – DiGeorge, PTH gene mutation etc • Infiltrative disease (thalassemia, hemochromatosis, Wilson’s disease) • Irradiation (131I therapy) Etiology – not due to deficient PTH secretion • Resistance to PTH action (pseudohypoparathyroidism) • Hypomagensemia (Functional hypopara – deficient PTH secretion and action) PTH controls mineral homeostasis PTH deficiency: • Decreased intestinal calcium absorption (low 1,25 Vitamin D) • Increased urinary calcium and magnesium excretion (decreased phosphate excretion) • Decreased bone resorption Consequences of PTH deficincy • Low serum calcium and magnesium, high serum phosphate - symptoms • Hypercalciuria (kidney stones, nephrocalcinosis, CKD) • High calcium*phosphate product = soft tissue calcifications (cataracts, basal ganglia) Clinical manifestations are due to hypocalcemia • Treatment to normalize serum calcium – Calcium supplements (carbonate or citrate) – Vitamin D • calcitriol - onset 1-2 days, offset 2-3 days • ergocalciferol (less desirable) – onset 10-14 days, offset 14-75 days – Thiazide diuretics Goal of treatment of hypopara – Low normal serum calcium (8-8.5mg/dl) – 24 hour urine calcium<300 mg/24 hrs – Calcium*phosphate product <55 Parathyroidectomy patient story Two days after surgery I experienced tetney, followed by a pth test less than 3. I felt awful, tingled, ached and couldn't concentrate. After my second ER trip for tetney I was placed on calcium, magnesium, and calcitriol while being assured that my para would wake up and I would feel normal again. Nearly five months later I have a pth of 9.6 and am still struggling to manage my calcium keeping it in the low 8's. Since that day I have experienced many symptoms and struggled to regain my previous energy and health. Trying to explain my condition to friends and family is daunting and confusing. Even medical doctors are unfamiliar with my "rare disorder" and I am still trying to make sense of it all. Some days I feel great while other days I struggle to just go to work. There are muscle aches, twitches, tingling and mood swings. Therapeutic challenges • Hypo- and hypercalcemia • Poor quality of life – brain fog, tingling, cramping (claw, perching), numbness, twitching, poor exercise tolerance, headaches, insomnia, needing to carry calcium tablets • Long term complications Hypopara is the only endocrine deficiency for which there is no FDA approved replacement therapy Use of PTH for hypopara NOT FDA APPROVED • Prevent hypo and hypercalcemia • Improve QOL (Prevent wide fluctuations in serum calcium) • Decrease the amount of supplements • Minimize hypercalciuria PTH replacement therapy • PTH(1-34) approved for osteoporosis in the US and elsewhere • PTH(1-84) approved for osteoporosis in Europe PTH(1-34) for hypoparathyroidism 20 subjects treated with PTH vs. calcitriol in cross-over design Winer et al JAMA 276:631, 1996 Winer et al JAMA 276:631, 1996 PTH 1,34: 1 vs 2 daily injections 17 subjects treated for 28 weeks in crossover design Twice daily PTH produced less variability in calcium levels Winer et al JCEM 88:4214, 1998 PTH 1-34: twice daily injection vs. pump 8 patients: cross-over Mean daily PTH dose was 65% lower during pump Tx Winer et al JCEM 97:391, 2012 PTH (1-34) for hypopara • May be helpful in reducing fluctuations in serum calcium • Needs to be dosed twice a day • Not approved for hypopara but available for treatment of osteoporosis (teriparatide) Use of PTH (1-84) for hypopara • 62 subjects in a randomized placebo controlled trial given 100mcg of PTH • Calcium dose reduced by 75%, calcitriol dose by 73%: 15 subjects stopped calcium completely • 11 subjects developed hypercalcemia (Supplement dose was not titrated unless subjects developed hypercalcemia) Sikjaer et al JBMR 26:23581, 2011 ------PTH (1-84) Placebo Sikjaer et al JBMR 26:23581, 2011 30 subjects given 100mcg of PTH(1-84) every other day in open label study over 24 months Reduction in supplement doses Serum calcium improved, low risk of hypercalcemia Rubin et al Osteo Int 21:1927, 2010 Randomized double blind placebo control trial of rhPTH(1,84) 134 subjects randomized (2:1) to escalating doses of PTH or placebo for 24 weeks Inclusion criteria • Age 1885 y • HypoPARA for ≥18 mo • calcitriol ≥0.25 µg/d and oral Ca ≥1 g/d over diet • Normal TFT or stable thyroid replacement Exclusion criteria • activating CaSR mutation or ↓ responsiveness to PTH • thyroid cancer within 5 y • GI disease • Serum 25D levels <1.5ULN • Pregnant or lactating Randomized double blind placebo control trial of rhPTH(1,84) • Primary endpoint 50% in calcium + 50% in active VitD While maintaining normal serum calcium Bilezikian et al, 2012 Endocrine Soc S18-3 Randomized double blind placebo control trial of rhPTH(1,84) Secondary endpoints − Percent change in oral Ca supplement at Week 24 − Percent who achieve supplement independence − Frequency of clinical symptoms of hypocalcemia Weeks 16 - 24 Bilezikian et al, 2012 Endocrine Soc S18-3 Study Design 100µg 75µg 50µg Optimization 2-16 weeks Titration 12 weeks PTH or placebo injection daily Maintenance 12 weeks Adjust active vitamin D and then calcium Randomization End of study During titration phase weekly visit with progressive increase in PTH dose until calcitriol eliminated and oral calcium <500mg/day Guideline used for reducing supplements • Start PTH 50µg; reduce calcitriol by 50% • Test serum calcium 1-2 days later and if – Ca <8mg% - resume calcitriol – Ca 8-9mg% - no change – Ca 9.1-10.5 stop calcitriol, retest next day – Ca 10.6-11.9 stop calcitriol, reduce calcium by 50%, retest next day Adjustment at the discretion of physician Patient in PTH (1-84) study Patient Demographics rhPTH(1-84) (n=90) Placebo (n=44) Total (n=134) Mean age, year 47.0 48.5 47.5 Women, n (%) 69 (77) 36 (82) 105 (78) Caucasian, n (%) 85 (94) 43 (98) 128 (96) Mean BMI, kg/m2 29.3 29.2 29.2 Geographic area, n (%) North America Europe 49 (54) 41 (46) 25 (57) 19 (43) 74 (55) 60 (45) Hypoparathyroidism etiology, n (%) Postsurgical Idiopathic Autoimmune disease Other (genetic, radiation) 68 (76) 14 (16) 5 (6) 3 (3) 31 (71) 8 (18) 4 (9) 1 (2) 99 (74) 22 (16) 9 (7) 4 (3) Variable Mannstadt et al. Endo Soc 2012, SUN-34130 Primary Endpoint: Responder Rate at Week 24 rhPTH(1-84) n=90 Placebo n=44 70 Primary Endpoint* 48/90 Responders Rate, % 60 50 40 30 20 10 1/44 0 1 2 3 4 5 6 8 12 16 20 24 Week  53% rhPTH(1-84) vs 2% placebo (P<0.001*) Bilezikian et al, 2012 Endocrine Soc S18-3 31 Secondary Endpoint: Active Vitamin D Independence and Oral Ca Dose ≤500 mg/day rhPTH(1-84) n=90 Placebo n=44 Patients Who Met the Criteria, % 70 60 Secondary Endpoint* 36/84 50 40 30 20 10 0 1 2 3 4 5 6 8 12 16 20 24 Week  43% rhPTH(1-84) vs 5% PBO (P<0.001*) Bilezikian et al, 2012 Endocrine Soc S18-3 32 Secondary Endpoint: Clinical Symptoms of Hypocalcemia During Weeks 16-24 Clinical Symptoms of Hypocalcemia Overall (P=0.392) rhPTH(1-84) n=90 Placebo n=44 n % n % 30 33 18 41 Includes paresthesia (include oral), muscle spasms, hypoesthesia (include oral and facial), tetany, back pain, myalgia, muscle twitching, throat tightness, musculoskeletal pain, anxiety Bilezikian et al, 2012 Endocrine Soc S18-333 Albumin-corrected Serum Ca Levels rhPTH(1-84) n=90 Placebo n=44 Mean (SD) Albumin Corrected Total Serum Ca Concentration, mg/dL 11 Serum Ca laboratory normal range of 8.4 to 10.6 mg/dL 10 9 Serum Ca target range of 8.0 to 9.0 mg/dL 8 7 7 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Week  Albumin-corrected total serum Ca levels remained at or above baseline level in the rhPTH(1-84)-treated patients despite large reductions in active vitamin D and oral Ca doses Bilezikian et al, 2012 Endocrine Soc S18-334 Placebo Serum and Urine Ca Levels Serum Ca target range of 8.0 to 9.0 mg/dL Normal urine Ca excretion 50-300 mg/24 hr 700 600 10 500 400 9 300 200 8 100 Mean (SD) 24-Hour Urinary Ca Excretion, mg/24 h Mean (SD) Albumin Corrected Total Serum Ca Concentration, mg/dL Placebo Urine Serum 11 0 7 7 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Week  In the placebo group, urine Ca excretion is directly related to serum Ca levels Bilezikian et al, 2012 Endocrine Soc S18-335 rhPTH(1-84) Serum and Urine Ca Levels Serum Ca target range of 8.0 to 9.0 mg/dL Normal urine Ca excretion 50-300 mg/24 hr 700 600 10 500 400 9 300 200 8 100 Mean (SD) 24-Hour Urinary Ca Excretion, mg/24 h Mean (SD) Albumin Corrected Total Serum Ca Concentration, mg/dL rhPTH(1-84) n=90 Urine Serum 11 0 7 7 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Week  Albumin-corrected total serum Ca levels remained at or above baseline level in the rhPTH(1-84)-treated patients with a small decrease in mean 24-hour urinary Ca excretion Bilezikian et al, 2012 Endocrine Soc S18-336 Summary of AEs and SAEs During Treatment Period (Weeks 1-24) Patients, n (%) rhPTH(1-84) n=90 Placebo n=44 n % n % AEs 81 90 42 96 Serious AE 5* 6 2 5 AE leading to discontinuation 3† 3 0 0 Deaths 0 0 0 0 *Treatment-related hypercalcemia requiring brief hospitalization (n=1) †Hypertension (n=1); stroke (n=1); multiple events (n=1) Bilezikian et al, 2012 Endocrine Soc S18-3 37 Incidence of Hypocalcemia and Hypercalcemia During Study Period rhPTH(1-84) n=90 Placebo n=44 n % n % Optimization (~2–16 wks) 7 8 2 5 Treatment, Titration (Week 0 - 12) 9 10 7 16 Treatment, Stable (Weeks 16 – 24) 30 33 18 41 Post-treatment (4 wks) 28 31 4 9 Optimization (~2–16 wks) 3 3 0 0 Treatment, Titration (Week 0-12) 12 13 1 2 Treatment, Stable (Weeks 16 – 24) 8 9 0 0 Post-treatment (4 wks) 2 2 3 7 Hypocalcemia Hypercalcemia 38 Shoback et al. Endocrine Soc 2012, SUN-325 Response to PTH is similar in surgical and non-surgical • Among the 99 postsurgical patients, 57% were responders in the rhPTH(1-84) group vs 3% in the placebo group (P<0.001). • Among the 35 nonsurgical patients, 41% were responders in the rhPTH(1-84) group, compared with 0% in the placebo group (P=0.013). Schoback et al, 2012 ATA annual meeting Vokes et al, 2013 Endo Surgeons meeting Lower doses of PTH may be effective in some patients • 46 hypopara patients randomized to either 25µg (22 subjects) or 50µg (24 subjects) of PTH(1-84) by daily injection for 8 weeks • Reduction in supplements to <500mg of calcium and <0.25µg of calcitriol (with serum calcium >7.5mg/dl): – 18% of 25µg group – 25% of 50µg group Vokes et al, 2012 ASBMR 2012 PTH (1-84) Tx of hypoparathyroidism • Allows reduction or even elimination of oral calcium and calcitriol • Decreased fluctuations in serum calcium • Overall higher calcium levels without hypercalciuria • Patients report improved quality of life and improved exercise tolerance • Flexible dosing is important due to interindividual variability in the response to PTH • Normal levels of 25(OH) Vitamin D Effect of PTH Tx on bone • Hypopara patients have low bone turnover and high BMD • PTH (1-84) Tx restores bone turnover Patient with recent parathyroid surgery 52Y/O woman who is s/p 3.5 gland excision for PHPT from 4-gland hyperplasia. She has had continued symptoms of numbness/tingling in her toes and fingertips that has not subsided since her surgery. She states that once these symptoms start she gets anxious which usually exacerbates her symptoms. Findings during surgery Left side exploration Right side exploration time -22 -7 8 15 -15 5 10 PTH 83 67 51 52 13 6 70 ½ parathyroid left lower parathyroid gland left in place Patient was initially on calcium and calcitriol but since calcium was 9.2 2 weeks post op calcitriol was stopped 1 month postop • • • • Calcium 8.1 mg/dl (8.4-10.2) Albumin 4.4 mg/dl (3.5 – 5.0) Ionized calcium 4.2 mg/dl (4.6 – 5.4) Phosphate 5.1 (2.5 – 4.2 mg/dl) Hungry Bone? More labs • • • • • • • Calcium 8.1 mg/dl (8.4-10.2) Albumin 4.4 mg/dl (3.5 – 5.0) Ionized calcium 4.2 mg/dl (4.6 – 5.4) Phosphate 5.1 (2.5 – 4.2 mg/dl) PTH 29 pg/ml (15-75) 25(OH) vitamin D 43 ng/ml (10-52) 1,25 (OH) Vitamin D 29 pg/ml (15-75) Partial hypopara? Thank You! ???